Electrogenic aspartate/glutamate antiporter SLC25A13 (also known as Aralar2 and citrin) shares protein sequence similarity with Aralar1. Both are Ca(2+)-stimulated aspartate/glutamate transporters in mitochondria []. Like Aralar1, Aralar2 contains an N-terminal calcium binding domain (EF-hand domains) and a C-terminal domain that is characteristic for the mitochondrial solute-carriers []. Unlike Aralar1, Aralar2 is expressed in human non-excitable tissues [].Mutations in Aralar2 gene cause Citrullinemia 2 (CTLN2), which is a form of citrullinemia, an autosomal recessive disease characterised primarily by elevated serum and urine citrulline levels [, ]. Many many symptoms of CTLN2 are interpretable based on the function of citrin as a aspartate glutamate carrier with a role in urea synthesis and the malate-aspartate shuttle [].
