Regulator of autophagy that contributes to antagonize BECN1-mediated cellular autophagy at the endoplasmic reticulum. Participates in the interaction of BCL2 with BECN1 and is required for BCL2-mediated depression of endoplasmic reticulum Ca(2+) stores during autophagy. Contributes to BIK-initiated autophagy, while it is not involved in BIK-dependent activation of caspases. Involved in life span control, probably via its function as regulator of autophagy (By similarity). Binds 1 [2Fe-2S] cluster. E is 0 +/- 10 mV for 2Fe-2S at pH 7.5. Homodimer. Interacts with BCL2; the interaction is direct and disrupted by BIK interaction with BCL2. Interacts with BCL2L1. Interacts with ITPR1 (By similarity). According to PubMed:19451219, it mainly localizes to the mitochondrion outer membrane and localizes only at low level to the endoplasmic reticulum. However, inverse results are observed in human cells. Brain. Expression decreases in an age-dependent manner. Premature aging associated with a shortened life span, probably caused by mitochondrial degeneration and autophagy. 8 week old mice begin to acquire a set of aged appearance phenomena remarkably similar to those of premature aging syndrome, including prominent eyes and protruding ears. Ocular abnormalities are observed: mice develop opaque eyes and blindness, which is accompanied by cornea damage at 20 week old. The opacity of the cornea is due to debris deposition in the scar tissue outside the cornea. In addition, corneal neovascularization is observed, possibly impairing vision. An early depigmentation in the fur at around 48 week old is also observed; furthermore, hair follicle atrophy and a decreased hair density is detected. A decrease in the hair regrowth rate is also observed. Additionally, the skin of 48-week-old mice exhibits a phenotype with a noticeably thickened dermis, an expanded surface, and a significant decrease in subcutaneous adipose tissue and muscle. The trabeculae of the femur are noticeably thinner and dual energy X-ray absorptiometer (DEXA) detects a decrease in femur density after 8 week old. Mice also display a significant lordokyphosis phenotype after 12 week old; leading to a decrease in mean thoracic volume and thence pulmonary function abnormalities. Muscle degeneration is detectable at 3 week old with a progressive degeneration of muscle fibers and the magnitude of the degeneration exacerbated with age. Belongs to the CISD protein family. CISD2 subfamily.