Lipid-driven sorting and fission

Changes in membrane shape during trafficking require proteins, and those proteins are thought to operate mechanically to extrude or squeeze membranes. But biological membranes are also thought to be poised near a phase transition between liquid-ordered (L_o) and liquid-disordered (L_d) states. Aurélien Roux, Patricia Bassereau, Bruno Goud (Institut Curie, Paris, France), and colleagues now report that in vitro tube formation is favored from L_d domains, and phase separation induces fission. Proteins that affect lipid distributions in vivo may thus favor or disfavor tubulation and fission events during protein trafficking.

The preferential tubulation from L_d domains makes sense, as reduced interactions between lipid head groups make these domains more easily deformable. The French team used biotinylated lipids and kinesin-laden beads to pull tubes out of lipid...