Involved in chloroplast protein import across the inner envelope membrane. Acts also as a chloroplast permease regulating the iron transport and homeostasis. Involved in the uptake and sequestration of iron in plastids. Homomultimer. Part of the translocon complex. Ubiquitous. Highest expression in green tissues and very low levels in mature pollen. Seedling lethal when grown on soil. Albino or chlorotic dwarfed plants that accumulate unprocessed precursor proteins and chloroplast ferritin clusters when grown in vitro.