Coupling cofactor--a novel regulatory component in G protein-mediated signalling?

C Nanoff; M Freissmuth

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PubMed · 9727497

Coupling cofactor--a novel regulatory component in G protein-mediated signalling?

C Nanoff·M Freissmuth

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Abstract

The model for studying the mechanism of G protein-mediated signalling cannot account for the observation that high-affinity binding of agonists to many different receptors is not dissociated by the addition of high concentrations of guanine nucleotides. Using the cerebral A1-adenosine receptor as a model system, we have recently identified a component which is responsible for this phenomenon. This protein, termed the coupling cofactor, can be solubilized from brain membranes and chromatographically resolved from both the G proteins and the receptor. Following reconstitution into appropriate acceptor membranes, the coupling cofactor confers resistance of high-affinity agonist binding to guanine nucleotides. The coupling cofactor acts as a brake and limits receptor-dependent signal amplification; in addition, it is a candidate for participating in the higher level organization of receptors and G proteins in membranes and in the membrane-delimited cross-talk between individual receptors. Here, we present a working hypothesis on the possible biological roles of the coupling cofactor.

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Animals GTP-Binding Proteins Humans Receptors, Cell Surface Signal Transduction Journal Article Research Support, Non-U.S. Gov't Review

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C Nanoff, M Freissmuth. 1997. Coupling cofactor--a novel regulatory component in G protein-mediated signalling?. https://pubmed.ncbi.nlm.nih.gov/9727497/

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