Phosphorylation by MAPKAP kinase 2 activates Mg(2+)-ATPase activity of myosin II.

Mitogen-activated protein kinase activated protein (MAPKAP) kinase-2 was found to phosphorylate the regulatory light chain of myosin II (MRLC) in vitro in the absence of Ca2+/calmodulin. The tryptic peptides recovered from the MRLC phosphorylated by MAPKAP kinase-2 were identical to the phosphopeptides recovered from myosin light chain kinase (MLCK… (More)