InterPro domain: IPR028608

Proteins in this entry are probable cytosolic iron-sulfur (FeS) protein assembly proteins from eucaryotes, including Cia1 from Saccharomyces cerevisiae and CIAO1 from humans. Iron-sulfur [Fe-S] clusters are ubiquitous and evolutionary ancient prosthetic groups that are required to sustain fundamental life processes [ 1 ]. They can be used as part of catalytic centres for chemical sensing, stabilise protein structure and determine protein function [ 2 ].

In Saccharomyces cerevisiae, Cia1 is a component of cytosolic iron-sulfur cluster assembly (CIA) system (consists of Nar1, Nbp35 and Cia1). It is involved in a late step of Fe/S cluster incorporation into target proteins [ 3 ].

In humans, it is also a component of the human CIA system. Moreover, it binds to IOP1 and forms the MMXD complex (MMS19, XPD, MIP18 and ANT2), which is involved in chromosome segregation [ 4 , 5 ].

1. Structure, function, and formation of biological iron-sulfur clusters. Annu. Rev. Biochem. 74, 247-81
2. Cytosolic iron-sulfur cluster assembly (CIA) system: factors, mechanism, and relevance to cellular iron regulation. J. Biol. Chem. 285, 26745-51
3. The essential WD40 protein Cia1 is involved in a late step of cytosolic and nuclear iron-sulfur protein assembly. Mol. Cell. Biol. 25, 10833-41
4. IOP1 protein is an external component of the human cytosolic iron-sulfur cluster assembly (CIA) machinery and functions in the MMS19 protein-dependent CIA pathway. J. Biol. Chem. 288, 16680-9
5. MMXD, a TFIIH-independent XPD-MMS19 protein complex involved in chromosome segregation. Mol. Cell 39, 632-40