The G-protein-coupled receptor phosphatase: a protein phosphatase type 2A with a distinct subcellular distribution and substrate specificity.

Published

Journal Article

Phosphorylation of G-protein-coupled receptors plays an important role in regulating their function. In this study the G-protein-coupled receptor phosphatase (GRP) capable of dephosphorylating G-protein-coupled receptor kinase-phosphorylated receptors is described. The GRP activity of bovine brain is a latent oligomeric form of protein phosphatase type 2A (PP-2A) exclusively associated with the particulate fraction. GRP activity is observed only when assayed in the presence of protamine or when phosphatase-containing fractions are subjected to freeze/thaw treatment under reducing conditions. Consistent with its identification as a member of the PP-2A family, the GRP is potently inhibited by okadaic acid but not by I-2, the specific inhibitor of protein phosphatase type 1. Solubilization of the membrane-associated GRP followed by gel filtration in the absence of detergent yields a 150-kDa peak of latent receptor phosphatase activity. Western blot analysis of this phosphatase reveals a likely subunit composition of AB alpha C. PP-2A of this subunit composition has previously been characterized as a soluble enzyme, yet negligible soluble GRP activity was observed. The subcellular distribution and substrate specificity of the GRP suggests significant differences between it and previously characterized forms of PP-2A.

Full Text

Duke Authors

Cited Authors

  • Pitcher, JA; Payne, ES; Csortos, C; DePaoli-Roach, AA; Lefkowitz, RJ

Published Date

  • August 1995

Published In

Volume / Issue

  • 92 / 18

Start / End Page

  • 8343 - 8347

PubMed ID

  • 7667292

Pubmed Central ID

  • 7667292

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.92.18.8343

Language

  • eng