title: Localization of smg p25A/rab3A p25, a small GTP-binding protein, at the active zone of the rat neuromuscular junction.
abstract: smg p25A is a small G protein which has been suggested to regulate neurotransmitter release from the synapses. We investigated here the ultrastructural localization of this small G protein in the rat neuromuscular junction by an immunoperoxidase method. The results showed that smg p25A was distributed non-uniformly on the presynaptic plasma membrane and among the synaptic vesicles with the focal accumulation on the discrete presynaptic sites which corresponded to the active zones, the regions of the presynaptic plasma membrane specialized for the exocytosis of the synaptic vesicles. This unique distribution of smg p25A suggests that it plays an important role in the attachment and fusion of the synaptic vesicles with the active zones.
authors.affiliation: Department of Anatomy, Kobe University School of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mizoguchi
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: M
authors.initials: M
authors.lastname: Masutani
authors.forename: A
authors.initials: A
authors.lastname: Tamekane
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: N
authors.initials: N
authors.lastname: Minami
authors.forename: Y
authors.initials: Y
authors.lastname: Takai
authors.forename: C
authors.initials: C
authors.lastname: Ide
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D005260:Female; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000032:analysis*; D016253:Microscopy, Immunoelectron; D008959:Models, Neurological; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009469:Neuromuscular Junction / Q000502:physiology / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D016708:Synaptophysin / Q000032:analysis*; D020692:rab3 GTP-Binding Proteins
chemical_list: D009419:Nerve Tissue Proteins; D016708:Synaptophysin; D019204:GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins