News

01.12.2023

Ludger Santen elected as President of Saarland University

Ludger Santen, Professor forr Theoretical Physics (Saarland University) and director of the Center for Biophysics, has been elected to be become the President of Saarland University. His term will start on  April 1, 2024.
"I would like to expand the topic of sustainability, which is already part of cross-faculty research issues. This includes research into new materials, energy storage and the circular economy, to name just a few examples," says Ludger Santen. Here, as with many other topics, he would like to see committed colleagues. "I want to encourage people at both university locations to show the courage to take the initiative and I want to support this to the best of my ability."

Press release of Saarland University from December 1, 2023 (in German).

Vesicles driven by dynein and kinesin exhibit directional reversals without regulators

Intracellular vesicular transport along cytoskeletal filaments ensures targeted cargo delivery. Such transport is rarely unidirectional but rather bidirectional, with frequent directional reversals owing to the simultaneous presence of opposite-polarity motors. So far, it has been unclear whether such complex motility pattern results from the sole mechanical interplay between opposite-polarity motors or requires regulators.

In our receent publication in Nature Communications,  we - together with the group of Stefan Diez (TU Dresden) - demonstrate that a minimal system, comprising purified Dynein-Dynactin-BICD2 (DDB) and kinesin-3 (KIF16B) attached to large unilamellar vesicles, faithfully reproduces in vivo cargo motility, including runs, pauses, and reversals. Remarkably, opposing motors do not affect vesicle velocity during runs. Our computational model reveals that the engagement of a small number of motors is pivotal for transitioning between runs and pauses. Taken together, our results suggest that motors bound to vesicular cargo transiently engage in a tug-of-war during pauses. Subsequently, stochastic motor attachment and detachment events can lead to directional reversals without the need for regulators.

Publication:
Ashwin I. D’Souza, Rahul Grover, Gina A. Monzon, Ludger Santen & Stefan Diez: Vesicles driven by dynein and kinesin exhibit directional reversals without regulators. Nat. Commun. 14, 7532 (2023).10.1039/d3sm01045g.