G-protein binding domains of the angiotensin II AT1A receptors mapped with synthetic peptides selected from the receptor sequence

Hisashi Kai, R. Wayne Alexander, Masuko Ushio-Fukai, P. Reid Lyons, Marjorie Akers, Kathy K. Griendling

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

The vascular angiotensin II type 1 receptor (AT1AR) is a member of the G-protein-coupled receptor superfamily. We mapped the G-protein binding domains of the AT1AR using synthetic peptides selected from the receptor sequence, which interfere with AT1AR-G-protein coupling. Membrane GTPase activity was used as a measure of the functional coupling in rat vascular smooth muscle cells. Peptides corresponding to the N-terminal region of the second intracellular loop (residues 125-137), the N-terminal region of the third intracellular loop (217-227) and the juxtamembranous region of the C-terminal tail (304-316) inhibited angiotensin II-induced GTPase activation by 30%, 30%, and 70%, respectively. The latter two domains (217-227 and 304-316) are predicted to form amphiphilic α-helices. Only the peptide representing residues 217-227 stimulated basal activity (45%). No synthetic peptide had a significant effect on either the number or the affinity of the AT1AR binding. These observations indicate that domains of the second and third regions and the cytoplasmic tail of the AT1AR interact with G-proteins, and that multiple contacts with these receptor domains may be important for binding and activation of the G-proteins.

Original languageEnglish (US)
Pages (from-to)781-787
Number of pages7
JournalBiochemical Journal
Volume332
Issue number3
DOIs
StatePublished - Jun 15 1998
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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