Component of the cytosolic iron-sulfur protein assembly (CIA) complex, a multiprotein complex that mediates the incorporation of iron-sulfur cluster into extramitochondrial Fe/S proteins (PubMed:23891004). As a CIA complex component and in collaboration with CIAO1 specifically matures ACO1 and stabilizes IREB2, connecting cytosolic iron-sulfur protein maturation with cellular iron regulation (PubMed:23891004). May play a role in chromosome segregation through establishment of sister chromatid cohesion. May induce apoptosis in collaboration with APAF1 (PubMed:25716227). Monomer and homodimer (PubMed:22683786). Component of the CIA complex (PubMed:23891004). Interacts with CIAO1 (PubMed:23891004, PubMed:22683786). Interacts with IREB2 (PubMed:23891004). Interacts with APAF1 (PubMed:25716227). Substantially enriched in macrophages. Belongs to the MIP18 family.