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BP: Fachverband Biologische Physik

BP 12: Molecular Motors

BP 12.2: Vortrag

Dienstag, 12. März 2013, 10:00–10:15, H43

Bi-directionality of Single Kinesin-5 Cin8 Molecules is Mediated by the Tail Domains — •André Düselder¹, Christina Thiede¹, Alice Wiesbaum¹, Vladimir Fridman², Dieter Klopfenstein¹, Olga Zaitsava³, Marcel E. Janson³, Larisa Gheber², and Christoph F. Schmidt¹ — ¹Georg-August-Universität, Göttingen, DE — ²Ben-Gurion University of the Negev, Beer-Sheva, IL — ³Wageningen University, Wageningen, NL

The tetrameric yeast Kinesin-5 Cin8 can switch from a fast minus-end to a slow plus-end-directed motion. We found evidence that binding between two microtubules switches the motor to plus-end motility. We hypothesized that the tail domains of Cin8 influence the adjacent motor domains, depending on the binding state between microtubules. We designed two different motor constructs to test our hypothesis. To rule out any head-tail-interactions we removed the tail domains of Cin8 (Cin8Δtail). This construct retained its ability to link and slide apart two microtubules. Its motility on single microtubules, however, was under all conditions slow, intermittent, and mostly plus end directed. We also constructed a stably dimeric Cin8/Kinesin-1 chimera (Cin8Kin), consisting of head and neck linker of Cin8 fused to the stalk of Kinesin-1. This chimera showed a similar motility as Cin8Δtail. We therefore conclude that the Cin8 head domains are inherently bidirectional and that the interaction between tail and motor domains of Cin8 are responsible for stably switching the motility to either plus- or minus-end directed motion.