Journal articles: 'Nonmucle Myosin IIs (NM-IIs)'

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Lee, Kyoung Hwan, Guidenn Sulbarán, Shixin Yang, Ji Young Mun, Lorenzo Alamo, Antonio Pinto, Osamu Sato, et al. "Interacting-heads motif has been conserved as a mechanism of myosin II inhibition since before the origin of animals." Proceedings of the National Academy of Sciences 115, no. 9 (February 14, 2018): E1991—E2000. http://dx.doi.org/10.1073/pnas.1715247115.

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Electron microscope studies have shown that the switched-off state of myosin II in muscle involves intramolecular interaction between the two heads of myosin and between one head and the tail. The interaction, seen in both myosin filaments and isolated molecules, inhibits activity by blocking actin-binding and ATPase sites on myosin. This interacting-heads motif is highly conserved, occurring in invertebrates and vertebrates, in striated, smooth, and nonmuscle myosin IIs, and in myosins regulated by both Ca2+ binding and regulatory light-chain phosphorylation. Our goal was to determine how early this motif arose by studying the structure of inhibited myosin II molecules from primitive animals and from earlier, unicellular species that predate animals. Myosin II from Cnidaria (sea anemones, jellyfish), the most primitive animals with muscles, and Porifera (sponges), the most primitive of all animals (lacking muscle tissue) showed the same interacting-heads structure as myosins from higher animals, confirming the early origin of the motif. The social amoeba Dictyostelium discoideum showed a similar, but modified, version of the motif, while the amoeba Acanthamoeba castellanii and fission yeast (Schizosaccharomyces pombe) showed no head–head interaction, consistent with the different sequences and regulatory mechanisms of these myosins compared with animal myosin IIs. Our results suggest that head–head/head–tail interactions have been conserved, with slight modifications, as a mechanism for regulating myosin II activity from the emergence of the first animals and before. The early origins of these interactions highlight their importance in generating the inhibited (relaxed) state of myosin in muscle and nonmuscle cells.

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Dey, Sumit K., Raman K. Singh, Shyamtanu Chattoraj, Shekhar Saha, Alakesh Das, Kankan Bhattacharyya, Kaushik Sengupta, Shamik Sen, and Siddhartha S. Jana. "Differential role of nonmuscle myosin II isoforms during blebbing of MCF-7 cells." Molecular Biology of the Cell 28, no. 8 (April 15, 2017): 1034–42. http://dx.doi.org/10.1091/mbc.e16-07-0524.

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Bleb formation has been correlated with nonmuscle myosin II (NM-II) activity. Whether three isoforms of NM-II (NM-IIA, -IIB and -IIC) have the same or differential roles in bleb formation is not well understood. Here we report that ectopically expressed, GFP-tagged NM-II isoforms exhibit different types of membrane protrusions, such as multiple blebs, lamellipodia, combinations of both, or absence of any such protrusions in MCF-7 cells. Quantification suggests that 50% of NM-IIA-GFP–, 29% of NM-IIB-GFP–, and 19% of NM-IIC1-GFP–expressing MCF-7 cells show multiple bleb formation, compared with 36% of cells expressing GFP alone. Of interest, NM-IIB has an almost 50% lower rate of dissociation from actin filament than NM-IIA and –IIC1 as determined by FRET analysis both at cell and bleb cortices. We induced bleb formation by disruption of the cortex and found that all three NM-II-GFP isoforms can reappear and form filaments but to different degrees in the growing bleb. NM-IIB-GFP can form filaments in blebs in 41% of NM-IIB-GFP–expressing cells, whereas filaments form in only 12 and 3% of cells expressing NM-IIA-GFP and NM-IIC1-GFP, respectively. These studies suggest that NM-II isoforms have differential roles in the bleb life cycle.

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Wang, Aibing, Neil Billington, Robert S. Adelstein, and James R. Sellers. "Expression and Characterization of Full Length Nonmuscle Myosin IIs." Biophysical Journal 100, no. 3 (February 2011): 594a. http://dx.doi.org/10.1016/j.bpj.2010.12.3425.

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Lin, Yu-Hung, Yen-Yi Zhen, Kun-Yi Chien, I.-Ching Lee, Wei-Chi Lin, Mei-Yu Chen, and Li-Mei Pai. "LIMCH1 regulates nonmuscle myosin-II activity and suppresses cell migration." Molecular Biology of the Cell 28, no. 8 (April 15, 2017): 1054–65. http://dx.doi.org/10.1091/mbc.e15-04-0218.

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Nonmuscle myosin II (NM-II) is an important motor protein involved in cell migration. Incorporation of NM-II into actin stress fiber provides a traction force to promote actin retrograde flow and focal adhesion assembly. However, the components involved in regulation of NM-II activity are not well understood. Here we identified a novel actin stress fiber–associated protein, LIM and calponin-homology domains 1 (LIMCH1), which regulates NM-II activity. The recruitment of LIMCH1 into contractile stress fibers revealed its localization complementary to actinin-1. LIMCH1 interacted with NM-IIA, but not NM-IIB, independent of the inhibition of myosin ATPase activity with blebbistatin. Moreover, the N-terminus of LIMCH1 binds to the head region of NM-IIA. Depletion of LIMCH1 attenuated myosin regulatory light chain (MRLC) diphosphorylation in HeLa cells, which was restored by reexpression of small interfering RNA–resistant LIMCH1. In addition, LIMCH1-depleted HeLa cells exhibited a decrease in the number of actin stress fibers and focal adhesions, leading to enhanced cell migration. Collectively, our data suggest that LIMCH1 plays a positive role in regulation of NM-II activity through effects on MRLC during cell migration.

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Saha, Shekhar, Sumit K. Dey, Provas Das, and Siddhartha S. Jana. "Increased expression of nonmuscle myosin IIs is associated with 3MC-induced mouse tumor." FEBS Journal 278, no. 21 (September 19, 2011): 4025–34. http://dx.doi.org/10.1111/j.1742-4658.2011.08306.x.

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Yuen, Samantha L., Ozgur Ogut, and Frank V. Brozovich. "Nonmuscle myosin is regulated during smooth muscle contraction." American Journal of Physiology-Heart and Circulatory Physiology 297, no. 1 (July 2009): H191—H199. http://dx.doi.org/10.1152/ajpheart.00132.2009.

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The participation of nonmuscle myosin in force maintenance is controversial. Furthermore, its regulation is difficult to examine in a cellular context, as the light chains of smooth muscle and nonmuscle myosin comigrate under native and denaturing electrophoresis techniques. Therefore, the regulatory light chains of smooth muscle myosin (SM-RLC) and nonmuscle myosin (NM-RLC) were purified, and these proteins were resolved by isoelectric focusing. Using this method, intact mouse aortic smooth muscle homogenates demonstrated four distinct RLC isoelectric variants. These spots were identified as phosphorylated NM-RLC (most acidic), nonphosphorylated NM-RLC, phosphorylated SM-RLC, and nonphosphorylated SM-RLC (most basic). During smooth muscle activation, NM-RLC phosphorylation increased. During depolarization, the increase in NM-RLC phosphorylation was unaffected by inhibition of either Rho kinase or PKC. However, inhibition of Rho kinase blocked the angiotensin II-induced increase in NM-RLC phosphorylation. Additionally, force for angiotensin II stimulation of aortic smooth muscle from heterozygous nonmuscle myosin IIB knockout mice was significantly less than that of wild-type littermates, suggesting that, in smooth muscle, activation of nonmuscle myosin is important for force maintenance. The data also demonstrate that, in smooth muscle, the activation of nonmuscle myosin is regulated by Ca2+-calmodulin-activated myosin light chain kinase during depolarization and a Rho kinase-dependent pathway during agonist stimulation.

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Pleines, Irina, and Bernhard Nieswandt. "RhoA/ROCK guides NMII on the way to MK polyploidy." Blood 128, no. 26 (December 29, 2016): 3025–26. http://dx.doi.org/10.1182/blood-2016-11-746685.

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A unique feature of megakaryocyte maturation is the switch from mitosis to replication of DNA without cell division, a process termed endomitosis. In this issue of Blood, Roy et al elegantly demonstrate that RhoA/ROCK signaling is critical for the differential activity and localization of nonmuscle myosin (NM) IIA and IIB isoforms at the megakaryocyte cleavage furrow, a key step in the induction of endomitosis.1

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Breckenridge, Mark T., Natalya G. Dulyaninova, and Thomas T. Egelhoff. "Multiple Regulatory Steps Control Mammalian Nonmuscle Myosin II Assembly in Live Cells." Molecular Biology of the Cell 20, no. 1 (January 2009): 338–47. http://dx.doi.org/10.1091/mbc.e08-04-0372.

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To better understand the mechanism controlling nonmuscle myosin II (NM-II) assembly in mammalian cells, mutant NM-IIA constructs were created to allow tests in live cells of two widely studied models for filament assembly control. A GFP-NM-IIA construct lacking the RLC binding domain (ΔIQ2) destabilizes the 10S sequestered monomer state and results in a severe defect in recycling monomers during spreading, and from the posterior to the leading edge during polarized migration. A GFP-NM-IIA construct lacking the nonhelical tailpiece (Δtailpiece) is competent for leading edge assembly, but overassembles, suggesting defects in disassembly from lamellae subsequent to initial recruitment. The Δtailpiece phenotype was recapitulated by a GFP-NM-IIA construct carrying a mutation in a mapped tailpiece phosphorylation site (S1943A), validating the importance of the tailpiece and tailpiece phosphorylation in normal lamellar myosin II assembly control. These results demonstrate that both the 6S/10S conformational change and the tailpiece contribute to the localization and assembly of myosin II in mammalian cells. This work furthermore offers cellular insights that help explain platelet and leukocyte defects associated with R1933-stop alleles of patients afflicted with human MYH9-related disorder.

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Osagie, Oloruntoba Ismail, Zhigui Li, Shijun Mi, Jennifer T. Aguilan, and Gloria S. Huang. "ARID1A interacts with nonmuscle myosin IIA to regulate cancer cell motility." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e17036-e17036. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e17036.

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e17036 Background: ARID1A (BAF250A), a member of the SWI/SNF chromatin remodeling complex, is one of the most frequently mutated genes in human cancer. Here we report the discovery of a novel protein-protein interaction between ARID1A and the actin-binding motor protein, non-muscle myosin IIA (NM IIA) encoded by the myosin heavy chain 9 ( MYH9). Methods: The ARID1A immunoprecipitated protein complex was separated by gel electrophoresis followed by analysis of the peptide digested gel bands by C18-Reversed Phase chromatography using an Ultimate 3000 RSLCnano System (Thermo Scientific) equipped with an Acclaim PepMap C18 column (Thermo Scientific) and connected to a TriVersa NanoMate nanoelectrospray source (Advion) and a linear ion trap LTQ-XL mass spectrometer (Thermo Scientific). Protein identification was performed by Mascot search engine v. 2.5.1 (Matrix Science) against NCBI Homo sapiens database. Scaffold software v. 4.5.1 (Proteome Software Inc.) was used to validate the MS/MS peptide and protein identification based on 99% protein and 95% peptide probabilities. Immunoprecipitation and immunoblotting were done to evaluate the protein-protein interaction in ARID1A-wild type cell lines. Isogenic engineered cell lines, ES2 shRNA-control or shRNA- ARID1A stable transfection , and HCT116 control or ARID1A knockout by CRISPR-Cas9 (Horizon Discovery) were used to evaluate the effect of ARID1A loss on NM IIA expression and phosphorylation, and on cell migration by in vitro scratch assay with time lapse imaging. Results: Scaffold analysis of peptide spectra identified NM IIA with > 99% probability in the ARID1A immunopurified protein complex. In the ARID1A wildtype cell lines ES2 and KLE, endogenous NM IIA co-immunoprecipitated with ARID1A and vice versa. ES2 sh ARID1A cells had decreased total and phosphorylated NM IIA expression, and impaired cell migration compared to control cells. Similarly, HCT116 ARID1A homozygous knockout cells had impaired cell migration compared with HCT116 control cells. Conclusions: We report for the first time that ARID1A interacts with NM IIA to regulate cancer cell motility. Further investigation is ongoing to elucidate the significance of this newly identified function of ARID1A.

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Liu, Xiong, Neil Billington, Shi Shu, Shu-Hua Yu, Grzegorz Piszczek, James R. Sellers, and Edward D. Korn. "Effect of ATP and regulatory light-chain phosphorylation on the polymerization of mammalian nonmuscle myosin II." Proceedings of the National Academy of Sciences 114, no. 32 (July 24, 2017): E6516—E6525. http://dx.doi.org/10.1073/pnas.1702375114.

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Addition of 1 mM ATP substantially reduces the light scattering of solutions of polymerized unphosphorylated nonmuscle myosin IIs (NM2s), and this is reversed by phosphorylation of the regulatory light chain (RLC). It has been proposed that these changes result from substantial depolymerization of unphosphorylated NM2 filaments to monomers upon addition of ATP, and filament repolymerization upon RLC-phosphorylation. We now show that the differences in myosin monomer concentration of RLC-unphosphorylated and -phosphorylated recombinant mammalian NM2A, NM2B, and NM2C polymerized in the presence of ATP are much too small to explain their substantial differences in light scattering. Rather, we find that the decrease in light scattering upon addition of ATP to polymerized unphosphorylated NM2s correlates with the formation of dimers, tetramers, and hexamers, in addition to monomers, an increase in length, and decrease in width of the bare zones of RLC-unphosphorylated filaments. Both effects of ATP addition are reversed by phosphorylation of the RLC. Our data also suggest that, contrary to previous models, assembly of RLC-phosphorylated NM2s at physiological ionic strength proceeds from folded monomers to folded antiparallel dimers, tetramers, and hexamers that unfold and polymerize into antiparallel filaments. This model could explain the dynamic relocalization of NM2 filaments in vivo by dephosphorylation of RLC-phosphorylated filaments, disassembly of the dephosphorylated filaments to folded monomers, dimers, and small oligomers, followed by diffusion of these species, and reassembly of filaments at the new location following rephosphorylation of the RLC.

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Halder, Debdatta, Shekhar Saha, Raman K. Singh, Indranil Ghosh, Ditipriya Mallick, Sumit K. Dey, Arijit Ghosh, Benu Brata Das, Somiranjan Ghosh, and Siddhartha S. Jana. "Nonmuscle myosin IIA and IIB differentially modulate migration and alter gene expression in primary mouse tumorigenic cells." Molecular Biology of the Cell 30, no. 12 (June 2019): 1463–76. http://dx.doi.org/10.1091/mbc.e18-12-0790.

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Though many cancers are known to show up-regulation of nonmuscle myosin (NM) IIA and IIB, the mechanism by which NMIIs aid in cancer development remains unexplored. Here we demonstrate that tumor-generating, fibroblast-like cells isolated from 3-methylcholanthrene (3MC)-induced murine tumor exhibit distinct phospho-dependent localization of NMIIA and NMIIB at the perinuclear area and tip of the filopodia and affect cell migration differentially. While NMIIA-KD affects protrusion dynamics and increases cell directionality, NMIIB-KD lowers migration speed and increases filopodial branching. Strategically located NMIIs at the perinuclear area colocalize with the linker of nucleoskeleton and cytoskeleton (LINC) protein Nesprin2 and maintain the integrity of the nuclear-actin cap. Interestingly, knockdown of NMIIs results in altered expression of genes involved in epithelial-to-mesenchymal transition, angiogenesis, and cellular senescence. NMIIB-KD cells display down-regulation of Gsc and Serpinb2, which is strikingly similar to Nesprin2-KD cells as assessed by quantitative PCR analysis. Further gene network analysis predicts that NMIIA and NMIIB may act on similar pathways but through different regulators. Concomitantly, knockdown of NMIIA or NMIIB lowers the growth rate and tumor volume of 3MC-induced tumor in vivo. Altogether, these results open a new window to further investigate the effect of LINC-associated perinuclear actomyosin complex on mechanoresponsive gene expression in the growing tumor.

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Du, Min, Guozheng Wang, Igor L. Barsukov, Stephane R. Gross, Richard Smith, and Philip S. Rudland. "Direct interaction of metastasis-inducing S100P protein with tubulin causes enhanced cell migration without changes in cell adhesion." Biochemical Journal 477, no. 6 (March 27, 2020): 1159–78. http://dx.doi.org/10.1042/bcj20190644.

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Overexpression of S100P promotes breast cancer metastasis in animals and elevated levels in primary breast cancers are associated with poor patient outcomes. S100P can differentially interact with nonmuscle myosin (NM) isoforms (IIA > IIC > IIB) leading to the redistribution of actomyosin filaments to enhance cell migration. Using COS-7 cells which do not naturally express NMIIA, S100P is now shown to interact directly with α,β-tubulin in vitro and in vivo with an equilibrium Kd of 2–3 × 10−7 M. The overexpressed S100P is located mainly in nuclei and microtubule organising centres (MTOC) and it significantly reduces their number, slows down tubulin polymerisation and enhances cell migration in S100P-induced COS-7 or HeLa cells. It fails, however, to significantly reduce cell adhesion, in contrast with NMIIA-containing S100P-inducible HeLa cells. When taxol is used to stabilise MTs or colchicine to dissociate MTs, S100P's stimulation of migration is abolished. Affinity-chromatography of tryptic digests of α and β-tubulin on S100P-bound beads identifies multiple S100P-binding sites consistent with S100P binding to all four half molecules in gel-overlay assays. When screened by NMR and ITC for interacting with S100P, four chemically synthesised peptides show interactions with low micromolar dissociation constants. The two highest affinity peptides significantly inhibit binding of S100P to α,β-tubulin and, when tagged for cellular entry, also inhibit S100P-induced reduction in tubulin polymerisation and S100P-enhancement of COS-7 or HeLa cell migration. A third peptide incapable of interacting with S100P also fails in this respect. Thus S100P can interact directly with two different cytoskeletal filaments to independently enhance cell migration, the most important step in the metastatic cascade.

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Chen, Xin, Yun-Qian Gao, Yan-Yan Zheng, Wei Wang, Pei Wang, Juan Liang, Wei Zhao, et al. "The intragenic microRNA miR199A1 in the dynamin 2 gene contributes to the pathology of X-linked centronuclear myopathy." Journal of Biological Chemistry 295, no. 26 (April 29, 2020): 8656–67. http://dx.doi.org/10.1074/jbc.ra119.010839.

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Mutations in the myotubularin 1 (MTM1) gene can cause the fatal disease X-linked centronuclear myopathy (XLCNM), but the underlying mechanism is incompletely understood. In this report, using an Mtm1−/y disease model, we found that expression of the intragenic microRNA miR-199a-1 is up-regulated along with that of its host gene, dynamin 2 (Dnm2), in XLCNM skeletal muscle. To assess the role of miR-199a-1 in XLCNM, we crossed miR-199a-1−/− with Mtm1−/y mice and found that the resultant miR-199a-1-Mtm1 double-knockout mice display markers of improved health, as evidenced by lifespans prolonged by 30% and improved muscle strength and histology. Mechanistic analyses showed that miR-199a-1 directly targets nonmuscle myosin IIA (NM IIA) expression and, hence, inhibits muscle postnatal development as well as muscle maturation. Further analysis revealed that increased expression and phosphorylation of signal transducer and activator of transcription 3 (STAT3) up-regulates Dnm2/miR-199a-1 expression in XLCNM muscle. Our results suggest that miR-199a-1 has a critical role in XLCNM pathology and imply that this microRNA could be targeted in therapies to manage XLCNM.

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Weißenbruch, Kai, Justin Grewe, Marc Hippler, Magdalena Fladung, Moritz Tremmel, Kathrin Stricker, Ulrich Sebastian Schwarz, and Martin Bastmeyer. "Distinct roles of nonmuscle myosin II isoforms for establishing tension and elasticity during cell morphodynamics." eLife 10 (August 10, 2021). http://dx.doi.org/10.7554/elife.71888.

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Nonmuscle myosin II (NM II) is an integral part of essential cellular processes, including adhesion and migration. Mammalian cells express up to three isoforms termed NM IIA, B, and C. We used U2OS cells to create CRISPR/Cas9-based knockouts of all three isoforms and analyzed the phenotypes on homogenously coated surfaces, in collagen gels, and on micropatterned substrates. In contrast to homogenously coated surfaces, a structured environment supports a cellular phenotype with invaginated actin arcs even in the absence of NM IIA-induced contractility. A quantitative shape analysis of cells on micropatterns combined with a scale-bridging mathematical model reveals that NM IIA is essential to build up cellular tension during initial stages of force generation, while NM IIB is necessary to elastically stabilize NM IIA-generated tension. A dynamic cell stretch/release experiment in a three-dimensional scaffold confirms these conclusions and in addition reveals a novel role for NM IIC, namely the ability to establish tensional homeostasis.

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Sanger, Joseph W., Jushuo Wang, Jennifer White, and Jean M. Sanger. "Distribution and dynamics of nonmuscle myosins IIs in cardiac and in skeletal muscle cells." FASEB Journal 24, S1 (April 2010). http://dx.doi.org/10.1096/fasebj.24.1_supplement.180.7.

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Li, Xiaofei, Callie McLain, Michael S. Samuel, Michael F. Olson, and Glenn L. Radice. "Actomyosin-mediated cellular tension promotes Yap nuclear translocation and myocardial proliferation through α5 integrin signaling." Development, January 9, 2023. http://dx.doi.org/10.1242/dev.201013.

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The cardiomyocyte phenotypic switch from a proliferative to terminally differentiated state results in the loss of regenerative potential of the mammalian heart shortly after birth. Nonmuscle myosin IIB (NM IIB)-mediated actomyosin contractility regulates cardiomyocyte cytokinesis in the embryonic heart, and NM IIB levels decline after birth suggesting a role for cellular tension in the regulation of cardiomyocyte cell cycle activity in the postnatal heart. To investigate the role of actomyosin contractility in cardiomyocyte cell cycle arrest, we conditionally-activated ROCK2 kinase domain (ROCK2:ER) in the murine postnatal heart. Here we show that α5/β1 integrin and fibronectin matrix increase in response to actomyosin-mediated tension. Moreover, activation of ROCK2:ER promotes nuclear translocation of Yap, a mechanosensitive transcriptional co-activator, and enhances cardiomyocyte proliferation. Finally, we show that reduction of myocardial α5 integrin rescues the myocardial proliferation phenotype in ROCK2:ER hearts. These data demonstrate that cardiomyocytes respond to increase intracellular tension by altering their intercellular contacts in favor of cell-matrix interactions leading to Yap nuclear translocation, thus uncovering a novel function for nonmuscle myosin contractility in promoting cardiomyocyte proliferation in the postnatal heart.

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Liu, Yingqi, Rui Li, Xin-xin Chen, Yubao Zhi, Ruiguang Deng, En-min Zhou, Songlin Qiao, and Gaiping Zhang. "Nonmuscle Myosin Heavy Chain IIA Recognizes Sialic Acids on Sialylated RNA Viruses To Suppress Proinflammatory Responses via the DAP12-Syk Pathway." mBio 10, no. 3 (May 7, 2019). http://dx.doi.org/10.1128/mbio.00574-19.

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ABSTRACT Viral infections induce proinflammatory signaling cascades and inflammatory cytokine production, which is precisely regulated for host benefits. In the current study, we unravel a previously unappreciated role of nonmuscle myosin heavy chain IIA (NMHC-IIA) as a negative regulator in inflammatory responses. We identified that cell surface NMHC-IIA recognized sialic acids on sialylated RNA viruses during early infections and interacted with an immune adaptor DNAX activation protein of 12 kDa (DAP12) to recruit downstream spleen tyrosine kinase (Syk), leading to suppressed virus-triggered proinflammatory responses. More importantly, recognition of sialylated RNA viruses or sialic acid mimics by NMHC-IIA was shown to inhibit lipopolysaccharide (LPS)-induced proinflammatory responses via the DAP12-Syk pathway. These findings uncover a novel negative regulation mechanism of proinflammatory responses and provide a molecular basis to design anti-inflammatory drugs. IMPORTANCE NMHC-IIA, a subunit of nonmuscle myosin IIA (NM-IIA), takes part in diverse physiological processes, including cell movement, cell shape maintenance, and signal transduction. Recently, NMHC-IIA has been demonstrated to be a receptor or factor contributing to viral infections. Here, we identified that NMHC-IIA recognizes sialic acids on sialylated RNA viruses, vesicular stomatitis virus (VSV) and porcine reproductive and respiratory syndrome virus (PRRSV). Upon recognition, NMHC-IIA associates with the transmembrane region of DAP12 to recruit Syk. Activation of the DAP12-Syk pathway impairs the host antiviral proinflammatory cytokine production and signaling cascades. More importantly, sialic acid mimics and sialylated RNA viruses enable the antagonism of LPS-triggered proinflammatory responses through engaging the NMHC-IIA–DAP12-Syk pathway. These results actually support that NMHC-IIA is involved in negative modulation of the host innate immune system, which provides a molecular basis for prevention and control of the sialylated RNA viruses and treatment of inflammatory diseases.

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Taskinen, Maria Emilia, Elisa Närvä, James R. W. Conway, Laura Soto Hinojosa, Sergio Lilla, Anja Mai, Nicola De Franceschi, et al. "MASTL promotes cell contractility and motility through kinase-independent signaling." Journal of Cell Biology 219, no. 6 (April 20, 2020). http://dx.doi.org/10.1083/jcb.201906204.

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Microtubule-associated serine/threonine-protein kinase-like (MASTL) is a mitosis-accelerating kinase with emerging roles in cancer progression. However, possible cell cycle–independent mechanisms behind its oncogenicity remain ambiguous. Here, we identify MASTL as an activator of cell contractility and MRTF-A/SRF (myocardin-related transcription factor A/serum response factor) signaling. Depletion of MASTL increased cell spreading while reducing contractile actin stress fibers in normal and breast cancer cells and strongly impairing breast cancer cell motility and invasion. Transcriptome and proteome profiling revealed MASTL-regulated genes implicated in cell movement and actomyosin contraction, including Rho guanine nucleotide exchange factor 2 (GEF-H1, ARHGEF2) and MRTF-A target genes tropomyosin 4.2 (TPM4), vinculin (VCL), and nonmuscle myosin IIB (NM-2B, MYH10). Mechanistically, MASTL associated with MRTF-A and increased its nuclear retention and transcriptional activity. Importantly, MASTL kinase activity was not required for regulation of cell spreading or MRTF-A/SRF transcriptional activity. Taken together, we present a previously unknown kinase-independent role for MASTL as a regulator of cell adhesion, contractility, and MRTF-A/SRF activity.

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Journal articles on the topic 'Nonmucle Myosin IIs (NM-IIs)'

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