Is phosphorylation the main physiological action of myosin light chain kinase?
The 155-kDa component of bovine stomach, which exhibits a strong actomyosin (AM) activating activity and a relatively weak myosin light chain kinase (MLCK) activity, has a strong affinity for the actin filament and the actin-binding site is confined to an 80 amino acid residue on its N-terminal side. This affinity may play a crucial role in AM activation. Some reagents preferentially abolish either the AM-activating effect or MLCK activity. In conclusion, MLCK of the 155-kDa component does not play a fundamental role in activating the AM system as far as the in vitro system is concerned. The possible mechanism of AM activation by the component is discussed.
Ebashi
S
S
National Institute for Physiological Sciences, Aichi, Japan.
Kuwayama
H
H
D000205:Actomyosin / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D002417:Cattle; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation
D000205:Actomyosin; D009219:Myosin-Light-Chain Kinase