Phosphorylation of phosphoprotein phosphatase inhibitor-2 (I-2) in rat fat cells

J. C. Lawrence, Jeffrey Hiken, Barry Burnette, A. A. DePaoli-Roach

Research output: Contribution to journalArticle

17 Scopus citations


Fat cells were incubated with 32Pi for 2 h before the [32P]I-2 was immunoprecipitated, subjected to SDS PAGE, and detected by autoradiography. [32P]I-2 (Mr = 32,000) was not recovered when excess purified I-2 was added with the antiserum or when nonimmune serum was used. Immunoprecipitated I-2 was heat-stable, inhibited phosphatase activity, and could be synergistically phosphorylated by casein kinase II and FA GSK-3. Several times more [32P]phosphoserine than [32P]phosphothreonine was found in I-2 from 32P-labeled cells. Insulin increased the 32P-content of I-2 by as much as 40%, suggesting that phosphorylation of I-2 might be involved in the effect of insulin on stimulating protein dephosphorylation.

Original languageEnglish (US)
Pages (from-to)197-203
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - Jan 15 1988

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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