Walking revolution

ﾩ 2003 BRANDON PLETSC

The paper:

A. Yildiz et al., "Kinesin walks hand-over-hand," Science, 303:676-8, 2004. (Cited in 72 papers) | [PubMed]

The finding:

In 2004 Paul Selvin's group at the University of Illinois Urbana-Champaign and collaborators at the University of California, San Francisco, used fluorescence imaging with one-nanometer accuracy (FIONA) to demonstrate that kinesin walks in a hand-over-hand fashion, disproving prior studies which suggested it had inchworm-like motion.

The surprise:

According to their calculations in a later paper, kinesin appeared to zip along at 12nm/sec. Selvin says they now believe this breakneck pace to be an artifact of microtubule whiplash.

The follow-up:

Selvin's group showed that FIONA could be used in vivo and that dynein and kinesin move in opposite directions. Now, to understand motor movement directionality, the lab has created chimeric proteins from MyosinV which moves toward the plus-end of actin filaments and MyosinVI which moves toward the minus end.

Selvin's take:

"This technique is so simple, straightforward. If (kinesin) walks hand over hand, the rear foot goes forward and moves twice the length - 16 nm. I think that's why the paper had a big impact. You can just look at (the data) and know the answer."

The work ahead:

Matthew Lang at Massachusetts Institute of Technology says the paper, "definitely helped to solidify the walking mechanism." But, he adds "We lack a molecular picture of the inner-workings?. I don't think the story's over. I don't think we even know 50% of it."