Highly read on www.cell.com 19 Mar–2 April

Improved high-speed imaging of single molecules shows protein motors use random motions to clamber towards their targets.

When muscles contract or cells divide, the necessary movements depend on foot-like projections of the protein myosin 'stepping' their way to binding sites on strands of the protein actin. Researchers led by Yale E. Goldman at the University of Pennsylvania in Philadelphia attached a dye to a myosin subunit, then used superfast switching of polarized light from multiple directions to take microsecond-scale snapshots that revealed the subunit's orientation and rotations. After detaching from one binding site, myosin takes a forward step that propels it only about two-thirds of the distance towards the next site. Wild gyrations get it the rest of the way. The group is now using the same technique to reveal the dynamics of molecular motors involved in processes such as protein synthesis.

Biophys. J. 104, 1263–1273 (2013)