Can promote mitochondrial permeability transition and facilitate necrotic cell death under different types of stress conditions. Monomer. Interacts with LRPPRC (PubMed:11827465). May interact with BCL2L1; an interaction with BCL2L1 was observed using a peptide, but not with the full-length protein (PubMed:21639858). The full-length protein would have to undergo a major conformation change for the interaction to occur (PubMed:21639858). Interacts with PDCD6 (PubMed:27784779). Mainly localized to the cytoplasm with a much lower abundance in the mitochondrion. Detected in placenta. Forms a distorted beta-barrel structure, with two helices that are packed against the outer surface of the barrel. Belongs to the HEBP family. Has been described as heme-binding protein in mouse, but His-42, a residue essential for heme binding in mouse, is not conserved in all orthologs, or in the heme-binding family member HEBP1.