Plays a role as a neuroprotective and antiapoptotic factor. Highly expressed in the kidney, heart muscle and testis. Down-regulated 6 hours following staurosporine (STS) treatment and up-regulated 24 hours following STS treatment. Down-regulated 6 hours following beta-carotene treatment. Belongs to the humanin family. The humanin peptide has been shown to be biologically active but is the product of a mitochondrial gene, MT-RNR2. The mechanisms allowing the production and the secretion of humanin from the mitochondrial gene remaining unclear, the possibility exist that the physiologically active humanin peptide is encoded by one of the related genes present in the nuclear genome including the one described here (PubMed:19477263).