Gelsolin is Ca2+-sensitive regulator of actomyosin system in platelet.

Effects of gelsolin on the actomyosin system in platelet have been studied. MgATPase activity of platelet actomyosin is enhanced up to two folds by 200 nM of platelet gelsolin in the presence, but not in the absence of Ca ion. The half maximum enhancement is observed at the concentration of Ca2+ around 10(-5) M. The effect of gelsolin to enhance the ATPase activity of actomyosin is potentiated by tropomyosin, which is a Ca2+-insensitive actomyosin enhancer. The results indicate that gelsolin may control the activity of actomyosin system in platelets.