BICD2 is a centriolar protein that controls mother-daughter centriole engagement and the licensing of duplication

Centrosomes and the centrioles at their core have key cellular roles that require their duplication exactly once during each cell cycle. Abnormal centriole numbers can contribute to the onset of different pathologies and thus different mechanisms have evolved to tightly control centriole duplication. Importantly, centriole pairs are barred from duplicating until they go through a not completely understood process of licensing that includes the physical separation of older (mother) and younger (daughter) centrioles. Here we report that the dynein adaptor BICD2 is a centriolar protein with a previously unknown dynein-independent role controlling mother-daughter centriole engagement. We show that a pool of BICD2 resides at the centrosome, surrounding mother centrioles close to the daughter centriole. Removal of BICD2 results in premature centriole disengagement in G2 and early M and in centriole amplification in both non-transformed and transformed cells. We characterize the molecular determinants of BICD2 centriolar localization and suggest that this localization, and thus the role of BICD2 at the centriole, is controlled by phosphorylation. Our findings reveal a novel function of BICD2, independent of its ability to interact with dynein, which is crucial for the regulation of centriole licensing and the centrosome duplication cycle.