title: The tetraspanin web revisited by super-resolution microscopy.
abstract: The spatial organization of membrane proteins in the plasma membrane is critical for signal transduction, cell communication and membrane trafficking. Tetraspanins organize functional higher-order protein complexes called 'tetraspanin-enriched microdomains (TEMs)' via interactions with partner molecules and other tetraspanins. Still, the nanoscale organization of TEMs in native plasma membranes has not been resolved. Here, we elucidated the size, density and distribution of TEMs in the plasma membrane of human B cells and dendritic cells using dual color stimulated emission depletion (STED) microscopy. We demonstrate that tetraspanins form individual nanoclusters smaller than 120 nm and quantified that a single tetraspanin CD53 cluster contains less than ten CD53 molecules. CD53 and CD37 domains were adjacent to and displayed only minor overlap with clusters containing tetraspanins CD81 or CD82. Moreover, CD53 and CD81 were found in closer proximity to their partners MHC class II and CD19 than to other tetraspanins. Although these results indicate that tetraspanin domains are adjacently positioned in the plasma membrane, they challenge the current view of the tetraspanin web of multiple tetraspanin species organized into a single domain. This study increases the molecular understanding of TEMs at the nanoscale level which is essential for comprehending tetraspanin function in cell biology.
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Malou
authors.initials: M
authors.lastname: Zuidscherwoude
authors.affiliation: Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Göttfert
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Vera Marie E
authors.initials: VM
authors.lastname: Dunlock
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Carl G
authors.initials: CG
authors.lastname: Figdor
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Geert
authors.initials: G
authors.lastname: van den Bogaart
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Annemiek B
authors.initials: AB
authors.lastname: van Spriel
mesh_terms: D018941:Antigens, CD19 / Q000378:metabolism; D001402:B-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003713:Dendritic Cells / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D060265:Tetraspanin 25 / Q000378:metabolism; D060225:Tetraspanin 28 / Q000378:metabolism; D059470:Tetraspanins / Q000378:metabolism*
chemical_list: D018941:Antigens, CD19; D000949:Histocompatibility Antigens Class II; D060265:Tetraspanin 25; D060225:Tetraspanin 28; D059470:Tetraspanins