Site-directed mutagenesis of the cytoplasmic domains of the human beta 2-adrenergic receptor. Localization of regions involved in G protein-receptor coupling.

Published

Journal Article

Numerous plasma membrane-bound receptors are coupled to various effectors via a family of guanine nucleotide regulatory proteins (G proteins). Amino acid sequences of these receptors, deduced from cDNA and genomic clones, indicate the presence of seven transmembrane-spanning domains. Alignment of the available amino acid sequences of these G protein-linked receptors reveals striking homologies in regions predicted to lie near the cytoplasmic surface of the cell membrane. As these areas are likely those which interact with G proteins, we reasoned that systematic introduction of non-native sequence into these highly conserved regions of the human beta 2-adrenergic receptor would allow resolution of loci participating directly in receptor-G protein coupling. Based on this strategy, we constructed 19 mutant receptor species comprising substitutions and deletions of native sequence in the putative cytoplasmic domains of human beta 2-adrenergic receptor. By monitoring ligand binding characteristics and receptor-mediated stimulation of adenylyl cyclase, we have determined that the C-terminal portion of the third cytoplasmic loop and the N-terminal segment of the cytoplasmic tail appear to be critical for productive receptor-coupling to G proteins. In addition, we have implicated two other areas of the receptor that possibly play supportive roles in maintaining proper orientation of the G protein binding site. These comprise the second cytoplasmic loop and a conserved cysteine residue in the cytoplasmic tail.

Full Text

Duke Authors

Cited Authors

  • O'Dowd, BF; Hnatowich, M; Regan, JW; Leader, WM; Caron, MG; Lefkowitz, RJ

Published Date

  • November 5, 1988

Published In

Volume / Issue

  • 263 / 31

Start / End Page

  • 15985 - 15992

PubMed ID

  • 2846532

Pubmed Central ID

  • 2846532

International Standard Serial Number (ISSN)

  • 0021-9258

Language

  • eng

Conference Location

  • United States