Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 25: Posters: Molecular Motors
BP 25.2: Poster
Donnerstag, 29. März 2012, 17:30–19:30, Poster A
The highly-processive kinesin-8, Kip3p, derails from microtubule protofilaments — •Aniruddha Mitra1,2, Bert Nitzsche1,2, Volker Bormuth1,3, Felix Ruhnow1,2, Marko Stroch1, Burkhard Rammner4, Jonathon Howard1, and Stefan Diez1,2 — 1MPI-CBG, Dresden, Germany — 2B CUBE, Dresden, Germany — 3Institut Curie, Paris, France — 4Scimotion, Hamburg, Germany
Kinesin-8 controls microtubule length based on its depolymerization activity at microtubule plus-ends preceded by highly processive motility. However, the mechanism confering high motor processivity even on crowded microtubules in the cytoplasm is not known. We therefore asked if kinesin-8 is capable of switching protofilaments during its plus-end directed motility along the microtubule lattice. We performed in vitro gliding motility assays on surfaces coated with the budding yeast kinesin-8, Kip3p, and measured the rotations of the microtubules around their longitudinal axis using quantum dots in combination with fluorescence-interference contrast microscopy and 2D nanometer tracking. We observed counterclockwise rotations with periodictities unrelated to the microtubule supertwist. Such rotations indicate that the motors do not follow the axes of individual protofilaments but rather switch between them perpetually. We hypothesize that this behaviour, which distinguishes kinesin-8 from the processive protofilament tracker kinesin-1, (i) results from a comparetively long neck linker, non-centrally attached to the motor domain and (ii) is essential for high processivity.