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Directionality and processivity of molecular motors
Hideo Higuchi1, Sharyn A Endow
1Center for Interdisciplinary Research and Department of Metallurgy, Graduate School of Engineering, Tohoku University, 980-8579, Sendai, Japan. higuchi@material.tohoku.ac.jp
Current Opinion in Cell Biology
|January 17, 2002
Summary
New insights into motor directionality reveal how molecular motors move. Non-processive motors use a hand-over-hand mechanism, confirmed by experiments on myosin V and kinesin, to ensure efficient movement.
Area of Science:
- Molecular biology
- Biophysics
- Cellular mechanics
Background:
- Molecular motors are essential for intracellular transport.
- Understanding motor directionality and processivity is key to cellular function.
- Current models predict specific binding states for processive motors.
Purpose of the Study:
- To investigate the mechanism of altered directionality in molecular motors.
- To confirm predictions regarding the processive two-heads-bound state.
- To elucidate the binding and hydrolysis cycle of non-processive motors.
Main Methods:
- Analysis of a mutant with altered motor directionality.
- Electron microscopy to visualize myosin V.
- Unbinding experiments to study kinesin.
Main Results:
- Confirmed the prediction of a two-heads-bound state for processive motors.
- Electron microscopy validated this state for myosin V.
- Unbinding experiments supported this model for kinesin.
- Emerging evidence suggests non-processive motors use a single-head binding and release mechanism.
Conclusions:
- The study provides new insights into the directionality of molecular motors.
- The findings support a hand-over-hand mechanism for non-processive motors.
- Experimental evidence validates current models for processive motor function.