The protein encoded by this gene is a mitochondrial protein that is induced by high levels of glucose and is associated with diabetic nephropathy. The encoded protein appears to increase mitochondrial biogenesis, which could lead to renal fibrosis. Another function of this protein is that of a guanyltransferase, adding GMP to the 5' end of tRNA(His). Several transcript variants encoding different isoforms have been found for this gene.