UMMS Affiliation

Department of Physiology

Publication Date


Document Type



Animals; Antibodies; Mice; Myosin Type II; NIH 3T3 Cells; Phosphorylation; Phosphoserine; Platelet-Derived Growth Factor; Protein Kinase C; Protein Kinase Inhibitors; Receptors, Platelet-Derived Growth Factor; Sensitivity and Specificity


Life Sciences | Medicine and Health Sciences


Phosphorylation of the regulatory light chain of myosin II (MLC(20)) at the activation sites promotes both the motor activity and the filament formation of myosin II, thus playing an important role in various cell motile processes. In contrast, the physiological function of phosphorylation of MLC(20) at the inhibitory sites is unknown. Here we report for the first time the function of the inhibitory site phosphorylation in the cells. We successfully produced the antibodies specifically recognizing the phosphorylation sites of MLC(20) at Ser1, and the platelet-derived growth factor (PDGF)-induced change in the phosphorylation at the Ser1 was monitored. The phosphorylation of MLC(20) at the Ser1 significantly increased during the PDGF-induced actin cytoskeletal reorganization. PDGF disassembled the stress fibers, and this was attenuated with the expression of unphosphorylatable MLC(20) at the Ser1/Ser2 phosphorylation sites. The present results suggest that the down-regulation of myosin II activity achieved by the phosphorylation at the Ser1/Ser2 sites plays an important role in the normal reorganization of actomyosin filaments triggered by PDGF receptor stimulation.

DOI of Published Version



Mol Biol Cell. 2007 Dec;18(12):5081-90. Epub 2007 Oct 10. Link to article on publisher's site

Journal/Book/Conference Title

Molecular biology of the cell

Related Resources

Link to Article in PubMed

PubMed ID




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