Reorganisation of peripheral actin filaments as a prelude to exocytosis.

Evidence is presented, from studies on the adrenal chromaffin cell, that reorganisation of the cortical actin network is necessary to allow granules to reach exocytotic sites in stimulated cells. This reorganisation may involve changes in actin filament cross-linking, assembly and interactions with secretory granule and plasma membranes. The possibility is discussed that cytoskeletal elements including the membrane-binding proteins caldesmon, p70 and p36 may be involved in granule-plasmalemmal interactions immediately prior to exocytosis.