The function of ENSG00000132780 (NASP, nuclear autoantigenic sperm protein) is as follows. Component of the histone chaperone network (PubMed:22195965). Binds and stabilizes histone H3-H4 not bound to chromatin to maintain a soluble reservoir and modulate degradation by chaperone-mediated autophagy (PubMed:22195965). Required for DNA replication, normal cell cycle progression and cell proliferation. Forms a cytoplasmic complex with HSP90 and H1 linker histones and stimulates HSP90 ATPase activity. NASP and H1 histone are subsequently released from the complex and translocate to the nucleus where the histone is released for binding to DNA. . [Isoform 1]: Stabilizes soluble histone H3-H4. . [Isoform 2]: Stabilizes soluble histone H3-H4. .