This protein family, refers to a domain of unknown function. The precise role of this protein domain remains to be elucidated. This family of proteins is found in eukaryotes and are typically between 256 and 320 amino acids in length. There is a single completely conserved residue, phenylalanine (F), that may be functionally important. In humans, the protein is found in the position, chromosome 4 open reading frame 47.