title: A Model for Shaping Membrane Sheets by Protein Scaffolds.
abstract: Membranes of peripheral endoplasmic reticulum form intricate morphologies consisting of tubules and sheets as basic elements. The physical mechanism of endoplasmic-reticulum shaping has been suggested to originate from the elastic behavior of the sheet edges formed by linear arrays of oligomeric protein scaffolds. The heart of this mechanism, lying in the relationships between the structure of the protein scaffolds and the effective intrinsic shapes and elastic properties of the sheets' edges, has remained hypothetical. Here we provide a detailed computational analysis of these issues. By minimizing the elastic energy of membrane bending, we determine the effects of a rowlike array of semicircular arclike membrane scaffolds on generation of a membrane fold, which shapes the entire membrane surface into a flat double-membrane sheet. We show, quantitatively, that the sheet's edge line tends to adopt a positive or negative curvature depending on the scaffold's geometrical parameters. We compute the effective elastic properties of the sheet edge and analyze the dependence of the equilibrium distance between the scaffolds along the edge line on the scaffold geometry.
authors.affiliation: Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel; Nuclear Physics Division, Soreq Nuclear Research Center, Yavne, Israel.
authors.forename: Yonatan
authors.initials: Y
authors.lastname: Schweitzer
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Tom
authors.initials: T
authors.lastname: Shemesh
authors.affiliation: Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel. Electronic address: michk@post.tau.ac.il.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Kozlov
mesh_terms: D004548:Elasticity; D004721:Endoplasmic Reticulum / Q000737:chemistry; D007425:Intracellular Membranes / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D008962:Models, Theoretical; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation
chemical_list: D008565:Membrane Proteins