Dissecting the function and regulation of the dual specificity kinase DYRK at the centriolar satellites and primary cilium

The centrosome/cilium complex plays critical roles during important cellular and organismal processes. In mammalian cells, it is composed of the centrosome, the primary cilium and the centriolar satellites. At the core of the centrosome are two centrioles, which are essential for the assembly of cilia including the primary cilium, which functions as a hub for developmentally important signaling pathways. Centriolar satellites are granules that localize and move around centrosomes. These vertebrate-specific structures have emerged as important regulators of primary cilium assembly and function. Importantly, structural and functional defects of centrosomes, cilia and centriolar satellites cause various human diseases including ciliopathies, primary microcephaly and cancer. In order to uncover the pathogenesis of these diseases, a complete understanding of the mechanisms by which they are assembled, maintained and remodelled are required. To this end, I investigated the function and regulation of Dual specificity tyrosine-phosphorylation-regulated kinase 3 (DYRK3) during primary cilium assembly based on its identified in proteomic datasets of the motile cilia and regulatory functions during centriolar satellite biogenesis. First, I used proximity-based labelling approach, BioID, and generated the first in vivo proximity interaction map for wild type DYRK3 and its kinase-dead mutant. This map revealed proximity interactions between DYRK3 and regulators of primary cilium assembly and function. To test this, I inhibited DYRK3 activity in mammalian cell lines and multiciliated epithelial cultures, and showed that DYRK3 is required for primary and motile cilia assembly, respectively. These results identify DYRK3 as a new player of cilia biogenesis and advances our understanding of kinase-dependent regulation of this process.