title: Synaptophysin and synapsin I as tools for the study of the exo-endocytotic cycle.
abstract: Synaptophysin, an integral protein of the synaptic vesicle membrane, and synapsin I, a phosphoprotein associated with the cytoplasmic side of synaptic vesicles, represent useful markers that allow to follow the movements of the vesicle membrane during recycling. The use of antibodies against these proteins to label nerve terminals during experimental treatments which stimulate secretion has provided evidence that during the exo-endocytotic cycle synaptic vesicles transiently fuse with the axolemma, from which they are specifically recovered. When recycling is blocked, exocytosis leads to the permanent incorporation of the synaptic vesicle membrane into the axolemma and to diffusion of the vesicle components in the plane of the membrane.
authors.affiliation: Bruno Ceccarelli Center for the Study of Peripheral Neuropathies and Neuromuscular Diseases, University of Milano Medical School.
authors.forename: F
authors.initials: F
authors.lastname: Valtorta
authors.forename: F T
authors.initials: FT
authors.lastname: Tarelli
authors.forename: L
authors.initials: L
authors.lastname: Campanati
authors.forename: A
authors.initials: A
authors.lastname: Villa
authors.forename: P
authors.initials: P
authors.lastname: Greengard
mesh_terms: D000818:Animals; D004705:Endocytosis; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D016704:Synapsins; D013572:Synaptic Vesicles / Q000378:metabolism*; D016708:Synaptophysin
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016704:Synapsins; D016708:Synaptophysin