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 Role of Myosin Light Chain Phosphorylation in the Regulation of Cytokinesis

2001 ◽  
Vol 26 (6) ◽  
pp. 639-644 ◽  
Author(s):  
Fumio Matsumura ◽  
Go Totsukawa ◽  
Yoshihiko Yamakita ◽  
Shigeko Yamashiro
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Light Chain Phosphorylation

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.

Evaluation of myosin light chain phosphorylation in isolated pancreatic acini

1988 ◽  
Vol 254 (1) ◽  
pp. G130-G134 ◽  
Author(s):  
D. B. Burnham ◽  
H. D. Soling ◽  
J. A. Williams
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Specific Activity ◽  
Sucrose Solution ◽  
Myosin Light Chain Phosphorylation ◽  
Pancreatic Acini ◽  
Myosin Subunits ◽  
Sepharose 4B ◽  
Stimulation Of

The role of contractile proteins in secretory granule exocytosis was evaluated by determining whether myosin light chain phosphorylation was altered during stimulation of secretion in mouse pancreatic acini. Acinar myosin was purified by extraction into isosmotic sucrose solution containing 40 mM pyrophosphate followed by ammonium sulfate precipitation and Sepharose 4B-CL chromatography. Myosin was eluted as a single peak of K+-EDTA ATPase activity and was purified over 2,000-fold to a final ATPase specific activity of 0.96 mumol.min-1.mg protein-1. Three major myosin subunits of apparent Mr of 200,000, 20,000, and 17,000 were present in the purified myosin preparation. A fourth protein of Mr 21,000 was also present. Purification of myosin from 32P-labeled acini revealed the Mr 200,000, 21,000, and 20,000 proteins to be heavily labeled. The effect of cholecystokinin octapeptide (CCK-8) on myosin phosphorylation was studied after isolation of myosin from 32P-labeled acinar lysates by immunoprecipitation. Treatment of acini for 1-10 min with a concentration of CCK-8 that gives a maximal secretory response caused a 25-40% increase in light chain labeling. Treatment with a supramaximal CCK-8 concentration produced a 50-80% increase in light chain labeling. Phosphorylation of myosin heavy chain was not significantly affected by secretagogue treatment. These results indicate that stimulation of pancreatic acinar secretion is accompanied by an increase in 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 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

The role of myosin light chain phosphorylation in the regulation of contractile activity

1983 ◽  
Vol 11 (2) ◽  
pp. 154-154 ◽  
Author(s):  
J. KENDRICK-JONES ◽  
R. C. SMITH ◽  
R. CRAIG ◽  
W. Z. CANDE ◽  
P. J. TOOTH ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Contractile Activity ◽  
Myosin Light Chain Phosphorylation
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