Picking the clathrin lock

Endocytic cargos are ensheathed in a clathrin coat—a complicated woven lattice that looks like it could never be pried apart. Yet uncoating occurs soon after vesicles are released from the plasma membrane, thanks to Hsc70 and its cochaperone auxilin. New structures of the clathrin coat with and without auxilin reveal a possible latch that might spring open to release the clathrin lock.

The structures come from Alexander Fotin, Tomas Kirchhausen, Stephen Harrison, Thomas Walz (Harvard Medical School, Boston, MA), and colleagues. Existing electron micrograph (EM) structures were “unsatisfying,” says Kirchhausen, because “you couldn't see the contacts.” The Boston team selected the best of their EM images of purified clathrin cages, clustered the images by orientation, and removed error-prone, distorted structures. After fitting the computer-generated structure with existing X-ray structures of...