The Galpha protein Gpa2 controls yeast differentiation by interacting with kelch repeat proteins that mimic Gbeta subunits

Redox status changes exert critical impacts on necrotic/apoptotic and normal cellular processes. We report here a widely expressed Ca2+-permeable cation channel, LTRPC2, activated by micromolar levels of H2O2 and agents that produce reactive oxygen/nitrogen species. This sensitivity of LTRPC2 to redox state modifiers was attributable to an agonistic binding of nicotinamide adenine dinucleotide (beta-NAD+) to the MutT motif. Arachidonic acid and Ca2+ were important positive regulators for LTRPC2. Heterologous LTRPC2 expression conferred susceptibility to death on HEK cells. Antisense oligonucleotide experiments revealed physiological involvement of "native" LTRPC2 in H2O2- and TNFalpha-induced Ca2+ influx and cell death. Thus, LTRPC2 represents an important intrinsic mechanism that mediates Ca2+ and Na+ overload in response to disturbance of redox state in cell death.