Articoli di riviste sul tema "Acetylation α-Tubulin"
Segui questo link per vedere altri tipi di pubblicazioni sul tema: Acetylation α-Tubulin.
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Acetylation α-Tubulin".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Chu, Chih-Wen, Fajian Hou, Junmei Zhang, Lilian Phu, Alex V. Loktev, Donald S. Kirkpatrick, Peter K. Jackson, Yingming Zhao e Hui Zou. "A novel acetylation of β-tubulin by San modulates microtubule polymerization via down-regulating tubulin incorporation". Molecular Biology of the Cell 22, n. 4 (15 febbraio 2011): 448–56. http://dx.doi.org/10.1091/mbc.e10-03-0203.
Abstract (sommario):
Dynamic instability is a critical property of microtubules (MTs). By regulating the rate of tubulin polymerization and depolymerization, cells organize the MT cytoskeleton to accommodate their specific functions. Among many processes, posttranslational modifications of tubulin are implicated in regulating MT functions. Here we report a novel tubulin acetylation catalyzed by acetyltransferase San at lysine 252 (K252) of β-tubulin. This acetylation, which is also detected in vivo, is added to soluble tubulin heterodimers but not tubulins in MTs. The acetylation-mimicking K252A/Q mutants were incorporated into the MT cytoskeleton in HeLa cells without causing any obvious MT defect. However, after cold-induced catastrophe, MT regrowth is accelerated in San-siRNA cells while the incorporation of acetylation-mimicking mutant tubulins is severely impeded. K252 of β-tubulin localizes at the interface of α-/β-tubulins and interacts with the phosphate group of the α-tubulin-bound GTP. We propose that the acetylation slows down tubulin incorporation into MTs by neutralizing the positive charge on K252 and allowing tubulin heterodimers to adopt a conformation that disfavors tubulin incorporation.
2
Calogero, Alessandra Maria, Milo Jarno Basellini, Huseyin Berkcan Isilgan, Francesca Longhena, Arianna Bellucci, Samanta Mazzetti, Chiara Rolando, Gianni Pezzoli e Graziella Cappelletti. "Acetylated α-Tubulin and α-Synuclein: Physiological Interplay and Contribution to α-Synuclein Oligomerization". International Journal of Molecular Sciences 24, n. 15 (31 luglio 2023): 12287. http://dx.doi.org/10.3390/ijms241512287.
Abstract (sommario):
Emerging evidence supports that altered α-tubulin acetylation occurs in Parkinson’s disease (PD), a neurodegenerative disorder characterized by the deposition of α-synuclein fibrillary aggregates within Lewy bodies and nigrostriatal neuron degeneration. Nevertheless, studies addressing the interplay between α-tubulin acetylation and α-synuclein are lacking. Here, we investigated the relationship between α-synuclein and microtubules in primary midbrain murine neurons and the substantia nigra of post-mortem human brains. Taking advantage of immunofluorescence and Proximity Ligation Assay (PLA), a method allowing us to visualize protein–protein interactions in situ, combined with confocal and super-resolution microscopy, we found that α-synuclein and acetylated α-tubulin colocalized and were in close proximity. Next, we employed an α-synuclein overexpressing cellular model and tested the role of α-tubulin acetylation in α-synuclein oligomer formation. We used the α-tubulin deacetylase HDAC6 inhibitor Tubacin to modulate α-tubulin acetylation, and we evaluated the presence of α-synuclein oligomers by PLA. We found that the increase in acetylated α-tubulin significantly induced α-synuclein oligomerization. In conclusion, we unraveled the link between acetylated α-tubulin and α-synuclein and demonstrated that α-tubulin acetylation could trigger the early step of α-synuclein aggregation. These data suggest that the proper regulation of α-tubulin acetylation might be considered a therapeutic strategy to take on PD.
3
Yang, Wulin, Xiangxiang Guo, Shermaine Thein, Feng Xu, Shigeki Sugii, Peter W. Baas, George K. Radda e Weiping Han. "Regulation of adipogenesis by cytoskeleton remodelling is facilitated by acetyltransferase MEC-17-dependent acetylation of α-tubulin". Biochemical Journal 449, n. 3 (9 gennaio 2013): 605–12. http://dx.doi.org/10.1042/bj20121121.
Abstract (sommario):
Cytoskeleton remodelling is a prerequisite step for the morphological transition from preadipocytes to mature adipocytes. Although microtubules play a pivotal role in organizing cellular structure, regulation of microtubule dynamics during adipogenesis remains unclear. In the present paper we show that acetylation of α-tubulin is up-regulated during adipogenesis, and adipocyte development is dependent on α-tubulin acetylation, as expression of an acetylation-resistant α-tubulin mutant significantly inhibits adipogenesis. Moreover, acetylation of α-tubulin is under the control of the acetyltransferase MEC-17 and deacetylases SIRT2 (Sirtuin 2) and HDAC6 (histone deacetylase 6). Adipocyte development is inhibited in MEC-17-knockdown cells, but enhanced in MEC-17-overexpressing cells. Finally, we show that katanin, a microtubule-severing protein with enhanced activity on acetylated α-tubulin, is actively involved in adipogenesis. We propose that co-ordinated up-regulation of α-tubulin acetylation initiates cytoskeleton remodelling by promoting α-tubulin severing by katanin which, in turn, allows expansion of lipid droplets and accelerates the morphological transition toward mature adipocytes.
4
Carmona, Bruno, H. Susana Marinho, Catarina Lopes Matos, Sofia Nolasco e Helena Soares. "Tubulin Post-Translational Modifications: The Elusive Roles of Acetylation". Biology 12, n. 4 (6 aprile 2023): 561. http://dx.doi.org/10.3390/biology12040561.
Abstract (sommario):
Microtubules (MTs), dynamic polymers of α/β-tubulin heterodimers found in all eukaryotes, are involved in cytoplasm spatial organization, intracellular transport, cell polarity, migration and division, and in cilia biology. MTs functional diversity depends on the differential expression of distinct tubulin isotypes and is amplified by a vast number of different post-translational modifications (PTMs). The addition/removal of PTMs to α- or β-tubulins is catalyzed by specific enzymes and allows combinatory patterns largely enriching the distinct biochemical and biophysical properties of MTs, creating a code read by distinct proteins, including microtubule-associated proteins (MAPs), which allow cellular responses. This review is focused on tubulin-acetylation, whose cellular roles continue to generate debate. We travel through the experimental data pointing to α-tubulin Lys40 acetylation role as being a MT stabilizer and a typical PTM of long lived MTs, to the most recent data, suggesting that Lys40 acetylation enhances MT flexibility and alters the mechanical properties of MTs, preventing MTs from mechanical aging characterized by structural damage. Additionally, we discuss the regulation of tubulin acetyltransferases/desacetylases and their impacts on cell physiology. Finally, we analyze how changes in MT acetylation levels have been found to be a general response to stress and how they are associated with several human pathologies.
5
Antel, Matthew, Taylor Simao, Muhammed Burak Bener e Mayu Inaba. "Drosophila CG17003/leaky (lky) is required for microtubule acetylation in early germ cells in Drosophila ovary". PLOS ONE 17, n. 11 (7 novembre 2022): e0276704. http://dx.doi.org/10.1371/journal.pone.0276704.
Abstract (sommario):
Microtubule acetylation is found in populations of stable, long-lived microtubules, occurring on the conserved lysine 40 (K40) residue of α-tubulin by α-tubulin acetyltransferases (αTATs). α-tubulin K40 acetylation has been shown to stabilize microtubules via enhancing microtubule resilience against mechanical stress. Here we show that a previously uncharacterized αTAT, Drosophila CG17003/leaky (lky), is required for α-tubulin K40 acetylation in early germ cells in Drosophila ovary. We found that loss of lky resulted in a progressive egg chamber fusion phenotype accompanied with mislocalization of germline-specific Vasa protein in somatic follicle cells. The same phenotype was observed upon replacement of endogenous α-tubulin84B with non-acetylatable α-tubulin84BK40A, suggesting α-tubulin K40 acetylation is responsible for the phenotype. Chemical disturbance of microtubules by Colcemid treatment resulted in a mislocalization of Vasa in follicle cells within a short period of time (~30 min), suggesting that the observed mislocalization is likely caused by direct leakage of cellular contents between germline and follicle cells. Taken together, this study provides a new function of α-tubulin acetylation in maintaining the cellular identity possibly by preventing the leakage of tissue-specific gene products between juxtaposing distinct cell types.
6
Niu, Xiaoxiao, Chuan-Xi Mao, Shan Wang, Xiongxiong Wang, Youyu Zhang, Juncheng Hu, Ran Bi, Zhihua Liu e Jin Shan. "α-Tubulin acetylation at lysine 40 regulates dendritic arborization and larval locomotion by promoting microtubule stability in Drosophila". PLOS ONE 18, n. 2 (24 febbraio 2023): e0280573. http://dx.doi.org/10.1371/journal.pone.0280573.
Abstract (sommario):
Posttranslational modification of tubulin increases the dynamic complexity and functional diversity of microtubules. Acetylation of α-tubulin at Lys-40 is a highly conserved posttranslational modification that has been shown to improve the flexibility and resilience of microtubules. Here we studied the in vivo functions of α-tubulin acetylation by knocking-out Atat, the Drosophila α-tubulin acetyltransferase, and by mutating Lys-40 to Arg in α1-tubulin. We found a reduction in the dendritic arborization of larval class I dendritic arborization (da) neurons in both mutants. The dendritic developmental defects in atat mutants could be reversed by enhancing the stability of microtubules either through knocking down the microtubule severing protein Katanin 60 or through overexpressing tubulin-specific chaperone E, suggesting that α-tubulin deacetylation impairsed dendritic morphology by decreasing the stability of microtubules. Using time-lapse recordings, we found that atat and α1-tubulinK40R mutations dramatically increased the number of dendritic protrusions that were likely to be immature dendritic precursors. Finally, we showed that both Atat and α-tubulin acetylation were required in class I da neurons to control larval locomotion. These findings add novel insight into the current knowledge of the role of α-tubulin acetylation in regulating neuronal development and functions.
7
Fernández-Barrera, Jaime, Miguel Bernabé-Rubio, Javier Casares-Arias, Laura Rangel, Laura Fernández-Martín, Isabel Correas e Miguel A. Alonso. "The actin-MRTF-SRF transcriptional circuit controls tubulin acetylation via α-TAT1 gene expression". Journal of Cell Biology 217, n. 3 (10 gennaio 2018): 929–44. http://dx.doi.org/10.1083/jcb.201702157.
Abstract (sommario):
The role of formins in microtubules is not well understood. In this study, we have investigated the mechanism by which INF2, a formin mutated in degenerative renal and neurological hereditary disorders, controls microtubule acetylation. We found that silencing of INF2 in epithelial RPE-1 cells produced a dramatic drop in tubulin acetylation, increased the G-actin/F-actin ratio, and impaired myocardin-related transcription factor (MRTF)/serum response factor (SRF)–dependent transcription, which is known to be repressed by increased levels of G-actin. The effect on tubulin acetylation was caused by the almost complete absence of α-tubulin acetyltransferase 1 (α-TAT1) messenger RNA (mRNA). Activation of the MRTF-SRF transcriptional complex restored α-TAT1 mRNA levels and tubulin acetylation. Several functional MRTF-SRF–responsive elements were consistently identified in the α-TAT1 gene. The effect of INF2 silencing on microtubule acetylation was also observed in epithelial ECV304 cells, but not in Jurkat T cells. Therefore, the actin-MRTF-SRF circuit controls α-TAT1 transcription. INF2 regulates the circuit, and hence microtubule acetylation, in cell types where it has a prominent role in actin polymerization.
8
Even, Aviel, Giovanni Morelli, Loïc Broix, Chiara Scaramuzzino, Silvia Turchetto, Ivan Gladwyn-Ng, Romain Le Bail et al. "ATAT1-enriched vesicles promote microtubule acetylation via axonal transport". Science Advances 5, n. 12 (dicembre 2019): eaax2705. http://dx.doi.org/10.1126/sciadv.aax2705.
Abstract (sommario):
Microtubules are polymerized dimers of α- and β-tubulin that underlie a broad range of cellular activities. Acetylation of α-tubulin by the acetyltransferase ATAT1 modulates microtubule dynamics and functions in neurons. However, it remains unclear how this enzyme acetylates microtubules over long distances in axons. Here, we show that loss of ATAT1 impairs axonal transport in neurons in vivo, and cell-free motility assays confirm a requirement of α-tubulin acetylation for proper bidirectional vesicular transport. Moreover, we demonstrate that the main cellular pool of ATAT1 is transported at the cytosolic side of neuronal vesicles that are moving along axons. Together, our data suggest that axonal transport of ATAT1-enriched vesicles is the predominant driver of α-tubulin acetylation in axons.
9
Olenieva, V. D., D. I. Lytvyn, A. I. Yemets e Ya B. Blume. "Expression profiling of kinesins, involved in the development of autophagy in Arabidopsis thaliana, and the role of tubulin acetylation in the interaction of Atg8 protein with microtubules". Faktori eksperimental'noi evolucii organizmiv 22 (9 settembre 2018): 162–68. http://dx.doi.org/10.7124/feeo.v22.942.
Abstract (sommario):
Aim. To investigate the interrelation between changes in the expression levels of kinesin genes that are potentially involved in the development of stress-induced autophagy in Arabidopsis thaliana by means of microtubules, and the structural biology analysis of the role of α-tubulin acetylation in the regulation of interaction of α-tubulin with Atg8. Methods. The simulation of the influence of abiotic stresses. PCR analysis of changes in expression levels of kinesin genes. The molecular dynamics simulations of α-tubulin and Atg8 complexes were performed using the GROMACS 4.5.5 program. Results. It was shown that the changes in expression levels were caused by the influence of stressful stimuli. A significant increase in the transcriptional activity of the KIN5B, KIN12B, KIN12F genes after UV-B irradiation, the KIN6, KIN7O, KIN7D, KIN12B genes under osmotic-, and KIN6, KIN12B under salt stress was detected. By means of bioinformatics it was demonstrated that α-tubulin acetylation provides an enhanced interaction of α-tubulin and Atg8 protein. Conclusions. Obtained data point out the important role of kinesins and α-tubulin acetylation in realization of microtubules’ partaking in the development of stress-induced autophagy in plants.
Keywords: microtubules, α-tubulin, kinesins, Atg8 protein, stress-induced autophagy.
10
Sadoul, Karin, e Saadi Khochbin. "The growing landscape of tubulin acetylation: lysine 40 and many more". Biochemical Journal 473, n. 13 (28 giugno 2016): 1859–68. http://dx.doi.org/10.1042/bcj20160172.
Abstract (sommario):
Tubulin heterodimers are the building block of microtubules, which are major elements of the cytoskeleton. Several types of post-translational modifications are found on tubulin subunits as well as on the microtubule polymer to regulate the multiple roles of microtubules. Acetylation of lysine 40 (K40) of the α-tubulin subunit is one of these post-translational modifications which has been extensively studied. We summarize the current knowledge about the structural aspects of K40 acetylation, the functional consequences, the enzymes involved and their regulation. Most importantly, we discuss the potential importance of the recently discovered additional acetylation acceptor lysines in tubulin subunits and highlight the urgent need to study tubulin acetylation in a more integrated perspective.
11
Tomas-Roig, Jordi, Shyam Ramasamy, Diana Zbarsky, Ursula Havemann-Reinecke e Sigrid Hoyer-Fender. "Psychosocial stress and cannabinoid drugs affect acetylation of α-tubulin (K40) and gene expression in the prefrontal cortex of adult mice". PLOS ONE 17, n. 9 (21 settembre 2022): e0274352. http://dx.doi.org/10.1371/journal.pone.0274352.
Abstract (sommario):
The dynamics of neuronal microtubules are essential for brain plasticity. Vesicular transport and synaptic transmission, additionally, requires acetylation of α-tubulin, and aberrant tubulin acetylation and neurobiological deficits are associated. Prolonged exposure to a stressor or consumption of drugs of abuse, like marihuana, lead to neurological changes and psychotic disorders. Here, we studied the effect of psychosocial stress and the administration of cannabinoid receptor type 1 drugs on α-tubulin acetylation in different brain regions of mice. We found significantly decreased tubulin acetylation in the prefrontal cortex in stressed mice. The impact of cannabinoid drugs on stress-induced microtubule disturbance was investigated by administration of the cannabinoid receptor agonist WIN55,212–2 and/or antagonist rimonabant. In both, control and stressed mice, the administration of WIN55,212–2 slightly increased the tubulin acetylation in the prefrontal cortex whereas administration of rimonabant acted antagonistically indicating a cannabinoid receptor type 1 mediated effect. The analysis of gene expression in the prefrontal cortex showed a consistent expression of ApoE attributable to either psychosocial stress or administration of the cannabinoid agonist. Additionally, ApoE expression inversely correlated with acetylated tubulin levels when comparing controls and stressed mice treated with WIN55,212–2 whereas rimonabant treatment showed the opposite.
12
Xie, Xi, Ruibao Ren, Bao yuan Zhang e Ping Liu. "Suppression of Microtubule Acetylation Mediates Theanti-Leukemic Effect of CDK9 Inhibition". Blood 142, Supplement 1 (28 novembre 2023): 5772. http://dx.doi.org/10.1182/blood-2023-187901.
Abstract (sommario):
Suppression of Microtubule Acetylation Mediates the Anti-Leukemic Effect of CDK9 Inhibition Xi Xie1, BaoyuanZhang1, Ping Liu1, Ruibao Ren1,2 1. Shanghai Institute of Hematology, State Key Laboratory for Medical Genomics, National Research Center for Translational Medicine at Shanghai, International Center for Aging and Cancer, Collaborative Innovation Center of Hematology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China. 2. International Center for Aging and Cancer, Hainan Medical University, Haikou, Hainan Province, China. Cyclin-dependent kinase 9 (CDK9) is a crucial component of transcription and potential target for anti-cancer therapies, particularly for hematological malignancies. However, the precise mechanisms underlying the therapeutic effects of CDK9 inhibitors remain not fully understood. Here, we found that inhibiting CDK9 either pharmacologically or through gene downregulation, significantly reduced the levels of α-tubulin protein in a time- and dose-dependent manner. We further discovered that CDK9 inhibition led to increased susceptibility of α-tubulin to proteasomal degradation due to reduced acetylation at lysine 40 (K40), an important modification for microtubule stability. An acetylation-mimicking mutant of α-tubulin mitigated the anti-tumor effects of CDK9 inhibition. Mechanically, we identified that CDK9 inhibition downregulated the expression of ATAT1, the acetyltransferase responsible for α-tubulin acetylation, further compromising microtubule stability. Our study unravels a novel molecular mechanism by which CDK9 inhibition disrupts α-tubulin stability and provides valuable insights for exploring effective treatment regimens involving CDK9 inhibitors.
13
Aguilar, Andrea, Lars Becker, Thomas Tedeschi, Stefan Heller, Carlo Iomini e Maxence V. Nachury. "α-Tubulin K40 acetylation is required for contact inhibition of proliferation and cell–substrate adhesion". Molecular Biology of the Cell 25, n. 12 (15 giugno 2014): 1854–66. http://dx.doi.org/10.1091/mbc.e13-10-0609.
Abstract (sommario):
Acetylation of α-tubulin on lysine 40 marks long-lived microtubules in structures such as axons and cilia, and yet the physiological role of α-tubulin K40 acetylation is elusive. Although genetic ablation of the α-tubulin K40 acetyltransferase αTat1 in mice did not lead to detectable phenotypes in the developing animals, contact inhibition of proliferation and cell–substrate adhesion were significantly compromised in cultured αTat1−/− fibroblasts. First, αTat1−/− fibroblasts kept proliferating beyond the confluent monolayer stage. Congruently, αTat1−/− cells failed to activate Hippo signaling in response to increased cell density, and the microtubule association of the Hippo regulator Merlin was disrupted. Second, αTat1−/− cells contained very few focal adhesions, and their ability to adhere to growth surfaces was greatly impaired. Whereas the catalytic activity of αTAT1 was dispensable for monolayer formation, it was necessary for cell adhesion and restrained cell proliferation and activation of the Hippo pathway at elevated cell density. Because α-tubulin K40 acetylation is largely eliminated by deletion of αTAT1, we propose that acetylated microtubules regulate contact inhibition of proliferation through the Hippo pathway.
14
Kalebic, Nereo, Concepcion Martinez, Emerald Perlas, Philip Hublitz, Daniel Bilbao-Cortes, Karol Fiedorczuk, Annapaola Andolfo e Paul A. Heppenstall. "Tubulin Acetyltransferase αTAT1 Destabilizes Microtubules Independently of Its Acetylation Activity". Molecular and Cellular Biology 33, n. 6 (28 dicembre 2012): 1114–23. http://dx.doi.org/10.1128/mcb.01044-12.
Abstract (sommario):
Acetylation of α-tubulin at lysine 40 (K40) is a well-conserved posttranslational modification that marks long-lived microtubules but has poorly understood functional significance. Recently, αTAT1, a member of the Gcn5-relatedN-acetyltransferase superfamily, has been identified as an α-tubulin acetyltransferase in ciliated organisms. Here, we explored the function of αTAT1 with the aim of understanding the consequences of αTAT1-mediated microtubule acetylation. We demonstrate that α-tubulin is the major target of αTAT1 but that αTAT1 also acetylates itself in a regulatory mechanism that is required for effective modification of tubulin. We further show that in mammalian cells, αTAT1 promotes microtubule destabilization and accelerates microtubule dynamics. Intriguingly, this effect persists in an αTAT1 mutant with no acetyltransferase activity, suggesting that interaction of αTAT1 with microtubules, rather than acetylationper se, is the critical factor regulating microtubule stability. Our data demonstrate that αTAT1 has cellular functions that extend beyond its classical enzymatic activity as an α-tubulin acetyltransferase.
15
Rahimi, Amir Mohammad, Mingfang Cai, Irem Kılıҫ, Zahra Basir Kazerouni, Constanza Tapia Contreras e Sigrid Hoyer-Fender. "Expression of α-Tubulin Acetyltransferase 1 and Tubulin Acetylation as Selective Forces in Cell Competition". Cells 10, n. 2 (14 febbraio 2021): 390. http://dx.doi.org/10.3390/cells10020390.
Abstract (sommario):
The wound healing response of fibroblasts critically depends on the primary cilium, a sensory organelle protruding into the environment and comprising a stable axonemal structure. A characteristic marker for primary cilia is acetylation of axonemal tubulin. Although formation of primary cilia is under cell cycle control, the environmental cues affecting ciliation are not fully understood. Our purpose was, therefore, to study the impact of culture conditions on cilia formation in NIH3T3 fibroblasts. We quantified ciliation in different NIH3T3 sub-cell lines and culture conditions by immunodetection of primary cilia and counting. Quantitative Western blotting, qRT-PCR, and proliferation assays completed our investigation. We observed large differences between NIH3T3 sub-cell lines in their ability to generate acetylated primary cilia that correlated with cytoplasmic tubulin acetylation. We found no increased activity of the major tubulin deacetylase, HDAC6, but instead reduced expression of the α-tubulin acetyltransferase 1 (Atat1) as being causative. Our observations demonstrate that cells with reduced expression of Atat1 and tubulin acetylation proliferate faster, eventually displacing all other cells in the population. Expression of Atat1 and tubulin acetylation are therefore selective forces in cell competition.
16
Dorsch, Schuldt, Remedios, Schinkel, Jong, Michels, Kuster, Brundel e Velden. "Protein Quality Control Activation and Microtubule Remodeling in Hypertrophic Cardiomyopathy". Cells 8, n. 7 (18 luglio 2019): 741. http://dx.doi.org/10.3390/cells8070741.
Abstract (sommario):
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder. It is mainly caused by mutations in genes encoding sarcomere proteins. Mutant forms of these highly abundant proteins likely stress the protein quality control (PQC) system of cardiomyocytes. The PQC system, together with a functional microtubule network, maintains proteostasis. We compared left ventricular (LV) tissue of nine donors (controls) with 38 sarcomere mutation-positive (HCMSMP) and 14 sarcomere mutation-negative (HCMSMN) patients to define HCM and mutation-specific changes in PQC. Mutations in HCMSMP result in poison polypeptides or reduced protein levels (haploinsufficiency, HI). The main findings were 1) several key PQC players were more abundant in HCM compared to controls, 2) after correction for sex and age, stabilizing heat shock protein (HSP)B1, and refolding, HSPD1 and HSPA2 were increased in HCMSMP compared to controls, 3) α-tubulin and acetylated α-tubulin levels were higher in HCM compared to controls, especially in HCMHI, 4) myosin-binding protein-C (cMyBP-C) levels were inversely correlated with α-tubulin, and 5) α-tubulin levels correlated with acetylated α-tubulin and HSPs. Overall, carrying a mutation affects PQC and α-tubulin acetylation. The haploinsufficiency of cMyBP-C may trigger HSPs and α-tubulin acetylation. Our study indicates that proliferation of the microtubular network may represent a novel pathomechanism in cMyBP-C haploinsufficiency-mediated HCM.
17
Aslan, Joseph E., Kevin G. Phillips, Laura D. Healy, Asako Itakura, Jiaqing Pang e Owen J. T. McCarty. "Histone deacetylase 6-mediated deacetylation of α-tubulin coordinates cytoskeletal and signaling events during platelet activation". American Journal of Physiology-Cell Physiology 305, n. 12 (15 dicembre 2013): C1230—C1239. http://dx.doi.org/10.1152/ajpcell.00053.2013.
Abstract (sommario):
The tubulin cytoskeleton plays a key role in maintaining the characteristic quiescent discoid shape of resting platelets. Upon activation, platelets undergo a dramatic change in shape; however, little is known of how the microtubule system contributes to regulating platelet shape and function. Here we investigated the role of the covalent modification of α-tubulin by acetylation in the regulation of platelet physiology during activation. Superresolution microscopy analysis of the platelet tubulin cytoskeleton showed that the marginal band together with an interconnected web of finer tubulin structures collapsed upon platelet activation with the glycoprotein VI (GPVI)-agonist collagen-related peptide (CRP). Western blot analysis revealed that α-tubulin was acetylated in resting platelets and deacetylated during platelet activation. Tubacin, a specific inhibitor of the tubulin deacetylase HDAC6, prevented tubulin deacetylation upon platelet activation with CRP. Inhibition of HDAC6 upregulated tubulin acetylation and disrupted the organization of the platelet microtubule marginal band without significantly affecting platelet volume changes in response to CRP stimulation. HDAC6 inhibitors also inhibited platelet aggregation in response to CRP and blocked platelet signaling events upstream of platelet Rho GTPase activation. Together, these findings support a role for acetylation signaling in controlling the resting structure of the platelet tubulin marginal band as well as in the coordination of signaling systems that drive platelet cytoskeletal changes and aggregation.
18
Coombes, Courtney, Ami Yamamoto, Mark McClellan, Taylor A. Reid, Melissa Plooster, G. W. Gant Luxton, Joshua Alper, Jonathon Howard e Melissa K. Gardner. "Mechanism of microtubule lumen entry for the α-tubulin acetyltransferase enzyme αTAT1". Proceedings of the National Academy of Sciences 113, n. 46 (1 novembre 2016): E7176—E7184. http://dx.doi.org/10.1073/pnas.1605397113.
Abstract (sommario):
Microtubules are structural polymers inside of cells that are subject to posttranslational modifications. These posttranslational modifications create functionally distinct subsets of microtubule networks in the cell, and acetylation is the only modification that takes place in the hollow lumen of the microtubule. Although it is known that the α-tubulin acetyltransferase (αTAT1) is the primary enzyme responsible for microtubule acetylation, the mechanism for how αTAT1 enters the microtubule lumen to access its acetylation sites is not well understood. By performing biochemical assays, fluorescence and electron microscopy experiments, and computational simulations, we found that αTAT1 enters the microtubule lumen through the microtubule ends, and through bends or breaks in the lattice. Thus, microtubule structure is an important determinant in the acetylation process. In addition, once αTAT1 enters the microtubule lumen, the mobility of αTAT1 within the lumen is controlled by the affinity of αTAT1 for its acetylation sites, due to the rapid rebinding of αTAT1 onto highly concentrated α-tubulin acetylation sites. These results have important implications for how acetylation could gradually accumulate on stable subsets of microtubules inside of the cell.
19
Labisso, Wajana, Ana-Caroline Raulin, Lucky Nwidu, Artur Kocon, Declan Wayne, Amaia Erdozain, Benito Morentin et al. "The Loss of α- and β-Tubulin Proteins Are a Pathological Hallmark of Chronic Alcohol Consumption and Natural Brain Ageing". Brain Sciences 8, n. 9 (11 settembre 2018): 175. http://dx.doi.org/10.3390/brainsci8090175.
Abstract (sommario):
Repetitive excessive alcohol intoxication leads to neuronal damage and brain shrinkage. We examined cytoskeletal protein expression in human post-mortem tissue from Brodmann’s area 9 of the prefrontal cortex (PFC). Brain samples from 44 individuals were divided into equal groups of 11 control, 11 alcoholic, 11 non-alcoholic suicides, and 11 suicide alcoholics matched for age, sex, and post-mortem delay. Tissue from alcoholic cohorts displayed significantly reduced expression of α- and β-tubulins, and increased levels of acetylated α-tubulin. Protein levels of histone deacetylase-6 (HDAC6), and the microtubule-associated proteins MAP-2 and MAP-tau were reduced in alcoholic cohorts, although for MAPs this was not significant. Tubulin gene expressions increased in alcoholic cohorts but not significantly. Brains from rats administered alcohol for 4 weeks also displayed significantly reduced tubulin protein levels and increased α-tubulin acetylation. PFC tissue from control subjects had reduced tubulin protein expression that was most notable from the sixth to the eighth decade of life. Collectively, loss of neuronal tubulin proteins are a hallmark of both chronic alcohol consumption and natural brain ageing. The reduction of cytosolic tubulin proteins could contribute to the brain volumetric losses reported for alcoholic patients and the elderly.
20
Othman, Ahmad, Marcus Winogradzki, Shreya Patel, Waddell Holmes, Alan Blank e Jitesh Pratap. "The Role of Runx2 in Microtubule Acetylation in Bone Metastatic Breast Cancer Cells". Cancers 14, n. 14 (15 luglio 2022): 3436. http://dx.doi.org/10.3390/cancers14143436.
Abstract (sommario):
Bone metastasis of breast cancer results in severe bone loss, fractures, and death. Crosstalk between breast cancer cells and bone resident cells promotes osteoclast activity and the release of growth factors from the bone matrix resulting in aggressive tumor growth and bone loss. We and others have shown that Runt-related transcription factor-2 (Runx2) promotes metastatic tumor growth-associated bone loss. Breast cancer cells also induce autophagy to survive metabolic stress at the metastatic site. Recently, we reported a Runx2-dependent increase in autophagy. In this study, to examine the underlying mechanisms of metastasis and tumor resistance to stress, we used a bone metastatic isogenic variant of breast cancer MDA-MB-231 cells isolated from a xenograft tumor mouse model of metastasis. Our results with immunofluorescence and biochemical approaches revealed that Runx2 promotes microtubule (MT) stability to facilitate autophagy. Stable MTs are critical for autophagosome trafficking and display increased acetylation at Lysine 40 of α-tubulin. Runx2 silencing decreases acetylated α-tubulin levels. The expression levels of HDAC6 and αTAT1, which serve to regulate the acetylation of α-tubulin, were not altered with Runx2 silencing. We found that HDAC6 interaction with α-tubulin is inhibited by Runt-related factor-2 (Runx2). We show that the expression of wild-type Runx2 can restore the acetylated polymer of MTs in Runx2 knockdown cells, while the C-terminal deletion mutant fails to rescue the polymer of MTs. Importantly, cellular stress, such as glucose starvation also increases the acetylation of α-tubulin. We found that the loss of Runx2 increases the sensitivity of breast cancer cells to MT-targeting agents. Overall, our results indicate a novel regulatory mechanism of microtubule acetylation and suggest that Runx2 and acetylated microtubules may serve as therapeutic targets for bone metastatic tumors.
21
Yu, Jinyan, Zhongsen Ma, Sreerama Shetty, Mengshi Ma e Jian Fu. "Selective HDAC6 inhibition prevents TNF-α-induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema". American Journal of Physiology-Lung Cellular and Molecular Physiology 311, n. 1 (1 luglio 2016): L39—L47. http://dx.doi.org/10.1152/ajplung.00051.2016.
Abstract (sommario):
Lung endothelial damage contributes to the pathogenesis of acute lung injury. New strategies against lung endothelial barrier dysfunction may provide therapeutic benefits against lung vascular injury. Cell-cell junctions and microtubule cytoskeleton are basic components in maintaining endothelial barrier integrity. HDAC6, a deacetylase primarily localized in the cytoplasm, has been reported to modulate nonnuclear protein function through deacetylation. Both α-tubulin and β-catenin are substrates for HDAC6. Here, we examined the effects of tubastatin A, a highly selective HDAC6 inhibitor, on TNF-α induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema. Selective HDAC6 inhibition by tubastatin A blocked TNF-α-induced lung endothelial cell hyperpermeability, which was associated with increased α-tubulin acetylation and microtubule stability. Tubastatin A pretreatment inhibited TNF-α-induced endothelial cell contraction and actin stress fiber formation with reduced myosin light chain phosphorylation. Selective HDAC6 inhibition by tubastatin A also induced β-catenin acetylation in human lung endothelial cells, which was associated with increased membrane localization of β-catenin and stabilization of adherens junctions. HDAC6 knockdown by small interfering RNA also prevented TNF-α-induced barrier dysfunction and increased α-tubulin and β-catenin acetylation in endothelial cells. Furthermore, in a mouse model of endotoxemia, tubastatin A was able to prevent endotoxin-induced deacetylation of α-tubulin and β-catenin in lung tissues, which was associated with reduced pulmonary edema. Collectively, our data indicate that selective HDAC6 inhibition by tubastatin A is a potent approach against lung endothelial barrier dysfunction.
22
Liu, Pengfei, Shengwei Zhang, Jingyi Ma, Dongning Jin, Yali Qin e Mingzhou Chen. "Vimentin inhibits α-tubulin acetylation via enhancing α-TAT1 degradation to suppress the replication of human parainfluenza virus type 3". PLOS Pathogens 18, n. 9 (15 settembre 2022): e1010856. http://dx.doi.org/10.1371/journal.ppat.1010856.
Abstract (sommario):
We previously found that, among human parainfluenza virus type 3 (HPIV3) proteins, the interaction of nucleoprotein (N) and phosphoprotein (P) provides the minimal requirement for the formation of cytoplasmic inclusion bodies (IBs), which are sites of RNA synthesis, and that acetylated α-tubulin enhances IB fusion and viral replication. In this study, using immunoprecipitation and mass spectrometry assays, we determined that vimentin (VIM) specifically interacted with the N–P complex of HPIV3, and that the head domain of VIM was responsible for this interaction, contributing to the inhibition of IB fusion and viral replication. Furthermore, we found that VIM promoted the degradation of α-tubulin acetyltransferase 1 (α-TAT1), through its head region, thereby inhibiting the acetylation of α-tubulin, IB fusion, and viral replication. In addition, we identified a 20-amino-acid peptide derived from the head region of VIM that participated in the interaction with the N–P complex and inhibited viral replication. Our findings suggest that VIM inhibits the formation of HPIV3 IBs by downregulating α-tubulin acetylation via enhancing the degradation of α-TAT1. Our work sheds light on a new mechanism by which VIM suppresses HPIV3 replication.
23
Luo, J., S. Megee e I. Dobrinski. "288 THE EXPRESSION PATTERN OF ACETYLATED ALPHA-TUBULIN IS CONSERVED IN PORCINE AND MURINE SPERMATOGONIAL STEM CELLS". Reproduction, Fertility and Development 20, n. 1 (2008): 223. http://dx.doi.org/10.1071/rdv20n1ab288.
Abstract (sommario):
During mammalian spermatogenesis, spermatogonial stem cells (SSCs) reside in the stem cell niche on the basement membrane where they undergo self-renewing divisions. Differentiating daughter cells are located progressively more toward the tubular lumen where they ultimately form spermatozoa. The mechanisms responsible for maintenance of SSCs at the basement membrane are unclear. Microtubules consisting of α/β-tubulin heterodimers are associated with many cellular functions. Reversible acetylation of α-tubulin at Lys40 has been implicated in regulating microtubule stability and function. Acetylation of α-tubulin is abundant in stable microtubules but absent from dynamic cellular structures. Deacetylation of α-tubulin is controlled by histone deacetylase 6 which is predominantly expressed in mouse testis. Here, we tested the hypothesis that differential acetylation of α-tubulin might be involved in maintenance of SSCs. Immunohistochemistry for acetylated α-tubulin (Ac-α-Tu) and the spermatogonia specific proteins PGP 9.5, DAZL, and PLZF were used to characterize the expression pattern of Ac-α-Tu in porcine and murine germ cells at different stages of testis development. In immature boar testes, Ac-α-Tu was present exclusively in gonocytes but not in other testicular cells at 1 week of age, and in a subset of spermatogonia at 10 weeks of age. At this age, spermatogonia are migrating to the basement membrane of the seminiferous tubules, and Ac-α-Tu appeared to be polarized toward the basement membrane. In immature mouse testes, Ac-α-Tu was present in germ cells and Sertoli cells at 6 days of age, whereas at 2 weeks of age, Ac-α-Tu expression was stronger in spermatogonia co-expressing PGP 9.5 and in spermatocytes than in Sertoli cells or PGP 9.5-negative spermatogonia. In adult boar and mouse testes, Ac-α-Tu was detected in a few single or paired spermatogonia expressing PGP 9.5 localized on the basement membrane as well as in spermatocytes, spermatids, and spermatozoa. Spermatogonia with high levels of Ac-α-Tu expressed PLZF but did not express DAZL, suggesting that only undifferentiated spermatogonia maintain a high level of Ac-α-Tu. When seminiferous tubules from 1-week-old and adult boar testes were maintained in vitro for 1–2 days, high levels of Ac-α-Tu were detected in single or paired round spermatogonia with a large nucleus, compared to low levels in elongated paired and aligned spermatogonia. The unique expression pattern of Ac-α-Tu in undifferentiated germ cells during postnatal development appears to be conserved in mammalian testes. Since Ac-α-Tu is a component of long-lived stable microtubules and reducing acetylation of α-tubulin enhances cell motility, these results suggest that stabilization of microtubules might contribute to the maintenance of spermatogonial stem cells. This work was supported by 1R01 RR 17359-05.
24
Sun, Wanwei, Xiaojian Ma, Heping Wang, Yanyun Du, Jianwen Chen, Huijun Hu, Ru Gao et al. "MYO1F regulates antifungal immunity by regulating acetylation of microtubules". Proceedings of the National Academy of Sciences 118, n. 30 (23 luglio 2021): e2100230118. http://dx.doi.org/10.1073/pnas.2100230118.
Abstract (sommario):
Opportunistic fungal infections have become one of the leading causes of death among immunocompromised patients, resulting in an estimated 1.5 million deaths each year worldwide. The molecular mechanisms that promote host defense against fungal infections remain elusive. Here, we find that Myosin IF (MYO1F), an unconventional myosin, promotes the expression of genes that are critical for antifungal innate immune signaling and proinflammatory responses. Mechanistically, MYO1F is required for dectin-induced α-tubulin acetylation, acting as an adaptor that recruits both the adaptor AP2A1 and α-tubulin N-acetyltransferase 1 to α-tubulin; in turn, these events control the membrane-to-cytoplasm trafficking of spleen tyrosine kinase and caspase recruitment domain-containing protein 9. Myo1f-deficient mice are more susceptible than their wild-type counterparts to the lethal sequelae of systemic infection with Candida albicans. Notably, administration of Sirt2 deacetylase inhibitors, namely AGK2, AK-1, or AK-7, significantly increases the dectin-induced expression of proinflammatory genes in mouse bone marrow–derived macrophages and microglia, thereby protecting mice from both systemic and central nervous system C. albicans infections. AGK2 also promotes proinflammatory gene expression in human peripheral blood mononuclear cells after Dectin stimulation. Taken together, our findings describe a key role for MYO1F in promoting antifungal immunity by regulating the acetylation of α-tubulin and microtubules, and our findings suggest that Sirt2 deacetylase inhibitors may be developed as potential drugs for the treatment of fungal infections.
25
Delgado, Inês L. S., João Gonçalves, Rita Fernandes, Sara Zúquete, Afonso P. Basto, Alexandre Leitão, Helena Soares e Sofia Nolasco. "Balancing Act: Tubulin Glutamylation and Microtubule Dynamics in Toxoplasma gondii". Microorganisms 12, n. 3 (28 febbraio 2024): 488. http://dx.doi.org/10.3390/microorganisms12030488.
Abstract (sommario):
The success of the intracellular parasite Toxoplasma gondii in invading host cells relies on the apical complex, a specialized microtubule cytoskeleton structure associated with secretory organelles. The T. gondii genome encodes three isoforms of both α- and β-tubulin, which undergo specific post-translational modifications (PTMs), altering the biochemical and biophysical proprieties of microtubules and modulating their interaction with associated proteins. Tubulin PTMs represent a powerful and evolutionarily conserved mechanism for generating tubulin diversity, forming a biochemical ‘tubulin code’ interpretable by microtubule-interacting factors. T. gondii exhibits various tubulin PTMs, including α-tubulin acetylation, α-tubulin detyrosination, Δ5α-tubulin, Δ2α-tubulin, α- and β-tubulin polyglutamylation, and α- and β-tubulin methylation. Tubulin glutamylation emerges as a key player in microtubule remodeling in Toxoplasma, regulating stability, dynamics, interaction with motor proteins, and severing enzymes. The balance of tubulin glutamylation is maintained through the coordinated action of polyglutamylases and deglutamylating enzymes. This work reviews and discusses current knowledge on T. gondii tubulin glutamylation. Through in silico identification of protein orthologs, we update the recognition of putative proteins related to glutamylation, contributing to a deeper understanding of its role in T. gondii biology.
26
Stoner, Michael W., Dharendra Thapa, Manling Zhang, Gregory A. Gibson, Michael J. Calderon, Claudette M. St. Croix e Iain Scott. "α-Lipoic acid promotes α-tubulin hyperacetylation and blocks the turnover of mitochondria through mitophagy". Biochemical Journal 473, n. 12 (10 giugno 2016): 1821–30. http://dx.doi.org/10.1042/bcj20160281.
Abstract (sommario):
Lysine acetylation is tightly coupled to the nutritional status of the cell, as the availability of its cofactor, acetyl-CoA, fluctuates with changing metabolic conditions. Recent studies have demonstrated that acetyl-CoA levels act as an indicator of cellular nourishment, and increased abundance of this metabolite can block the induction of cellular recycling programmes. In the present study we investigated the cross-talk between mitochondrial metabolic pathways, acetylation and autophagy, using chemical inducers of mitochondrial acetyl-CoA production. Treatment of cells with α-lipoic acid (αLA), a cofactor of the pyruvate dehydrogenase complex, led to the unexpected hyperacetylation of α-tubulin in the cytosol. This acetylation was blocked by pharmacological inhibition of mitochondrial citrate export (a source for mitochondria-derived acetyl-CoA in the cytosol), was dependent on the α-tubulin acetyltransferase (αTAT) and was coupled to a loss in function of the cytosolic histone deacetylase, HDAC6. We further demonstrate that αLA slows the flux of substrates through autophagy-related pathways, and severely limits the ability of cells to remove depolarized mitochondria through PTEN-associated kinase 1 (PINK1)-mediated mitophagy.
27
Shi, Lang, Zhixia Song, Chenglong Li, Fangjing Deng, Yao Xia, Jing Huang, Xiongfei Wu e Jiefu Zhu. "HDAC6 Inhibition Alleviates Ischemia- and Cisplatin-Induced Acute Kidney Injury by Promoting Autophagy". Cells 11, n. 24 (7 dicembre 2022): 3951. http://dx.doi.org/10.3390/cells11243951.
Abstract (sommario):
Histone deacetylase (HDAC) 6 exists exclusively in cytoplasm and deacetylates cytoplasmic proteins such as α-tubulin. HDAC6 dysfunction is associated with several pathological conditions in renal disorders, including UUO-induced fibrotic kidneys and rhabdomyolysis-induced nephropathy. However, the role of HDAC6 in ischemic acute kidney injury (AKI) and the mechanism by which HDAC6 inhibition protects tubular cells after AKI remain unclear. In the present study, we observed that HDAC6 was markedly activated in kidneys subjected to ischemia- and cisplatin (cis)-induced AKI treatment. Pharmacological inhibition of HDAC6 alleviated renal impairment and renal tubular damage after ischemia and cisplatin treatment. HDAC6 dysfunction was associated with decreased acetylation of α-tubulin at the residue of lysine 40 and autophagy. HDAC6 inhibition preserved acetyl-α-tubulin-enhanced autophagy flux in AKI and cultured tubular cells. Genetic ablation of the renal tubular (RT) Atg7 gene or pharmacological inhibition of autophagy suppressed the protective effects of HDAC6. Taken together, our study indicates that HDAC6 contributes to ischemia- and cisplatin-induced AKI by inhibiting autophagy and the acetylation of α-tubulin. These results suggest that HDAC6 could be a potential target for ischemic and nephrotoxic AKI.
28
Creppe, Catherine, e Marcus Buschbeck. "Elongator: An Ancestral Complex Driving Transcription and Migration through Protein Acetylation". Journal of Biomedicine and Biotechnology 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/924898.
Abstract (sommario):
Elongator is an evolutionary highly conserved complex. At least two of its cellular functions rely on the intrinsic lysine acetyl-transferase activity of the Elongator complex. Its two known substrates—Histone H3 and α-Tubulin—reflect the different roles of Elongator in the cytosol and the nucleus. A picture seems to emerge in which nuclear Elongator could regulate the transcriptional elongation of a subset of stress-inducible genes through acetylation of Histone H3 in the promoter-distal gene body. In the cytosol, Elongator-mediated acetylation of α-Tubulin contributes to intracellular trafficking and cell migration. Defects in both functions of Elongator have been implicated in neurodegenerative disorders.
29
Howes, Stuart C., Gregory M. Alushin, Toshinobu Shida, Maxence V. Nachury e Eva Nogales. "Effects of tubulin acetylation and tubulin acetyltransferase binding on microtubule structure". Molecular Biology of the Cell 25, n. 2 (15 gennaio 2014): 257–66. http://dx.doi.org/10.1091/mbc.e13-07-0387.
Abstract (sommario):
Tubulin undergoes posttranslational modifications proposed to specify microtubule subpopulations for particular functions. Most of these modifications occur on the C-termini of tubulin and may directly affect the binding of microtubule-associated proteins (MAPs) or motors. Acetylation of Lys-40 on α-tubulin is unique in that it is located on the luminal surface of microtubules, away from the interaction sites of most MAPs and motors. We investigate whether acetylation alters the architecture of microtubules or the conformation of tubulin, using cryo–electron microscopy (cryo-EM). No significant changes are observed based on protofilament distributions or microtubule helical lattice parameters. Furthermore, no clear differences in tubulin structure are detected between cryo-EM reconstructions of maximally deacetylated or acetylated microtubules. Our results indicate that the effect of acetylation must be highly localized and affect interaction with proteins that bind directly to the lumen of the microtubule. We also investigate the interaction of the tubulin acetyltransferase, αTAT1, with microtubules and find that αTAT1 is able to interact with the outside of the microtubule, at least partly through the tubulin C-termini. Binding to the outside surface of the microtubule could facilitate access of αTAT1 to its luminal site of action if microtubules undergo lateral opening between protofilaments.
30
Sharma, Chiranjeev, Yong Jin Oh, Byoungduck Park, Sooyeun Lee, Chul-Ho Jeong, Sangkil Lee, Ji Hae Seo e Young Ho Seo. "Development of Thiazolidinedione-Based HDAC6 Inhibitors to Overcome Methamphetamine Addiction". International Journal of Molecular Sciences 20, n. 24 (9 dicembre 2019): 6213. http://dx.doi.org/10.3390/ijms20246213.
Abstract (sommario):
Thiazolidinedione is a five-membered heterocycle that is widely used in drug discovery endeavors. In this study, we report the design, synthesis, and biological evaluation of a series of thiazolidinedione-based HDAC6 inhibitors. In particular, compound 6b exerts an excellent inhibitory activity against HDAC6 with an IC50 value of 21 nM, displaying a good HDAC6 selectivity over HDAC1. Compound 6b dose-dependently induces the acetylation level of α-tubulin via inhibition of HDAC6 in human neuroblastoma SH-SY5Y cell line. Moreover, compound 6b efficiently reverses methamphetamine-induced morphology changes of SH-SY5Y cells via regulating acetylation landscape of α-tubulin. Collectively, compound 6b represents a novel HDAC6-isoform selective inhibitor and demonstrates promising therapeutic potential for the treatment of methamphetamine addiction.
31
Patel, Shreya, Marcus Winogradzki, Ahmad Othman, Waddell Holmes e Jitesh Pratap. "Abstract 270: The novel control mechanism of the tubulin code and vesicular trafficking in breast cancer bone metastatic cells". Cancer Research 82, n. 12_Supplement (15 giugno 2022): 270. http://dx.doi.org/10.1158/1538-7445.am2022-270.
Abstract (sommario):
Abstract Metastasis of breast cancer (BC) to bone results in severe bone loss, fractures, and death. The crosstalk between BC cells and bone resident cells dramatically increases osteoclast activity, resulting in the release of growth factors from the bone matrix that causes aggressive tumor growth and bone loss. A potentially important aspect of this process is vesicular trafficking on microtubules (MTs) which can affect the output of signaling pathways and secretory activity of metastatic bone cells. MTs are cytoskeletal filaments composed of heterodimers, α- and β-tubulin. The tubulin isotypes and their variety of post-translational modifications (PTMs) control the properties and functions of MT filaments, a concept known as the ‘tubulin code’. Recent studies show an emerging link between alterations of the tubulin code with poor prognosis of breast cancer. However, the regulation of the code in metastatic bone cells is currently unknown. Tubulin acetylation occurs via α-tubulin N-acetyl transferase-1 (αTAT1) and can be reversed by histone deacetylase-6 (HDAC6). MTs lacking acetylation lose flexural rigidity and are prone to breaks following repetitive bending during vesicular trafficking. We found that HDAC6 interaction with α-tubulin is inhibited by a Runt-related factor (Runx2). Our biochemical, mass spectrometry and IPs analyses of MTs revealed that loss of Runx2 can reduce (i) acetylation and stability of MTs, (ii) interaction of HSP90 with α-tubulin, and (iii) levels of β 2a-tubulin. Our studies with Runx2 mutants indicate that the C-terminal of Runx2 serves a scaffolding function by interacting with MTs and HDAC6. Confocal microscopy revealed reduced puncta and altered distribution of endosomal vesicles and autophagosomes with Runx2 silencing. As MT targeting agents are often used as chemotherapeutics, we found that loss of Runx2 sensitizes breast cancer cells to docetaxel and vinblastine and reduces the secretion of IL-6. We found MDA-MB-231 cells metastasized to the bone show significant differences in microtubule isotype expression, with 10 of 19 studied showing 1.3 to 4.1 fold increases. Further analysis of whether Runx2 knockdown affects isotype expression, we found the majority of the 19 studied remain unchanged. Immunohistochemistry for Ac-α-Tub levels in bone metastatic patient samples shows significantly more Ac-α-Tub positive cells in metastatic bone tumors than primary tumors. These findings suggest a novel control mechanism of MTs stability via Runx2-HDAC6 interactions that can impact trafficking and cellular activity. Our results indicate that inhibition of Runx2 may sensitize metastatic tumors to MT targeting agents, and Runx2/HDAC6/Ac-α-Tub levels may serve as markers for metastatic tumors to help stratify patients for optimal treatment for metastatic bone disease. Citation Format: Shreya Patel, Marcus Winogradzki, Ahmad Othman, Waddell Holmes, Jitesh Pratap. The novel control mechanism of the tubulin code and vesicular trafficking in breast cancer bone metastatic cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 270.
32
Hu, Yi. "Post-translational modification of cytoskeleton regulates anti-tumor cytotoxicity in γδ T cells". Journal of Immunology 204, n. 1_Supplement (1 maggio 2020): 88.19. http://dx.doi.org/10.4049/jimmunol.204.supp.88.19.
Abstract (sommario):
Abstract γδ T cells based immunotherapy has emerged as a new treatment strategy for malignant tumors. The underlying cytotoxic mechanism against cancer cells involves surface receptor recognition molecules such as LFA-1, NKG2D, TRAIL, CD16, CD107a, and FasL, as well as cytokines such TNFα, IFNγ, perforin, and granzyme B. Previously, it has been shown that the cytoskeleton plays pivotal roles in T cell immunity. Nevertheless, the role of cytoskeleton in γδ T cell anti-tumor immunity remains largely unknown. In our work, we attempted to elucidate the functions of cytoskeleton in regulating the antitumor cytotoxicity of γδ T cells. We discovered that the acetylation of tubulin-α is positively correlated with γδ T cells cytotoxicity. While the down-regulation of tubulin-α acetylation in γδ T cells leads to decreased cancer cells killing efficacy, up-regulation could potentiate it through the expression of cytotoxic related molecules such as NKG2D, IFN-γ, CD16, and suppression of PD-1 molecule. Moreover, we observed that the acetylation of tubulin-α in γδ T cells drastically differs after challenged by MDA-MB-231, SkBr3, and MCF7 breast cancer cells, respectively, implying diverse γδ T cell immune responses towards these cell types. This result was further supported by the discrepancies in γδ T cell in vitro killing efficacy. Together, our work will provide important scientific references to further understand the cytoskeletal function in γδ T cell anti-tumor immunity.
33
Eshun-Wilson, Lisa, Rui Zhang, Didier Portran, Maxence V. Nachury, Daniel B. Toso, Thomas Löhr, Michele Vendruscolo, Massimiliano Bonomi, James S. Fraser e Eva Nogales. "Effects of α-tubulin acetylation on microtubule structure and stability". Proceedings of the National Academy of Sciences 116, n. 21 (9 maggio 2019): 10366–71. http://dx.doi.org/10.1073/pnas.1900441116.
Abstract (sommario):
Acetylation of K40 in α-tubulin is the sole posttranslational modification to mark the luminal surface of microtubules. It is still controversial whether its relationship with microtubule stabilization is correlative or causative. We have obtained high-resolution cryo-electron microscopy (cryo-EM) reconstructions of pure samples of αTAT1-acetylated and SIRT2-deacetylated microtubules to visualize the structural consequences of this modification and reveal its potential for influencing the larger assembly properties of microtubules. We modeled the conformational ensembles of the unmodified and acetylated states by using the experimental cryo-EM density as a structural restraint in molecular dynamics simulations. We found that acetylation alters the conformational landscape of the flexible loop that contains αK40. Modification of αK40 reduces the disorder of the loop and restricts the states that it samples. We propose that the change in conformational sampling that we describe, at a location very close to the lateral contacts site, is likely to affect microtubule stability and function.
34
Solinger, Jachen A., Roberta Paolinelli, Holger Klöß, Francesco Berlanda Scorza, Stefano Marchesi, Ursula Sauder, Dai Mitsushima, Fabrizio Capuani, Stephen R. Stürzenbaum e Giuseppe Cassata. "The Caenorhabditis elegans Elongator Complex Regulates Neuronal α-tubulin Acetylation". PLoS Genetics 6, n. 1 (22 gennaio 2010): e1000820. http://dx.doi.org/10.1371/journal.pgen.1000820.
35
Kim, Byeong-Seong, Taegwan Yoon e Jee-Yin Ahn. "Id2 regulates α-tubulin acetylation by Sirt2, promoting axon growth". IBRO Reports 6 (settembre 2019): S471. http://dx.doi.org/10.1016/j.ibror.2019.07.1484.
36
Kim, Go-Woon, Lin Li, Mohammad Ghorbani, Linya You e Xiang-Jiao Yang. "Mice lacking α-tubulin acetyltransferase 1 are viable but display α-tubulin acetylation deficiency and dentate gyrus distortion." Journal of Biological Chemistry 291, n. 48 (25 novembre 2016): 25279. http://dx.doi.org/10.1074/jbc.a113.464792.
37
Kim, Go-Woon, Lin Li, Mohammad Gorbani, Linya You e Xiang-Jiao Yang. "Mice Lacking α-Tubulin Acetyltransferase 1 Are Viable but Display α-Tubulin Acetylation Deficiency and Dentate Gyrus Distortion". Journal of Biological Chemistry 288, n. 28 (28 maggio 2013): 20334–50. http://dx.doi.org/10.1074/jbc.m113.464792.
38
Stemberger, Megan B., Julia A. Ju, Keyata N. Thompson, Trevor J. Mathias, Alexandra E. Jerrett, Katarina T. Chang, Eleanor C. Ory et al. "Hydrogen Peroxide Induces α-Tubulin Detyrosination and Acetylation and Impacts Breast Cancer Metastatic Phenotypes". Cells 12, n. 9 (27 aprile 2023): 1266. http://dx.doi.org/10.3390/cells12091266.
Abstract (sommario):
Levels of hydrogen peroxide are highly elevated in the breast tumor microenvironment compared to normal tissue. Production of hydrogen peroxide is implicated in the mechanism of action of many anticancer therapies. Several lines of evidence suggest hydrogen peroxide mediates breast carcinogenesis and metastasis, though the molecular mechanism remains poorly understood. This study elucidates the effects of exposure to elevated hydrogen peroxide on non-tumorigenic MCF10A mammary epithelial cells, tumorigenic MCF7 cells, and metastatic MDA-MB-231 breast cancer cells. Hydrogen peroxide treatment resulted in a dose- and time-dependent induction of two α-tubulin post-translational modifications—de-tyrosination and acetylation—both of which are markers of poor patient prognosis in breast cancer. Hydrogen peroxide induced the formation of tubulin-based microtentacles in MCF10A and MDA-MB-231 cells, which were enriched in detyrosinated and acetylated α-tubulin. However, the hydrogen peroxide-induced microtentacles did not functionally promote metastatic phenotypes of cellular reattachment and homotypic cell clustering. These data establish for the first time that microtentacle formation can be separated from the functions to promote reattachment and clustering, which indicates that there are functional steps that remain to be identified. Moreover, signals in the primary tumor microenvironment may modulate α-tubulin post-translational modifications and induce microtentacles; however, the functional consequences appear to be context-dependent.
39
Pongrakhananon, Varisa, Hiroko Saito, Sylvain Hiver, Takaya Abe, Go Shioi, Wenxiang Meng e Masatoshi Takeichi. "CAMSAP3 maintains neuronal polarity through regulation of microtubule stability". Proceedings of the National Academy of Sciences 115, n. 39 (6 settembre 2018): 9750–55. http://dx.doi.org/10.1073/pnas.1803875115.
Abstract (sommario):
The molecular mechanisms that guide each neuron to become polarized, forming a single axon and multiple dendrites, remain unknown. Here we show that CAMSAP3 (calmodulin-regulated spectrin-associated protein 3), a protein that regulates the minus-end dynamics of microtubules, plays a key role in maintaining neuronal polarity. In mouse hippocampal neurons, CAMSAP3 was enriched in axons. Although axonal microtubules were generally acetylated, CAMSAP3 was preferentially localized along a less-acetylated fraction of the microtubules. CAMSAP3-mutated neurons often exhibited supernumerary axons, along with an increased number of neurites having nocodazole-resistant/acetylated microtubules compared with wild-type neurons. Analysis using cell lines showed that CAMSAP3 depletion promoted tubulin acetylation, and conversely, mild overexpression of CAMSAP3 inhibited it, suggesting that CAMSAP3 works to retain nonacetylated microtubules. In contrast, CAMSAP2, a protein related to CAMSAP3, was detected along all neurites, and its loss did not affect neuronal polarity, nor did it cause increased tubulin acetylation. Depletion of α-tubulin acetyltransferase-1 (αTAT1), the key enzyme for tubulin acetylation, abolished CAMSAP3 loss-dependent multiple-axon formation. These observations suggest that CAMSAP3 sustains a nonacetylated pool of microtubules in axons, interfering with the action of αTAT1, and this process is important to maintain neuronal polarity.
40
Valenzuela-Fernández, Agustín, Susana Álvarez, Mónica Gordon-Alonso, Marta Barrero, Ángeles Ursa, J. Román Cabrero, Gerónimo Fernández et al. "Histone Deacetylase 6 Regulates Human Immunodeficiency Virus Type 1 Infection". Molecular Biology of the Cell 16, n. 11 (novembre 2005): 5445–54. http://dx.doi.org/10.1091/mbc.e05-04-0354.
Abstract (sommario):
Efficient human immunodeficiency virus (HIV)-1 infection depends on multiple interactions between the viral gp41/gp120 envelope (Env) proteins and cell surface receptors. However, cytoskeleton-associated proteins that modify membrane dynamics may also regulate the formation of the HIV-mediated fusion pore and hence viral infection. Because the effects of HDAC6-tubulin deacetylase on cortical α-tubulin regulate cell migration and immune synapse organization, we explored the possible role of HDAC6 in HIV-1-envelope-mediated cell fusion and infection. The binding of the gp120 protein to CD4+-permissive cells increased the level of acetylated α-tubulin in a CD4-dependent manner. Furthermore, overexpression of active HDAC6 inhibited the acetylation of α-tubulin, and remarkably, prevented HIV-1 envelope-dependent cell fusion and infection without affecting the expression and codistribution of HIV-1 receptors. In contrast, knockdown of HDAC6 expression or inhibition of its tubulin deacetylase activity strongly enhanced HIV-1 infection and syncytia formation. These results demonstrate that HDAC6 plays a significant role in regulating HIV-1 infection and Env-mediated syncytia formation.
41
Adamakis, Ioannis-Dimosthenis S., Emmanuel Panteris e Eleftherios P. Eleftheriou. "Tubulin Acetylation Mediates Bisphenol A Effects on the Microtubule Arrays of Allium cepa and Triticum turgidum". Biomolecules 9, n. 5 (11 maggio 2019): 185. http://dx.doi.org/10.3390/biom9050185.
Abstract (sommario):
The effects of bisphenol A (BPA), a prevalent endocrine disruptor, on both interphase and mitotic microtubule array organization was examined by immunofluorescence microscopy in meristematic root cells of Triticum turgidum (durum wheat) and Allium cepa (onion). In interphase cells of A. cepa, BPA treatment resulted in substitution of cortical microtubules by annular/spiral tubulin structures, while in T. turgidum BPA induced cortical microtubule fragmentation. Immunolocalization of acetylated α-tubulin revealed that cortical microtubules of T. turgidum were highly acetylated, unlike those of A. cepa. In addition, elevation of tubulin acetylation by trichostatin A in A. cepa resulted in microtubule disruption similar to that observed in T. turgidum. BPA also disrupted all mitotic microtubule arrays in both species. It is also worth noting that mitotic microtubule arrays were acetylated in both plants. As assessed by BPA removal, its effects are reversible. Furthermore, taxol-stabilized microtubules were resistant to BPA, while recovery from oryzalin treatment in BPA solution resulted in the formation of ring-like tubulin conformations. Overall, these findings indicate the following: (1) BPA affects plant mitosis/cytokinesis by disrupting microtubule organization. (2) Microtubule disassembly probably results from impairment of free tubulin subunit polymerization. (3) The differences in cortical microtubule responses to BPA among the species studied are correlated to the degree of tubulin acetylation.
42
Carbajal, Agustín, María E. Chesta, C. Gastón Bisig e Carlos A. Arce. "A novel method for purification of polymerizable tubulin with a high content of the acetylated isotype". Biochemical Journal 449, n. 3 (9 gennaio 2013): 643–48. http://dx.doi.org/10.1042/bj20121439.
Abstract (sommario):
Tubulin can be acetylated/deacetylated on Lys40 of the α-subunit. Studies of the post-translational acetylation/deacetylation of tubulin using biochemical techniques require tubulin preparations that are enriched in AcTubulin (acetylated tubulin) and (for comparison) preparations lacking AcTubulin. Assembly–disassembly cycling of microtubules gives tubulin preparations that contain little or no AcTubulin. In the present study we demonstrated that this result is owing to the presence of high deacetylating activity in the extracts. This deacetylating activity in rat brain homogenates was inhibited by TSA (Trichostatin A) and tubacin, but not by nicotinamide, indicating that HDAC6 (histone deacetylase 6) is involved. TSA showed no effect on microtubule polymerization or depolymerization. We utilized these properties of TSA to prevent deacetylation during the assembly–disassembly procedure. The effective inhibitory concentration of TSA was 3 μM in the homogenate and 1 μM in the subsequent cycling steps. By comparison with immunopurified AcTubulin, we estimated that ~64% of the tubulin molecules in the three cycled preparations were acetylated. The protein profiles of these tubulin preparations, as assessed by SDS/PAGE and Coomassie Blue staining, were identical to that of a preparation completely lacking AcTubulin obtained by assembly–disassembly cycles in the absence of TSA. The tyrosination state and in vitro assembly–disassembly kinetics were the same regardless of the degree of acetylation.
43
Qu, Pengxiang, Zhenzi Zuo, Zhengqing Liu, Zhihan Niu, Ying Zhang, Yue Du, Xiaonan Ma et al. "Sperm-borne small RNAs regulate α-tubulin acetylation and epigenetic modification of early bovine somatic cell nuclear transfer embryos". Molecular Human Reproduction 25, n. 8 (1 maggio 2019): 471–82. http://dx.doi.org/10.1093/molehr/gaz023.
Abstract (sommario):
AbstractAccumulated evidence indicates that sperm-borne small RNA plays a crucial role in embryonic development, especially the absence of the sperm-borne small RNA might be a major cause of the abnormal development of cloned embryos. In this study, we found that sperm-borne small RNA can affect abnormal pronuclear-like structures, postpone the timing of first embryo cleavage and enhance developmental competence of bovine somatic cell nuclear transfer (SCNT) embryos. In addition, the supplementation of sperm-borne small RNA can significantly increase live birth rates and decrease the birth weights of cloned offspring. To investigate the underlying mechanisms, the levels of α-tubulin K40 acetylation (Ac α-tubulin K40) and histone H3 lysine 9 trimethylation (H3K9me3) during early embryo development were investigated in SCNT embryos with sperm-borne small RNA supplementation (termed as T-NT), compared to those normal SCNT embryos and embryos obtained from standard IVF. The results showed that sperm-borne small RNA can significantly decrease the H3K9me3 levels at the pronuclear and two-cell stages, while significantly increase Ac α-tubulin K40 levels at anaphase and telophase of bovine SCNT embryos during the first cleavage. Collectively, our study for the first time demonstrates that sperm-borne small RNA plays a crucial role in the developmental competence of SCNT embryos by regulating H3K9me3 and Ac α-tubulin K40. Further studies will be required to determine how sperm small RNA regulate the H3K9me3 and Acα-tubulin K40. Our study suggests that the supplementation of sperm-borne small RNA is a potential application to improve the cloning efficiency.
44
Cueva, Juan G., Jen Hsin, Kerwyn Casey Huang e Miriam B. Goodman. "Posttranslational Acetylation of α-Tubulin Constrains Protofilament Number in Native Microtubules". Current Biology 22, n. 12 (giugno 2012): 1066–74. http://dx.doi.org/10.1016/j.cub.2012.05.012.
45
Ohkawa, Noriaki, Shunichiro Sugisaki, Eri Tokunaga, Kazuko Fujitani, Mitsutoshi Setou e Kaoru Inokuchi. "ARD1-NAT1 complex regulates neuronal dendritic arborization through α-tubulin acetylation". Neuroscience Research 58 (gennaio 2007): S88. http://dx.doi.org/10.1016/j.neures.2007.06.1080.
46
Li, Wande, Yinzhi Zhao e Iih-Nan Chou. "Nickel (Ni2+) Enhancement of α-Tubulin Acetylation in Cultured 3T3 Cells". Toxicology and Applied Pharmacology 140, n. 2 (ottobre 1996): 461–70. http://dx.doi.org/10.1006/taap.1996.0243.
47
Ryu, Na Mi, e Jung Min Kim. "The role of the α-tubulin acetyltransferase αTAT1 in the DNA damage response". Journal of Cell Science 133, n. 17 (11 agosto 2020): jcs246702. http://dx.doi.org/10.1242/jcs.246702.
Abstract (sommario):
ABSTRACTLysine 40 acetylation of α-tubulin (Ac-α-tubulin), catalyzed by the acetyltransferase αTAT1, marks stabilized microtubules. Recently, there is growing evidence to suggest crosstalk between the DNA damage response (DDR) and microtubule organization; we therefore investigated whether αTAT1 is involved in the DDR. Following treatment with DNA-damaging agents, increased levels of Ac-α-tubulin were detected. We also observed significant induction of Ac-α-tubulin after depletion of DNA repair proteins, suggesting that αTAT1 is positively regulated in response to DNA damage. Intriguingly, αTAT1 depletion decreased DNA damage-induced replication protein A (RPA) phosphorylation and foci formation. Moreover, DNA damage-induced cell cycle arrest was significantly delayed in αTAT1-depleted cells, indicating defective checkpoint activation. The checkpoint defects seen upon αTAT1 deficiency were restored by expression of wild-type αTAT1, but not by αTAT1-D157N (a catalytically inactive αTAT1), indicating that the role of αTAT1 in the DDR is dependent on enzymatic activity. Furthermore, αTAT1-depleted direct repeat GFP (DR-GFP) U2OS cells had a significant decrease in the frequency of homologous recombination repair. Collectively, our results suggest that αTAT1 may play an essential role in DNA damage checkpoints and DNA repair through its acetyltransferase activity.
48
Santo, Loredana, Teru Hideshima, Andrew L. Kung, Jen-Chieh Tseng, David Tamang, Min Yang, Matthew Jarpe et al. "Pharmacodynamic and Pharmacokinetic Properties of a Novel and Selective HDAC6 Inhibitor, ACY-1215, in Combination with Bortezomib in Multiple Myeloma". Blood 118, n. 21 (18 novembre 2011): 2912. http://dx.doi.org/10.1182/blood.v118.21.2912.2912.
Abstract (sommario):
Abstract Abstract 2912 HDAC enzymes are being studied as novel therapeutic targets in several cancers including multiple myeloma (MM). In particular, the combination of proteasome inhibitors (e.g. bortezomib (BZ)) with Histone Deacetylase (HDAC) inhibitors have shown very promising results in pre-clinical MM models. HDAC6, a Class II HDAC, has been linked to the activity of aggresomes that degrade unfolded and misfolded ubiquitinated proteins. Targeting both proteasomal and aggresomal protein degradation systems with proteasome inhibitors and HDAC inhibitors, respectively, induces accumulation of polyubiquitinated proteins, followed by activation of apoptotic cascades. Here we investigated the preclinical activity of an HDAC6 selective inhibitor ACY-1215 in MM, either alone or in combination with BZ. In vitro enzyme assays showed that ACY-1215 has potent inhibitory activity against HDAC6 (IC50 0.0054 mM) compared to the other HDACs, including Class I HDACs. Maximal cytotoxicity of ACY-1215 against MM cell lines was observed at 48h, with IC50 values ranging from 2–8 μM. To investigate the specific inhibitory effect of ACY-1215 on HDAC6 activity, we evaluated its effect on acetylation of a-tubulin. ACY-1215 induces potent acetylation of a-tubulin at low doses and triggers acetylation of lysine on histone H3 and histone H4 only at much higher doses, confirming its selective inhibitory effect on HDAC6 activity. Importantly, this selective inhibition was also observed in patient MM cells, where ACY-1215 increased acetylated a-tubulin after 4 h of treatment. We next combined low doses of ACY-1215 with BZ and showed synergistic anti MM activity, resulting in apoptosis via caspase-3, -8, -9 and poly (ADP) ribosome polymerase activation. Moreover, the combination of ACY-1215 plus BZ increased the accumulation of polyubiquitinated proteins compared to either agent alone. To investigate the effect of ACY-1215 on aggresome formation, MM.1S cells treated with ACY-1215 1 μM and/or BZ 2.5 nM for 12 h were stained with immunofluorescent anti-ubiquitin antibody. BZ-treated cells showed perinuclear structures consistent with aggresome formation, which was disrupted when BZ and ACY-1215 were combined. This result supports the synergistic anti MM activity of ACY-1215 with BZ. We also evaluated the in vivo anti-MM effect of combination therapy using two different xenograft models in SCID mice: plasmacytoma model and disseminated MM model. ACY-1215 in combination with BZ triggered more significant anti-MM activity than either agent alone in suppressing tumor growth and prolonging host survival in both models, without significant adverse effects. To optimize the design of future clinical trials, we conducted pharmacokinetic and pharmacodynamic studies in our plasmacytoma model. ACY-1215 peak plasma levels were observed at 4 h, which were unaffected by the addition of BZ. To further characterize the activity of ACY-1215 against HDAC6 in vivo, we evaluated the acetylation of α-tubulin in mouse blood cells by flow cytometry. The maximum levels of blood cell α-tubulin acetylation were observed at 4 h, providing an important biomarker for future clinical trials. Importantly, levels of acetylated α-tubulin were also detected in tumor tissue from treated mice in a similar time frame to peak blood levels, suggesting that ACY-1215 is readily absorbed by tumor tissue. Moreover, ACY-1215 did not accumulate in tumor tissue, as shown by the decline of acetylated α-tubulin in blood cells and tumor tissue by 24 h post-dose, which parallels the elimination of ACY-1215 from blood. We further confirmed the HDAC6 selectivity of ACY-1215 in our in vivo models by investigating the effect of the drug combination on histone acetylation in tumor tissue. WB analysis and IHC did not show a significant increase in acetylated histone H3 (lys 18), while demonstrating a robust acetylation of α-tubulin, the primary marker of HDAC6 inhibition by ACY-1215 at the cellular level. The results from our in vitro and in vivo studies therefore show significant and synergistic anti-MM activity of ACY-1215 in combination with BZ and provided the rationale for the ongoing phase I/II clinical trial in patients with relapsed or relapsed/refractory MM. Moreover, our pharmacodynamic helped inform the design of correlative studies, which will establish whether acetylated α-tubulin can be used as predictive biomarker of HDAC6 inhibition and disease response. Disclosures: Hideshima: Acetylon: Consultancy. Kung:Acetylon Pharmaceuticals, Inc.: Consultancy. Tamang:Acetylon Pharmaceuticals, Inc.: Employment. Yang:Acetylon Pharmaceuticals, Inc.: Employment. Jarpe:Acetylon Pharmaceuticals, Inc.: Employment. van Duzer:Acetylon Pharmaceuticals, Inc.: Employment. Mazitschek:Acetylon Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees. Ogier:Acetylon Pharmaceuticals, Inc.: Employment. Bradner:Acetylon: Consultancy. Anderson:celgene: Consultancy, Honoraria; Millennium: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Acetylon Pharmaceuticals Inc: founder. Jones:Acetylon Pharmaceuticals, Inc.: Employment. Raje:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Acetylon: Research Funding.
49
Read, M., T. Sherwin, S. P. Holloway, K. Gull e J. E. Hyde. "Microtubular organization visualized by immunofluorescence microscopy during erythrocytic schizogony in Plasmodium falciparum and investigation of post-translational modifications of parasite tubulin". Parasitology 106, n. 3 (aprile 1993): 223–32. http://dx.doi.org/10.1017/s0031182000075041.
Abstract (sommario):
SUMMARYWe describe a novel procedure for the immunofluorescent investigation of Plasmodium falciparum. This has allowed us to visualize clearly microtubular structures and their changing conformation through the erythrocytic cell-cycle, to the stage of cytodifferentiation leading to merozoite release. The images of spindle development we observed, together with an analysis of nuclear body numbers in large numbers of parasites, indicate that there is an apparent asynchrony in chromosomal multiplication within a single parasite. Using antibodies specific for post-translational modification of α- tubulin, we also demonstrate that the C-terminal tyrosine-containing epitope of P. falciparum α-tubulin I is similar to that of other organisms. Lysine-40 in the same molecule, a target for highly specific in vivo acetylation in some organisms, is unmodified in the blood stages we examined here. After in vitro acetylation of this residue, however, the epitope to which it contributes was recognized by antibody, showing that the conformation of this part of the molecule is also conserved, despite a lack of primary sequence homology immediately downstream of the target lysine residue.
50
Shimazu, Tadahiro, Sueharu Horinouchi e Minoru Yoshida. "Multiple Histone Deacetylases and the CREB-binding Protein Regulate Pre-mRNA 3′-End Processing". Journal of Biological Chemistry 282, n. 7 (17 dicembre 2006): 4470–78. http://dx.doi.org/10.1074/jbc.m609745200.
Abstract (sommario):
Trichostatin A (TSA), a specific inhibitor of histone deacetylases (HDACs), induces acetylation of various non-histone proteins such as p53 and α-tubulin. We purified several acetylated proteins by the affinity to an anti-acetylated lysine (AcLys) antibody from cells treated with TSA and identified them by mass spectrometry. Here we report on acetylation of CFIm25, a component of mammalian cleavage factor Im (CF Im), and poly(A) polymerase (PAP), a polyadenylating enzyme for the pre-mRNA 3′-end. The residues acetylated in these proteins were mapped onto the regions required for interaction with each other. Whereas CBP acetylated these proteins, HDAC1, HDAC3, HDAC10, SIRT1, and SIRT2 were involved in in vivo deacetylation. Acetylation of the CFIm25 occurred depending on the cleavage factor complex formation. Importantly, the interaction between PAP and CF Im complex was decreased by acetylation. We also demonstrated that acetylation of PAP inhibited the nuclear localization of PAP by inhibiting the binding to the importin α/β complex. These results suggest that CBP and HDACs regulate the 3′-end processing machinery and modulate the localization of PAP through the acetylation and deacetylation cycle.