Plays a role in acrosome expansion and establishment of normal sperm morphology during spermatogenesis. Important for male fertility. Primarily found in the equatorial segment of the acrosome (PubMed:18448843). The tyrosine phosphorylated protein localizes to a smaller region within the equatorial segment (PubMed:18448843). Also expressed weakly in the principal segment (By similarity). Detected in spermatozoa (at protein level). N-glycosylated.