The molecular machinery for fast and slow neurosecretion.
Recent studies indicate that the molecular machinery for synaptic vesicle docking and fusion consists of a triad of botulinum/tetanus neurotoxin substrates (synaptobrevin, syntaxin, SNAP-25) that are homologues of proteins required for constitutive secretion. Proposed low-affinity Ca2+ sensors that regulate exocytosis remain to be identified, although recent studies on synaptotagmin suggest that it, along with other proteins, could play this role. Regulated peptide secretion from dense-core granules has been found to utilize a similar machinery for docking/fusion, and recent studies indicate that this pathway involves a pre-docking step that is regulated by a higher affinity Ca2+ sensor.
Department of Biochemistry, University of Wisconsin, Madison 53706.
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Martin
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins; D003600:Cytosol / Q000378:metabolism; D005089:Exocytosis; D006801:Humans; D008562:Membrane Glycoproteins / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000502:physiology; D009420:Nervous System / Q000378:metabolism*; D009474:Neurons / Q000502:physiology; D009498:Neurotoxins / Q000494:pharmacology; D013572:Synaptic Vesicles / Q000502:physiology; D050857:Synaptotagmins
D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D050857:Synaptotagmins; D002118:Calcium