Reference: Connor JH, et al. (1998) Inhibitor-1 interaction domain that mediates the inhibition of protein phosphatase-1. J Biol Chem 273(42):27716-24

Reference Help

Abstract

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.

Reference Type
Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, P.H.S. | Comparative Study
Authors
Connor JH, Quan HN, Ramaswamy NT, Zhang L, Barik S, Zheng J, Cannon JF, Lee EY, Shenolikar S
Primary Lit For
Additional Lit For
Review For

Interaction Annotations

Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations

Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations

Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations

Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference