Journal articles: 'Dynamin Related Protein 1 (Drp1)'

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Perry, Heather M., Liping Huang, Rebecca J. Wilson, Amandeep Bajwa, Hiromi Sesaki, Zhen Yan, Diane L. Rosin, David F. Kashatus, and Mark D. Okusa. "Dynamin-Related Protein 1 Deficiency Promotes Recovery from AKI." Journal of the American Society of Nephrology 29, no. 1 (October 30, 2017): 194–206. http://dx.doi.org/10.1681/asn.2017060659.

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The proximal tubule epithelium relies on mitochondrial function for energy, rendering the kidney highly susceptible to ischemic AKI. Dynamin-related protein 1 (DRP1), a mediator of mitochondrial fission, regulates mitochondrial function; however, the cell-specific and temporal role of DRP1 in AKI in vivo is unknown. Using genetic murine models, we found that proximal tubule–specific deletion of Drp1 prevented the renal ischemia-reperfusion–induced kidney injury, inflammation, and programmed cell death observed in wild-type mice and promoted epithelial recovery, which associated with activation of the renoprotective β-hydroxybutyrate signaling pathway. Loss of DRP1 preserved mitochondrial structure and reduced oxidative stress in injured kidneys. Lastly, proximal tubule deletion of DRP1 after ischemia-reperfusion injury attenuated progressive kidney injury and fibrosis. These results implicate DRP1 and mitochondrial dynamics as an important mediator of AKI and progression to fibrosis and suggest that DRP1 may serve as a therapeutic target for AKI.

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Breitzig, Mason T., Matthew D. Alleyn, Richard F. Lockey, and Narasaiah Kolliputi. "A mitochondrial delicacy: dynamin-related protein 1 and mitochondrial dynamics." American Journal of Physiology-Cell Physiology 315, no. 1 (July 1, 2018): C80—C90. http://dx.doi.org/10.1152/ajpcell.00042.2018.

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The constant physiological flux of mitochondrial fission and fusion is inextricably tied to the maintenance of cellular bioenergetics and the fluidity of mitochondrial networks. Yet, the intricacies of this dynamic duo remain unclear in diseases that encompass mitochondrial dysregulation. Particularly, the role of the GTPase fission protein dynamin-related protein 1 (Drp1) is of profound interest. Studies have identified that Drp1 participates in complex signaling pathways, suggesting that the function of mitochondria in pathophysiology may extend far beyond energetics alone. Research indicates that, in stressed conditions, Drp1 translocation to the mitochondria leads to elevated fragmentation and mitophagy; however, despite this, there is limited knowledge about the mechanistic regulation of Drp1 in disease conditions. This review highlights literature about fission, fusion, and, more importantly, discusses Drp1 in cardiac, neural, carcinogenic, renal, and pulmonary diseases. The therapeutic desirability for further research into its contribution to diseases that involve mitochondrial dysregulation is also discussed.

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Ugarte-Uribe, Begoña, Hans-Michael Müller, Miki Otsuki, Walter Nickel, and Ana J. García-Sáez. "Dynamin-related Protein 1 (Drp1) Promotes Structural Intermediates of Membrane Division." Journal of Biological Chemistry 289, no. 44 (September 18, 2014): 30645–56. http://dx.doi.org/10.1074/jbc.m114.575779.

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Drp1 is a dynamin-like GTPase that mediates mitochondrial and peroxisomal division in a process dependent on self-assembly and coupled to GTP hydrolysis. Despite the link between Drp1 malfunction and human disease, the molecular details of its membrane activity remain poorly understood. Here we reconstituted and directly visualized Drp1 activity in giant unilamellar vesicles. We quantified the effect of lipid composition and GTP on membrane binding and remodeling activity by fluorescence confocal microscopy and flow cytometry. In contrast to other dynamin relatives, Drp1 bound to both curved and flat membranes even in the absence of nucleotides. We also found that Drp1 induced membrane tubulation that was stimulated by cardiolipin. Moreover, Drp1 promoted membrane tethering dependent on the intrinsic curvature of the membrane lipids and on GTP. Interestingly, Drp1 concentrated at membrane contact surfaces and, in the presence of GTP, formed discrete clusters on the vesicles. Our findings support a role of Drp1 not only in the formation of lipid tubes but also on the stabilization of tightly apposed membranes, which are intermediate states in the process of mitochondrial fission.

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Oliver, Darryll, and P. Reddy. "Dynamics of Dynamin-Related Protein 1 in Alzheimer’s Disease and Other Neurodegenerative Diseases." Cells 8, no. 9 (August 23, 2019): 961. http://dx.doi.org/10.3390/cells8090961.

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The purpose of this article is to highlight the role of dynamin-related protein 1 (Drp1) in abnormal mitochondrial dynamics, mitochondrial fragmentation, autophagy/mitophagy, and neuronal damage in Alzheimer’s disease (AD) and other neurological diseases, including Parkinson’s, Huntington’s, amyotrophic lateral sclerosis, multiple sclerosis, diabetes, and obesity. Dynamin-related protein 1 is one of the evolutionarily highly conserved large family of GTPase proteins. Drp1 is critical for mitochondrial division, size, shape, and distribution throughout the neuron, from cell body to axons, dendrites, and nerve terminals. Several decades of intense research from several groups revealed that Drp1 is enriched at neuronal terminals and involved in synapse formation and synaptic sprouting. Different phosphorylated forms of Drp1 acts as both increased fragmentation and/or increased fusion of mitochondria. Increased levels of Drp1 were found in diseased states and caused excessive fragmentation of mitochondria, leading to mitochondrial dysfunction and neuronal damage. In the last two decades, several Drp1 inhibitors have been developed, including Mdivi-1, Dynasore, P110, and DDQ and their beneficial effects tested using cell cultures and mouse models of neurodegenerative diseases. Recent research using genetic crossing studies revealed that a partial reduction of Drp1 is protective against mutant protein(s)-induced mitochondrial and synaptic toxicities. Based on findings from cell cultures, mouse models and postmortem brains of AD and other neurodegenerative disease, we cautiously conclude that reduced Drp1 is a promising therapeutic target for AD and other neurological diseases.

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Strack, Stefan, Theodore J. Wilson, and J. Thomas Cribbs. "Cyclin-dependent kinases regulate splice-specific targeting of dynamin-related protein 1 to microtubules." Journal of Cell Biology 201, no. 7 (June 24, 2013): 1037–51. http://dx.doi.org/10.1083/jcb.201210045.

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Fission and fusion reactions determine mitochondrial morphology and function. Dynamin-related protein 1 (Drp1) is a guanosine triphosphate–hydrolyzing mechanoenzyme important for mitochondrial fission and programmed cell death. Drp1 is subject to alternative splicing of three exons with previously unknown functional significance. Here, we report that splice variants including the third but excluding the second alternative exon (x01) localized to and copurified with microtubule bundles as dynamic polymers that resemble fission complexes on mitochondria. A major isoform in immune cells, Drp1-x01 required oligomeric assembly and Arg residues in alternative exon 3 for microtubule targeting. Drp1-x01 stabilized and bundled microtubules and attenuated staurosporine-induced mitochondrial fragmentation and apoptosis. Phosphorylation of a conserved Ser residue adjacent to the microtubule-binding exon released Drp1-x01 from microtubules and promoted mitochondrial fragmentation in a splice form–specific manner. Phosphorylation by Cdk1 contributed to dissociation of Drp1-x01 from mitotic microtubules, whereas Cdk5-mediated phosphorylation modulated Drp1-x01 targeting to interphase microtubules. Thus, alternative splicing generates a latent, cytoskeletal pool of Drp1 that is selectively mobilized by cyclin-dependent kinase signaling.

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Mooli, Raja Gopal Reddy, Dhanunjay Mukhi, Zhonghe Chen, Nia Buckner, and Sadeesh K. Ramakrishnan. "An indispensable role for dynamin-related protein 1 in beige and brown adipogenesis." Journal of Cell Science 133, no. 18 (August 25, 2020): jcs247593. http://dx.doi.org/10.1242/jcs.247593.

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ABSTRACTEmerging evidence indicates that proper mitochondrial dynamics are critical for adipocyte differentiation and functional thermogenic capacity. We found that the mitochondrial fission protein dynamin-related protein 1 (DRP1, also known as DNML1) is highly expressed in brown adipose tissue compared to expression in white adipose tissue, and these expression levels increase during brown adipocyte differentiation. Our results reveal that the inhibition of DRP1 using mdivi-1 mitigates beige adipocyte differentiation and differentiation-associated mitochondrial biogenesis. We found that DRP1 is essential for the induction of the early-phase beige adipogenic transcriptional program. Intriguingly, inhibition of DRP1 is dispensable following the induction of beige adipogenesis and adipogenesis-associated mitochondrial biogenesis. Altogether, we demonstrate that DRP1 in preadipocytes plays an essential role in beige and brown adipogenesis.This article has an associated First Person interview with the first author of the paper.

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Cheng, Wen-Yu, Kuan-Chih Chow, Ming-Tsang Chiao, Yi-Chin Yang, and Chiung-Chyi Shen. "Higher Levels of Dynamin-related Protein 1 are Associated with Reduced Radiation Sensitivity of Glioblastoma Cells." Current Neurovascular Research 17, no. 4 (December 14, 2020): 446–63. http://dx.doi.org/10.2174/1567202617666200623123638.

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Background: Dynamin-related protein 1 (DRP1) is a GTPase involved in mitochondrial fission, mitochondrial protein import, and drug sensitivity, suggesting an association with cancer progression. This study was conducted to evaluate the prognostic significance of DRP1 in glioblastoma multiforme (GBM). Methods: DRP1 expression was measured by immunohistochemistry and Western blotting. Correlations between DRP1 expression and clinicopathological parameters were determined by statistical analysis. Differences in survival were compared using the log-rank test. DRP1 expression was detected in 87.2% (41/47) of the investigated patients with GBM. Results: The patients with higher DRP1 levels had worse survival (p = 0.0398). In vitro, the silencing of DRP1 reduced cell proliferation, invasive potential, and radiation resistance. The addition of shikonin inhibited DRP1 expression and increased drug uptake. Moreover, shikonin reduced the nuclear entry of DNA repair-associated enzymes and increased radiation sensitivity, suggesting that reducing DRP1 expression could inhibit DNA repair and increase the radiation sensitivity of GBM cells. Conclusion: Our results indicate that DRP1 overexpression is a prospective radio-resistant phenotype in GBM. Therefore, DRP1 could be a potential target for improving the effectiveness of radiation therapy.

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Bian, Xiyun, Jingman Xu, Huanhuan Zhao, Quan Zheng, Xiaolin Xiao, Xiaofang Ma, Yanxia Li, Xinping Du, and Xiaozhi Liu. "Zinc-Induced SUMOylation of Dynamin-Related Protein 1 Protects the Heart against Ischemia-Reperfusion Injury." Oxidative Medicine and Cellular Longevity 2019 (July 22, 2019): 1–11. http://dx.doi.org/10.1155/2019/1232146.

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Background. Zinc plays a role in mitophagy and protects cardiomyocytes from ischemia/reperfusion injury. This study is aimed at investigating whether SUMOylation of Drp1 is involved in the protection of zinc ion on cardiac I/R injury. Methods. Mouse hearts were subjected to 30 minutes of regional ischemia followed by 2 hours of reperfusion (ischemia/reoxygenation (I/R)). Infarct size and apoptosis were assessed. HL-1 cells were subjected to 24 hours of hypoxia and 6 hours of reoxygenation (hypoxia/reoxygenation (H/R)). Zinc was given 5 min before reperfusion for 30 min. SENP2 overexpression plasmid (Flag-SENP2), Drp1 mutation plasmid (Myc-Drp1 4KR), and SUMO1 siRNA were transfected into HL-1 cells for 48 h before hypoxia. Effects of zinc on SUMO family members were analyzed by Western blotting. SUMOylation of Drp1, apoptosis and the collapse of mitochondrial membrane potential (ΔΨm), and mitophagy were evaluated. Results. Compared with the control, SUMO1 modification level of proteins in the H/R decreased, while this effect was reversed by zinc. In the setting of H/R, zinc attenuated myocardial apoptosis, which was reversed by SUMO1 siRNA. Similar effects were observed in SUMO1 KO mice exposed to H/R. In addition, the dynamin-related protein 1 (Drp1) is a target protein of SUMO1. The SUMOylation of Drp1 induced by zinc regulated mitophagy and contributed to the protective effect of zinc on H/R injury. Conclusions. SUMOylation of Drp1 played an essential role in zinc-induced cardio protection against I/R injury. Our findings provide a promising therapeutic approach for acute myocardial I/R injury.

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Tanner, Michael J., Jingli Wang, Rong Ying, Tisha B. Suboc, Mobin Malik, Allison Couillard, Amberly Branum, Venkata Puppala, and Michael E. Widlansky. "Dynamin-related protein 1 mediates low glucose-induced endothelial dysfunction in human arterioles." American Journal of Physiology-Heart and Circulatory Physiology 312, no. 3 (March 1, 2017): H515—H527. http://dx.doi.org/10.1152/ajpheart.00499.2016.

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Intensive glycemic regulation has resulted in an increased incidence of hypoglycemia. Hypoglycemic burden correlates with adverse cardiovascular complications and contributes acutely and chronically to endothelial dysfunction. Prior data indicate that mitochondrial dysfunction contributes to hypoglycemia-induced endothelial dysfunction, but the mechanisms behind this linkage remain unknown. We attempt to determine whether clinically relevant low-glucose (LG) exposures acutely induce endothelial dysfunction through activation of the mitochondrial fission process. Characterization of mitochondrial morphology was carried out in cultured endothelial cells by using confocal microscopy. Isolated human arterioles were used to explore the effect LG-induced mitochondrial fission has on the formation of detrimental reactive oxygen species (ROS), bioavailability of nitric oxide (NO), and endothelial-dependent vascular relaxation. Fluorescence microscopy was employed to visualize changes in mitochondrial ROS and NO levels and videomicroscopy applied to measure vasodilation response. Pharmacological disruption of the profission protein Drp1 with Mdivi-1 during LG exposure reduced mitochondrial fragmentation among vascular endothelial cells (LG: 0.469; LG+Mdivi-1: 0.276; P = 0.003), prevented formation of vascular ROS (LG: 2.036; LG+Mdivi-1: 1.774; P = 0.005), increased the presence of NO (LG: 1.352; LG+Mdivi-1: 1.502; P = 0.048), and improved vascular dilation response to acetylcholine (LG: 31.6%; LG+Mdivi-1; 78.5% at maximum dose; P < 0.001). Additionally, decreased expression of Drp1 via siRNA knockdown during LG conditions also improved vascular relaxation. Exposure to LG imparts endothelial dysfunction coupled with altered mitochondrial phenotypes among isolated human arterioles. Disruption of Drp1 and subsequent mitochondrial fragmentation events prevents impaired vascular dilation, restores mitochondrial phenotype, and implicates mitochondrial fission as a primary mediator of LG-induced endothelial dysfunction. NEW & NOTEWORTHY Acute low-glucose exposure induces mitochondrial fragmentation in endothelial cells via Drp1 and is associated with impaired endothelial function in human arterioles. Targeting of Drp1 prevents fragmentation, improves vasofunction, and may provide a therapeutic target for improving cardiovascular complications among diabetics. Listen to this article’s corresponding podcast @ http://ajpheart.podbean.com/e/mitochondrial-dynamics-impact-endothelial-function/ .

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Yu, Rong, Tong Liu, Chenfei Ning, Fei Tan, Shao-Bo Jin, Urban Lendahl, Jian Zhao, and Monica Nistér. "The phosphorylation status of Ser-637 in dynamin-related protein 1 (Drp1) does not determine Drp1 recruitment to mitochondria." Journal of Biological Chemistry 294, no. 46 (September 18, 2019): 17262–77. http://dx.doi.org/10.1074/jbc.ra119.008202.

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Recruitment of the GTPase dynamin-related protein 1 (Drp1) to mitochondria is a central step required for mitochondrial fission. Reversible Drp1 phosphorylation has been implicated in the regulation of this process, but whether Drp1 phosphorylation at Ser-637 determines its subcellular localization and fission activity remains to be fully elucidated. Here, using HEK 293T cells and immunofluorescence, immunoblotting, RNAi, subcellular fractionation, co-immunoprecipitation assays, and CRISPR/Cas9 genome editing, we show that Drp1 phosphorylated at Ser-637 (Drp1pS637) resides both in the cytosol and on mitochondria. We found that the receptors mitochondrial fission factor (Mff) and mitochondrial elongation factor 1/2 (MIEF1/2) interact with and recruit Drp1pS637 to mitochondria and that elevated Mff or MIEF levels promote Drp1pS637 accumulation on mitochondria. We also noted that protein kinase A (PKA), which mediates phosphorylation of Drp1 on Ser-637, is partially present on mitochondria and interacts with both MIEFs and Mff. PKA knockdown did not affect the Drp1-Mff interaction, but slightly enhanced the interaction between Drp1 and MIEFs. In Drp1-deficient HEK 293T cells, both phosphomimetic Drp1-S637D and phospho-deficient Drp1-S637A variants, like wild-type Drp1, located to the cytosol and to mitochondria and rescued a Drp1 deficiency-induced mitochondrial hyperfusion phenotype. However, Drp1-S637D was less efficient than Drp1-WT and Drp1-S637A in inducing mitochondrial fission. In conclusion, the Ser-637 phosphorylation status in Drp1 is not a determinant that controls Drp1 recruitment to mitochondria.

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Fealy, Ciaran E., Anny Mulya, Nicola Lai, and John P. Kirwan. "Exercise training decreases activation of the mitochondrial fission protein dynamin-related protein-1 in insulin-resistant human skeletal muscle." Journal of Applied Physiology 117, no. 3 (August 1, 2014): 239–45. http://dx.doi.org/10.1152/japplphysiol.01064.2013.

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Defects in mitochondrial dynamics, the processes of fission, fusion, and mitochondrial autophagy, may contribute to metabolic disease including type 2 diabetes. Dynamin-related protein-1 (Drp1) is a GTPase protein that plays a central role in mitochondrial fission. We hypothesized that aerobic exercise training would decrease Drp1 Ser616 phosphorylation and increase fat oxidation and insulin sensitivity in obese (body mass index: 34.6 ± 0.8 kg/m2) insulin-resistant adults. Seventeen subjects performed supervised exercise for 60 min/day, 5 days/wk at 80–85% of maximal heart rate for 12 wk. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp, and fat oxidation was determined by indirect calorimetry. Skeletal muscle biopsies were obtained from the vastus lateralis muscle before and after the 12-wk program. The exercise intervention increased insulin sensitivity 2.1 ± 0.2-fold ( P < 0.01) and fat oxidation 1.3 ± 0.3-fold ( P < 0.01). Phosphorylation of Drp1 at Ser616 was decreased (pre vs. post: 0.81 ± 0.15 vs. 0.58 ± 0.14 arbitrary units; P < 0.05) following the intervention. Furthermore, reductions in Drp1 Ser616 phosphorylation were negatively correlated with increases in fat oxidation ( r = −0.58; P < 0.05) and insulin sensitivity (rho = −0.52; P < 0.05). We also examined expression of genes related to mitochondrial dynamics. Dynamin1-like protein (DNM1L; P < 0.01), the gene that codes for Drp1, and Optic atrophy 1 (OPA1; P = 0.05) were significantly upregulated following the intervention, while there was a trend towards an increase in expression of both mitofusin protein MFN1 ( P = 0.08) and MFN2 ( P = 0.07). These are the first data to suggest that lifestyle-mediated improvements in substrate metabolism and insulin sensitivity in obese insulin-resistant adults may be regulated through decreased activation of the mitochondrial fission protein Drp1.

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Ko, Huey-Jiun, Cheng-Yu Tsai, Shean-Jaw Chiou, Yun-Ling Lai, Chi-Huei Wang, Jiin-Tsuey Cheng, Tsung-Hsien Chuang, et al. "The Phosphorylation Status of Drp1-Ser637 by PKA in Mitochondrial Fission Modulates Mitophagy via PINK1/Parkin to Exert Multipolar Spindles Assembly during Mitosis." Biomolecules 11, no. 3 (March 13, 2021): 424. http://dx.doi.org/10.3390/biom11030424.

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Mitochondrial fission and fusion cycles are integrated with cell cycle progression. Here we first re-visited how mitochondrial ETC inhibition disturbed mitosis progression, resulting in multipolar spindles formation in HeLa cells. Inhibitors of ETC complex I (rotenone, ROT) and complex III (antimycin A, AA) decreased the phosphorylation of Plk1 T210 and Aurora A T288 in the mitotic phase (M-phase), especially ROT, affecting the dynamic phosphorylation status of fission protein dynamin-related protein 1 (Drp1) and the Ser637/Ser616 ratio. We then tested whether specific Drp1 inhibitors, Mdivi-1 or Dynasore, affected the dynamic phosphorylation status of Drp1. Similar to the effects of ROT and AA, our results showed that Mdivi-1 but not Dynasore influenced the dynamic phosphorylation status of Ser637 and Ser616 in Drp1, which converged with mitotic kinases (Cdk1, Plk1, Aurora A) and centrosome-associated proteins to significantly accelerate mitotic defects. Moreover, our data also indicated that evoking mito-Drp1-Ser637 by protein kinase A (PKA) rather than Drp1-Ser616 by Cdk1/Cyclin B resulted in mitochondrial fission via the PINK1/Parkin pathway to promote more efficient mitophagy and simultaneously caused multipolar spindles. Collectively, this study is the first to uncover that mito-Drp1-Ser637 by PKA, but not Drp1-Ser616, drives mitophagy to exert multipolar spindles formation during M-phase.

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Yamamori, Tohru, Satoshi Ike, Tomoki Bo, Tomoya Sasagawa, Yuri Sakai, Motofumi Suzuki, Kumiko Yamamoto, Masaki Nagane, Hironobu Yasui, and Osamu Inanami. "Inhibition of the mitochondrial fission protein dynamin-related protein 1 (Drp1) impairs mitochondrial fission and mitotic catastrophe after x-irradiation." Molecular Biology of the Cell 26, no. 25 (December 15, 2015): 4607–17. http://dx.doi.org/10.1091/mbc.e15-03-0181.

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Accumulating evidence suggests that mitochondrial dynamics is crucial for the maintenance of cellular quality control and function in response to various stresses. However, the role of mitochondrial dynamics in cellular responses to ionizing radiation (IR) is still largely unknown. In this study, we provide evidence that IR triggers mitochondrial fission mediated by the mitochondrial fission protein dynamin-related protein 1 (Drp1). We also show IR-induced mitotic catastrophe (MC), which is a type of cell death associated with defective mitosis, and aberrant centrosome amplification in mouse embryonic fibroblasts (MEFs). These are attenuated by genetic or pharmacological inhibition of Drp1. Whereas radiation-induced aberrant centrosome amplification and MC are suppressed by the inhibition of Plk1 and CDK2 in wild-type MEFs, the inhibition of these kinases is ineffective in Drp1-deficient MEFs. Furthermore, the cyclin B1 level after irradiation is significantly higher throughout the time course in Drp1-deficient MEFs than in wild-type MEFs, implying that Drp1 is involved in the regulation of cyclin B1 level. These findings strongly suggest that Drp1 plays an important role in determining the fate of cells after irradiation via the regulation of mitochondrial dynamics.

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Stepanyants, Natalia, Patrick J. Macdonald, Christopher A. Francy, Jason A. Mears, Xin Qi, and Rajesh Ramachandran. "Cardiolipin's propensity for phase transition and its reorganization by dynamin-related protein 1 form a basis for mitochondrial membrane fission." Molecular Biology of the Cell 26, no. 17 (September 2015): 3104–16. http://dx.doi.org/10.1091/mbc.e15-06-0330.

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Cardiolipin (CL) is an atypical, dimeric phospholipid essential for mitochondrial dynamics in eukaryotic cells. Dynamin-related protein 1 (Drp1), a cytosolic member of the dynamin superfamily of large GTPases, interacts with CL and functions to sustain the balance of mitochondrial division and fusion by catalyzing mitochondrial fission. Although recent studies have indicated a role for CL in stimulating Drp1 self-assembly and GTPase activity at the membrane surface, the mechanism by which CL functions in membrane fission, if at all, remains unclear. Here, using a variety of fluorescence spectroscopic and imaging approaches together with model membranes, we demonstrate that Drp1 and CL function cooperatively in effecting membrane constriction toward fission in three distinct steps. These involve 1) the preferential association of Drp1 with CL localized at a high spatial density in the membrane bilayer, 2) the reorganization of unconstrained, fluid-phase CL molecules in concert with Drp1 self-assembly, and 3) the increased propensity of CL to transition from a lamellar, bilayer arrangement to an inverted hexagonal, nonbilayer configuration in the presence of Drp1 and GTP, resulting in the creation of localized membrane constrictions that are primed for fission. Thus we propose that Drp1 and CL function in concert to catalyze mitochondrial division.

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Liu, Wei-Lun, Chia-Yang Li, Wei-Chung Cheng, Chia-Yuan Chang, Yung-Hsiang Chen, Chi-Yu Lu, Shu-Chi Wang, et al. "High Mobility Group Box 1 Promotes Lung Cancer Cell Migration and Motility via Regulation of Dynamin-Related Protein 1." International Journal of Molecular Sciences 22, no. 7 (March 31, 2021): 3628. http://dx.doi.org/10.3390/ijms22073628.

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High mobility group box 1 (HMGB1) has been demonstrated to promote the migration and invasion of non-small cell lung cancer (NSCLC). However, the mechanism of action of HMGB1 in regulating tumor mobility remains unclear. Therefore, we aimed to investigate whether HMGB1 affects mitochondria distribution and regulates dynamin-related protein 1 (DRP1)-mediated lamellipodia/filopodia formation to promote NSCLC migration. The regulation of mitochondrial membrane tension, dynamics, polarization, fission process, and cytoskeletal rearrangements in lung cancer cells by HMGB1 was analyzed using confocal microscopy. The HMGB1-mediated regulation of DRP1 phosphorylation and colocalization was determined using immunostaining and co-immunoprecipitation assays. The tumorigenic potential of HMGB1 was assessed in vivo and further confirmed using NSCLC patient samples. Our results showed that HMGB1 increased the polarity and mobility of cells (mainly by regulating the cytoskeletal system actin and microtubule dynamics and distribution), promoted the formation of lamellipodia/filopodia, and enhanced the expression and phosphorylation of DRP1 in both the nucleus and cytoplasm. In addition, HMGB1 and DRP1 expressions were positively correlated and exhibited poor prognosis and survival in patients with lung cancer. Collectively, HMGB1 plays a key role in the formation of lamellipodia and filopodia by regulating cytoskeleton dynamics and DRP1 expression to promote lung cancer migration.

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Jiang, Hui, Feng Chen, DianZe Song, Xiaoqin Zhou, Long Ren, and Mei Zeng. "Dynamin-Related Protein 1 Is Involved in Mitochondrial Damage, Defective Mitophagy, and NLRP3 Inflammasome Activation Induced by MSU Crystals." Oxidative Medicine and Cellular Longevity 2022 (October 25, 2022): 1–22. http://dx.doi.org/10.1155/2022/5064494.

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Excessive generation of reactive oxygen species (ROS) has great impacts on MSU crystal-induced inflammation. Drp1-dependent mitochondrial fission is closely associated with mitochondrial ROS levels. However, whether Drp1 signaling contributes to MSU crystal-induced inflammation remains unclear. Mice bone marrow-derived macrophages (BMDMs) were primed with LPS and then stimulated with MSU suspensions for 12 h. The protein levels associated with mitochondrial dynamics, oxidative stress, and mitophagy were detected by Western blot. BMDMs were loaded with MitoTracker Green probe to detect mitochondrial morphology. To measure mitochondrial reactive oxygen species (ROS) and total ROS levels, cells were loaded, respectively, with MitoSOX and DHE probes. The effects of Mito-TEMPO, an antioxidant that targets the mitochondria or DRP1 inhibitor (Mdivi-1) on MSU crystal-induced peritonitis and arthritis mouse models, were evaluated. Our study revealed that MSU crystal stimulation resulted in elevation of mitochondrial fragmentation of BMDMs. Treatment with Mito-TEMPO or Drp1 knockdown significantly ameliorated the mitochondrial damage induced by MSU crystals. BMDMs exposure to MSU crystals increased the expression of auto/mitophagy marker proteins and promoted the fusion of mitophagosomes with lysosomes, leading to accumulation of mitolysosomes. Drp1 knockdown alleviated defective mitophagy and activation of the NLRP3 inflammasome in MSU crystal-treated BMDMs. This study indicates that there is crosstalk between mitochondrial ROS and Drp1 signaling in MSU crystal-induced inflammation. Drp1 signaling is involved in MSU crystal-induced mitochondrial damage, impaired mitophagy and NLRP3 inflammasome activation.

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Macdonald, Patrick J., Natalia Stepanyants, Niharika Mehrotra, Jason A. Mears, Xin Qi, Hiromi Sesaki, and Rajesh Ramachandran. "A dimeric equilibrium intermediate nucleates Drp1 reassembly on mitochondrial membranes for fission." Molecular Biology of the Cell 25, no. 12 (June 15, 2014): 1905–15. http://dx.doi.org/10.1091/mbc.e14-02-0728.

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The GTPase dynamin-related protein 1 (Drp1) catalyzes mitochondrial division, but the mechanisms remain poorly understood. Much of what is attributed to Drp1’s mechanism of action in mitochondrial membrane fission parallels that of prototypical dynamin in endocytic vesicle scission. Unlike the case for dynamin, however, no lipid target for Drp1 activation at the mitochondria has been identified. In addition, the oligomerization properties of Drp1 have not been well established. We show that the mitochondria-specific lipid cardiolipin is a potent stimulator of Drp1 GTPase activity, as well as of membrane tubulation. We establish further that under physiological conditions, Drp1 coexists as two morphologically distinct polymeric species, one nucleotide bound in solution and the other membrane associated, which equilibrate via a dimeric assembly intermediate. With two mutations, C300A and C505A, that shift Drp1 polymerization equilibria in opposite directions, we demonstrate that dimers, and not multimers, potentiate the reassembly and reorganization of Drp1 for mitochondrial membrane remodeling both in vitro and in vivo.

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Nolden, Kelsey A., John M. Egner, Jack J. Collier, Oliver M. Russell, Charlotte L. Alston, Megan C. Harwig, Michael E. Widlansky, et al. "Novel DNM1L variants impair mitochondrial dynamics through divergent mechanisms." Life Science Alliance 5, no. 12 (August 1, 2022): e202101284. http://dx.doi.org/10.26508/lsa.202101284.

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Imbalances in mitochondrial and peroxisomal dynamics are associated with a spectrum of human neurological disorders. Mitochondrial and peroxisomal fission both involve dynamin-related protein 1 (DRP1) oligomerisation and membrane constriction, although the precise biophysical mechanisms by which distinct DRP1 variants affect the assembly and activity of different DRP1 domains remains largely unexplored. We analysed four unreported de novo heterozygous variants in the dynamin-1-like gene DNM1L, affecting different highly conserved DRP1 domains, leading to developmental delay, seizures, hypotonia, and/or rare cardiac complications in infancy. Single-nucleotide DRP1 stalk domain variants were found to correlate with more severe clinical phenotypes, with in vitro recombinant human DRP1 mutants demonstrating greater impairments in protein oligomerisation, DRP1-peroxisomal recruitment, and both mitochondrial and peroxisomal hyperfusion compared to GTPase or GTPase-effector domain variants. Importantly, we identified a novel mechanism of pathogenesis, where a p.Arg710Gly variant uncouples DRP1 assembly from assembly-stimulated GTP hydrolysis, providing mechanistic insight into how assembly-state information is transmitted to the GTPase domain. Together, these data reveal that discrete, pathological DNM1L variants impair mitochondrial network maintenance by divergent mechanisms.

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Horn, Sarah R., Michael J. Thomenius, Erika Segear Johnson, Christopher D. Freel, Judy Q. Wu, Jonathan L. Coloff, Chih-Sheng Yang, et al. "Regulation of mitochondrial morphology by APC/CCdh1-mediated control of Drp1 stability." Molecular Biology of the Cell 22, no. 8 (April 15, 2011): 1207–16. http://dx.doi.org/10.1091/mbc.e10-07-0567.

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Homeostatic maintenance of cellular mitochondria requires a dynamic balance between fission and fusion, and controlled changes in morphology are important for processes such as apoptosis and cellular division. Interphase mitochondria have been described as an interconnected network that fragments as cells enter mitosis, and this mitotic mitochondrial fragmentation is known to be regulated by the dynamin-related GTPase Drp1 (dynamin-related protein 1), a key component of the mitochondrial division machinery. Loss of Drp1 function and the subsequent failure of mitochondrial division during mitosis lead to incomplete cytokinesis and the unequal distribution of mitochondria into daughter cells. During mitotic exit and interphase, the mitochondrial network reforms. Here we demonstrate that changes in mitochondrial dynamics as cells exit mitosis are driven in part through ubiquitylation of Drp1, catalyzed by the APC/CCdh1 (anaphase-promoting complex/cyclosome and its coactivator Cdh1) E3 ubiquitin ligase complex. Importantly, inhibition of Cdh1-mediated Drp1 ubiquitylation and proteasomal degradation during interphase prevents the normal G1 phase regrowth of mitochondrial networks following cell division.

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Terrero, David, Amit Tiwari, and Dayanidhi Raman. "Abstract P1-13-12: Targeting Dynamin-related protein 1 for the management of taxane-resistant triple-negative breast cancer." Cancer Research 83, no. 5_Supplement (March 1, 2023): P1–13–12—P1–13–12. http://dx.doi.org/10.1158/1538-7445.sabcs22-p1-13-12.

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Abstract The development of drug resistance is a primary cause of chemotherapy failure in the treatment of triple-negative breast cancer (TNBC). Some cancer cells are resistant to drugs with unrelated structures and mechanisms of action, a phenomenon known as multidrug resistance (MDR). Although taxanes such as docetaxel and paclitaxel are effective against non-metastatic and metastatic TNBC and other types of breast cancer, they eventually become ineffective due to development of drug resistance. Mitochondrial dynamics has gained significant attention as a means to treat MDR and non-MDR cancers. Mitochondrial dynamics determine the number, shape, and location of mitochondria within cells, which are fundamental to the health of the cell. Among its key components is the mitochondrial fission-promoting dynamin-related protein 1 (Drp1). There is mounting evidence indicating that both Drp1 and its phosphorylated form promote cancer survival, resistance to apoptosis, and chemoresistance. We observed increased phosphorylation of Drp1 at Ser616 as well as phosphorylation of its upstream kinase ERK1/2 in TNBC lines SUM159PT and its paclitaxel-resistant derivative that we developed called SUM159PT/PAC200 that displays more than an 80-fold increase in resistance to paclitaxel. Using CRISPR-Cas9 technology, we knocked out the gene encoding Drp1 in both lines. When Drp1 is genetically ablated, paclitaxel resistance in SUM159PT/PAC200 was significantly reversed. Furthermore, proliferation, migration, and invasion capabilities were decreased in both parental and paclitaxel-resistant Drp1 knockout lines. In SUM159PT/PAC200 Drp1-KO cells, a mesenchymal to epithelial transition (MET) was observed as indicated by downregulation of mesenchymal markers such as N-cadherin and -catenin, and upregulation of the epithelial marker ZO-1. Interestingly, Drp1 knockout halted the ability of SUM159PT/PAC200 to form colonies in soft agar. SUM159PT/PAC200 cells strongly express the MDR pump P-glycoprotein (ABCB1), to which paclitaxel is a known substrate, and genetically targeting Drp1 reduced the expression to almost undetectable levels. Taken together, these findings suggest that Drp1 is both a resistance factor and a key protein in breast cancer proliferation and dissemination, making it a promising actionable molecular target in the treatment of TNBC. Further studies are in progress to understand the role of Drp1 in the development and maintenance of MDR phenotype, proliferation, and invasion. Citation Format: David Terrero, Amit Tiwari, Dayanidhi Raman. Targeting Dynamin-related protein 1 for the management of taxane-resistant triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-13-12.

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Fan, Kexia, Xiao Ding, Zhenle Zang, Yin Zhang, Xiaoshuang Tang, Xiangdong Pei, Qingbo Chen, et al. "Drp1-Mediated Mitochondrial Metabolic Dysfunction Inhibits the Tumor Growth of Pituitary Adenomas." Oxidative Medicine and Cellular Longevity 2022 (March 23, 2022): 1–23. http://dx.doi.org/10.1155/2022/5652586.

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Metabolic changes have been suggested to be a hallmark of tumors and are closely associated with tumorigenesis. In a previous study, we demonstrated the role of lactate dehydrogenase in regulating abnormal glucose metabolism in pituitary adenomas (PA). As the key organelle of oxidative phosphorylation (OXPHOS), mitochondria play a vital role in the energy supply for tumor cells. However, few attempts have been made to elucidate mitochondrial metabolic homeostasis in PA. Dynamin-related protein 1 (Drp1) is a member of the dynamin superfamily of GTPases, which mediates mitochondrial fission. This study is aimed at investigating whether Drp1 affects the progression of PA through abnormal mitochondrial metabolism. We analyzed the expression of dynamin-related protein 1 (Drp1) in 20 surgical PA samples. The effects of Drp1 on PA growth were assessed in vitro and in xenograft models. We found an upregulation of Drp1 in PA samples with a low proliferation index. Knockdown or inhibition of Drp1 enhanced the proliferation of PA cell lines in vitro, while overexpression of Drp1 could reversed such effects. Mechanistically, overexpressed Drp1 damaged mitochondria by overproduction of reactive oxygen species (ROS), which induced mitochondrial OXPHOS inhibition and decline of ATP production. The energy deficiency inhibited proliferation of PA cells. In addition, overexpressed Drp1 promoted cytochrome c release from damaged mitochondria into the cytoplasm and then activated the downstream caspase apoptotic cascade reaction, which induced apoptosis of PA cells. Moreover, the decreased ATP production induced by Drp1 overexpressing activated the AMPK cellular energy stress sensor and enhanced autophagy through the AMPK-ULK1 pathway, which might play a protective role in PA growth. Furthermore, overexpression of Drp1 repressed PA growth in vivo. Our data indicates that Drp1-mediated mitochondrial metabolic dysfunction inhibits PA growth by affecting cell proliferation, apoptosis, and autophagy. Selectively targeting mitochondrial metabolic homeostasis stands out as a promising antineoplastic strategy for PA therapy.

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Otasevic, Vesna, Lela Surlan, Milica Vucetic, Ivan Tulic, Biljana Buzadzic, Ana Stancic, Aleksandra Jankovic, et al. "Expression patterns of mitochondrial OXPHOS components, mitofusin 1 and dynamin-related protein 1 are associated with human embryo fragmentation." Reproduction, Fertility and Development 28, no. 3 (2016): 319. http://dx.doi.org/10.1071/rd13415.

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Developmental dysfunction in embryos, such as a lethal level of fragmentation, is assumed to be mitochondrial in origin. This study investigated the molecular basis of mitochondrial impairment in embryo fragmentation. Transcription patterns of factors that determine mitochondrial functionality: (i) components of the oxidative phosphorylation (OXPHOS) – complex I, cytochrome b, complex IV and ATP synthase; (ii) mitochondrial membrane potential (MMP); (iii) mitochondrial DNA (mtDNA) content and (iv) proteins involved in mitochondrial dynamics, mitofusin 1 (Mfn1) and dynamin related protein 1 (Drp1) were examined in six-cells Day 3 non-fragmented (control), low-fragmented (LF) and high-fragmented (HF) human embryos. Gene expression of mitochondria-encoded components of complex I and IV, cytochrome b and mtDNA were increased in HF embryos compared with control and LF embryos. In LF embryos, expression of these molecules was decreased compared with control and HF embryos. Both classes of fragmented embryos had decreased MMP compared with control. LF embryos had increased gene expression of Mfn1 accompanied by decreased expression of Drp1, while HF embryos had decreased Mfn1 expression but increased Drp1 expression. The study revealed that each improper transcriptional (in)activation of mitochondria-encoded components of the OXPHOS during early in vitro embryo development is associated with a decrease in MMP and with embryo fragmentation. The results also showed the importance of mitochondrial dynamics in fragmentation, at least in the extent of this process.

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Park, Hong-Su, Guanqun Liu, Qiang Liu, and Yan Zhou. "Swine Influenza Virus Induces RIPK1/DRP1-Mediated Interleukin-1 Beta Production." Viruses 10, no. 8 (August 9, 2018): 419. http://dx.doi.org/10.3390/v10080419.

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Nucleotide-binding domain and leucine-rich repeat-containing protein 3 (NLRP3) inflammasome plays a pivotal role in modulating lung inflammation in response to the influenza A virus infection. We previously showed that the swine influenza virus (SIV) infection induced NLRP3 inflammasome-mediated IL-1β production in primary porcine alveolar macrophages (PAMs), and we were interested in examining the upstream signaling events that are involved in this process. Here, we report that the SIV-infection led to dynamin-related protein 1 (DRP1) phosphorylation at serine 579 and mitochondrial fission in PAMs. IL-1β production was dependent on the reactive oxygen species (ROS) production, and DRP1 phosphorylation resulted in the upregulation of the NLRP3 inflammasome. Furthermore, the requirement of the kinase activity of receptor-interacting protein kinase 1 (RIPK1) for the IL-1β production and RIPK1-DRP1 association suggested that RIPK1 is an upstream kinase for DRP1 phosphorylation. Our results reveal a critical role of the RIPK1/DRP1 signaling axis, whose activation leads to mitochondrial fission and ROS release, in modulating porcine NLRP3 inflammasome-mediated IL-1β production in SIV-infected PAMs.

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Han, Xiao-Jian, Yun-Fei Lu, Shun-Ai Li, Taku Kaitsuka, Yasufumi Sato, Kazuhito Tomizawa, Angus C. Nairn, Kohji Takei, Hideki Matsui, and Masayuki Matsushita. "CaM kinase Iα–induced phosphorylation of Drp1 regulates mitochondrial morphology." Journal of Cell Biology 182, no. 3 (August 11, 2008): 573–85. http://dx.doi.org/10.1083/jcb.200802164.

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Mitochondria are dynamic organelles that frequently move, divide, and fuse with one another to maintain their architecture and functions. However, the signaling mechanisms involved in these processes are still not well characterized. In this study, we analyze mitochondrial dynamics and morphology in neurons. Using time-lapse imaging, we find that Ca2+ influx through voltage-dependent Ca2+ channels (VDCCs) causes a rapid halt in mitochondrial movement and induces mitochondrial fission. VDCC-associated Ca2+ signaling stimulates phosphorylation of dynamin-related protein 1 (Drp1) at serine 600 via activation of Ca2+/calmodulin-dependent protein kinase Iα (CaMKIα). In neurons and HeLa cells, phosphorylation of Drp1 at serine 600 is associated with an increase in Drp1 translocation to mitochondria, whereas in vitro, phosphorylation of Drp1 results in an increase in its affinity for Fis1. CaMKIα is a widely expressed protein kinase, suggesting that Ca2+ is likely to be functionally important in the control of mitochondrial dynamics through regulation of Drp1 phosphorylation in neurons and other cell types.

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Losón, Oliver C., Zhiyin Song, Hsiuchen Chen, and David C. Chan. "Fis1, Mff, MiD49, and MiD51 mediate Drp1 recruitment in mitochondrial fission." Molecular Biology of the Cell 24, no. 5 (March 2013): 659–67. http://dx.doi.org/10.1091/mbc.e12-10-0721.

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Several mitochondrial outer membrane proteins—mitochondrial fission protein 1 (Fis1), mitochondrial fission factor (Mff), mitochondrial dynamics proteins of 49 and 51 kDa (MiD49 and MiD51, respectively)—have been proposed to promote mitochondrial fission by recruiting the GTPase dynamin-related protein 1 (Drp1), but fundamental issues remain concerning their function. A recent study supported such a role for Mff but not for Fis1. In addition, it is unclear whether MiD49 and MiD51 activate or inhibit fission, because their overexpression causes extensive mitochondrial elongation. It is also unknown whether these proteins can act in the absence of one another to mediate fission. Using Fis1-null, Mff-null, and Fis1/Mff-null cells, we show that both Fis1 and Mff have roles in mitochondrial fission. Moreover, immunofluorescence analysis of Drp1 suggests that Fis1 and Mff are important for the number and size of Drp1 puncta on mitochondria. Finally, we find that either MiD49 or MiD51 can mediate Drp1 recruitment and mitochondrial fission in the absence of Fis1 and Mff. These results demonstrate that multiple receptors can recruit Drp1 to mediate mitochondrial fission.

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Ma, Yu, Yujing Zhang, Yuanyuan Xiao, and Fang Xiao. "Increased Mitochondrial Fragmentation Mediated by Dynamin-Related Protein 1 Contributes to Hexavalent Chromium-Induced Mitochondrial Respiratory Chain Complex I-Dependent Cytotoxicity." Toxics 8, no. 3 (July 29, 2020): 50. http://dx.doi.org/10.3390/toxics8030050.

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Hexavalent chromium (Cr(VI)) pollution is a severe public health problem in the world. Although it is believed that mitochondrial fragmentation is a common phenomenon in apoptosis, whether excessive fission is crucial for apoptosis remains controversial. We previously confirmed that Cr(VI) mainly targeted mitochondrial respiratory chain complex I (MRCC I) to induce reactive oxygen species (ROS)-mediated apoptosis, but the related mechanism was unclear. In this study, we found Cr(VI) targeted MRCC I to induce ROS accumulation and triggered mitochondria-related cytotoxicity. Cr(VI)-induced cytotoxicity was alleviated by pretreatment of Glutamate/malate (Glu/Mal; MRCC I substrates), and was aggravated by cotreatment of rotenone (ROT; MRCC I inhibitor). Cr(VI) induced excessive mitochondrial fragmentation and mitochondrial dynamin-related protein 1 (Drp1) translocation, the application of Drp1-siRNA alleviated Cr(VI)-induced apoptosis. The cytotoxicity in the Drp1-si plus Cr(VI) treatment group was alleviated by the application of Glu/Mal, and was aggravated by the application of ROT. Drp1 siRNA promoted the inhibition of Glu/Mal on Cr(VI)-induced cytotoxicity, and alleviated the aggravation of ROT on Cr(VI)-induced cytotoxicity. Taken together, Cr(VI)-induced Drp1 modulation was dependent on MRCC I inhibition-mediated ROS production, and Drp1-mediated mitochondrial fragmentation contributed to Cr(VI)-induced MRCC I-dependent cytotoxicity, which provided the experimental basis for further elucidating Cr(VI)-induced cytotoxicity.

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Watanabe, T., M. S. Saotome, M. N. Nobuhara, H. K. Katoh, T. U. Urushida, H. S. Sato, and H. H. Hayashi. "Dynamin-Related Protein 1 (DRP1) manipulates myocardial insulin resistance through mitochondrial ROS production." European Heart Journal 34, suppl 1 (August 2, 2013): 1756. http://dx.doi.org/10.1093/eurheartj/eht308.1756.

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Moore, Timothy M., Zhenqi Zhou, Amanda J. Lin, Nareg Kalajian, Kevin Corey, Kate Whitney, Joe Lee, et al. "The Role Of Dynamin-related Protein 1 (drp1) In The Adaptations To Exercise." Medicine & Science in Sports & Exercise 50, no. 5S (May 2018): 114–15. http://dx.doi.org/10.1249/01.mss.0000535461.35442.02.

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Zhang, Juan, Yu Zhang, Wenshuang Wu, Fang Wang, Xinyu Liu, Guanghou Shui, and Chunlai Nie. "Guanylate-binding protein 2 regulates Drp1-mediated mitochondrial fission to suppress breast cancer cell invasion." Cell Death & Disease 8, no. 10 (October 2017): e3151-e3151. http://dx.doi.org/10.1038/cddis.2017.559.

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Abstract Guanylate-binding protein 2 (GBP2) is a member of the large GTPase superfamily that is strongly induced by interferon-γ (IFN-γ). Although the biochemical characteristics of GBP2 have been reported in detail, its biological function has not been thoroughly elucidated to date. To the best of our knowledge, this study presents the first demonstration that GBP2 inhibits mitochondrial fission and cell metastasis in breast cancer cells both in vitro and in vivo. Our previous work demonstrated that dynamin-related protein 1 (Drp1)-dependent mitochondrial fission has a key role in breast cancer cell invasion. In this study, we demonstrate that GBP2 binds directly to Drp1. Elimination of Drp1 by shRNA or Mdivi-1 (a Drp1-specific inhibitor) suppressed GBP2’s regulatory function. Furthermore, GBP2 blocks Drp1 translocation from the cytosol to mitochondria, thereby attenuating Drp1-dependent mitochondrial fission and breast cancer cell invasion. In summary, our data provide new insights into the function and molecular mechanisms underlying GBP2’s regulation of breast cancer cell invasion.

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Ma, Jun, and Fei Sun. "Expression, purification, crystallization and preliminary crystallographic study of the cytoplasmic domain of the mitochondrial dynamics protein MiD51." Acta Crystallographica Section F Structural Biology Communications 70, no. 5 (April 15, 2014): 596–99. http://dx.doi.org/10.1107/s2053230x14006827.

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Mitochondria play central roles in many cellular and physiological processes. They are highly dynamic organelles and continually undergo fusion and fission. Mitochondrial dynamics protein 51 kDa (MiD51), an integral mitochondrial outer membrane protein, recruits dynamin-related protein 1 (Drp1; a mitochondrial fission protein) to mitochondria and facilitates Drp1-directed mitochondrial fission. In this study, the cytoplasmic domain of MiD51 was overexpressed inEscherichia coli, purified and crystallized. An X-ray diffraction data set was collected to a resolution of 3.1 Å and the crystal belonged to space groupP41212, with unit-cell parametersa=b= 90.1,c= 124.7 Å, α = β = γ = 90°. The asymmetric unit had the highest probability of containing one molecule, with a Matthews coefficient of 3.32 Å3 Da−1and a solvent content of 63.0%.

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Longo, Fabiana, Sara Benedetti, Alberto A. Zambon, Maria Grazia Natali Sora, Chiara Di Resta, Daniele De Ritis, Angelo Quattrini, Francesca Maltecca, Maurizio Ferrari, and Stefano Carlo Previtali. "Impaired turnover of hyperfused mitochondria in severe axonal neuropathy due to a novel DRP1 mutation." Human Molecular Genetics 29, no. 2 (September 7, 2019): 177–88. http://dx.doi.org/10.1093/hmg/ddz211.

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Abstract Mitochondria undergo continuous cycles of fusion and fission in response to physiopathological stimuli. The key player in mitochondrial fission is dynamin-related protein 1 (DRP1), a cytosolic protein encoded by dynamin 1-like (DNM1L) gene, which relocalizes to the outer mitochondrial membrane, where it assembles, oligomerizes and drives mitochondrial division upon guanosine-5′-triphosphate (GTP) hydrolysis. Few DRP1 mutations have been described so far, with patients showing complex and variable phenotype ranging from early death to encephalopathy and/or optic atrophy. The disease is the consequence of defective mitochondrial fission due to faulty DRP1 function. However, the underlying molecular mechanisms and the functional consequences at mitochondrial and cellular level remain elusive. Here we report on a 5-year-old girl presenting psychomotor developmental delay, global hypotonia and severe ataxia due to axonal sensory neuropathy harboring a novel de novo heterozygous missense mutation in the GTPase domain of DRP1 (NM_012062.3:c.436G>A, NP_036192.2: p.D146N variant in DNM1L). Patient’s fibroblasts show hyperfused/balloon-like giant mitochondria, highlighting the importance of D146 residue for DRP1 function. This dramatic mitochondrial rearrangement phenocopies what observed overexpressing DRP1-K38A, a well-known experimental dominant negative version of DRP1. In addition, we demonstrated that p.D146N mutation has great impact on peroxisomal shape and function. The p.D146N mutation compromises the GTPase activity without perturbing DRP1 recruitment or assembly, causing decreased mitochondrial and peroxisomal turnover. In conclusion, our findings highlight the importance of sensory neuropathy in the clinical spectrum of DRP1 variants and, for the first time, the impact of DRP1 mutations on mitochondrial turnover and peroxisomal functionality.

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Chandra, Partha K., Ibolya Rutkai, Hogyoung Kim, Stephen E. Braun, Asim B. Abdel-Mageed, Debasis Mondal, and David W. Busija. "Latent HIV-Exosomes Induce Mitochondrial Hyperfusion Due to Loss of Phosphorylated Dynamin-Related Protein 1 in Brain Endothelium." Molecular Neurobiology 58, no. 6 (February 14, 2021): 2974–89. http://dx.doi.org/10.1007/s12035-021-02319-8.

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AbstractDamage to the cerebral vascular endothelium is a critical initiating event in the development of HIV-1-associated neurocognitive disorders. To study the role of mitochondria in cerebral endothelial dysfunction, we investigated how exosomes, isolated from both cell lines with integrated provirus and HIV-1 infected primary cells (HIV-exosomes), accelerate the dysfunction of primary human brain microvascular endothelial cells (HBMVECs) by inducing mitochondrial hyperfusion, and reducing the expression of phosphorylated endothelial nitric oxide synthase (p-eNOS). The quantitative analysis of the extracellular vesicles (EVs) indicates that the isolated EVs were predominantly exosomes. It was further supported by the detection of exosomal markers, and the absence of large EV-related protein in the isolated EVs. The exosomes were readily taken up by primary HBMVECs. HIV-exosomes induce cellular and mitochondrial superoxide production but reduce mitochondrial membrane potential in HBMVECs. HIV-exosomes increase mitochondrial hyperfusion, possibly due to loss of phosphorylated dynamin-related protein 1 (p-DRP1). HIV-exosomes, containing the HIV-Tat protein, and viral Tat protein reduce the expression of p-DRP1 and p-eNOS, and accelerate brain endothelial dysfunction. Finally, exosomes isolated from HIV-1 infected primary human peripheral blood mononuclear cells (hPBMCs) produce more exosomes than uninfected controls and reduce both p-DRP1 and p-eNOS expressions in primary HBMVECs. Our novel findings reveal the significant role of HIV-exosomes on dysregulation of mitochondrial function, which induces adverse changes in the function of the brain microvascular endothelium.

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Wasiak, Sylwia, Rodolfo Zunino, and Heidi M. McBride. "Bax/Bak promote sumoylation of DRP1 and its stable association with mitochondria during apoptotic cell death." Journal of Cell Biology 177, no. 3 (April 30, 2007): 439–50. http://dx.doi.org/10.1083/jcb.200610042.

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Dynamin-related protein 1 (DRP1) plays an important role in mitochondrial fission at steady state and during apoptosis. Using fluorescence recovery after photobleaching, we demonstrate that in healthy cells, yellow fluorescent protein (YFP)–DRP1 recycles between the cytoplasm and mitochondria with a half-time of 50 s. Strikingly, during apoptotic cell death, YFP-DRP1 undergoes a transition from rapid recycling to stable membrane association. The rapid cycling phase that characterizes the early stages of apoptosis is independent of Bax/Bak. However, after Bax recruitment to the mitochondrial membranes but before the loss of mitochondrial membrane potential, YFP-DRP1 becomes locked on the membrane, resulting in undetectable fluorescence recovery. This second phase in DRP1 cycling is dependent on the presence of Bax/Bak but independent of hFis1 and mitochondrial fragmentation. Coincident with Bax activation, we detect a Bax/Bak-dependent stimulation of small ubiquitin-like modifier-1 conjugation to DRP1, a modification that correlates with the stable association of DRP1 with mitochondrial membranes. Altogether, these data demonstrate that the apoptotic machinery regulates the biochemical properties of DRP1 during cell death.

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Tang, Jiayu, Zhiping Hu, Jieqiong Tan, Sonlin Yang, and Liuwang Zeng. "Parkin Protects against Oxygen-Glucose Deprivation/Reperfusion Insult by Promoting Drp1 Degradation." Oxidative Medicine and Cellular Longevity 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/8474303.

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Ischemic stroke results in severe brain damage and remains one of the leading causes of death and disability worldwide. Effective neuroprotective therapies are needed to reduce brain damage resulting from ischemic stroke. Mitochondria are crucial for cellular energy production and homeostasis. Modulation of mitochondrial function mediates neuroprotection against ischemic brain damage. Dynamin-related protein 1 (Drp1) and parkin play a key role in regulating mitochondrial dynamics. They are potential therapeutic targets for neuroprotection in ischemic stroke. Protective effects of parkin-Drp1 pathway on mitochondria were assessed in a cellular ischemia-reperfusion injury model. Mouse neuroblastoma Neuro2a (N2a) cells were subjected to oxygen-glucose deprivation/reperfusion (OGDR) insult. OGDR induces mitochondrial fragmentation. The expression of Drp1 protein is increased after OGDR insult, while the parkin protein level is decreased. The altered protein level of Drp1 after OGDR injury is mediated by parkin through ubiquitin proteasome system (UPS). Drp1 depletion protects against OGDR induced mitochondrial damage and apoptosis. Meanwhile, parkin overexpression protects against OGDR induced apoptosis and mitochondrial dysfunction, which is attenuated by increased expression of Drp1. Our data demonstrate that parkin protects against OGDR insult through promoting degradation of Drp1. This neuroprotective potential of parkin-Drp1 pathway against OGDR insult will pave the way for developing novel neuroprotective agents for cerebral ischemia-reperfusion related disorders.

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Pryde, Kenneth R., Heather L. Smith, Kai-Yin Chau, and Anthony H. V. Schapira. "PINK1 disables the anti-fission machinery to segregate damaged mitochondria for mitophagy." Journal of Cell Biology 213, no. 2 (April 18, 2016): 163–71. http://dx.doi.org/10.1083/jcb.201509003.

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Mitochondrial fission is essential for the degradation of damaged mitochondria. It is currently unknown how the dynamin-related protein 1 (DRP1)–associated fission machinery is selectively targeted to segregate damaged mitochondria. We show that PTEN-induced putative kinase (PINK1) serves as a pro-fission signal, independently of Parkin. Normally, the scaffold protein AKAP1 recruits protein kinase A (PKA) to the outer mitochondrial membrane to phospho-inhibit DRP1. We reveal that after damage, PINK1 triggers PKA displacement from A-kinase anchoring protein 1. By ejecting PKA, PINK1 ensures the requisite fission of damaged mitochondria for organelle degradation. We propose that PINK1 functions as a master mitophagy regulator by activating Parkin and DRP1 in response to damage. We confirm that PINK1 mutations causing Parkinson disease interfere with the orchestration of selective fission and mitophagy by PINK1.

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Richter, Viviane, Catherine S. Palmer, Laura D. Osellame, Abeer P. Singh, Kirstin Elgass, David A. Stroud, Hiromi Sesaki, Marc Kvansakul, and Michael T. Ryan. "Structural and functional analysis of MiD51, a dynamin receptor required for mitochondrial fission." Journal of Cell Biology 204, no. 4 (February 10, 2014): 477–86. http://dx.doi.org/10.1083/jcb.201311014.

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Mitochondrial fission is important for organelle transport, inheritance, and turnover, and alterations in fission are seen in neurological disease. In mammals, mitochondrial fission is executed by dynamin-related protein 1 (Drp1), a cytosolic guanosine triphosphatase that polymerizes and constricts the organelle. Recruitment of Drp1 to mitochondria involves receptors including Mff, MiD49, and MiD51. MiD49/51 form foci at mitochondrial constriction sites and coassemble with Drp1 to drive fission. Here, we solved the crystal structure of the cytosolic domain of human MiD51, which adopts a nucleotidyltransferase fold. Although MiD51 lacks catalytic residues for transferase activity, it specifically binds guanosine diphosphate and adenosine diphosphate. MiD51 mutants unable to bind nucleotides were still able to recruit Drp1. Disruption of an additional region in MiD51 that is not part of the nucleotidyltransferase fold blocked Drp1 recruitment and assembly of MiD51 into foci. MiD51 foci are also dependent on the presence of Drp1, and after scission they are distributed to daughter organelles, supporting the involvement of MiD51 in the fission apparatus.

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Lee, Youngil, Hwa-Youn Lee, Rita A. Hanna, and Åsa B. Gustafsson. "Mitochondrial autophagy by Bnip3 involves Drp1-mediated mitochondrial fission and recruitment of Parkin in cardiac myocytes." American Journal of Physiology-Heart and Circulatory Physiology 301, no. 5 (November 2011): H1924—H1931. http://dx.doi.org/10.1152/ajpheart.00368.2011.

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The Bcl2/adenovirus E1B 19-kDa interacting protein 3 (Bnip3) is an atypical BH3-only protein that is associated with mitochondrial dysfunction and cell death. Bnip3 is also a potent inducer of mitochondrial autophagy, and in this study we have investigated the mechanisms by which Bnip3 induces autophagy in cardiac myocytes. We found that Bnip3 induced mitochondrial translocation of dynamin-related protein 1 (Drp1), a protein involved in mitochondrial fission in adult myocytes. Drp1-mediated mitochondrial fission correlated with increased autophagy, and inhibition of Drp1 reduced Bnip3-mediated autophagy. Overexpression of Drp1K38E, a dominant negative of Drp1, or mitofusin 1 prevented mitochondrial fission and autophagy by Bnip3. Also, inhibition of mitochondrial fission or autophagy resulted in increased death of myocytes overexpressing Bnip3. Moreover, Bnip3 promoted translocation of the E3 ubiquitin ligase Parkin to mitochondria, which was prevented in the presence of a Drp1 inhibitor. Interestingly, induction of autophagy by Bnip3 was reduced in Parkin-deficient myocytes. Thus our data suggest that induction of autophagy in response to Bnip3 is a protective response activated by the cell that involves Drp1-mediated mitochondrial fission and recruitment of Parkin.

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Chae, Unbin, Ju-Sik Min, Hyun Hee Leem, Hyun-Shik Lee, Hong Jun Lee, Sang-Rae Lee, and Dong-Seok Lee. "Chrysophanol Suppressed Glutamate-Induced Hippocampal Neuronal Cell Death via Regulation of Dynamin-Related Protein 1-Dependent Mitochondrial Fission." Pharmacology 100, no. 3-4 (2017): 153–60. http://dx.doi.org/10.1159/000477814.

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Chrysophanic acid, or chrysophanol, is an anthraquinone found in Rheum palmatum, which was used in the preparation of oriental medicine in ancient China. The hippocampus plays a major role in controlling the activities of the short- and long-term memory. It is one of the major regions affected by excessive cell death in Alzheimer's disease. Therefore, neuronal cell-death modulation in the hippocampus is important for maintaining neuronal function. We investigated chrysophanol's effects on glutamate-induced hippocampal neuronal cell death. Chrysophanol reduced glutamate-induced cell death via suppression of proapoptotic factors and reactive oxygen species generation. Furthermore, it downregulated glutamate-induced mitochondrial fission by inhibiting dynamin-related protein 1 (Drp1) dephosphorylation. Thus, chrysophanol suppressed hippocampal neuronal cell death via inhibition of Drp1-dependent mitochondrial fission, and can be used as a therapeutic agent for treating neuronal cell death-mediated neurodegenerative diseases.

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Atkins, Kathleen, Asish Dasgupta, Kuang-Hueih Chen, Jeff Mewburn, and Stephen L. Archer. "The role of Drp1 adaptor proteins MiD49 and MiD51 in mitochondrial fission: implications for human disease." Clinical Science 130, no. 21 (September 22, 2016): 1861–74. http://dx.doi.org/10.1042/cs20160030.

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Mitochondrial morphology is governed by the balance of mitochondrial fusion, mediated by mitofusins and optic atrophy 1 (OPA1), and fission, mediated by dynamin-related protein 1 (Drp1). Disordered mitochondrial dynamics alters metabolism, proliferation, apoptosis and mitophagy, contributing to human diseases, including neurodegenerative syndromes, pulmonary arterial hypertension (PAH), cancer and ischemia/reperfusion injury. Post-translational regulation of Drp1 (by phosphorylation and SUMOylation) is an established means of modulating Drp1 activation and translocation to the outer mitochondrial membrane (OMM). This review focuses on Drp1 adaptor proteins that also regulate fission. The proteins include fission 1 (Fis1), mitochondrial fission factor (Mff) and mitochondrial dynamics proteins of 49 kDa and 51 kDa (MiD49, MiD51). Heterologous MiD overexpression sequesters inactive Drp1 on the OMM, promoting fusion; conversely, increased endogenous MiD creates focused Drp1 multimers that optimize OMM scission. The triggers that activate MiD-bound Drp1 in disease states are unknown; however, MiD51 has a unique capacity for ADP binding at its nucleotidyltransferase domain. Without ADP, MiD51 inhibits Drp1, whereas ADP promotes MiD51-mediated fission, suggesting a link between metabolism and fission. Confusion over whether MiDs mediate fusion (by sequestering inactive Drp1) or fission (by guiding Drp1 assembly) relates to a failure to consider cell types used and to distinguish endogenous compared with heterologous changes in expression. We speculate that endogenous MiDs serve as Drp1-binding partners that are dysregulated in disease states and may be important targets for inhibiting cell proliferation and ischemia/reperfusion injury. Moreover, it appears that the composition of the fission apparatus varies between disease states and amongst individuals. MiDs may be important targets for inhibiting cell proliferation and attenuating ischemia/reperfusion injury.

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Huang, Shiyuan, Xiaona Wang, Xinmei Wu, Jiale Yu, JinJing Li, Xiaoyuan Huang, Chunfang Zhu, and Hongshan Ge. "Yap regulates mitochondrial structural remodeling during myoblast differentiation." American Journal of Physiology-Cell Physiology 315, no. 4 (October 1, 2018): C474—C484. http://dx.doi.org/10.1152/ajpcell.00112.2018.

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Yes-associated protein (Yap) is a core transcriptional coactivator in the downstream Hippo pathway that regulates cell proliferation and tissue growth. However, its role in the regulation of myoblast differentiation remains unclear. Regulation of mitochondrial networks by dynamin-related protein 1 (Drp1) and mitofusion 2 (Mfn2) is crucial for the activation of myoblast differentiation. In the present study, we investigated the interplay between the Hippo/Yap pathway and protein contents of Mfn2 and Drp1 during myoblast differentiation. The Hippo/Yap pathway was inactivated at the early stage of myoblast differentiation due to the decreased ratio of phosphorylated mammalian sterile 20 kinases 1/2 (p-Mst1/2) to Mst1/2, phosphorylated large tumor suppressor 1 (p-Lats1) to Lats1, and phosphorylated Yap (serine 112, p-Yap S112) to Yap, which resulted in the translocation of Yap from cytoplasm to nucleus, increased protein content of Drp1, and mitochondrial fission events. Downregulation of Yap inhibited myoblast differentiation and decreased the content of Drp1, which resulted in elongated mitochondria, fused mitochondrial networks, and collapsed mitochondrial membrane potential. Together, our data indicate that inactivation of the Hippo/Yap pathway could induce mitochondrial fission by promoting Drp1 content at the early stage of myoblast differentiation.

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41

Rochon, Kristy, Anibal Tornes Blanco, and Jason Mears. "Conformational Changes in Solution Multimers of Dynamin-related Protein 1 (Drp1) Facilitate Functional Assembly." Microscopy and Microanalysis 26, S2 (July 30, 2020): 804–5. http://dx.doi.org/10.1017/s1431927620015895.

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Rochon, Kristy, Brianna Bauer, and Jason A. Mears. "Conformational changes in solution multimers of dynamin-related protein 1 (Drp1) facilitates functional assembly." Biophysical Journal 122, no. 3 (February 2023): 42a. http://dx.doi.org/10.1016/j.bpj.2022.11.440.

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Alvarez, Frances, Louie Zhou, and Jason A. Mears. "Structural Studies of Dynamin-Related Protein 1 (DRP1) Provide Mechanistic Insight into Mitochondrial Fission." Biophysical Journal 104, no. 2 (January 2013): 351a. http://dx.doi.org/10.1016/j.bpj.2012.11.1948.

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Francy, Christopher A., Chris Frohlich, Oliver Daumke, and Jason A. Mears. "Defining Membrane Interactions that Drive Dynamin Related Protein 1 (Drp1) Oligomerization using cryo-EM." Biophysical Journal 110, no. 3 (February 2016): 157a. http://dx.doi.org/10.1016/j.bpj.2015.11.882.

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Nguyen, Nicholas, Meifang Yu, Vinit Reddy, Ariana Acevedo-Diaz, Enzo Mesarick, Joseph Abi Jaoude, Min Yuan, John Asara, and Cullen Taniguchi. "Comparative Untargeted Metabolomic Profiling of Induced Mitochondrial Fusion in Pancreatic Cancer." Metabolites 11, no. 9 (September 15, 2021): 627. http://dx.doi.org/10.3390/metabo11090627.

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Mitochondria are dynamic organelles that constantly alter their shape through the recruitment of specialized proteins, like mitofusin-2 (Mfn2) and dynamin-related protein 1 (Drp1). Mfn2 induces the fusion of nearby mitochondria, while Drp1 mediates mitochondrial fission. We previously found that the genetic or pharmacological activation of mitochondrial fusion was tumor suppressive against pancreatic ductal adenocarcinoma (PDAC) in several model systems. The mechanisms of how these different inducers of mitochondrial fusion reduce pancreatic cancer growth are still unknown. Here, we characterized and compared the metabolic reprogramming of these three independent methods of inducing mitochondrial fusion in KPC cells: overexpression of Mfn2, genetic editing of Drp1, or treatment with leflunomide. We identified significantly altered metabolites via robust, orthogonal statistical analyses and found that mitochondrial fusion consistently produces alterations in the metabolism of amino acids. Our unbiased methodology revealed that metabolic perturbations were similar across all these methods of inducing mitochondrial fusion, proposing a common pathway for metabolic targeting with other drugs.

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Yuan, Yanggang, Aiqing Zhang, Jia Qi, Hui Wang, Xi Liu, Min Zhao, Suyan Duan, et al. "p53/Drp1-dependent mitochondrial fission mediates aldosterone-induced podocyte injury and mitochondrial dysfunction." American Journal of Physiology-Renal Physiology 314, no. 5 (May 1, 2018): F798—F808. http://dx.doi.org/10.1152/ajprenal.00055.2017.

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Mitochondrial dysfunction is increasingly recognized as an important factor in glomerular diseases. Previous study has shown that mitochondrial fission contributed to mitochondrial dysfunction. However, the mechanism of mitochondrial fission on mitochondrial dysfunction in aldosterone-induced podocyte injury remains ambiguous. This study aimed to investigate the pathogenic effect of mitochondrial fission both in vivo and in vitro. In an animal model of aldosterone-induced nephropathy, inhibition of the mitochondrial fission protein dynamin-related protein 1 (Drp1) suppressed aldosterone-induced podocyte injury. In cultured podocytes, aldosterone dose dependently induced Drp1 expression. Knockdown of Drp1 inhibited aldosterone-induced mitochondrial fission, mitochondrial dysfunction, and podocyte apoptosis. Furthermore, aldosterone dose dependently induced p53 expression. Knockdown of p53 inhibited aldosterone-induced Drp1 expression, mitochondrial dysfunction, and podocyte apoptosis. These findings implicated that aldosterone induced mitochondrial dysfunction and podocyte injury mediated by p53/Drp1-dependent mitochondrial fission, which may provide opportunities for therapeutic intervention for podocyte injury.

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Zou, Peng, Longhua Liu, Louise D. Zheng, Kyle K. Payne, Masoud H. Manjili, Michael O. Idowu, Jinfeng Zhang, Eva M. Schmelz, and Zhiyong Cheng. "Coordinated Upregulation of Mitochondrial Biogenesis and Autophagy in Breast Cancer Cells: The Role of Dynamin Related Protein-1 and Implication for Breast Cancer Treatment." Oxidative Medicine and Cellular Longevity 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/4085727.

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Overactive mitochondrial fission was shown to promote cell transformation and tumor growth. It remains elusive how mitochondrial quality is regulated in such conditions. Here, we show that upregulation of mitochondrial fission protein, dynamin related protein-1 (Drp1), was accompanied with increased mitochondrial biogenesis markers (PGC1α, NRF1, and Tfam) in breast cancer cells. However, mitochondrial number was reduced, which was associated with lower mitochondrial oxidative capacity in breast cancer cells. This contrast might be owing to enhanced mitochondrial turnover through autophagy, because an increased population of autophagic vacuoles engulfing mitochondria was observed in the cancer cells. Consistently, BNIP3 (a mitochondrial autophagy marker) and autophagic flux were significantly upregulated, indicative of augmented mitochondrial autophagy (mitophagy). The upregulation of Drp1 and BNIP3 was also observed in vivo (human breast carcinomas). Importantly, inhibition of Drp1 significantly suppressed mitochondrial autophagy, metabolic reprogramming, and cancer cell viability. Together, this study reveals coordinated increase of mitochondrial biogenesis and mitophagy in which Drp1 plays a central role regulating breast cancer cell metabolism and survival. Given the emerging evidence of PGC1αcontributing to tumor growth, it will be of critical importance to target both mitochondrial biogenesis and mitophagy for effective cancer therapeutics.

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Kim, Boa, Ji-Seok Kim, Yisang Yoon, Mayra C. Santiago, Michael D. Brown, and Joon-Young Park. "Inhibition of Drp1-dependent mitochondrial division impairs myogenic differentiation." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 305, no. 8 (October 15, 2013): R927—R938. http://dx.doi.org/10.1152/ajpregu.00502.2012.

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Mitochondria are dynamic organelles forming a tubular network that is continuously fusing and dividing to control their morphology and functions. Recent literature has shed new light on a potential link between the dynamic behavior of mitochondria and muscle development. In this study, we investigate the role of mitochondrial fission factor dynamin-related protein 1 (Drp1) in myogenic differentiation. We found that differentiation of C2C12 myoblasts induced by serum starvation was accompanied by a gradual increase in Drp1 protein expression (to ∼350% up to 3 days) and a fast reduction of Drp1 phosphorylation at Ser-637 (to ∼30%) resulting in translocation of Drp1 protein from the cytosol to mitochondria. During differentiation, treatment of myoblasts with mitochondrial division inhibitor ( mdivi-1), a specific inhibitor of Drp1 GTPase activity, caused extensive formation of elongated mitochondria, which coincided with increased apoptosis evidenced by both enhanced caspase-3 activity and increased number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells. Furthermore, the mdivi-1-treated myotubes ( day 3 in differentiation media) showed a reduction in mitochondrial DNA content, mitochondrial mass, and membrane potential in a dose-dependent manner indicating defects in mitochondrial biogenesis during myogenic differentiation. Most interestingly, mdivi-1 treatment significantly suppressed myotube formation in both C2C12 cells and primary myoblasts. Likewise, stable overexpression of a dominant negative mutant Drp1 (K38A) dramatically reduced myogenic differentiation. These data suggest that Drp-1-dependent mitochondrial division is a necessary step for successful myogenic differentiation, and perturbation of mitochondrial dynamics hinders normal mitochondrial adaptations during muscle development. Therefore, in the present study, we report a novel physiological role of mitochondrial dynamics in myogenic differentiation.

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Haun, Florian, Tomohiro Nakamura, and Stuart A. Lipton. "Dysfunctional Mitochondrial Dynamics in the Pathophysiology of Neurodegenerative Diseases." Journal of Cell Death 6 (January 2013): JCD.S10847. http://dx.doi.org/10.4137/jcd.s10847.

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Mitochondrial dysfunction occurs in neurodegenerative diseases, however molecular mechanisms underlying this process remain elusive. Emerging evidence suggests that nitrosative stress, mediated by reactive nitrogen species (RNS), may play a role in mitochondrial pathology. Here, we review findings that highlight the abnormal mitochondrial morphology observed in many neurodegenerative disorders including Alzheimer's, Parkinson's, and Huntington's diseases. One mechanism whereby RNS can affect mitochondrial function and thus neuronal survival occurs via protein S-nitrosylation, representing chemical reaction of a nitric oxide (NO) group with a critical cysteine thiol. In this review, we focus on the signaling pathway whereby S-nitrosylation of the mitochondrial fission protein Drp1 (dynamin-related protein 1; forming S-nitrosothiol (SNO)-Drp1) precipitates excessive mitochondrial fission or fragmentation and consequent bioenergetic compromise. Subsequently, the formation of SNO-Drp1 leads to synaptic damage and neuronal death. Thus, intervention in the SNO-Drp1 pathway may provide therapeutic benefit in neurodegenerative diseases.

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Liu, Ruijin, Si-cong Wang, Ming Li, Xiao-hui Ma, Xiao-nan Jia, Yue Bu, Lei Sun, and Kai-jiang Yu. "An Inhibitor of DRP1 (Mdivi-1) Alleviates LPS-Induced Septic AKI by Inhibiting NLRP3 Inflammasome Activation." BioMed Research International 2020 (July 11, 2020): 1–11. http://dx.doi.org/10.1155/2020/2398420.

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Mitochondria play an essential role in energy metabolism. Oxygen deprivation can poison cells and generate a chain reaction due to the free radical release. In patients with sepsis, the kidneys tend to be the organ primarily affected and the proximal renal tubules are highly susceptible to energy metabolism imbalances. Dynamin-related protein 1 (DRP1) is an essential regulator of mitochondrial fission. Few studies have confirmed the role and mechanism of DRP1 in acute kidney injury (AKI) caused by sepsis. We established animal and cell sepsis-induced AKI (S-AKI) models to keep DRP1 expression high. We found that Mdivi-1, a DRP1 inhibitor, can reduce the activation of the NOD-like receptor pyrin domain-3 (NLRP3) inflammasome-mediated pyroptosis pathway and improve mitochondrial function. Both S-AKI models showed that Mdivi-1 was able to prevent the mitochondrial content release and decrease the expression of NLRP3 inflammasome-related proteins. In addition, silencing NLRP3 gene expression further emphasized the pyroptosis importance in S-AKI occurrence. Our results indicate that the possible mechanism of action of Mdivi-1 is to inhibit mitochondrial fission and protect mitochondrial function, thereby reducing pyroptosis. These data can provide a potential theoretical basis for Mdivi-1 potential use in the S-AKI prevention.

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Journal articles on the topic 'Dynamin Related Protein 1 (Drp1)'

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