IGF-I induces caveolin 1 tyrosine phosphorylation and translocation in the lipid rafts.
Caveolin 1, a component of caveolae, regulates signalling pathways compartmentalization interacting with tyrosine kinase receptors and their substrates. The role of caveolin 1 in the Insulin Receptor (IR) signalling has been well investigated. On the contrary, the functional link between caveolin 1 and IGF-I Receptor (IGF-IR) remains largely unknown. Here we show that (1) IGF-IR colocalizes with caveolin 1 in the lipid rafts enriched fractions on plasmamembrane in R-IGF-IR(WT) cells, (2) IGF-I induces caveolin 1 phosphorylation at the level of tyrosine 14, (3) this effect is rapid and results in the translocation of caveolin 1 and in the formation of membrane patches on cell surface. These actions are IGF-I specific since we did not detect caveolin 1 redistribution in insulin stimulated R(-) cells overexpressing IRs.
Department of Endocrinology and Metabolism, University of Genoa, Genoa, Italy.
Davide
D
Maggi
Claudia
C
Biedi
Daniela
D
Segat
Daniela
D
Barbero
Danilo
D
Panetta
Renzo
R
Cordera
D000818:Animals; D001692:Biological Transport; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D002478:Cells, Cultured; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D051379:Mice; D010766:Phosphorylation; D014162:Transfection
C495541:Cav1 protein, mouse; D051242:Caveolin 1; D022461:Caveolins; D007334:Insulin-Like Growth Factor I