CARDIAC MYOCYTES EXPRESS MESSENGER-RNA FOR 10 RGS PROTEINS - CHANGES IN RGS MESSENGER-RNA EXPRESSION IN VENTRICULAR MYOCYTES AND CULTURED ATRIA

Regulators of G-protein signalling (RGS) are recently identified prote ins that shorten the lifetime of the activated G protein. We now show that rat cardiac myocytes express mRNA for at least 10 RGS. The mRNA f or RGS-r is barely detectable in rat ventricles, but increases more th an 20-fold during the 60- to 90-min process of isolating ventricular m yocytes, and after 90 min of culture of atrial pieces in medium with C a2+. Both in myocytes and in atria, the rise in RGS-r is transient. Th e mRNA for cardiac RGS5, but not RGS-r, is developmentally regulated. These studies suggest that rapid regulation of RGS levels may be a new mechanism that governs how signals are transmitted across the cardiac cell membrane. (C) 1998 Federation of European Biochemical Societies.