Synaptotagmin I and IV define distinct populations of neuronal transport vesicles

Frédérique Berton, Véronique Cornet, Cécile Iborra, Juan Garrido, Bénédicte Dargent, Mitsunori Fukuda, Michael Seagar, Béatrice Marquèze

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)

Abstract

Mammalian synaptotagmins constitute a multigene family of at least 11 membrane proteins. We have characterized synaptotagmin IV using antibodies directed against the C2A domain of the protein. Antibodies reacted specifically with a protein band that migrated as a 41-44 kDa doublet. Synaptotagmin IV expression was regulated throughout development. A strong decrease in the amount detected by Western blotting occurred between postnatal day 5 and adulthood, in agreement with studies on the expression of synaptotagmin IV transcripts. In subcellular fractionation, synaptotagmin IV was not detected in the synaptic vesicle-enriched fraction. Immunofluorescence microscopy was concordant with this finding. In 6-day-old rat cerebellum and cultured hippocampal neurons the subcellular distribution of synaptotagmin IV was clearly different from that of synaptotagmin I. Synaptotagmin IV displayed a punctate non-polarized distribution on neuronal extensions, whereas synaptotagmin I staining was essentially synaptic. Synaptotagmin IV staining was also observed in the soma in strong perinuclear fluorescent puncta superimposed on that of Golgi/TGN markers. Furthermore, synaptotagmin IV was seen in the proximal part of the growth cone domain and not in the microfilament-rich region which includes filopodia. Co-localizations with the adhesion molecules vinculin and zyxin at the proximal part of growth cones were observed. Synaptotagmin IV may thus be involved in the regulation of specific membrane-trafficking pathways during brain development.

Original languageEnglish
Pages (from-to)1294-1302
Number of pages9
JournalEuropean Journal of Neuroscience
Volume12
Issue number4
DOIs
Publication statusPublished - 2000 May 9
Externally publishedYes

Keywords

  • Development
  • Golgi
  • Growth cone
  • Rat synaptotagmin
  • Synaptic vesicle

ASJC Scopus subject areas

  • Neuroscience(all)

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