Aurora Kinase A proximity interactome reveals centriolar satellites as regulators of its function during primary cilium biogenesis

Aurora kinase A (AURKA) is a conserved kinase that plays crucial roles in numerous cellular processes. Although AURKA overexpression is frequent in human cancers, its pleiotropic functions and complex spatiotemporal regulation have presented challenges in its therapeutic targeting. An essential step to overcome these challenges is the identification of the full range of AURKA regulators and substrates, which are often weak and transient. Previous proteomic studies were limited in monitoring dynamic and non-mitotic AURKA interactions. Here, we generated the first in vivo proximity interactome of AURKA, which consisted of 247 proteins involving multiple biological processes and cellular compartments. Importantly, AURKA had extensive proximity interactions to centriolar satellites, key regulators of the primary cilium. Affinity pulldown and phosphoproteomics experiments confirmed this proximity relationship at the physical level. Loss-of-function experiments defined satellites as negative regulators of AURKA activity, abundance and localization in quiescent cells. Notably, loss of satellites increased AURKA activation at the basal body and resulted in defective cilium assembly and enhanced cilium disassembly. Collectively, our results provide a powerful resource for dissecting AURKA function and regulation and uncover proteostatic regulation of AURKA by centriolar satellites as a new regulatory mechanism for its non-mitotic functions.