Although most of the molecules involved in TCR signaling have likely been identified, our understanding of the basal signaling versus the induced signaling states are rather rudimentary. Tyrosine kinases and phosphatases maintain the dynamic equilibrium that controls and maintains the both the basal state and changes in their functional activities or spatial localization are important for Induced tyrosine phosphorylation. This project focuses on understanding the specificity and complex regulation of these tyrosine kinases and phosphatases on at the plasma membrane. Understanding the regulation of phosphorylation of the TCR cytoplasmic Z-chain as well as of LAT proteins will be the endpoints we will focus on. We will use: purified recombinant proteins;novel genetically controlled kinase inhibitors;a model two dimensional lipid bilayer system containing defined quantities of recombinant proteins;and, computational modeling to describe and compare the simple bilayer system to existing well-studied intact cekks or membranes of model cellular systems. We will compare the biochemical behavior of such two dimensional models to cellular systems in an iterative way, increasing component complexity and by applying computational modeling. We expect such analyses to reveal expected as well as unanticipated behaviors. We also expect the comparison of the simple system to more complex systems to reveal the presence of regulatory pathways that may not have previously been appreciated, such as positive and negative feedback circuitry. We clearly recognize that we cannot model all of the complexity of TCR signaling but we aim to understand the detailed mechanisms controlling tyrosine phosphorylation of the TCR Z-chain and how these events lead to LAT phosphorylation. The overall goal of project #1 is to understand the specificity and regulation of protein tyrosine kinases and phosphatases involved In TCR signaling that lead to ITAM and LAT phosphorylation at the membrane surface. We will: 1) define the molecular basis for specificity for Lck and ZAP-70 for ITAMs and LAT, respectively;2) develop an analog sensitive inhibitor system for Lck;3) define the mechanisms that control ITAM phosphorylation by Lck;and, 4) define the mechanisms that control LAT phosphorylation by ZAP-70.
Biochemical signaling events by the T cell receptor (TCR) for antigen controls T cell responses but our understanding of these signaling events Is very rudimentary. These studies aim to understand how the enzymes, kinases and phosphatases, that the TCR controls are regulated on a surface model membrane, as they would be in a cell. These studies could lead to novel therapies of T cells mediated diseases.
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|Thill, Peter A; Weiss, Arthur; Chakraborty, Arup K (2016) Phosphorylation of a Tyrosine Residue on Zap70 by Lck and Its Subsequent Binding via an SH2 Domain May Be a Key Gatekeeper of T Cell Receptor Signaling In Vivo. Mol Cell Biol 36:2396-402|
|Chen, Hang; Thill, Peter; Cao, Jianshu (2016) Transitions in genetic toggle switches driven by dynamic disorder in rate coefficients. J Chem Phys 144:175104|
|Rooney, Gemma E; Goodwin, Alice F; Depeille, Philippe et al. (2016) Human iPS Cell-Derived Neurons Uncover the Impact of Increased Ras Signaling in Costello Syndrome. J Neurosci 36:142-52|
|Chan, Alice Y; Punwani, Divya; Kadlecek, Theresa A et al. (2016) A novel human autoimmune syndrome caused by combined hypomorphic and activating mutations in ZAP-70. J Exp Med 213:155-65|
|Huang, William Y C; Yan, Qingrong; Lin, Wan-Chen et al. (2016) Phosphotyrosine-mediated LAT assembly on membranes drives kinetic bifurcation in recruitment dynamics of the Ras activator SOS. Proc Natl Acad Sci U S A 113:8218-23|
|Chung, Jean K; Lee, Young Kwang; Lam, Hiu Yue Monatrice et al. (2016) Covalent Ras Dimerization on Membrane Surfaces through Photosensitized Oxidation. J Am Chem Soc 138:1800-3|
|Ashouri, Judith F; Weiss, Arthur (2016) Endogenous Nur77 Is a Specific Indicator of Antigen Receptor Signaling in Human T and B Cells. J Immunol :|
|Christensen, Sune M; Triplet, Meredith G; Rhodes, Christopher et al. (2016) Monitoring the Waiting Time Sequence of Single Ras GTPase Activation Events Using Liposome Functionalized Zero-Mode Waveguides. Nano Lett 16:2890-5|
|Shah, Neel H; Wang, Qi; Yan, Qingrong et al. (2016) An electrostatic selection mechanism controls sequential kinase signaling downstream of the T cell receptor. Elife 5:|
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