Bidirectional helical motility of cytoplasmic dynein around microtubules
Abstract
Cytoplasmic dynein is a molecular motor responsible for minus-end directed motility along microtubules (MTs). Dynein motility has previously been studied on surface-immobilized MTs, which constrains the motors to move in two dimensions. Here, we explored the full trajectory of dynein motility in three dimensions using an MT bridge assay. We found that dynein moves in a helical trajectory around the MT with an average pitch of ~500 nm. Unlike other cytoskeletal motors that produce torque in a specific direction, dynein generates torque in either direction, resulting in bidirectional helical motion. Dynein has a net preference for right-handed rotation, suggesting that the heads tend to bind to the closest tubulin binding site when taking sideways steps. This bidirectional helical motility may allow dynein to avoid roadblocks in dense cytoplasmic environments during cargo transport.
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© 2014, Can et al.
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