ncts

Centrosome amplification in cancer cells results in an excess of centrosomes that cluster and decluster throughout the cell cycle, a process critical for tumorigenesis. Here, we have uncovered that the mitotic kinesin HSET is a multifaceted regulator of centrosome clustering dynamics. We show that HSET contributes to centrosome clustering by forming co-condensates with the centrosomal protein CDK5RAP2, promoting its transport toward microtubule minus-ends via enhanced motor processivity. Effective transport of large CDK5RAP2 condensates, independently of their size, overcomes cytosolic viscosity to cluster large foci of pericentriolar material within cells. Our simulations indicate that elevated HSET levels and motor processivity in cancer cells together promote centrosomal clustering efficiency. Furthermore, HSET’s ATP-independent self-assembly prevents centrosomal declustering. These activities position HSET as a critical regulator of centrosome clustering dynamics during the cell cycle, adding another layer of regulation to centrosome assembly and underscoring its potential as a target for cancer therapeutics.