ZIP kinase identified as a novel myosin regulatory light chain kinase in HeLa cells.
A novel myosin light chain kinase (MLCK) cDNA was isolated from a HeLa cell cDNA library. The deduced amino acid sequence was identical to that of a zipper-interacting protein kinase (ZIPK) which mediates apoptosis [Kawai et al. (1998) Mol. Cell. Biol. 18, 1642-1651]. Here we found that HeLa ZIPK phosphorylated the regulatory light chain of myosin II (MRLC) at both serine 19 and threonine 18 in a Ca2+/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 non-muscle MLCK that phosphorylates MRLC at two sites.
Murata-Hori
M
M
Department of Biological Science, Faculty of Science, Hiroshima University, Higashi-Hiroshima, Japan.
Suizu
F
F
Iwasaki
T
T
Kikuchi
A
A
Hosoya
H
H
D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D018076:DNA, Complementary; D064550:Death-Associated Protein Kinases; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; D018076:DNA, Complementary; D064550:Death-Associated Protein Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D009219:Myosin-Light-Chain Kinase