Structural basis of bilayer deformation by membrane-associated scaffolds
This is an Open Access Thesis
The assembly of amphipathic lipids into fluid bilayers that are impermeable to macromolecules is fundamental to the existence of viruses, organelles, and cells. Conversely, membrane compartmentalization poses problems, since essential processes like cell division, cell migration, endo-, exo-, and transcytosis all require cells to remodel and even break their membranes without opening lethal leaks. Evolutionary forces have consequently generated proteins that can reversibly mold membranes into planes, spheres, cylinders, and saddle-shaped surfaces. Principally, the BAR (Bin, Amphiphysin, RVS) domain superfamily of proteins are recruited from the cytoplasm to induce or stabilize states of high membrane curvature, while the Dynamin superfamily of 'large GTPases' facilitate the fission of various vesicles and organelles. Members of the BAR domain superfamily often work in concert with members of the Dynamin superfamily to form and then fission membrane tubules. Here, we describe the membrane deforming properties of select F-BAR modules and the GTPase dynamin-1 that were discovered though reconstitution and direct visualization of these proteins as they shape and break model membranes.