Deciphering the cellular roles of pericentriolar satellites using an inducible degron system.

• Applicant: Dr. Julia Tischer
• Subject Area: Cell Biology
• Term: from 2016 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 323093744

Centrosomes are protein-rich organelles in the cell that are implicated in cell division, signalling and cilia formation. In proliferating cells the centrosome promotes mitotic spindle assembly and the correct partitioning of the chromosomes into daughter cells during cell division. In quiescent (non-proliferating) cells the centrosome templates the assembly of the primary cilium, a sensory and signalling organelle present in the plasma membrane. Centrosome number, composition, location and function must therefore be tightly regulated not only in proliferating but also in quiescent cells. Pericentriolar satellites are small, protein-rich granules that cluster around the centrosome. They have been implicated in the regulation of both centrosomes and cilia, but their precise contribution remains unclear. A particularly interesting possibility is that pericentriolar satellites integrate cellular signals to decide whether and when to convert centrosomes into primary cilia. So far, satellite function has been studied through depletion of the essential satellite scaffold, PCM1. Although informative, this method achieves PCM1 depletion after several days and is thus ill-suited to study the immediate effects of satellite loss. The key objective of this proposal is to establish a new experimental tool that allows rapid and reversible removal of the PCM1 protein and its associated satellites. The method will involve the insertion of a small tag onto the PCM1 protein. This tag will be recognised by the cells own degradation machinery after addition of a particular compound. Using this technology, I will be able to address how satellites regulate centrosome and cilia assembly as well as their maintenance in proliferating and quiescent cells. Additionally, I will investigate how these functions may differ between ciliated and non-ciliated cell types. Super-resolution and live-cell microscopy as well as biochemical approaches will be used in these studies. Investigating the regulatory role of pericentriolar satellites to centrosome and cilia function will help us to better understand their contribution to neurodevelopmental disorders and cancer.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professorin Dr. Fanni Gergely