Controlling centriole growth by a homeostatic clock

Controlling centriole growth by a homeostatic clock

Centrioles are organelles that perform key functions during cell division -as part of centrosomes- and ciliogenesis. These small structures are duplicated in each cellular division via the growth of a daughter centriole from the side of its mother. While the regulation of centriole and centrosome number in cells has been well characterised, the mechanisms controlling centriole growth have remained elusive to date.

Aydogan and colleagues (Raff lab) have used live imaging of early fly embryos, coupled with quantitative tools, to report a novel function for Polo-like Kinase 4 (Plk-4) in regulating centriole size. They observed that Plk4 drives centriole growth by linearly promoting the addition of building blocks (Sas-6 molecules) onto the proximal side of daughter centrioles throughout early/mid S-phase and halting growth once centrioles have reached their correct size. This homeostatic clock role of Plk4 is attributed to its predicted suicidal activity – the more active the kinase is, the faster it triggers its own degradation. This study sheds light on an enzyme that acts as a clock to control centriole growth and proposes a novel mechanism for organelle size regulation.

Sonia Muliyil

Aydogan MG, Wainman A, Saurya S, Steinacker TL, Caballe A, Novak ZA, Baumbach J, Muschalik N, Raff JW. (2018).

J Cell Biol. 217(4):1233-1248.