Characterization of the interaction between DARPP-32 and protein phosphatase 1 (PP-1): DARPP-32 peptides antagonize the interaction of PP-1 with binding proteins

Young Guen Kwon, Hsien Bin Huang, Frédéric Desdouits, Jean Antoine Girault, Paul Greengard, Angus C. Nairn

Research output: Contribution to journalArticlepeer-review

100 Citations (Scopus)

Abstract

The catalytic subunit of PP-1 (PP-1C) is potently inhibited (IC50, ≃1 nM) by DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, M(r)32,000), inhibitor-1, and inhibitor-2. The NH2-terminal 50 amino acid residues of DARPP-32 and inhibitor-1 are similar, and phosphorylation of a common threonine residue (Thr-34/Thr-35) is necessary for inhibition of PP-1C. We have characterized further the interaction between DARPP-32 and PP-1C. Using synthetic peptides derived from the NH2-terminal region of DARPP-32, residues 6-11, RKKIQF, have been shown to be required for inhibition of PP- 1C. Peptides containing this motif were able to antagonize the inhibition of PP-1C by phospho-DARPP-32 and phosphoinhibitor-1. The inhibition of PP-1C by inhibitor-2, but not by okadaic acid, microcystin, or calyculin A, was also attenuated by these antagonist peptides. These results together with results from other studies support a model in which two subdomains of phospho-DARPP- 32 interact with PP-1C. The region encompassing phospho-Thr-34 appears to interact with the active site of the enzyme blocking enzyme activity. The region encompassing the RKKIQF motif binds to a domain of PP-1C removed from the active site. Amino acid sequence analysis indicates that basic and hydrophobic features of the RKKIQF motif are conserved in the binding domains of certain PP-1C targeting proteins, suggesting that interaction of inhibitor proteins and targeting proteins may be mutually exclusive.

Original languageEnglish
Pages (from-to)3536-3541
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume94
Issue number8
DOIs
Publication statusPublished - 1997 Apr 15

All Science Journal Classification (ASJC) codes

  • General

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