title: Domain formation in membranes with quenched protein obstacles: lateral heterogeneity and the connection to universality classes.
abstract: We show that lateral fluidity in membranes containing quenched protein obstacles belongs to the universality class of the two-dimensional random-field Ising model. The main feature of this class is the absence of a phase transition: there is no critical point and macroscopic domain formation does not occur. Instead there is only one phase. This phase is highly heterogeneous with a structure consisting of microdomains. The presence of quenched protein obstacles thus provides a mechanism to stabilize lipid rafts in equilibrium. Crucial for two-dimensional random-field Ising universality is that the obstacles are randomly distributed and have a preferred affinity to one of the lipid species. When these conditions are not met standard Ising or diluted Ising universality applies. In these cases a critical point does exist which then marks the onset toward macroscopic demixing.
authors.affiliation: Institute of Theoretical Physics, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Fischer
authors.forename: R L C
authors.initials: RL
authors.lastname: Vink
mesh_terms: D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry; D008560:Membrane Fluidity; D021962:Membrane Microdomains / Q000737:chemistry*; D008954:Models, Biological; D008958:Models, Molecular; D044367:Phase Transition; D011506:Proteins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D011506:Proteins