Erik Schäffer

Nanomechanics of Cellular Machines

University of Tübingen
Faculty in: IMPRS

Vita

PhD work in polymer physics, Konstanz and Groningen Universities, 1998-2001
Postdoctoral training, MPI of Molecular Cell Biology and Genetics, Dresden, 2002-06
Group leader, TU Dresden, 2007-12
Professor for Cellular Nanoscience at the University of Tübingen since 2012

Research Interest
Molecular machines are fascinating devices that drive self-organization in cells. While the protein components of many biological machines have been identified, the mechanical principles that govern the operation of biological machines are poorly understood. For example, how much force can they generate; and what limits their speed and efficiency? We use and develop single-molecule fluorescence and label-free microscopy, high-resolution optical tweezers and novel trapping probes to measure intermolecular forces that are central to biological questions such as how kinesin motor proteins move and diffuse along microtubules, orchestrate plant cytokinesis, or how damaged DNA is repaired via homologous recombination.

On the left side is a fluorescent image of single motor proteins. Motion of two diffusing kinesin molecules on a microtubule shown as a time series kymograph. On the right side is a schematic illustrating the measurement of the the friction force between the motor and its microtubule track. — Figure 1. Left: Fluorescent image of single motor proteins. Motion of two diffusing kinesin molecules (green) on a microtubule (red) shown as a time series kymograph. Right: Schematic. By dragging diffusing kinesin molecules with laser tweezers over a microtubule, the friction force between the motor and its microtubule track can be measured very precisely.

Figure 1. Left: Fluorescent image of single motor proteins. Motion of two diffusing kinesin molecules (green) on a microtubule (red) shown as a time series kymograph.
Right: Schematic. By dragging diffusing kinesin molecules with laser tweezers over a microtubule, the friction force between the motor and its microtubule track can be measured very precisely.

Kinesin motor transports vesicle along microtubule.

Rotational hand-over-hand kinesin stepping mechanism with substeps. Animation made by Janet Iwasa based on Sudhakar 2021 & Ramaiya 2017.

https://www.youtube.com/watch?v=plvQCOE9s_k

Available PhD Projects in the IMPRS

High resolution tracking of kinesin motors

Selected Reading

Swathi Sudhakar, Mohammad Kazem Abdosamadi, Tobias Jörg Jachowski, Michael Bugiel, Anita Jannasch, Erik Schäffer (2021) Germanium nanospheres for ultraresolution picotensiometry of kinesin motors. Science 371:eabd9944
Ramaiya A, Roy B, Bugiel M, Schäffer E (2017) Kinesin rotates unidirectionally and generates torque while walking on microtubules. PNAS 114: 10894–10899.
Bormuth V, Varga V, Howard J, Schäffer E (2009). Protein friction limits diffusive and directed movements of kinesin motors on microtubules. Science 325:870-873.