Involvement of caveolae and caveolae-like domains in signalling, cell survival and angiogenesis

Caveolae, the flask-shaped membrane invaginations abundant in endothelial cells, have acquired a prominent role in signal transduction. Evidence, that events occurring in caveolae participate in cell survival and angiogenesis, has been recently substantiated by the identification of two novel caveolar constituents: prostacyclin synthase (PGIS) and the cellular form of prion protein (PrP^c). We have shown that PGIS, previously described as an endoplasmic reticulum component, is bound to caveolin-1 (cav-1) and localized in caveolae in human endothelial cells. By generating prostacyclin, PGIS is involved in angiogenesis. Previous observations regarding the localization of PrP^c in caveolae-like membrane domains (CLDs) have been recently confirmed and extended. It has been demonstrated that PrP^c is bound to cav-1 and, by recruiting Fyn kinase, can participate in signal transduction events connected to cell survival and differentiation. The new entries of PGIS and PrP^c in caveolar components place caveolae and CLDs at the centre of a network, where cells decide whether to proliferate or differentiate and whether to survive or to suicide by apoptosis.