Exocytosis relating proteins in the nervous system.
Hypothetical models of the molecular mechanism underlying presynaptic exocytosis were reviewed and the exocytosis relating proteins were categorized into four groups: docking, anchoring, fusion and inhibiting proteins. HPC-1/syntaxin, an axonal membrane protein, was classified as an anchoring protein, not as the vesicle docking protein, because electron microscopic study using cryoimmunogold technique revealed that HPC-1 distributed over the entire axonal membrane, where the synaptic vesicles were not 'docked' to the membrane. Since selective toxin or antibody against HPC-1 affected exocytosis, HPC-1 might be a necessary component for the exocytosis, but HPC-1 by itself seemed to have no ability to bind synaptic vesicles to the membrane in vivo. The molecular mechanism for Ca-dependent, rapid exocytosis and possible roles of the exocytosis relating proteins in the neurite morphogenesis are discussed.
Yamaguchi
K
K
Department of Physiology II, Kyorin University, School of Medicine, Tokyo, Japan.
Akagawa
K
K
D000595:Amino Acid Sequence; D000818:Animals; D005089:Exocytosis / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D008959:Models, Neurological; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009424:Nervous System Physiological Phenomena; D016501:Neurites / Q000502:physiology; D050765:Qa-SNARE Proteins; D050827:Syntaxin 1
D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; C494212:STX1A protein, human; D050827:Syntaxin 1