title: Visualization of endoplasmic reticulum subdomains in cultured cells.
abstract: The lipids and proteins in eukaryotic cells are continuously exchanged between cell compartments, although these retain their distinctive composition and functions despite the intense interorganelle molecular traffic. The techniques described in this paper are powerful means of studying protein and lipid mobility and trafficking in vivo and in their physiological environment. Fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) are widely used live-cell imaging techniques for studying intracellular trafficking through the exo-endocytic pathway, the continuity between organelles or subcompartments, the formation of protein complexes, and protein localization in lipid microdomains, all of which can be observed under physiological and pathological conditions. The limitations of these approaches are mainly due to the use of fluorescent fusion proteins, and their potential drawbacks include artifactual over-expression in cells and the possibility of differences in the folding and localization of tagged and native proteins. Finally, as the limit of resolution of optical microscopy (about 200 nm) does not allow investigation of the fine structure of the ER or the specific subcompartments that can originate in cells under stress (i.e. hypoxia, drug administration, the over-expression of transmembrane ER resident proteins) or under pathological conditions, we combine live-cell imaging of cultured transfected cells with ultrastructural analyses based on transmission electron microscopy.
authors.affiliation: Fondazione Filarete; Department of Biotechnology and Translational Medicine, University of Milan; Neuroscience Institute, National Research Council (CNR).
authors.forename: Matteo
authors.initials: M
authors.lastname: Fossati
authors.affiliation: Department of Biotechnology and Translational Medicine, University of Milan; Neuroscience Institute, National Research Council (CNR); Department of Health Science, "Magna Graecia" University of Catanzaro.
authors.forename: Nica
authors.initials: N
authors.lastname: Borgese
authors.affiliation: Department of Biotechnology and Translational Medicine, University of Milan; Neuroscience Institute, National Research Council (CNR).
authors.forename: Sara Francesca
authors.initials: SF
authors.lastname: Colombo
authors.affiliation: Fondazione Filarete; Department of Biotechnology and Translational Medicine, University of Milan; m.francolini@in.cnr.it.
authors.forename: Maura
authors.initials: M
authors.lastname: Francolini
mesh_terms: D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D036681:Fluorescence Recovery After Photobleaching; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D051381:Rats; D014162:Transfection
chemical_list: D049452:Green Fluorescent Proteins