RGS proteins provide biochemical control of agonist-evoked [Ca2+](i) oscillations

Agonist-evoked [Ca2+](i) oscillations have been considered a biophysical ph enomenon reflecting the regulation of the IP3 receptor by [Ca2+](i). Here w e show that [Ca2+](i) oscillations are a biochemical phenomenon emanating f rom regulation of Ca2+ signaling by the regulators of G protein signaling ( RGS) proteins. [Ca2+](i) oscillations evoked by G protein-coupled receptors require the action of RGS proteins. Inhibition of endogenous RGS protein a ction disrupted agonist-evoked [Ca2+](i) oscillations by a stepwise convers ion to a sustained response. Based on these findings and the effect of muta nt RGS proteins and anti-RGS protein antibodies on Ca2+ signaling, we propo se that RGS proteins within the G protein-coupled receptor complexes provid e a biochemical control of [Ca2+](i) oscillations.