SKM 2023 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 23: Single Molecule Biophysics

BP 23.5: Vortrag

Donnerstag, 30. März 2023, 10:45–11:00, BAR 0106

Superpower behavior of the budding yeast kinesin-8 — •Anita Jannasch, Brent Fielden, Michael Bugiel, and Erik Schäffer — Universität Tübingen

Kinesin-8 motor proteins can regulate microtubule dynamics and their length. Furthermore, they can crosslink microtubules and slide them relative to each other. These properties make the motor important for cell division. The budding yeast kinesin-8, Kip3, depolymerizes microtubule in a collective, force and length-dependent manner. The latter is due to the motor's very high processivity. Recently, we found that contrary to the depolymerization activity of multiple motors, a single Kip3 motor stabilizes microtubules. Compared to conventional kinesin, Kip3 is more than 10x slower and can generate about a 5x lower maximum force suggesting that it is a low power motor. Surprisingly, using high-precision optical tweezers, we observed that single Kip3 bound via a nanobody to optically trapped microspheres occasionally moved about 6x faster generating 3x higher forces compared to its usual behavior. This superpower behavior is almost comparable to conventional kinesin, but it is unclear whether it is related to one of its biological functions. The nanobody coupling also reduced the compliance of the system and thereby improved the spatiotemporal resolution. With the improved resolution, we were able to detect 4-nm mechanical substeps of the motor. In the long term, a better understanding of the various talents of Kip3 on the molecular level will have implications for cell division and associated diseases.