Inhibitory effects of ML-9, wortmannin, and Y-27632 on the chemotaxis of vascular smooth muscle cells in response to platelet-derived growth factor-BB

The chemotactic migration, toward platelet-derived growth factor-BE of SM3, a cell line established from rabbit aorta smooth muscle, was examined by the Boyden chamber method. Myosin Light-chain ((MLC) kinase inhibitors ML-9 and wortmannin, and the Rho kinase inhibitor Y-27632 effectively reduced the migration. However, neither membrane ruffling nor the phosphorylation of MLC was inhibited concomitantly. The reduction is discussed with reference to a novel property of MLC kinase, which stimulates myosin ATPase activity without phosphorylating MLC [Ye ct al, (1999) Proc. Natl. Acad. Sci. USA 96, 6666-6671].