B30.2-like domain proteins: a growing family.

The B30.2 domain is a conserved domain of around 170 amino acids. It is found associated with different protein domains: immunoglobulin domain in the case of butyrophilin and Ring Finger domain in the case of Ret Finger Protein. B30.2 should therefore be considered a migratory domain. We here report new members of these families as well as new protein families having the B30.2 domain, and we tentatively propose a general function for this domain.