TPTE, a testis-specific PTEN family member, drives spermatogenesis via PI(4,5)P₂ synthesis

Phosphatidylinositol(4,5) bisphosphate (PI(4,5)P₂) is the most abundant phosphoinositides species and plays regulatory roles in spermatogenesis. However, the role of the phosphatases that regulate the production of PI(4,5)P₂ during spermatogenesis has not been well studied. Here, we found that transmembrane phosphatase with tensin homology (TPTE), a testis-specific phosphatase and tensin homolog (PTEN) family member that catalyzes the generation of PI(4,5)P₂, is important for spermatogenesis. The expression of TPTE is abnormally down-regulated in the testes of patients with non-obstructive azoospermia (NOA). In mouse, TPTE-deficiency reduced sperm count and decreased sperm motility, due to abnormal DNA double-strand break (DSB) repair in spermatocytes and flagellar defects in spermatids. TPTE catalyzes the generation of PI(4,5)P₂, inhibiting the protein kinase B/mammalian target of rapamycin (AKT/mTOR) signaling pathway. During spermiogenesis, TPTE regulates AKT/mTOR-dependent translation of negative microtubule regulator PDZ and LIM domain 1 (PDLIM1) during the development of flagella. In meiosis, TPTE regulates the protein expression of RAD50 double strand break repair protein (RAD50), and promotes homologous recombination initiation. Collectively, our findings establish the important role of TPTE during spermatogenesis, providing new insights into the regulation of PI(4,5)P₂ generation in male reproduction.