Aurora Kinase-A Inactivates DNA Damage-Induced Apoptosis and Spindle Assembly Checkpoint Response Functions of p73

SummaryElevated Aurora kinase-A expression is correlated with abrogation of DNA damage-induced apoptotic response and mitotic spindle assembly checkpoint (SAC) override in human tumor cells. We report that Aurora-A phosphorylation of p73 at serine235 abrogates its transactivation function and causes cytoplasmic sequestration in a complex with the chaperon protein mortalin. Aurora-A phosphorylated p73 also facilitates inactivation of SAC through dissociation of the MAD2-CDC20 complex in cells undergoing mitosis. Cells expressing phosphor-mimetic mutant (S235D) of p73 manifest altered growth properties, resistance to cisplatin- induced apoptosis, as well as premature dissociation of the MAD2-CDC20 complex, and accelerated mitotic exit with SAC override in the presence of spindle damage. Elevated cytoplasmic p73 in Aurora-A overexpressing primary human tumors corroborates the experimental findings.

► Aurora-A abrogates p73 functions in DNA damage response and SAC pathways
► Mortalin tethers Aurora-A phosphorylated p73 in the cytoplasm
► Aurora-A phosphorylation of p73 regulates Mad2-Cdc20 SAC complex
► Cytoplasmic p73 correlates with Aurora-A expression levels in primary human tumors