Links the unfolded protein response and programmed cell death and mediates mitochondrial-dependent apoptosis (PubMed:21673659, PubMed:21673967). Induces cell death and disruption of the mitochondrial transmembrane potential via the mitochondrial phosphate carrier MIR1 (PubMed:21673659). Dispensible for starvation-induced autophagy (PubMed:21926971). Translocated from predominantly vacuolar sites in healthy cells to mitochondria upon apoptosis induction. No effect on autophagy during nitrogen starvation. Belongs to the BI1 family. LFG subfamily.