Ubiquitin-like protein 4B (UBL4B)

Ubiquitin-like protein 4B (UBL4B) is a testis-specific autosomal retrogene that emerged from the X-linked housekeeping gene UBL4A in mammals through retroposition[3][1]. UBL4B is expressed specifically in post-meiotic male germ cells (especially during late spermiogenesis), and encodes a cytoplasmic protein with a conserved ubiquitin-like domain, similar to other ubiquitin-related modifiers[3]. While its ancestral paralog UBL4A is broadly expressed and involved in protein metabolism and immune responses, the functional significance of UBL4B appears specialized for male germ cell maturation and is dispensable for overall spermatogenesis or fertility, as knockout mice show no major reproductive or developmental defects[1][3]. There is currently no evidence that UBL4B plays a direct role as a therapeutic drug target, nor does it have established links to disease, pathogenic mechanisms, or known drug interactions.

Other names

UBL4BFLJ25690ubiquitin like 4Bubiquitin-like protein 4B