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


Autoria(s): Pitcher, JA; Payne, ES; Csortos, C; DePaoli-Roach, AA; Lefkowitz, RJ
Data(s)

29/08/1995

Formato

8343 - 8347

Identificador

http://www.ncbi.nlm.nih.gov/pubmed/7667292

Proc Natl Acad Sci U S A, 1995, 92 (18), pp. 8343 - 8347

0027-8424

http://hdl.handle.net/10161/7839

Relação

Proc Natl Acad Sci U S A

10.1073/pnas.92.18.8343

Tipo

Journal Article

Cobertura

United States

Resumo

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.

Idioma(s)

ENG

Palavras-Chave #Animals #Blotting, Western #Brain #Cattle #Cell Membrane #Chromatography, Gel #GTP-Binding Proteins #Humans #Phosphoprotein Phosphatases #Receptor Protein-Tyrosine Kinases #Receptors, Cell Surface #Spodoptera #Subcellular Fractions #Substrate Specificity