The effect of myosin light chain phosphorylation on the actin-stimulated ATPase activity of myosin minifilaments.
It has been shown that in the absence of KCl, the actin-stimulated Mg2+-ATPase activity of rabbit skeletal myosin minifilaments with phosphorylated regulatory lights chains (LC2) exceeds 3-4-fold that of myosin minifilaments with dephosphorylated LC2. Addition of KCl leads to a decrease in the difference between the two ATPase activities. LC2 phosphorylation considerably increases the rate of ATPase reaction and only slightly decreases the affinity of myosin minifilaments for F-actin. It is suggested that the unusual effect of LC2 phosphorylation on the kinetic parameters of the actin-stimulated ATPase reaction of myosin minifilaments can be accounted for by its influence on the interaction between myosin heads which results in the ordered self-assembly of minifilaments.
D000199:Actins / Q000494:pharmacology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D007700:Kinetics; D009132:Muscles / Q000032:analysis; D009218:Myosins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits
D000199:Actins; D010750:Phosphoproteins; D011189:Potassium Chloride; D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins