Nanoclusters of the resting T cell antigen receptor (TCR) localize to non-raft domains

• Published in: Biochimica et biophysica acta Vol. 1853; no. 4; pp. 802 - 809
• Main Authors: Beck-García, Katharina, Beck-García, Esmeralda, Bohler, Sheila, Zorzin, Carina, Sezgin, Erdinc, Levental, Ilya, Alarcón, Balbino, Schamel, Wolfgang W.A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2015
• Subjects: Animals; Cholesterol; Green Fluorescent Proteins - metabolism; Humans; Jurkat Cells; Lipid; Lipids - chemistry; Medicin och hälsovetenskap; Membrane; Membrane Microdomains - metabolism; Mice; Nanoclustering; Nanoparticles - chemistry; Protein Binding; Protein Structure, Tertiary; Protein Transport; Rats; Receptors, Antigen, T-Cell - metabolism; Recombinant Fusion Proteins - metabolism; TCR; Unilamellar Liposomes - metabolism; Membrane; TCR; Nanoclustering; Lipid; Cholesterol
• ISSN: 0167-4889; 0006-3002; 1879-2596; 1878-2434
• DOI: 10.1016/j.bbamcr.2014.12.017

In the last decade an increasing number of plasma membrane (PM) proteins have been shown to be non-randomly distributed but instead forming submicron-sized oligomers called nanoclusters. Nanoclusters exist independently of the ligand-bound state of the receptors and their existence implies a high degree of lateral organisation of the PM and its proteins. The mechanisms that drive receptor nanoclustering are largely unknown. One well-defined example of a transmembrane receptor that forms nanoclusters is the T cell antigen receptor (TCR), a multisubunit protein complex whose nanoclustering influences its activity. Membrane lipids, namely cholesterol and sphingomyelin, have been shown to contribute to TCR nanoclustering. However, the identity of the membrane microdomain in which the TCR resides remains controversial. Using a GFP-labeled TCR we show here that the resting TCR localized in the disordered domain of giant PM vesicles (GPMVs) and PM spheres (PMSs) and that single and nanoclustered TCRs are found in the high-density fractions in sucrose gradients. Both findings are indicative of non-raft localization. We discuss possible mechanisms of TCR nanoclustering in T cells. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling. •We use giant PM vesicles and PM spheres to analyze TCR localization.•Resting TCR nanoclusters are localized in the non-raft domain.•We discuss possible mechanisms of TCR nanoclustering.