The mammalian sperm flagellum contains two cytoskeletal structures associated with the axoneme: the outer dense fibers surrounding the axoneme in the midpiece and principal piece and the fibrous sheath surrounding the outer dense fibers in the principal piece of the tail. Defects in these structures are associated with abnormal tail morphology, reduced sperm motility, and infertility. In the rat, the protein encoded by this gene associates with an outer dense fiber protein via a leucine zipper motif and localizes to the microtubules of the manchette and axoneme during sperm tail development. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Dec 2015]
Alternative Names
acrosomal protein ACR55 associated with outer dense fiber formation in elongating spermatids cancer/testis antigen 127 outer dense fiber-associated protein SPAG4 Sad1 and UNC84 domain containing 4 sperm antigen 4 sperm tail protein SUN domain-containing protein 4