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Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1.

Publication ,  Journal Article
Connor, JH; Quan, HN; Ramaswamy, NT; Zhang, L; Barik, S; Zheng, J; Cannon, JF; Lee, EY; Shenolikar, S
Published in: J Biol Chem
October 16, 1998

Inhibitor-1 (I-1), a cyclic AMP-regulated phosphoprotein, inhibits protein phosphatase-1 (PP1) activity in response to hormones. The molecular mechanism for PP1 inhibition by I-1 remains unknown. Mutation of nine acidic residues lining a proposed I-1-binding channel in rabbit PP1alpha yielded one mutant (E256A) slightly impaired in its inhibition by I-1, with the IC50 increased by 3-fold, and one mutant (E275R) located in the beta12-beta13 loop that showed 4-fold enhanced inhibition by I-1. Substituting Tyr-272, a proposed binding site for the toxins okadaic acid and microcystin-LR, in the beta12-beta13 loop with Trp, Phe, Asp, Arg, or Ala impaired PP1alpha inhibition by I-1 by 8-10-fold. Chemical mutagenesis of the Saccharomyces cerevisiae PP1 gene (GLC7) yielded 20 point mutations in the PP1 coding region. Two-hybrid analyses and biochemical assays of these yeast enzymes identified four additional residues in the beta12-beta13 loop that were required for PP1 binding and inhibition by I-1. Ten-fold higher concentrations of I-1 were required to inhibit these mutants. Finally, deletion of the beta12-beta13 loop from PP1alpha maintained full enzyme activity, but attenuated inhibition by I-1 by >100-fold. These data identified the beta12-beta13 loop in the PP1 catalytic subunit as a domain that mediates binding and enzyme inhibition by I-1.

Duke Scholars

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

October 16, 1998

Volume

273

Issue

42

Start / End Page

27716 / 27724

Location

United States

Related Subject Headings

  • Proteins
  • Protein Phosphatase 1
  • Phosphoprotein Phosphatases
  • Peptides, Cyclic
  • Okadaic Acid
  • Mutagenesis
  • Models, Molecular
  • Microcystins
  • Marine Toxins
  • Humans
 

Citation

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Connor, J. H., Quan, H. N., Ramaswamy, N. T., Zhang, L., Barik, S., Zheng, J., … Shenolikar, S. (1998). Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1. J Biol Chem, 273(42), 27716–27724. https://doi.org/10.1074/jbc.273.42.27716
Connor, J. H., H. N. Quan, N. T. Ramaswamy, L. Zhang, S. Barik, J. Zheng, J. F. Cannon, E. Y. Lee, and S. Shenolikar. “Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1.J Biol Chem 273, no. 42 (October 16, 1998): 27716–24. https://doi.org/10.1074/jbc.273.42.27716.
Connor JH, Quan HN, Ramaswamy NT, Zhang L, Barik S, Zheng J, et al. Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1. J Biol Chem. 1998 Oct 16;273(42):27716–24.
Connor, J. H., et al. “Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1.J Biol Chem, vol. 273, no. 42, Oct. 1998, pp. 27716–24. Pubmed, doi:10.1074/jbc.273.42.27716.
Connor JH, Quan HN, Ramaswamy NT, Zhang L, Barik S, Zheng J, Cannon JF, Lee EY, Shenolikar S. Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1. J Biol Chem. 1998 Oct 16;273(42):27716–27724.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

October 16, 1998

Volume

273

Issue

42

Start / End Page

27716 / 27724

Location

United States

Related Subject Headings

  • Proteins
  • Protein Phosphatase 1
  • Phosphoprotein Phosphatases
  • Peptides, Cyclic
  • Okadaic Acid
  • Mutagenesis
  • Models, Molecular
  • Microcystins
  • Marine Toxins
  • Humans