Synaptotagmin is an inositol polyphosphate binding protein: Isolation and characterization as an ins 1,3,4,5-P4 binding protein

Michio Niinobe, Yoshihide Yamaguchi, Mitsunori Fukuda, Katsuhiko Mikoshiba

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)

Abstract

We isolated a binding protein for inositol 1,3,4,5-tetrakisphosphate (InsP4) from detergent-solubilized mouse cerebellar membrane fractions by sequential column chromatographies. Partial amino acid sequencing of the purified sample revealed that the protein is essentially identical to rat synaptotagmin II, an integral membrane protein of synaptic vesicles. Immunoprecipitation experiment of [3H]lnsP4 binding activity of the purified protein using polyclonal antibody against the C2A domain of rat synaptotagmin II also revealed that mouse synaptotagmin II is the InsP4 binding protein (IP4BP). Scatchard analysis of InsP4 binding to the IP4BP/synaptotagmin indicates a single binding site with a Kd of 30 nM. The present finding that InsP4 binds strongly to synaptotagmin II suggests an important role for inositol polyphosphates in the regulation of neurotransmitter release.

Original languageEnglish
Pages (from-to)1036-1042
Number of pages7
JournalBiochemical and biophysical research communications
Volume205
Issue number2
DOIs
Publication statusPublished - 1994 Dec 15
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Synaptotagmin is an inositol polyphosphate binding protein: Isolation and characterization as an ins 1,3,4,5-P4 binding protein'. Together they form a unique fingerprint.

Cite this