Central member of the cytosolic iron-sulfur (Fe-S) protein assembly (CIA) pathway (PubMed:23104832). Involved in leaf polarity formation (PubMed:21070412). Promotes leaf adaxial identity (PubMed:21070412). May play a role in the cell cycle progression and is required for cell proliferation (PubMed:21070412). Part of a complex formed of AE7, CIA1, MMS19 and NAR1. Interacts with CIA1 and MMS19, but not with NAR1. Expressed in the embryo, shoot apical meristem, leaf primordia, inflorescence and all floral organs. Expressed throughout the globular-stage, heart-stage and torpedo-stage embryos. Embryonic lethality when homozygous. Belongs to the MIP18 family.