Roles of MRLC kinase during cytokinesis

从HeLa细胞cDNA文库中分离到一个新的肌球蛋白轻链激酶cDNA。推断出的氨基酸序列与介导细胞凋亡的拉链相互作用蛋白激酶（ZIPK）相同（Kawai et al. Mcl.）。细胞。生物工程学报，18,1642-1651,1998)。我们发现HeLa ZIPK磷酸化了myosin II调节轻链。（MRLC）在19号丝氨酸和18号苏氨酸上均以ca^2^+/钙调蛋白独立的方式存在。HeLa ZIPK磷酸化myosin II导致肌动蛋白激活的MgATPase活性激活。HeLa ZIPK是来自非肌肉细胞的第一个在两个位点磷酸化MRLC的激酶。

A novel myosin light chain kinase cDNA was isolated from HeLa cells cDNA library. The deduced amino acid sequence was identical to that of zipper interacting protein kinase (ZIPK) which mediated apoptosis (Kawai et. al. Mcl. Cell. Bxol. 18, 1642-1651, 1998). Here we found that HeLa ZIPK phosphorylated myosin II regulatory light chain. (MRLC) at both serine 19 and threonine 18 in ca^2^+/calmodulin independent manner. Phosphorylation of myosin II by HeLa ZIPK resulted in activation of actin-activated MgATPase activity of myosin II.HeLa ZIPK is the first kinase from nonmuscle cells that phosphorylates MRLC at two sites.