Protein kinase C-mediated interphase lamin B phosphorylation and solubilization

Philippe Collas, Larry Thompson, Alan P. Fields, Dominic L. Poccia, Jean Claude Courvalin

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

Disassembly of the sperm nuclear envelope at fertilization is one of the earliest events in the development of the male pronucleus. We report that nuclear lamina disassembly in interphase sea urchin egg cytosol is a result of lamin B phosphorylation mediated by protein kinase C (PKC). Lamin B of permeabilized sea urchin sperm nuclei incubated in fertilized egg G1 phase cytosolic extract is phosphorylated within 1 min of incubation and solubilized prior to sperm chromatin decondensation. Phosphorylation is Ca2+-dependent. It is reversibly inhibited by the PKC-specific inhibitor chelerythrine, a PKC pseudosubstrate inhibitor peptide, and a PKC substrate peptide, but not by inhibitors of PKA, p34(cdc2) or calmodulin kinase II. Phosphorylation is inhibited by immunodepletion of cytosolic PKC and restored by addition of purified rat brain PKC. Sperm lamin B is a substrate for rat brain PKC in vitro, resulting in lamin B solubilization. Two-dimensional phosphopeptide maps of lamin B phosphorylated by the cytosolic kinase and by purified rat PKC are virtually identical. These data suggest that PKC is the major kinase required for interphase disassembly of the sperm lamina.

Original languageEnglish (US)
Pages (from-to)21274-21280
Number of pages7
JournalJournal of Biological Chemistry
Volume272
Issue number34
DOIs
StatePublished - Aug 22 1997

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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