This gene encodes a member of the nicotinamide/nicotinic acid mononucleotide adenylyltransferase family. These enzymes use ATP to catalyze the synthesis of nicotinamide adenine dinucleotide or nicotinic acid adenine dinucleotide from nicotinamide mononucleotide or nicotinic acid mononucleotide, respectively. The encoded protein is localized to mitochondria and may also play a neuroprotective role as a molecular chaperone. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Jan 2011].