IGF-I regulates caveolin 1 and IRS1 interaction in caveolae.
Caveolae are hot spots in IGF-I signalling as suggested by the facts that IGF-I receptors localize in caveolae, directly interact with and tyrosine phosphorylate caveolin 1, the major caveolar protein. Also a number of IGF-IR substrates reside in caveolae, supporting a role of these organelles in the regulation of IGF-I action. Recently, we have demonstrated that IGF-I could specifically regulate Shc phosphorylation in caveolae. Here we show that also IRS1 localizes in this region where it is tyrosine phosphorylated in the presence of IGF-I. Moreover, IRS1 co-immunoprecipitates with caveolin 1 and the specific phosphocaveolin 1-IRS1 interaction is increased by IGF-I.
Department of Endocrinology and Metabolism, University of Genova, Genoa, Italy.
Danilo
D
Panetta
Claudia
C
Biedi
Silvia
S
Repetto
Renzo
R
Cordera
Davide
D
Maggi
D000818:Animals; D021941:Caveolae / Q000187:drug effects / Q000378:metabolism*; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D002460:Cell Line; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D014443:Tyrosine / Q000378:metabolism
D051242:Caveolin 1; D022461:Caveolins; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D014443:Tyrosine; D007334:Insulin-Like Growth Factor I