ZIP kinase is responsible for the phosphorylation of myosin II and necessary for cell motility in mammalian fibroblasts
Komatsu, Satoshi ; Ikebe, Mitsuo
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Keywords
Antibodies, Phospho-Specific
Apoptosis Regulatory Proteins
Calcium-Calmodulin-Dependent Protein Kinases
Cell Line
Cell Movement
Cell Polarity
Enzyme Inhibitors
Fibroblasts
Leucine Zippers
Myosin Light Chains
Myosin Type II
Myosin-Light-Chain Kinase
Phosphorylation
Protein-Serine-Threonine Kinases
RNA Interference
Subcellular Fractions
Physiology
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Abstract
Reorganization of actomyosin is an essential process for cell migration and myosin regulatory light chain (MLC20) phosphorylation plays a key role in this process. Here, we found that zipper-interacting protein (ZIP) kinase plays a predominant role in myosin II phosphorylation in mammalian fibroblasts. Using two phosphorylation site-specific antibodies, we demonstrated that a significant portion of the phosphorylated MLC20 is diphosphorylated and that the localization of mono- and diphosphorylated myosin is different from each other. The kinase responsible for the phosphorylation was ZIP kinase because (a) the kinase in the cell extracts phosphorylated Ser19 and Thr18 of MLC20 with similar potency; (b) immunodepletion of ZIP kinase from the cell extracts markedly diminished its myosin II kinase activity; and (c) disruption of ZIP kinase expression by RNA interference diminished myosin phosphorylation, and resulted in the defect of cell polarity and migration efficiency. These results suggest that ZIP kinase is critical for myosin phosphorylation and necessary for cell motile processes in mammalian fibroblasts.
Source
J Cell Biol. 2004 Apr 26;165(2):243-54. Epub 2004 Apr 19. Link to article on publisher's site