title: Condensation of the plasma membrane at the site of T lymphocyte activation.
abstract: After activation, T lymphocytes restructure their cell surface to form membrane domains at T cell receptor (TCR)-signaling foci and immunological synapses (ISs). To address whether these rearrangements involve alteration in the structure of the plasma membrane bilayer, we used the fluorescent probe Laurdan to visualize its lipid order. We observed a condensation of the plasma membrane at TCR activation sites. The formation of ordered domains depends on the presence of the transmembrane protein linker for the activation of T cells and Src kinase activity. Moreover, these ordered domains are stabilized by the actin cytoskeleton. Membrane condensation occurs upon TCR stimulation alone but is prolonged by CD28 costimulation with TCR. In ISs, which are formed by conjugates of TCR transgenic T lymphocytes and cognate antigen-presenting cells, similar condensed membrane phases form first in central regions and later at the periphery of synapses. The formation of condensed membrane domains at T cell activation sites biophysically reflects membrane raft accumulation, which has potential implications for signaling at ISs.
authors.affiliation: Centre for Vascular Research at the School of Medical Sciences, University of New South Wales, Sydney 2052 NSW, Australia. k.gaus@unsw.edu.au
authors.forename: Katharina
authors.initials: K
authors.lastname: Gaus
authors.forename: Elena
authors.initials: E
authors.lastname: Chklovskaia
authors.forename: Barbara
authors.initials: B
authors.lastname: Fazekas de St Groth
authors.forename: Wendy
authors.initials: W
authors.lastname: Jessup
authors.forename: Thomas
authors.initials: T
authors.lastname: Harder
mesh_terms: D000818:Animals; D018106:CD28 Antigens / Q000494:pharmacology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D019169:Jurkat Cells; D008051:Lipid Bilayers / Q000378:metabolism; D008055:Lipids / Q000032:analysis; D008213:Lymphocyte Activation / Q000502:physiology*; D021962:Membrane Microdomains / Q000378:metabolism; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D013601:T-Lymphocytes / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D018106:CD28 Antigens; D008051:Lipid Bilayers; D008055:Lipids; D011948:Receptors, Antigen, T-Cell