Interaction between RGS7 and polycystin

Regulators of G protein signaling (RGS) proteins accelerate the intrinsic G TPase activity of certain G alpha subunits and thereby modulate a number of G protein-dependent signaling cascades, Currently, little is known about t he regulation of RGS proteins themselves, We identified a short-lived RGS p rotein, RGS7, that is rapidly degraded through the proteasome pathway. The degradation of RGS7 is inhibited by interaction with a C-terminal domain of polycystin, the protein encoded by PKD1, a gene involved in autosomal-domi nant polycystic kidney disease. Furthermore, membranous expression of C-ter minal polycystin relocalized RGS7. Our results indicate that rapid degradat ion and interaction with integral membrane proteins are potential means of regulating RGS proteins.