PhD project

Supervisor: Jordan Raff

Almost every cell in your body is born with a single pair of centrioles. These tiny structures organise two crucial organelles—cilia and centrosomes—that have vital roles in many aspects of cellular organisation (e.g. cell division, cell polarity, cell signalling). The dysfunction of these organelles has been linked to a bewildering plethora of human diseases, including cancer, obesity, retinal degeneration and microcephaly/dwarfism. The mechanisms linking these pathologies to organelle dysfunction are often poorly understood. These organelles are complicated nanomachines, probably made up of >400 different proteins. Our goal is to understand the molecular mechanisms that allow cells to build these nanomachines with such precision, and how mistakes in the assembly process can lead to such a wide variety of human diseases.

We recently individually knocked-out most of the ~13,000 genes in fly cells and found that, surprisingly, only ~12 are actually essential for centriole and centrosome assembly (the cells we used for these studies don’t make cilia, so we couldn’t assess cilia assembly). Remarkably, similar studies in worms identified a nearly identical set of genes, indicating that the pathway of centriole and centrosome assembly is highly conserved. In this project you will be using several advanced microscopy techniques to study the behaviour of fluorescently-tagged versions of normal and mutated versions of these key assembly proteins in living fly embryos. These embryos are ideal for studying centriole and centrosome assembly as we can observe 100s of centrioles and centrosomes as they proceed through multiple rounds of assembly and division in a short period of time. We are developing sophisticated tools to extract quantitative information about how centrosomes and their constituent parts behave. These studies are allowing us to work with mathematicians to formulate and test models about how these proteins work together to ensure that centrioles and centrosomes assemble at the right time, in the right place, and grow to the right size. We have also recently made exciting progress in trying to reconstitute centriole and centrosome assembly on the surface of synthetic beads. These studies are revealing some interesting and surprising principles that govern centriole and centrosome assembly, providing important clues to how these highly structured nanomachines function in health and disease.

Publications:

• Wong, S-S et al. (2022). Centrioles generate a local pulse of Polo/PLK1 activity to initiate mitotic centrosome assembly. EMBO J., Doi: 10.15252/embj.2022110891.
• Aydogan, et al. (2020). An autonomous oscillation times and executes centriole biogenesis. Cell, Doi: 10.1016/j.cell.2020.05.018. PMC7327525
• Raff, J.W. (2019). Phase separation and the centrosome: a fait accompli? Trends in Cell Biol., Doi: 10.1016/j.tcb.2019.04.001.
• Conduit P.T., et al. (2015). Centrosome function and assembly in animal cells. Nat. Rev. Cell and Mol. Biol. Doi: 10.1038/nrm4062.