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 (By similarity). Binds 1 [2Fe-2S] cluster. Homodimer. Belongs to the CISD protein family. CISD2 subfamily.