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

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.

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

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

Role of myosin light-chain phosphorylation in guinea pig gallbladder smooth muscle contraction

1994 ◽  
Vol 266 (3) ◽  
pp. G469-G474 ◽  
Author(s):  
R. J. Washabau ◽  
M. B. Wang ◽  
C. Dorst ◽  
J. P. Ryan
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Smooth Muscle Contraction ◽  
Myosin Light Chain Phosphorylation ◽  
Shortening Velocity ◽  
Cross Bridges ◽  
Isotonic Shortening

In acetylcholine (ACh)-stimulated gallbladder smooth muscle, we have previously shown that phosphorylation of the 20,000-Da myosin light chains is necessary for the initiation of contraction, that myosin is stably phosphorylated at steady state, and that dephosphorylation of cross bridges is not necessary for the slowing of cross-bridge cycling rates during the period of steady-state isometric stress. The present studies were undertaken to determine whether 1) K+ (60 or 80 mM) or cholecystokinin (CCK, 10(-8) M) stimulation is accompanied by changes in myosin light-chain phosphorylation in gallbladder smooth muscle and 2) dephosphorylated noncycling cross bridges exist in K(+)- or CCK-stimulated gallbladder smooth muscle. Isometric stress, isotonic shortening velocity, and myosin light-chain phosphorylation were determined during contraction with K+ or CCK. Steady-state isometric stress was reached within 2.5 min of stimulation with K+ or CCK and was maintained for the duration of the stimulation. Stimulation with K+ or CCK was associated with rapid increases in myosin light-chain phosphorylation and maintenance of myosin light-chain phosphorylation during the stimulation. In contrast, isotonic shortening velocity was maximal at 1 min of stimulation with either K+ or CCK and then declined significantly to values that were only 26-32% of the peak velocity. These data, along with data from previous experiments with ACh, suggest that myosin light-chain phosphorylation is essential in the initiation of contraction in gallbladder smooth muscle, regardless of the source of Ca2+ or of the contractile agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document