Reorganization of the subplasmalemmal cytoskeleton in association with exocytosis in rat mast cells

Abstract

The subplasmalernmal cytoskeleton in mast cells has been studied by scanning electron microscopy of the internal side of the plasma membrane. Rearrangement of the dense subplasmalemmal network of actin filaments took place following cell activation by compound 48/80 and secretion of histamine. The rearrangement was a withdrawal of the subplasmalemmal cytoskeleton from the exocytotic sites and the development of bare, filament-free areas around the sites. In calciumdepleted mast cells we demonstrated a dense network that was difficult to break. Activation of the calciumdepleted cells by compound 48/80 did not induce rearrangement of the network, and in parallel there was no secretion of histamine.