Biochemistry Building, 301
Tel:  +44 (0)20 7594 5054

Luke Tweedy is a PhD student in the biological physics group. He works on the role played by the shapes of cells in their responses to chemical gradients. He is also an active undergraduate teacher for the third year module in Integrative Systems Biology, and won postgraduate teaching awards in 2011 and 2013.


Chemotaxis is the directed movement of cells in response to chemical gradients. It is an extremely important process to understand, as it is a key part of how our immune system responds to wounds, how nerves develop and connect correctly, and how cancer spreads to new sites in the body.

When chemotaxing in shallow, difficult-to-sense gradients, cells of the slime mould Dictyostelium discoideum seem to behave differently, adpoting a signature shape in which two (or more) distinct protrusions called pseudopods stretch out from the body of the cell. As part of a collaborative research programme, Luke Tweedy has been exploring the role these pseudopods play in chemotaxis, and in particular has been studying their role in the accuracy with which cells choose their direction of movement.



Simulation of cell shape at low SNR: These simulations show the characteristic 'pseudopod splitting' behaviour of live cells in low SNR environments.



Simulation of cell shape at high SNR: In these simulations, pseudopod splitting disappears in favour of a broader leading front of activation.



Shape constrained 'mutant' simulation: Example of a shape-constrained simulation. These do not differ biochemically, but have more restrictive membrane parameters that prevent pseudopod splitting or extensive elongation.