Exocytosis in adrenal chromaffin cells.
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 Ca2+ signal to be investigated in detail. Ca2+ entry at the plasma membrane appears to be crucial for the activation of exocytosis. Ca2+ 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 Ca2+ stores is sufficient to activate a Ca2+ entry pathway. The elevation of cytosolic Ca2+ 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).
Burgoyne
R D
RD
Department of Physiology, University of Liverpool, UK.
Morgan
A
A
Robinson
I
I
Pender
N
N
Cheek
T R
TR
D000199:Actins / Q000378:metabolism; D000311:Adrenal Glands / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D002838:Chromaffin System / Q000378:metabolism / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology*
D000199:Actins; D002118:Calcium