Anti-Astrin Antibody, clone C-1 clone C-1, from mouse

Sperm-associated antigen 5 (UniProt: Q96R06; also known as Astrin, Deepest, Mitotic spindle-associated protein p126, MAP126) is encoded by the SPAG5 gene (Gene ID: 10615) in human. Astrin is a homodimeric protein with a globular head domain and a long stalk. It is an essential component of the mitotic spindle. Astrin is highly expressed in testis and is detected at low levels in placenta, liver, pancreas, thymus and colon. Its expression is cell cycle-regulated, with an increase from prophase to cytokinesis and return to basal levels at the next G1 phase. In non-dividing cells Astrin is associated with microtubules unless under cellular stress, then it is localized in stress granules. In non-mitotic cells, upon stress induction, it inhibits mTORC1 association and recruits the mTORC1 component RPTOR to stress granules, thereby preventing mTORC1 hyperactivation-induced apoptosis. Astrin is required for normal chromosome segregation and progression into anaphase. It is also required for chromosome alignment, normal timing of sister chromatid segregation, and maintenance of spindle pole architecture. In complex with SKAP, it promotes stable microtubule-kinetochore attachments. Depletion of astrin in cells is shown to result in the activation of p53-dependent apoptosis that elevates Bax expression and increases Caspase-3 activity. Astrin can be phosphorylated at multiple sites by Aurora kinase A. (Ref.: Yang, YC., et al. (2006). Biochem. Biophys. Res. Commun. 343(2); 428-434).