Changes in caveolin subtype protein expression in aging rat organs

it is now accepted that caveolin plays a key role in signal transduction by directly binding to and regulating the function of molecules involved in t ransmembrane signaling, such as ras, suggesting that the amount of caveolin within cells may be an important factor in determining the cellular signal ing. We investigated the ontogenic changes in the protein amount of caveoli n subtypes, as well as ras protein expression in various organs (the heart, lungs, and muscles) obtained from aging rats (neonates, young and old adul ts). Our results demonstrated that caveolin protein expression changed onto genically in a subtype-dependent manner. In lungs, for example, caveolin-1 expression changed in an opposite manner to caveolin-3 expression. while in the heart caveolin-1 and -3 changed in parallel. Ras expression showed an ontogenic increase in lungs and a decrease in muscles, which were both para llel to caveolin-1 expression. Our results suggest that the regulation of t ransmembrane signaling by caveolin may differ among developmental stages an d caveolin subtypes. (C) 2001 Elsevier Science Ireland Ltd. Ail rights rese rved.