A model for cooperativity of kinesin-4 motors by communicating through the microtubule track

Abstract

Kinesin-4 motor proteins at nanomolar concentrations can accumulate at microtubule plus ends, regulating the microtubule length. Recent experimental studies showed that at picomolar motor concentrations, under which nearly no motor crowding can occur, the run length of the kinesin-4 motor increases whereas the velocity decreases with the motor concentration, indicating the presence of a long-range communication between the motors through the microtubule track. However, the mechanism of the long-range communication is illusive. Here, based on the proposal that large conformational changes of the tubulin induced by the strong interaction with a kinesin head can propagate along the microtubule such that influence the tubulin-binding energy of other motors distant away, the dynamics of the kinesin-4 motor at the picomolar motor concentrations is studied theoretically, explaining quantitatively the experimental data. Moreover, the lifetime of the motor when multiple motors are jammed near the plus ends at high motor concentrations is studied theoretically.