In order to examine the mechanisms underlying smooth-muscle cell proliferation, we investigated effect of platelet-derived growth factor (PDGF) dimers on proliferation of rabbit vascular smooth-muscle cells (VSMCs) and also involvement of phospholipase C (PLC) isoforms in the signal transduction. PDGF-BB and -AB, but not -AA, stimulated cell proliferation and intracellular production of inositol trisphosphate. Northern and Western analyses demonstrated that VSMCs mainly expressed PLC-gamma 2 and PLC-delta 1 among four PLC isoforms tested. A number of cellular proteins, including PLC-gamma 2, but not PLC-delta 1, were phosphorylated on a tyrosine residue by the stimulation of either PDGF-BB or -AB. These results suggest a functional association of PDGF receptor and PLC-gamma 2 that might be responsible for PDGF-dependent VSMC growth. In addition, the expression of PLC-gamma 2 was extremely low in the primary VSMC cultures and was induced during further cultivation of the primary cultures, indicating that an acquisition of PDGF-signal-transducing components, including PLC-gamma 2, may be an important step for proliferation of smooth-muscle cells.
Evidence for involvement of phospholipase C-γ2 in signal transduction of platelet-derived growth factor in vascular smooth-muscle cells
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Y Homma, H Sakamoto, M Tsunoda, M Aoki, T Takenawa, T Ooyama; Evidence for involvement of phospholipase C-γ2 in signal transduction of platelet-derived growth factor in vascular smooth-muscle cells. Biochem J 15 March 1993; 290 (3): 649–653. doi: https://doi.org/10.1042/bj2900649
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