Catalyzes the transport of 2-oxoglutarate (alpha-oxoglutarate) across the inner mitochondrial membrane in an electroneutral exchange for malate (PubMed:3814587, PubMed:8363582, PubMed:27479487). Can also exchange 2-oxoglutarate for other dicarboxylic acids such as malonate, succinate, maleate and oxaloacetate, although with lower affinity (PubMed:8363582). Contributes to several metabolic processes, including the malate-aspartate shuttle, the oxoglutarate/isocitrate shuttle, in gluconeogenesis from lactate, and in nitrogen metabolism (PubMed:14598172). Maintains mitochondrial fusion and fission events, and the organization and morphology of cristae (By similarity). Involved in the regulation of apoptosis (By similarity). Helps protect from cytotoxic-induced apoptosis by modulating glutathione levels in mitochondria (By similarity). (S)-malate(in) + 2-oxoglutarate(out) = (S)-malate(out) + 2-oxoglutarate(in) 2-oxoglutarate(out) + malonate(in) = 2-oxoglutarate(in) + malonate(out) 2-oxoglutarate(out) + succinate(in) = 2-oxoglutarate(in) + succinate(out) 2-oxoglutarate(out) + maleate(in) = 2-oxoglutarate(in) + maleate(out) 2-oxoglutarate(out) + oxaloacetate(in) = 2-oxoglutarate(in) + oxaloacetate(out) Heart, liver and brain. The N-terminus is blocked. Belongs to the mitochondrial carrier (TC 2.A.29) family.