Cooperation of ADP-ribosylation factor 1 (Arf1) and Coatomer in membrane scission

Formation of coated vesicles requires two manipulations of the lipid bilayer. First, membrane curvature is induced driving bud formation. Second, a scission reaction at the bud neck releases the vesicle. Here we investigate cooperative effects of Arf1 and coatomer to membrane deformation, ultimately leading to COPI bud formation, and membrane scission. Both a dimerisation-deficient Arf1 mutant, Arf1Y35A, and an Arf1 variant lacking the N-terminal amphipathic helix fail to exert membrane surface activity, resulting in scission-arrest. Dimerisation of these mutants by chemical-crosslinking restores membrane surface activity, however only the chemically dimerised Arf1 mutant Y35A can overcome the scission-arrest.