Centrioles are cylindrical organelles that duplicate once per cell cycle, with the new ‘daughter’ centriole growing to the same size as the ‘mother’. They comprise a central cartwheel and its surrounding microtubule blades, and it is thought that these two structures assemble at opposite ends of the daughter centriole as it grows. Jordan Raff's group previously demonstrated that Polo-like kinase 4 (Plk4) oscillates at the proximal end of the nascent daughter to time the growth of the cartwheel. In this study (Aydogan, Hankins et al., 2022), they address how centriole microtubule growth is regulated. They focus on CP110 and Cep97, two proteins that localise at the distal end of the centriole and inhibit microtubule growth. Using early Drosophila embryos as a model, they employ live imaging to demonstrate that CP110–GFP and GFP–Cep97 are recruited to daughter centrioles in a cyclical manner. CP110 and Cep97 levels peak in mid S-phase, when the daughters are known to stop growing, but this cessation of growth does not appear to be caused by the accumulation of a threshold level of CP110 or Cep97 at the distal end. Instead, they find that perturbing the levels of CP110 or Cep97 influences both the Plk4 oscillation and the growth dynamics of the cartwheel at the opposite end of the centriole. This crosstalk between the distal and proximal ends might help to explain how the growth of the centriole cartwheel and microtubules is coordinated.
