Kinesin's walk: Springy or gated head coordination?

Authored by Richard J. Wilson

Date Published: 2009-05

DOI: 10.1016/j.biosystems.2008.12.002

Sponsors: United Kingdom Engineering and Physical Sciences Research Council (EPSRC)

Platforms: C

Model Documentation: Other Narrative

Model Code URLs: Model code not found

Abstract

Conventional kinesin (kinesin-1) is a motor protein that performs a vital function in the eukaryotic cell: it actively transports cargo to required destinations. Kinesin pulls cargo along microtubule tracks using twin linked motor domains (heads) that bind the microtubule, hydrolyse ATP, and alternately step forward. The detail of the kinesin walk has yet to be discovered but a prominent theory is that the mechanism is rectified Brownian motion (RBM) biased by linker zippering. There is evidence that an ATP binding gate coordinates the heads. The hypothesis proposed here is that the gate is unnecessary, that entropic linker strain is sufficient to enable procession. An agent-based computer simulation has been devised to explore head coordination in the RBM model. Walking was found to emerge in silico without a gate to synchronise the heads. Further investigation of the model by applying a range of hindering loads resulted in backstepping or detachment with similar characteristics to behaviour observed in vitro. It is unclear whether kinesin waits at an obstacle but adding an ATP hydrolysis gate to the model in order to force waiting resulted in the model behaving less realistically under load. It is argued here that an RBM model free of gating is a good candidate for explaining kinesin procession. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Tags

Agent-based modeling ATP gating Entropic strain Motor protein procession Rectified Brownian motion