Phosphoprotein phosphatase inhibitor-2 is phosphorylated at both serine and threonine residues in mouse diaphragm

Anna A. DePaoli-Roach, Fook Thean Lee

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Phosphoprotein phosphatase inhibitor-2 (i-2) was rapidly isolated from mouse diaphragm extracts by the use of specific antibodies. The i-2 so obtained was associated with ATP-Mg and Fa/GSK-3 dependent phosphatase activity, supporting the idea that i-2 is in fact a component of this form of phosphatase. Inhibitor-2 isolated from diaphragms incubated with [32P]phosphate contained both phosphoserine (~ 90%) and phosphothreonine (~ 10%). Therefore, i-2 is multiply phosphorylated in mouse diaphragm and the potential exists for control of the ATP-Mg-dependent phosphatase via multiple phosphorylation sites in vivo.

Original languageEnglish (US)
Pages (from-to)430-432
Number of pages3
JournalFEBS Letters
Issue number2
StatePublished - Apr 22 1985



  • Antibody
  • ATP-Mg-dependent phosphatase
  • Inhibitor-2
  • Mouse diaphragm
  • Protein phosphorylation
  • Type 1 phosphatase

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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