Orchestration of phosphorylation in time and space
Dr Peter THORPE
Queen Mary University of London, United Kingdom
Thursday, October 10th 2019 - 10 a.m.
- Auditorium, IGBMC
Hosted by Izabela SUMARA
Accurate chromosome segregation is driven by the kinetochore, a large protein complex that assembles on centromeres on every sister chromatid by attaching chromosomes to the mitotic spindle via microtubules. A tightly controlled spatiotemporal recruitment of regulatory proteins to the centromere-kinetochore-microtubule axis is key in orchestrating mitosis. Many of these regulators control kinetochore assembly/maintenance and/or microtubule attachment by post-translational modifications such as phosphorylation and ubiquitination. We have used the Synthetic Physical Interaction (SPI) technology to separately associate each member of the budding yeast proteome with kinetochore components representing each of the major kinetochore subcomplexes. We then reverse the assay and associate a candidate regulator separately with every member of the proteome including most of the kinetochore proteins. This method identifies candidate regulators of kinetochore function, some with known roles. We focus on the Polo-like kinase, Cdc5, which when constitutively associated with many kinetochore components, produces a cell growth arrest phenotype, depending on the sublocalisation at the kinetochore in both a kinase-dependent and independent manner. We investigate the role of the spindle assembly checkpoint (SAC) and the polo-box domain (PBD) of Cdc5 in the observed phenotypes. This work suggests that Cdc5 acts sequentially across the kinetochore in a wave from the inner to outer kinetochore.