A role for Ni in the hormonal stimulation of adenylate cyclase.

Published

Journal Article

The best understood system for transduction of extracellular messages into intracellular signals is the hormone receptor-coupled adenylate cyclase. In such systems receptors are functionally coupled to the enzyme by two special proteins, termed the stimulatory and inhibitory guanine nucleotide regulatory proteins (Ns and Ni, respectively). These proteins, thought to mediate, respectively, stimulatory and inhibitory influences on the adenylate cyclase, are members of a larger class of heterotrimeric guanine nucleotide regulatory proteins involved in membrane signal transduction. We have studied the interactions of the various components of the adenylate cyclase system by co-reconstituting pure beta-adrenergic receptors, pure Ns and Ni, and functionally resolved preparations of the catalyst in phospholipid vesicles. In the absence of Ni, beta-adrenergic receptor/Ns-mediated catecholamine stimulation of the enzyme is relatively modest (approximately 1.3-fold). Surprisingly, however, when Ni is also present, stimulation increases dramatically (up to 7-8-fold) because of a greater suppression of basal relative to agonist-stimulated enzyme activity. Thus, Ni may actually be required for maximal agonist stimulation as well as for inhibition of the adenylate cyclase.

Full Text

Duke Authors

Cited Authors

  • Cerione, RA; Staniszewski, C; Caron, MG; Lefkowitz, RJ; Codina, J; Birnbaumer, L

Published Date

  • November 21, 1985

Published In

Volume / Issue

  • 318 / 6043

Start / End Page

  • 293 - 295

PubMed ID

  • 2999605

Pubmed Central ID

  • 2999605

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/318293a0

Language

  • eng

Conference Location

  • England