title: Cutting Edge: Localization of linker for activation of T cells to lipid rafts is not essential in T cell activation and development.
abstract: It has been proposed that upon T cell activation, linker for activation of T cells (LAT), a transmembrane adaptor protein localized to lipid rafts, orchestrates formation of multiprotein complexes and activates signaling cascades in lipid rafts. However, whether lipid rafts really exist or function remains controversial. To address the importance of lipid rafts in LAT function, we generated a fusion protein to target LAT to nonraft fractions using the transmembrane domain from a nonraft protein, linker for activation of X cells (LAX). Surprisingly, this fusion protein functioned well in TCR signaling. It restored MAPK activation, calcium flux, and NFAT activation in LAT-deficient cells. To further study the function of this fusion protein in vivo, we generated transgenic mice that express this protein. Analysis of these mice indicated that it was fully capable of replacing LAT in thymocyte development and T cell function. Our results demonstrate that LAT localization to lipid rafts is not essential during normal T cell activation and development.
authors.affiliation: Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Minghua
authors.initials: M
authors.lastname: Zhu
authors.forename: Shudan
authors.initials: S
authors.lastname: Shen
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Olivia
authors.initials: O
authors.lastname: Granillo
authors.forename: Weiguo
authors.initials: W
authors.lastname: Zhang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000276:immunology*; D000818:Animals; D015153:Blotting, Western; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D021962:Membrane Microdomains / Q000276:immunology*; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D010750:Phosphoproteins / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C110810:LAT protein, human; D008565:Membrane Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins