Calcium signaling in mitochondria is important in order for it to function in response to a variety of extracellular stimuli. Signaling begins with Ca(2+) entry in mitochondria via the Ca(2+) uniporter followed by Ca(2+) activation of three dehydrogenases in the mitochondrial matrix. ARALAR, the neuronal Ca(2+)-binding mitochondrial aspartate-glutamate carrier, has Ca(2+) binding domains facing the extramitochondrial space and functions in the malate-aspartate NADH shuttle (MAS). ARALAR is enc