An inducible multiciliated cell line resolves proteome dynamics and identifies CDK7 as a conserved regulator

Multiciliated cells (MCCs) are essential for generating directional fluid flow across specialized epithelia in various vertebrate organs. MCC differentiation involves a tightly regulated program characterized by massive centriole amplification. Although transcriptional control of MCC development is well characterized, insights into proteome dynamics have been limited due to the lack of suitable models. Here, we report the generation of a stable inducible MCC line, derived from Xenopus A6 kidney epithelial cells. Upon induction of the master regulator multicilin (MCI), most A6-MCI cells synchronously differentiate into mature MCCs in 48 h. Using this resource, custom antibodies, and super-resolution imaging, we characterized Xenopus deuterosomes, the platforms that allow massive centriole synthesis in vertebrate MCCs. We performed detailed proteomic profiling throughout differentiation, uncovered previously uncharacterized regulators and highlighted a critical role for CDK7 in Xenopus and human MCC differentiation. Our work provides a valuable resource for mechanistic studies of MCC biology and opens avenues to identify novel therapeutic targets for motile ciliopathies.