CEP192 and CEP152 bring PLK4 to the centriole

Centrioles serve as platforms for the assembly of centrosomes, the major microtubule-organizing centres of animal cells, and cilia, and are duplicated once during every cell cycle. Polo-like kinase 4 (PLK4) has been shown to be essential for centriole duplication, but it remains unclear how it is recruited to the centriole in mammalian cells or with which proteins it interacts. On page 3223, Katharina Sonnen, Erich Nigg and co-workers aim to answer these questions by focusing on the roles of CEP152, the mammalian homologue of Drosophila Asterless, which is known to meditate PLK4 recruitment in flies, and of CEP192, the mammalian homologue of Caenorhabditis elegans SPD-2, which targets a PLK4-related kinase in nematodes. They find that CEP192 recruits both CEP152 and PLK4 to the centrosome, and show that CEP192 directly binds to PLK4 through an N-terminal extension that is specific to its largest isoform. The authors also demonstrate that double depletion of CEP192 and CEP152 abolishes the recruitment of PLK4 to centrioles, as well as centriole duplication, suggesting that CEP192 and CEP152 cooperate in PLK4 targeting. Furthermore, they determine the domains of CEP192 and CEP152 that interact with PLK4 as being rich in negatively charged amino acids, which suggests that electrostatic interactions with the positively charged ‘polo-box domain’ mediate PLK4 recruitment to the centriole. Taken together, these data provide new insights into the spatiotemporal control of centriole duplication during the cell cycle.