This domain is found in proteins carrying other domains known to be involved in intracellular signalling pathways indicating that it might also be involved in these pathways. It has 4 highly conserved cysteine residues, suggesting that it can bind zinc ions. Moreover, it is found repeated in some members of this entry (such as ), which may indicate that these domains are able to interact with one another, raising the possibility that it mediates heterodimerisation. Mitochondrial intermembrane space import and assembly protein 40 (MIA40) from the yeast Ashbya gossypii also belongs to this entry. Experimental data showed that its cysteine residues have an structural role while the disulfide bond formed by the third and sixth cysteine residues seem to support a conformation essencial for the function of this protein [].
