Essential for normal spermatogenesis and male fertility (PubMed:31916570). Required for the completion of meiosis in male germ cells (PubMed:31916570). Predominantly localized to the cytoplasm (PubMed:11803038, PubMed:12606435). Translocates from the cytoplasm to the nucleus in the G2/M transition upon treatment with cadmium, cobalt or zinc (PubMed:11803038, PubMed:12606435). Expressed in spermatocytes and adult heart. Also expressed in fetal brain, heart, kidney and ovary. Testis (at protein level). Testis. Expressed as early as day 8, coincident with the entry of germ cells into meiosis. Expression then progressively increases. Expressed in the pachytene stage. Male mice are infertile due to arrested spermatogenesis at the pachytene stage. Belongs to the lin-54 family.