scholarly journals An Alternatively Spliced Isoform of Non-muscle Myosin II-C Is Not Regulated by Myosin Light Chain Phosphorylation

2009 ◽  
Vol 284 (17) ◽  
pp. 11563-11571 ◽  
Author(s):  
Siddhartha S. Jana ◽  
Kye-Young Kim ◽  
Jian Mao ◽  
Sachiyo Kawamoto ◽  
James R. Sellers ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Myosin Light Chain Phosphorylation ◽  
Alternatively Spliced ◽  
Muscle Myosin

Blebbistatin, a myosin II inhibitor, suppresses contraction and disrupts contractile filaments organization of skinned taenia cecum from guinea pig

2010 ◽  
Vol 298 (5) ◽  
pp. C1118-C1126 ◽  
Author(s):  
Masaru Watanabe ◽  
Masatoshi Yumoto ◽  
Hideyuki Tanaka ◽  
Hon Hui Wang ◽  
Takeshi Katayama ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Smooth Muscle Contraction ◽  
Myosin Light Chain Phosphorylation ◽  
Thin Filaments ◽  
Tension Development

To explore the precise mechanisms of the inhibitory effects of blebbistatin, a potent inhibitor of myosin II, on smooth muscle contraction, we studied the blebbistatin effects on the mechanical properties and the structure of contractile filaments of skinned (cell membrane permeabilized) preparations from guinea pig taenia cecum. Blebbistatin at 10 μM or higher suppressed Ca2+-induced tension development at any given Ca2+ concentration but had little effects on the Ca2+-induced myosin light chain phosphorylation. Blebbistatin also suppressed the 10 and 2.75 mM Mg2+-induced, “myosin light chain phosphorylation-independent” tension development at more than 10 μM. Furthermore, blebbistatin induced conformational change of smooth muscle myosin (SMM) and disrupted arrangement of SMM and thin filaments, resulting in inhibition of actin-SMM interaction irrespective of activation with Ca2+. In addition, blebbistatin partially inhibited Mg2+-ATPase activity of native actomyosin from guinea pig taenia cecum at around 10 μM. These results suggested that blebbistatin suppressed skinned smooth muscle contraction through disruption of structure of SMM by the agent.

scholarly journals Non-muscle Myosin II and Myosin Light Chain Kinase Are Downstream Targets for Vasopressin Signaling in the Renal Collecting Duct

2004 ◽  
Vol 279 (47) ◽  
pp. 49026-49035 ◽  
Author(s):  
Chung-Lin Chou ◽  
Birgitte M. Christensen ◽  
Sebastian Frische ◽  
Henrik Vorum ◽  
Ravi A. Desai ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Collecting Duct ◽  
Myosin Ii ◽  
Downstream Targets ◽  
Renal Collecting Duct ◽  
Muscle Myosin

Role of myosin II activity and the regulation of myosin light chain phosphorylation in astrocytomas

2007 ◽  
Vol 65 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Bodour Salhia ◽  
Jeong Hyun Hwang ◽  
Christian A. Smith ◽  
Mitsutoshi Nakada ◽  
Fiona Rutka ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Myosin Light Chain Phosphorylation

scholarly journals Rap1 Activation in Collagen Phagocytosis Is Dependent on Nonmuscle Myosin II-A

2008 ◽  
Vol 19 (12) ◽  
pp. 5032-5046 ◽  
Author(s):  
Pamela D. Arora ◽  
Mary Anne Conti ◽  
Shoshana Ravid ◽  
David B. Sacks ◽  
Andras Kapus ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Cell Attachment ◽  
Myosin Ii ◽  
Myosin Light Chain Phosphorylation ◽  
Nonmuscle Myosin ◽  
Permeabilized Cells ◽  
Collagen Phagocytosis ◽  
Rap1 Activation

Rap1 enhances integrin-mediated adhesion but the link between Rap1 activation and integrin function in collagen phagocytosis is not defined. Mass spectrometry of Rap1 immunoprecipitates showed that the association of Rap1 with nonmuscle myosin heavy-chain II-A (NMHC II-A) was enhanced by cell attachment to collagen beads. Rap1 colocalized with NM II-A at collagen bead-binding sites. There was a transient increase in myosin light-chain phosphorylation after collagen-bead binding that was dependent on myosin light-chain kinase but not Rho kinase. Inhibition of myosin light-chain phosphorylation, but not myosin II-A motor activity inhibited collagen-bead binding and Rap activation. In vitro binding assays demonstrated binding of Rap1A to filamentous myosin rods, and in situ staining of permeabilized cells showed that NM II-A filaments colocalized with F-actin at collagen bead sites. Knockdown of NM II-A did not affect talin, actin, or β1-integrin targeting to collagen beads but targeting of Rap1 and vinculin to collagen was inhibited. Conversely, knockdown of Rap1 did not affect localization of NM II-A to beads. We conclude that MLC phosphorylation in response to initial collagen-bead binding promotes NM II-A filament assembly; binding of Rap1 to myosin filaments enables Rap1-dependent integrin activation and enhanced collagen phagocytosis.

scholarly journals Non-muscle myosin II induces disassembly of actin stress fibres independently of myosin light chain dephosphorylation

2011 ◽  
Vol 1 (5) ◽  
pp. 754-766 ◽  
Author(s):  
Tsubasa S. Matsui ◽  
Roland Kaunas ◽  
Makoto Kanzaki ◽  
Masaaki Sato ◽  
Shinji Deguchi
Keyword(s):  
Light Chain ◽  
Actin Filaments ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Physiological Level ◽  
Cell Shortening ◽  
Applied Forces ◽  
Selective Disassembly ◽  
The Individual ◽  
Muscle Myosin

Dynamic remodelling of actin stress fibres (SFs) allows non-muscle cells to adapt to applied forces such as uniaxial cell shortening. However, the mechanism underlying rapid and selective disassembly of SFs oriented in the direction of shortening remains to be elucidated. Here, we investigated how myosin crossbridge cycling induced by MgATP is associated with SF disassembly. Moderate concentrations of MgATP, or [MgATP], induced SF contraction. Meanwhile, at [MgATP] slightly higher than the physiological level, periodic actin patterns emerged along the length of SFs and dispersed within seconds. The actin fragments were diverse in length, but comparable to those in characteristic sarcomeric units of SFs. These results suggest that MgATP-bound non-muscle myosin II dissociates from the individual actin filaments that constitute the sarcomeric units, resulting in unbundling-induced disassembly rather than end-to-end actin depolymerization. This rapid SF disassembly occurred independent of dephosphorylation of myosin light chain. In terms of effects on actin–myosin interactions, a rise in [MgATP] is functionally equivalent to a temporal decrease in the total number of actin–myosin crossbridges. Actin–myosin crossbridges are known to be reduced by an assisting load on myosin. Thus, the present study suggests that reducing the number of actin–myosin crossbridges promotes rapid and orientation-dependent disassembly of SFs after cell shortening.

scholarly journals Distinct Roles of Smooth Muscle and Non-muscle Myosin Light Chain-Mediated Smooth Muscle Contraction

2020 ◽  
Vol 11 ◽  
Author(s):  
Jie Sun ◽  
Yan-Ning Qiao ◽  
Tao Tao ◽  
Wei Zhao ◽  
Li-Sha Wei ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Initial Phase ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Smooth Muscle Contraction ◽  
Myosin Regulatory Light Chain ◽  
Gene Encoding ◽  
Muscle Myosin

Both smooth muscle (SM) and non-muscle (NM) myosin II are expressed in hollow organs such as the bladder and uterus, but their respective roles in contraction and corresponding physiological functions remain to be determined. In this report, we assessed their roles by analyzing mice deficient of Myl9, a gene encoding the SM myosin regulatory light chain (SM RLC). We find that global Myl9-deficient bladders contracted with an apparent sustained phase, despite no initial phase. This sustained contraction was mediated by NM myosin RLC (NM RLC) phosphorylation by myosin light chain kinase (MLCK). NM myosin II was expressed abundantly in the uterus and young mice bladders, of which the force was accordingly sensitive to NM myosin inhibition. Our findings reveal distinct roles of SM RLC and NM RLC in SM contraction.

scholarly journals Anillin Binds Nonmuscle Myosin II and Regulates the Contractile Ring

2005 ◽  
Vol 16 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Aaron F. Straight ◽  
Christine M. Field ◽  
Timothy J. Mitchison
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Cultured Cells ◽  
Contractile Activity ◽  
Myosin Ii ◽  
Human Cells ◽  
Myosin Light Chain Phosphorylation ◽  
Nonmuscle Myosin ◽  
Contractile Ring ◽  
Nonmuscle Myosin Ii

We demonstrate that the contractile ring protein anillin interacts directly with nonmuscle myosin II and that this interaction is regulated by myosin light chain phosphorylation. We show that despite their interaction, anillin and myosin II are independently targeted to the contractile ring. Depletion of anillin in Drosophila or human cultured cells results in cytokinesis failure. Human cells depleted for anillin fail to properly regulate contraction by myosin II late in cytokinesis and fail in abscission. We propose a role for anillin in spatially regulating the contractile activity of myosin II during cytokinesis.

scholarly journals Myosin light chain kinase steady-state kinetics: comparison of smooth muscle myosin II and nonmuscle myosin IIB as substrates

2016 ◽  
Vol 34 (7) ◽  
pp. 469-474 ◽  
Author(s):  
Diego B. Alcala ◽  
Brian D. Haldeman ◽  
Richard K. Brizendine ◽  
Agata K. Krenc ◽  
Josh E. Baker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Smooth Muscle Myosin ◽  
Nonmuscle Myosin ◽  
Steady State Kinetics ◽  
Muscle Myosin

Changes in cardiac muscle myosin light-chain phosphorylation associated with varying inotropic states

1981 ◽  
Vol 25 (3) ◽  
pp. 298-308 ◽  
Author(s):  
Arnold B. Meshkov ◽  
Rita A. Carey ◽  
Alfred A. Bove ◽  
William P. Santamore ◽  
James F. Spann
Keyword(s):  
Cardiac Muscle ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Light Chain Phosphorylation ◽  
Muscle Myosin
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