Bcl-2 modulates endoplasmic reticulum and mitochondrial calcium stores in PC12 cells

Abstract

Endoplasmic reticulum (ER) and mitochondria are intracellular organelles and their interactions are directly involved in different processes such as Ca(2+) signaling in cell survival and death mechanisms. Bcl-2 is an anti-apoptotic protein intrinsically related to ER and mitochondria, modulating Ca(2+) content in these organelles. We investigated the effects of Bcl-2 overexpression on ER and mitochondrial Ca(2+) dynamics in PC12 cells. Bcl-2 overexpressing and control cells were loaded with Fura 2/AM and stimulated with different drugs. Results showed that in Bcl-2 cells, ACh induced a lower Ca(2+) response compared to control. Ca(2+) release induced by TG was decreased in Bcl-2 cells, however, it was greater in Caff induced Ca(2+) rise. In addition, FCCP induced a higher Ca(2+) release in Bcl-2 cells. These results suggest that Bcl-2 overexpression modulate the ER Ca(2+) pools differently and the release of ER Ca(2+) may increase mitochondrial Ca(2+) accumulation. These alterations of intracellular Ca(2+) stores are important mechanisms for the control of Ca(2+) signaling.