Iron-sulfur cluster scaffold protein which can assemble [4Fe-4S] clusters and deliver them to target proteins. Monomer and homohexamer; the apo-NFU1 is a monomer, while the holo-NFU1 is a hexamer composed of a trimer of dimer that is probably linked by some 4Fe-4S cluster. Interacts with HIRA and EPM2A/laforin. Interacts with BOLA3. Interacts with HSPA9. Belongs to the NifU family.