The CISD2 protein is a zinc finger protein that is targeted to the endoplasmic reticular membrane. The protein binds an iron/sulfur cluster, and is speculated to be involved in calcium homeostasis. Defects in the protein have been implicated in the development of Wolfram Syndrome 2, a condition characterized by diabetes mellitus, optic atrophy, and sensorineural hearing loss.

Although the exact role played by the CISD2 protein in the pathogenesis of Wolfram Syndrome is not known, the mechanism of action of the protein is very similar to Wolframin, another protein implicated in the same disease condition. Thus, researchers hypothesize that defects in the protein result in impaired calcium homeostasis, that cause defects in protein folding, specifically insulin folding, and thus lead to diabetes and hearing loss.

The CISD2 gene spans a length of 19.5 kb on chromosome 4q. The mature cDNA is coded for by three exons, which in turn codes for a 15.2 kDa protein, consisting of 135 amino acids. The protein is predicted to have a transmembrane domain, as well as a zinc-finger domain of the CDGSH type. Such zinc-finger domains have been found in other proteins. However, their function is yet unknown.