This gene is a member of the mitochondrial carrier family. The encoded protein contains four EF-hand Ca(2+) binding motifs in the N-terminal domain, and localizes to mitochondria. The protein catalyzes the exchange of aspartate for glutamate and a proton across the inner mitochondrial membrane, and is stimulated by calcium on the external side of the inner mitochondrial membrane. Mutations in this gene result in citrullinemia, type II. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2009].