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GTP‐binding protein‐activator sequences in the insulin receptor
Author(s) -
Okamoto Toshimi,
Okamoto Takashi,
Murayama Yoshitake,
Hayashi Yujiro,
Ogata Etsuro,
Nishimoto Ikuo
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)81700-a
Subject(s) - autophosphorylation , insulin receptor , activator (genetics) , phosphorylation , tyrosine , g protein , tyrosine phosphorylation , biochemistry , chemistry , insulin , receptor , biology , microbiology and biotechnology , insulin resistance , endocrinology , protein kinase a
Some functions of the insulin receptor (insR) are assumed to be mediated by pertussis toxin‐sensitive G i /G o . proteins. Here we have located G‐protein‐activator domains in the cytoplasmic region of the human insR. We searched the sequence of insR and found three candidate regions at residues 1039‐1061, 1147‐1168 and 1325‐1345, referred to as ISRP 1, ISRP2 and ISRP3, respectively. Among them, the G i /G o ‐activating function was observed only in peptide ISRP3. ISRP1 specifically activated G 3 , whereas ISRP2 had no effect on G proteins. ISRP2 and ISRP3 contained five of six autophosphorylated tyrosine residues in insR. After tyrosine phosphorylation, ISRP2 showed specific G 1 ‐activating function, and ISRP3 potentiated its ability and became capable of activating G proteins generally. This is the first study that specifies G‐protein‐activator domains in insR and describes their modification by autophosphorylation.