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Regulation of cardiac insulin receptor function by guanosine nucleotides
Author(s) -
Russ Martina,
Reinauer Hans,
Eckel Jürgen
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81518-5
Subject(s) - nucleotide , guanosine , insulin , chemistry , function (biology) , medicine , endocrinology , receptor , microbiology and biotechnology , biochemistry , biology , gene
The present study examined the effect of GTP‐γ‐S on the function of insulin receptors partially purified from adult rat cardiomyocytes by WGA chromatography. GTP‐γ‐S increased receptor autophosphorylation about two times and fully mimicked the stimulatory action of insulin on poly(Glu:Tyr) phosphorylation with no additional effect of the hormone. The effect of GTP‐γ‐S was specific, dose‐dependent, and due to an increase in the V max of the kinase. In the presence of ATP or AMP‐PNP, insulin significantly enhanced the binding of [ 5 S]GTP‐γ‐S to the partially purified insulin receptor. The findings suggest coupling of the insulin receptor to a G‐protein which may be involved in the regulation of tyrosine kinase activity.