Contributes to normal sperm motility, but not essential for male fertility. Interacts with PRM2. Mainly nuclear. Also detected in cytoplasm near the midpiece of the flagellum. Strongly expressed in testis. Also detected at lower levels in epididymis, bone marrow and kidney. Viable with no gross morphological defects. Morphology of testis tissue and mature epididymal sperm is normal. Sperm counts are also normal. Sperm motility is reduced, however this has no significant effect on male fertility. Belongs to the TDRP family.