A spinning bead betrays the twisting action of dynamin.

DE CAMILLI/MACMILLAN

Aurélien Roux, Pietro de Camilli, and colleagues (Yale University, New Haven, CT) report the best evidence yet that dynamin uses mechanochemical activity—specifically a twisting action—to pinch off endocytic vesicles.

Dynamin was, early on, localized to the collar around the neck of forming endocytic vesicles. This suggested that dynamin may use the energy of GTP hydrolysis to directly pinch a membranous neck. Indeed, dynamin could tubulate lipids and break apart the tubules in vitro, although later it seemed that the breaking apart was happening as the samples dried on EM grids.

Meanwhile, Sandy Schmid (Scripps Research Institute, La Jolla, CA) had come up with a “regulatory GTPase” model: that dynamin was active not as it hydrolyzed GTP but in its GTP-bound form, which recruited other proteins to do the pinching. This theory was controversial, and...

The Rockefeller University Press
2006
The Rockefeller University Press
2006
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