Exocytosis in adrenal chromaffin cells
Burgoyne, R.D.; Morgan, A.; Robinson, I.; Pender, N.; Cheek, T.R.
Journal of Anatomy 183: 309-314
1993
ISSN/ISBN: 0021-8782 PMID: 8300418 Document Number: 412086
Recent advances have led to an increased understanding of the Ca-2+-signalling pathway leading to exocytosis in bovine adrenal chromaffin cells. Video-imaging studies have allowed the temporal and spatial aspects of the Ca-2+ signal to be investigated in detail. Ca-2+ entry at the plasma membrane appears to be crucial for the activation of exocytosis. Ca-2+ can enter through the nicotinic channel or characterised voltage-activated channels, or through other poorly defined pathways due to a variety of agonists. Emptying of internal Ca-2+ stores is sufficient to activate a Ca-2+ entry pathway. The elevation of cytosolic Ca-2+ concentration leads to a reorganisation of the cortical actin network and to the triggering of exocytosis. Studies on permeabilised chromaffin cells have resulted in the identification of some of the proteins that control Ca-2+-dependent exocytosis. These include the peripheral plasma membrane protein annexin II and the cytosolic proteins, protein kinase C and 14-3-3 proteins (Exo1).