Calcium mobilization is required for nuclear vesicle fusion in vitro: Implications for membrane traffic and IP3 receptor function

Kathleen M C Sullivan, William B. Busa, Katherine Lee Wilson

Research output: Contribution to journalArticle

Abstract

We studied the fusion of nuclear vesicles bound to chromatin in Xenopus egg extracts. Fusion was inhibited by 5 mM BAPTA, a Ca2+ buffer that suppresses cytosolic [Ca2+] gradients. The BAPTA-inhibited step in fusion was biochemically distinct from, and occurred later than, the GTPγS-sensitive step mediated by the monomeric GTPase, ADP-ribosylation factor. Exogenous inositol 1,4,5-trisphosphate (IP3), which triggers Ca2+ release from lumenal stores via IP3 receptors, stimulated fusion in the presence of BAPTA. This rescue was specific, because inositol 1,3,4-trisphosphate had no effect. Heparin, a potent antagonist of IP3 receptors, independently blocked fusion in an IP3-reversible manner. We suggest that phosphoinositide signaling may regulate nuclear vesicle fusion.

Original languageEnglish (US)
Pages (from-to)1411-1422
Number of pages12
JournalCell
Volume73
Issue number7
DOIs
StatePublished - Jul 2 1993

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Nuclear Fusion
Inositol 1,4,5-Trisphosphate Receptors
Fusion reactions
Calcium
Membranes
ADP-Ribosylation Factors
Inositol 1,4,5-Trisphosphate
GTP Phosphohydrolases
Xenopus
Phosphatidylinositols
Chromatin
Ovum
Heparin
Buffers
1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
In Vitro Techniques

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

Cite this

Calcium mobilization is required for nuclear vesicle fusion in vitro : Implications for membrane traffic and IP3 receptor function. / Sullivan, Kathleen M C; Busa, William B.; Wilson, Katherine Lee.

In: Cell, Vol. 73, No. 7, 02.07.1993, p. 1411-1422.

Research output: Contribution to journalArticle

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