Endogenous non-stimulatory peptides are important in aiding T cell activation by limiting quantities of antigen. This project will determine the molecular basis for the role of non- stimulatory MHC-peptide complexes. The importance of CD8 or TCR interaction with a non-stimulatory or positive selecting MHCp, compared to its binding to the antigenic MHCp will be determined using single-chain MHC class I-peptide molecules, where the peptide is fixed, and the CD8 or TCR binding site can be mutated. Induction of interaction between TCR and CD8 during recognition by antigen plus non-stimulatory peptides will be measured using FRET microscopy. FRET will also be used to determine whether the non-stimulatory and antigenic MHCp are brought close together during antigen recognition. We will measure early signaling responses to the endogenous, non- stimulatory or positive selecting peptides in the presence or absence of small amounts of antigen, to understand how the T cells can be pre-stimulated by these ligands. The relative importance of CD8 binding to non-stimulatory MHCp itself (i.e. the adhesion function of CD8) versus its importance in concentrating the kinase Lck, will be measured. Whether phosphorylation of other TCRs than those that bind to the antigenic MHCp occurs will be tested using a FRET biosensor. Two photon microscopy of T cells will be used to understand how T cell behavior alters with the affinity of the ligand for the TCR and with the presence or absence of non-stimulatory pMHC. Transgenic mice that express fluorescent CD8 molecules will be used to investigate cell surface dynamics of CD8 during migration and antigen recognition in situ.

Public Health Relevance

Development and activation of the T cell arm of the immune system is crucial to produce a useful immune response to foreign antigens and to avoid autoimmunity. This project investigates the molecular mechanism of T cell activation.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Marino, Pamela
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Scripps Research Institute
La Jolla
United States
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Paster, Wolfgang; Bruger, Annika M; Katsch, Kristin et al. (2015) A THEMIS:SHP1 complex promotes T-cell survival. EMBO J 34:393-409
Casas, Javier; Brzostek, Joanna; Zarnitsyna, Veronika I et al. (2014) Ligand-engaged TCR is triggered by Lck not associated with CD8 coreceptor. Nat Commun 5:5624
Rybakin, Vasily; Westernberg, Luise; Fu, Guo et al. (2014) Allelic exclusion of TCR ?-chains upon severe restriction of V? repertoire. PLoS One 9:e114320
Conche, Claire; Sauer, Karsten (2014) Uncovering the PI3Ksome: phosphoinositide 3-kinases and counteracting PTEN form a signaling complex with intrinsic regulatory properties. Mol Cell Biol 34:3356-8
Nabekura, Tsukasa; Kanaya, Minoru; Shibuya, Akira et al. (2014) Costimulatory molecule DNAM-1 is essential for optimal differentiation of memory natural killer cells during mouse cytomegalovirus infection. Immunity 40:225-34
Kong, Kok-Fai; Fu, Guo; Zhang, Yaoyang et al. (2014) Protein kinase C-? controls CTLA-4-mediated regulatory T cell function. Nat Immunol 15:465-72
Fu, Guo; Rybakin, Vasily; Brzostek, Joanna et al. (2014) Fine-tuning T cell receptor signaling to control T cell development. Trends Immunol 35:311-8
Fu, Guo; Casas, Javier; Rigaud, Stephanie et al. (2013) Themis sets the signal threshold for positive and negative selection in T-cell development. Nature 504:441-5
Hoerter, John A H; Brzostek, Joanna; Artyomov, Maxim N et al. (2013) Coreceptor affinity for MHC defines peptide specificity requirements for TCR interaction with coagonist peptide-MHC. J Exp Med 210:1807-21
Paster, Wolfgang; Brockmeyer, Claudia; Fu, Guo et al. (2013) GRB2-mediated recruitment of THEMIS to LAT is essential for thymocyte development. J Immunol 190:3749-56

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