Nuclear autoantigenic sperm protein (NASP)

Nuclear autoantigenic sperm protein (NASP) is a histone chaperone encoded by the NASP gene and primarily functions by binding and stabilizing histones H3 and H4 that are not bound to chromatin, thereby maintaining a soluble pool of histones in the cell[1][2][3][4][7][8][9][10]. NASP mediates histone transport into the nucleus of dividing cells and facilitates nucleosome assembly, protecting histones from degradation or aggregation, and helping adjust histone supply in response to cellular demands such as DNA replication or cell cycle progression[2][4][6][8][9][10]. NASP features distinct isoforms: the somatic form, expressed in all mitotic cells and coupled to the cell cycle, and the testicular form, expressed in embryonic tissues, tumor cells, and testis[1][3]. Structurally, NASP contains tetratricopeptide repeat (TPR) motifs, creating binding pockets for protein-protein interactions[2][10]. It operates within a network of histone chaperones and interacts with other proteins including HSP90 and ASF1 to ensure genome integrity by regulating histone metabolism and nucleosome formation[2][3][9][10]. While NASP does not function as a druggable therapeutic target like a receptor or enzyme, its essential role in chromatin biology and cell cycle regulation implicates it in diseases characterized by aberrant proliferation, such as cancer. There are currently no approved drugs that specifically target NASP, nor is it directly used as a biomarker or associated with notable safety concerns for therapeutic intervention.

Other names

NASPNuclear autoantigenic sperm proteinNASP histone chaperoneHistone H1-binding proteinFLB7527FLJ31599FLJ35510MGC19722MGC20372MGC2297DKFZp547F162PRO1999HMDRA1