scholarly journals 1K1648 Nonmuscle myosin II induces rapid disassembly of stress fibers independently of myosin regulatory light chain dephosphorylation(Cell biology 1,The 49th Annual Meeting of the Biophysical Society of Japan)

2011 ◽  
Vol 51 (supplement) ◽  
pp. S59-S60
Author(s):  
Tsubasa S Matsui ◽  
Masaaki Sato ◽  
Shinji Deguchi
Keyword(s):  
Annual Meeting ◽  
Light Chain ◽  
Cell Biology ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Stress Fibers ◽  
Myosin Regulatory Light Chain ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
Biophysical Society

scholarly journals Mammalian Nonmuscle Myosin II Binds to Anionic Phospholipids with Concomitant Dissociation of the Regulatory Light Chain

2016 ◽  
Vol 291 (48) ◽  
pp. 24828-24837 ◽  
Author(s):  
Xiong Liu ◽  
Shi Shu ◽  
Neil Billington ◽  
Chad D. Williamson ◽  
Shuhua Yu ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Nonmuscle Myosin ◽  
Anionic Phospholipids ◽  
Nonmuscle Myosin Ii

scholarly journals Nonmuscle myosin IIA dynamically guides regulatory light chain phosphorylation and assembly of nonmuscle myosin IIB

2021 ◽  
Author(s):  
Kai Weissenbruch ◽  
Magdalena Fladung ◽  
Justin Grewe ◽  
Laurent Baulesch ◽  
Ulrich Sebastian Schwarz ◽  
...  
Keyword(s):  
Light Chain ◽  
Mammalian Cells ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Force Generation ◽  
Nonmuscle Myosin ◽  
Force Output ◽  
Nonmuscle Myosin Ii ◽  
Phosphorylation Pattern ◽  
Regulatory Light Chain Phosphorylation

Nonmuscle myosin II minifilaments have emerged as central elements for force generation and mechanosensing by mammalian cells. Each minifilament can have a different composition and activity due to the existence of the three nonmuscle myosin II isoforms A, B and C and their respective phosphorylation pattern. We have used CRISPR/Cas9-based knockout cells, quantitative image analysis and mathematical modelling to dissect the dynamic processes that control the formation and activity of heterotypic minifilaments and found a strong asymmetry between isoforms A and B. Loss of NM IIA completely abrogates regulatory light chain phosphorylation and reduces the level of assembled NM IIB. Activated NM IIB preferentially co-assembles into pre-formed NM IIA minifilaments and stabilizes the filament in a force-dependent mechanism. NM IIC is only weakly coupled to these processes. We conclude that NM IIA and B play clearly defined complementary roles during assembly of functional minifilaments. NM IIA is responsible for the formation of nascent pioneer minifilaments. NM IIB incorporates into these and acts as a clutch that limits the force output to prevent excessive NM IIA activity. Together these two isoforms form a balanced system for regulated force generation.

scholarly journals Effect of ATP and regulatory light-chain phosphorylation on the polymerization of mammalian nonmuscle myosin II

2017 ◽  
Vol 114 (32) ◽  
pp. E6516-E6525 ◽  
Author(s):  
Xiong Liu ◽  
Neil Billington ◽  
Shi Shu ◽  
Shu-Hua Yu ◽  
Grzegorz Piszczek ◽  
...  
Keyword(s):  
Light Scattering ◽  
Light Chain ◽  
Myosin Ii ◽  
Monomer Concentration ◽  
Regulatory Light Chain ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
New Location ◽  
Regulatory Light Chain Phosphorylation

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.

scholarly journals Phosphorylation of Nonmuscle myosin II-A regulatory light chain resists Sendai virus fusion with host cells

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Provas Das ◽  
Shekhar Saha ◽  
Sunandini Chandra ◽  
Alakesh Das ◽  
Sumit K. Dey ◽  
...  
Keyword(s):  
Light Chain ◽  
Sendai Virus ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Host Cells ◽  
Nonmuscle Myosin ◽  
Virus Fusion ◽  
Nonmuscle Myosin Ii

scholarly journals The Nonmuscle Myosin Regulatory Light Chain Gene mlc-4 Is Required for Cytokinesis, Anterior-Posterior Polarity, and Body Morphology during Caenorhabditis elegans Embryogenesis

1999 ◽  
Vol 146 (2) ◽  
pp. 439-451 ◽  
Author(s):  
Christopher A. Shelton ◽  
J. Clayton Carter ◽  
Gregory C. Ellis ◽  
Bruce Bowerman
Keyword(s):  
Caenorhabditis Elegans ◽  
Light Chain ◽  
Myosin Ii ◽  
Regulatory Light Chain ◽  
Chain Gene ◽  
Nonmuscle Myosin ◽  
Light Chain Gene ◽  
C Elegans ◽  
Nonmuscle Myosin Ii ◽  
Anterior Posterior

Using RNA-mediated genetic interference in a phenotypic screen, we identified a conserved nonmuscle myosin II regulatory light chain gene in Caenorhabditis elegans, which we name mlc-4. Maternally supplied mlc-4 function is required for cytokinesis during both meiosis and mitosis and for establishment of anterior-posterior (a-p) asymmetries after fertilization. Reducing the function of mlc-4 or nmy-2, a nonmuscle myosin II gene, also leads to a loss of polarized cytoplasmic flow in the C. elegans zygote, supporting models in which cytoplasmic flow may be required to establish a-p differences. Germline P granule localization at the time of cytoplasmic flow is also lost in these embryos, although P granules do become localized to the posterior pole after the first mitosis. This result suggests that a mechanism other than cytoplasmic flow or mlc-4/nmy-2 activity can generate some a-p asymmetries in the C. elegans zygote. By isolating a deletion allele, we show that removing zygotic mlc-4 function results in an elongation phenotype during embryogenesis. An mlc-4/green fluorescent protein transgene is expressed in lateral rows of hypodermal cells and these cells fail to properly change shape in mlc-4 mutant animals during elongation.

scholarly journals Myosin Motors and Not Actin Comets Are Mediators of the Actin-based Golgi-to-Endoplasmic Reticulum Protein Transport

2003 ◽  
Vol 14 (2) ◽  
pp. 445-459 ◽  
Author(s):  
Juan M. Durán ◽  
Ferran Valderrama ◽  
Susana Castel ◽  
Juana Magdalena ◽  
Mónica Tomás ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Light Chain ◽  
Shiga Toxin ◽  
Actin Filaments ◽  
Protein Transport ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
Myosin Motors

We have previously reported that actin filaments are involved in protein transport from the Golgi complex to the endoplasmic reticulum. Herein, we examined whether myosin motors or actin comets mediate this transport. To address this issue we have used, on one hand, a combination of specific inhibitors such as 2,3-butanedione monoxime (BDM) and 1-[5-isoquinoline sulfonyl]-2-methyl piperazine (ML7), which inhibit myosin and the phosphorylation of myosin II by the myosin light chain kinase, respectively; and a mutant of the nonmuscle myosin II regulatory light chain, which cannot be phosphorylated (MRLC2AA). On the other hand, actin comet tails were induced by the overexpression of phosphatidylinositol phosphate 5-kinase. Cells treated with BDM/ML7 or those that express the MRLC2AA mutant revealed a significant reduction in the brefeldin A (BFA)-induced fusion of Golgi enzymes with the endoplasmic reticulum (ER). This delay was not caused by an alteration in the formation of the BFA-induced tubules from the Golgi complex. In addition, the Shiga toxin fragment B transport from the Golgi complex to the ER was also altered. This impairment in the retrograde protein transport was not due to depletion of intracellular calcium stores or to the activation of Rho kinase. Neither the reassembly of the Golgi complex after BFA removal nor VSV-G transport from ER to the Golgi was altered in cells treated with BDM/ML7 or expressing MRLC2AA. Finally, transport carriers containing Shiga toxin did not move into the cytosol at the tips of comet tails of polymerizing actin. Collectively, the results indicate that 1) myosin motors move to transport carriers from the Golgi complex to the ER along actin filaments; 2) nonmuscle myosin II mediates in this process; and 3) actin comets are not involved in retrograde transport.

Essential light chain of Drosophila nonmuscle myosin II

1995 ◽  
Vol 16 (5) ◽  
pp. 491-498 ◽  
Author(s):  
Kevin A. Edwards ◽  
Xiao-Jia Chang ◽  
Daniel P. Kiehart
Keyword(s):  
Light Chain ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Essential Light Chain ◽  
Nonmuscle Myosin Ii

scholarly journals LIMCH1 regulates nonmuscle myosin-II activity and suppresses cell migration

2017 ◽  
Vol 28 (8) ◽  
pp. 1054-1065 ◽  
Author(s):  
Yu-Hung Lin ◽  
Yen-Yi Zhen ◽  
Kun-Yi Chien ◽  
I-Ching Lee ◽  
Wei-Chi Lin ◽  
...  
Keyword(s):  
Cell Migration ◽  
Hela Cells ◽  
Myosin Ii ◽  
Focal Adhesions ◽  
Stress Fiber ◽  
Stress Fibers ◽  
Actin Stress Fiber ◽  
Nonmuscle Myosin ◽  
Head Region ◽  
Nonmuscle Myosin Ii

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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