This gene is located in the nonrecombining portion of the Y chromosome, and is expressed specifically in testis. It encodes a protein which is similar to XK (X-linked Kell blood group precursor), a putative membrane transport protein. This gene is present as two identical copies within a palindromic region; this record represents the more telomeric copy. [provided by RefSeq, Jul 2008]. COMPLETENESS: complete on the 3' end.