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Regulation of cardiac insulin receptor function by guanosine nucleotides
Author(s) -
Russ Martina,
Reinauer Hans,
Eckel Jürgen
Publication year - 1992
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(92)81464-w
Subject(s) - autophosphorylation , gtp' , insulin receptor , insulin , insulin receptor substrate , guanosine , receptor , irs2 , chemistry , medicine , endocrinology , biochemistry , biology , phosphorylation , protein kinase a , insulin resistance , enzyme
The present study examined the effect of [ 35 S]GTP on the function of insulin receptors partially purified from adult rat cardiomyocytes by WGA chromatography. [ 35 S]GTP 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 [ 35 S]GTP 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 [ 35 S]GTP 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.