[Frontiers in Bioscience 14, 2269-2284, January 1, 2009]

Five models for myosin V

Andrej Vilfan1

1J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia


1. Abstract
2. Introduction
3. Main findings
3.1. Stepping
3.2. Step size
3.3. Force-velocity relation
3.4. Processivity
3.5. Kinetics
3.5.1. Single-headed
3.5.2. Double-headed
4. Open questions
4.1. Head-head coordination
4.2. Lead head state
4.3. Sub-steps
4.4. How tight is the coupling between the hydrolysis cycle and the stepping?
4.5. Source of elasticity
5. Theoretical models
5.1. Overview
5.2. Discrete stochastic models
5.2.1. Kolomeisky and Fisher
5.2.2. Skau, Hoyle and Turner
5.2.3. Wu, Gao and Karplus
5.3. Mechano-chemical models
5.3.1. Lan and Sun
5.3.2. Elastic lever arm model
6. Conclusions
7. Acknowledgements
8. References


Myosin V was the first discovered processive motor from the myosin family. It has therefore been subject of a number of mechanical, kinetic, optical and structural studies and now belongs to the best characterised motor proteins. This effort has been accompanied by a number of different theoretical models. In this article we give an overview of them and discuss what they have in common and where the open questions are. The latter include the existence of sub-steps, the process that limits the run length, the nature of backward steps, the flexibility of the lever arm and the state of the lead head.