Despite significant progress in recent years in elucidating the intracellular biochemical consequences of T cell activation via the T cell receptor (TCR), the precise mechanism driving the initial communication of a signal across the membrane upon receptor ligation remains unknown. TCR clustering, coreceptor recruitment and conformational changes in the receptor have all been proposed to play important roles in signal initiation, but no widely accepted model has emerged. The structure and stoichiometry of the complete TCR/CD3 complex expressed at the T cell surface also remains an open question, and models involving a TCR valency of greater than one have been proposed. The goal of this project is to define the structural features that drive the assembly of the TCR/CD3 complex, and to examine the triggering mechanisms based on an understanding of the subunit interactions and the stoichiometry of the complex at the cell surface. An in vitro translation and assembly system will be one of the major tools for these studies, and the investigators have developed new methods for the preparation of ER microsomes that permit complex assembly experiments as well as approaches for isolation of key assembly intermediates. The preliminary data demonstrate unusual interactions between basic and acidic transmembrane residues of the TCR and associated CD3 chains. Assembly of each of the three CD3 dimers with the TCR requires two acidic CD3 and one basic TCR residue in the membrane, and in each case these three transmembrane residues appear to interact. The major hypothesis of this project is that these distinctive interactions among potentially charged transmembrane residues are critical not only in the assembly of the alpha-beta, gamma-delta and pre-TCR, but also in guiding the conformational changes that are induced upon receptor triggering. Specifically, these interaction points between the TCR and CD3 subunits in the membrane may be at the center of conformational movements of both extracellular and cytoplasmic domains that bring the signaling modules into close proximity upon receptor engagement. Such a conformational change may be induced by recruitment of TCR/CD3 complexes to lipid rafts, which have an increased thickness relative to the surrounding plasma membrane due to the presence of sphingolipids and cholesterol. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI054520-05
Application #
7232671
Study Section
Allergy and Immunology Study Section (ALY)
Program Officer
Mallia, Conrad M
Project Start
2003-04-01
Project End
2009-01-31
Budget Start
2007-04-01
Budget End
2009-01-31
Support Year
5
Fiscal Year
2007
Total Cost
$364,813
Indirect Cost
Name
Dana-Farber Cancer Institute
Department
Type
DUNS #
076580745
City
Boston
State
MA
Country
United States
Zip Code
02215
Dobbins, Jessica; Gagnon, Etienne; Godec, Jernej et al. (2016) Binding of the cytoplasmic domain of CD28 to the plasma membrane inhibits Lck recruitment and signaling. Sci Signal 9:ra75
Bettini, Matthew L; Guy, Clifford; Dash, Pradyot et al. (2014) Membrane association of the CD3? signaling domain is required for optimal T cell development and function. J Immunol 193:258-67
Schulze, Monika-Sarah E D; Wucherpfennig, Kai W (2012) The mechanism of HLA-DM induced peptide exchange in the MHC class II antigen presentation pathway. Curr Opin Immunol 24:105-11
Gagnon, Etienne; Schubert, David A; Gordo, Susana et al. (2012) Local changes in lipid environment of TCR microclusters regulate membrane binding by the CD3? cytoplasmic domain. J Exp Med 209:2423-39
Wen, Fei; Sethi, Dhruv K; Wucherpfennig, Kai W et al. (2011) Cell surface display of functional human MHC class II proteins: yeast display versus insect cell display. Protein Eng Des Sel 24:701-9
Sethi, Dhruv K; Schubert, David A; Anders, Anne-Kathrin et al. (2011) A highly tilted binding mode by a self-reactive T cell receptor results in altered engagement of peptide and MHC. J Exp Med 208:91-102
Wucherpfennig, Kai W; Sethi, Dhruv (2011) T cell receptor recognition of self and foreign antigens in the induction of autoimmunity. Semin Immunol 23:84-91
Call, Matthew E; Wucherpfennig, Kai W; Chou, James J (2010) The structural basis for intramembrane assembly of an activating immunoreceptor complex. Nat Immunol 11:1023-9
Pielak, Rafal M; Chou, James J (2010) Flu channel drug resistance: a tale of two sites. Protein Cell 1:246-58
Wucherpfennig, Kai W; Gagnon, Etienne; Call, Melissa J et al. (2010) Structural biology of the T-cell receptor: insights into receptor assembly, ligand recognition, and initiation of signaling. Cold Spring Harb Perspect Biol 2:a005140

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