Deciphering the molecular dynamics of centriole and centrosome biogenesis
Centrosomes are organelles composed of a pair of centrioles surrounded by a pericentriolar matrix (PCM) that perform a variety of key functions in the animal cell. Centrosomes duplicate precisely once during S-phase of the cell cycle; in G2-phase the two centrosomes move to opposite locations around the nucleus and expand their PCM to nucleate vast quantities of microtubules for mitotic spindle formation. Dysfunctions in the centrosome cycle have been associated with a wide range of pathologies and, in particular, centrosome amplification, an aberrant increase in centrosome numbers, is a hallmark of most human cancers. Centrosomes are complex machines composed of hundreds of proteins, however significant efforts over the past decades have identified the key elements which are essential for centriole and centrosome biogenesis. We can now address the molecular mechanisms that mediate interactions between key players and how these contribute to regulate the number and size of these organelles during the cell cycle. Elucidating these mechanisms is of great interest to cell biology and cancer research. This research proposal aims to investigate aspects of centriole and centrosome biogenesis using Drosophila melanogaster as an animal model. The main objectives are: 1), to reconstitute initial steps of centriole assembly using a hybrid in vivo/in vitro approach, where I will study the molecular dynamics of the interaction between key centriolar proteins Asl and Plk4, using functionalised microspheres as a scaffold and 2), to analyse the dynamic behaviour of single molecules of key centrosomal proteins Cnn and Spd-2 as they move throughout the PCM during expansion, using super-resolution microscopy techniques. We are confident that these studies will provide novel insights into the design principles and inner workings of these important organelles.