title: Glasslike Membrane Protein Diffusion in a Crowded Membrane.
abstract: Many functions of the plasma membrane depend critically on its structure and dynamics. Observation of anomalous diffusion in vivo and in vitro using fluorescence microscopy and single particle tracking has advanced our concept of the membrane from a homogeneous fluid bilayer with freely diffusing proteins to a highly organized crowded and clustered mosaic of lipids and proteins. Unfortunately, anomalous diffusion could not be related to local molecular details given the lack of direct and unlabeled molecular observation capabilities. Here, we use high-speed atomic force microscopy and a novel analysis methodology to analyze the pore forming protein lysenin in a highly crowded environment and document coexistence of several diffusion regimes within one membrane. We show the formation of local glassy phases, where proteins are trapped in neighbor-formed cages for time scales up to 10 s, which had not been previously experimentally reported for biological membranes. Furthermore, around solid-like patches and immobile molecules a slower glass phase is detected leading to protein trapping and creating a perimeter of decreased membrane diffusion.
authors: U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy , 163 avenue de Luminy, 13009 Marseille, France.
authors: Ignacio
authors: I
authors: Munguira
authors: U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy , 163 avenue de Luminy, 13009 Marseille, France.
authors: Ignacio
authors: I
authors: Casuso
authors: U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy , 163 avenue de Luminy, 13009 Marseille, France.
authors: Hirohide
authors: H
authors: Takahashi
authors: U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy , 163 avenue de Luminy, 13009 Marseille, France.
authors: Felix
authors: F
authors: Rico
authors: U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy , 163 avenue de Luminy, 13009 Marseille, France.
authors: Atsushi
authors: A
authors: Miyagi
authors: Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel , Mattenstrasse 26, CH-4058 Basel, Switzerland.
authors: Mohamed
authors: M
authors: Chami
authors: U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy , 163 avenue de Luminy, 13009 Marseille, France.
authors: Simon
authors: S
authors: Scheuring
mesh_terms: D004058:Diffusion; D008051:Lipid Bilayers / Q000737:chemistry*; D014118:Toxins, Biological / Q000737:chemistry*; D058989:Vitrification
chemical_list: D008051:Lipid Bilayers; D014118:Toxins, Biological; C107040:lysenin
keywords: anomalous diffusion; glass−glass transition; high-speed atomic force microscopy; membrane domains; membrane dynamics; single molecule