Ca2+ and secretory-vesicle dynamics.
Exocytosis in neurones and neuroendocrine cells is triggered by an increase in the cytosolic concentration of Ca2+, and is followed by endocytotic membrane retrieval. Electrophysiological studies have characterized the nature of the Ca2+ signal that is required for exocytosis, and have defined the Ca(2+)-dependent steps in exocytotic and endocytotic vesicle cycling. In parallel, biochemical approaches have led to the discovery of a range of proteins that appears to function in synaptic- and secretory-vesicle dynamics. The nature of the Ca(2+)-binding proteins, and how they interact with the identified components of the exocytotic and endocytotic machinery, remain key unresolved issues. However, it is apparent that exocytosis involves multiple Ca(2+)-binding proteins with different affinities, and that the Ca2+ sensor involved in the final membrane-fusion step has different affinities for Ca2+ in synapses and neuroendocrine cells.
Burgoyne
R D
RD
Physiological Laboratory, University of Liverpool, UK.
Morgan
A
A
D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000502:physiology; D005089:Exocytosis; D006801:Humans; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology; D009490:Neurosecretory Systems / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D002118:Calcium