Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 49: Molecular motors

BP 49.1: Invited Talk

Thursday, March 19, 2015, 16:45–17:15, H 1028

Directional bias in the kinesin superfamily of molecular motors — •Robert Cross — Warwick Medical School, Coventry CV4 7AL, UK

The molecular stepping mechanisms of various members of the kinesin family are being dissected by a number of labs using experimental protein engineering and single molecule mechanics. The mechanisms of directional bias are of major interest. Kinesin-1 walks towards microtubule plus ends, holding on with one motor head and biasing the attachment direction of the other. Some of this bias may originate in electrostatic steering. The stability of microtubule binding is strain-dependent, and this gives rise to biased detachment, in which the probability of detachment of each motor head depends on the magnitude and direction of the strain it experiences. Docking and undocking of the C-terminal neck linker domain will be strain dependent and can influence both microtubule binding and binding of the ATP fuel and the ADP product of ATP hydrolysis. Altering the tethering point of the motor domains can influence direction, but does not always do so. Other contributors to directional bias are also emerging. Recently, it has emerged that kinesin-5, the architect of bipolarity in the mitotic spindle, slows down and ultimately reverses direction as the number of motors engaged with the microtubule is progressively increased. Our own most recent work addresses the influence of the ATP:ADP ratio in the bathing solution on the directionality of kinesin-1.