This domain is found in proteins carrying other domains known to be involved in intracellular signalling pathways (such as Pfam:PF00071) 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 family (such as Swiss:Q9LMF3); this may indicate that these domains are able to interact with one another, raising the possibility that this domain mediates heterodimerisation.