Essential for spermiogenesis and male fertility (PubMed:29065458). Involved in the formation of acrosome during spermatogenesis (PubMed:16372119). Shift from Golgi to sperm acrosome. Testis-specific. Expressed in spermatocytes and round and elongated spermatids in the seminiferous tubules. Male mice are infertile with spermiogenic arrest and impaired differentiation of round spermatids into the mature spermatozoa. Belongs to the SPATA16 family.