Table of Contents

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Volume 25, Number 9
03 May 2006

pp 1795-2038

Single-molecule studies on myosin V reveal several new mechanisms the molecular motor may use to navigate in the heterogeneous intracellular environment. The experiments (see article on page 1795 of this issue) simultaneously examined nanometer-resolved translational movements and orientational changes of fluorescently-tagged motor proteins in vitro and established that every translational step is associated with tilting of the motor�s lever arm. Additional reorientations are detected when the motor is waiting between steps, suggesting that myosin V may �probe� its vicinity before executing the next working stroke. The results also show that the molecular motor can alter its course around actin, possibly to avoid obstacles. Taken together, the different mechanisms show myosin V to be a highly agile intracellular cargo transporter.

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