Rtn4 (red) marks ER (green) tubules.

RAPOPORT

Tom Rapoport (Harvard University, Boston, MA) presented his group's efforts to understand how organelle shapes are formed and maintained. The findings identify two protein families that create tubules out of ER membrane.

A sphere is the most stable membrane shape; deformations that increase membrane curvature cost energy and must be actively stabilized. Rapoport and colleagues, including Gia Voeltz, used an in vitro system for ER network formation to identify factors that create curved membrane shapes. With just membranes, salt, and GTP, their system produces a network of ER tubules.

This simple, self-contained system was not ideal for identifying the shape-creating components. “When we first saw [that] everything was already in the membrane,” said Rapoport in his talk, “we thought, ‘what a bummer.’” But the group found a way around this difficulty by using small molecule inhibitors to block...

The Rockefeller University Press
2006
The Rockefeller University Press
2006
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