Membrane tubulation induced by chiral crescent-shaped proteins

In living cells, structures of biomembranes are regulated by various proteins. We studied the protein assembly and membrane remodeling using coarse-grained meshless membrane simulations. We revealed how chirality of crescent-shaped protein rods changes their assembly and tubulation. The achiral rods deformed the membrane tube into an elliptical shape by stabilizing the edges of the ellipse. In contrast, the chiral rods formed a helical assembly that generated a cylindrical membrane tube with a constant radius in addition to the elliptical tube. This helical assembly could be further stabilized by the direct side-to-side attraction between the protein rods. The chirality also promotes the tubulation from a flat membrane. These results agree with experimental findings of the constant radius of membrane tubules induced by Bin/Amphiphysin/Rvs (BAR) superfamily proteins.