Cooperative molecular motors moving back and forth.
We use a two-state ratchet model to study the cooperative bidirectional motion of molecular motors on cytoskeletal tracks with randomly alternating polarities. Our model is based on a previously proposed model [Badoual, Proc. Natl. Acad. Sci. U.S.A. 99, 6696 (2002)] for collective motor dynamics and, in addition, takes into account the cooperativity effect arising from the elastic tension that develops in the cytoskeletal track due to the joint action of the walking motors. We show, both computationally and analytically, that this additional cooperativity effect leads to a dramatic reduction in the characteristic reversal time of the bidirectional motion, especially in systems with a large number of motors. We also find that bidirectional motion takes place only on (almost) apolar tracks, while on even slightly polar tracks the cooperative motion is unidirectional. We argue that the origin of these observations is the sensitive dependence of the cooperative dynamics on the difference between the number of motors typically working in and against the instantaneous direction of motion.
Department of Chemical Engineering, Ben Gurion University, Be'er Sheva 84105, Israel.
David
D
Gillo
Barak
B
Gur
Anne
A
Bernheim-Groswasser
Oded
O
Farago
D003198:Computer Simulation; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009068:Movement; D011336:Probability; D013997:Time Factors
D020409:Molecular Motor Proteins