UMMS Affiliation

Dept. of Physiology

Publication Date


Document Type



Animals; 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




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.

DOI of Published Version



J Cell Biol. 2004 Apr 26;165(2):243-54. Epub 2004 Apr 19. Link to article on publisher's site

Journal/Book/Conference Title

The Journal of cell biology

Related Resources

Link to Article in PubMed

PubMed ID


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Physiology Commons