Jonathon Pines - Overview

Regulation of mitosis in mammalian cells
We are studying how cells divide. In particular we are focusing on two main aspects of cell division: how the cell first initiates mitosis, and how the cell subsequently co-ordinates the different events of mitosis by ubiquitin-mediated proteolysis. We are assaying these processes in real time using time-lapse fluorescence microscopy.

We use GFP-fusion proteins to analyse the behaviour of cell cycle regulators in living cells. We use this assay to determine how their localisation is altered depending on the stage of the cell cycle, and to define the domains of the proteins that target them to specific subcellular structures. After defining these domains we use them to isolate the proteins that are responsible for targeting and controlling the individual mitotic regulators.

To understand how proteolysis is used to regulate progress through mitosis we assay the degradation of the GFP-fusion proteins in living cells, because their fluorescence is directly related to their protein levels. We are investigating the behaviour of key substrates at each stage of mitosis, including cyclin A, cyclin B1 and securin, and are using these to define the events and the mechanisms that trigger the destruction of specific proteins at specific times and in specific places.

Co-workers: Claire Acquaviva, Caroline Broad, Viji Draviam, Anja Hagting, Mark Jackman, Catherine Lindon, Takahiro Matsusaka, Jo Richardson, Rob Wolthuis.