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Coordination of type IV pilus motors

Lena Dewenter, Claudia Meel, Jan Ribbe



Movement of round bacteria along surfaces can be explained as a tug-of-war between pilus motors. Pili (red and black lines) act like grappling hooks that adhere to a surface. Each shortening pilus generates force. Vectorial addition of the forces predicts which pili most likely detach from the surface generating bacterial movement.



Many bacterial species use type IV pili for moving on surfaces. The pili act like grappling hooks undergoing cycles of polymerization, adhesion to the surface, and subsequent retraction. During retraction, the cell body moves towards the point of attachment. We have shown that multiple pili cooperate through a tug-of-war mechanism to generate bacterial movement. Currently, we are looking at the role of force generation of pili to understand bacteria switching from moving as individuals to the aggregation of bacterial colonies and biofilms. We are developing automated long-term microscopy approaches in combination with image processing to quantitatively analyse the dynamics of cluster formation. Measuring the interaction energies between bacteria and elucidating molecular determinants governing the interactions will be a particular challenge.

Main collaborators:
Stefan Klumpp, MPI Golm
Alexander Schmidt, WWU Münster
Hank Seifert, Northwestern University
George O’Toole, Dartmouth University
Rudolf Merkel, FZ Jülich

Review articles:
Maier, B. The bacterial type IV pilus system - a tunable molecular motor, Soft Matter, 9, 5667 - 5671 (2013)