title: Dynamics of GPI-anchored proteins on the surface of living cells.
abstract: Rather than being distributed homogeneously on the cell surface, proteins are probably aggregated in clusters or in specific domains. Some of these domains (lipid rafts) have lipid compositions, which differ from their surrounding membrane. They have been implicated in cell signaling, cell adhesion, and cholesterol homeostasis. Estimates of their size vary from 40 to 350 nm in diameter depending on the study and cell type used. Rafts are enriched in glycosphingolipids and cholesterol and appear to be in a more ordered lipid phase. Although there is some knowledge of their function in cell signaling, less is known about their assembly and dynamics in cells at various temperatures. We use image correlation spectroscopy and dynamic image correlation spectroscopy to study the clustering and diffusion of glycosylphosphatidylinositol (GPI)-anchored proteins within the plasma membrane of living cells at various temperatures. We find that GPI-anchored proteins occur both as monomers and in clusters at the cell surface. The propensities to cluster as well as the diffusion coefficient of these clusters are strongly temperature dependent. At 37 degrees C the GPI-anchored proteins are highly dynamic with a lower state of clustering than at lower temperatures.
authors.affiliation: Department of Chemical and Biological Engineering, Institute of Molecular Biophysics, University of Maine, Orono, Maine, USA.
authors.forename: Anja
authors.initials: A
authors.lastname: Nohe
authors.forename: Eleonora
authors.initials: E
authors.lastname: Keating
authors.forename: Marc
authors.initials: M
authors.lastname: Fivaz
authors.forename: F Gisou
authors.initials: FG
authors.lastname: van der Goot
authors.forename: Nils O
authors.initials: NO
authors.lastname: Petersen
mesh_terms: D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002522:Chlorocebus aethiops; D003198:Computer Simulation; D003505:Cyclodextrins / Q000008:administration & dosage*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological
chemical_list: D003505:Cyclodextrins; D017261:Glycosylphosphatidylinositols