The T cell auto-reactivity that lies at the heart of many autoimmune diseases arises from the very properties that allow T cells to mount an effective immune response. Thus, to understand the etiology of different autoimmune diseases will require a thorough and integrated understanding of the mechanisms that control T cell activation. The long-term objective of my research is to understand the biochemistry of T cell reactivity. Currently, my laboratory is studying how two related proteins, Sts-1 and Sts-2, act in concert to negatively regulate T cell signaling pathways. The role of Sts-1 and -2 in controlling TCR signaling pathways was revealed by a strain of mice engineered to lack the Sts genes. T cells from Sts- 1/2-/- mice dramatically hyper-proliferate in response to TCR stimulation. This hyper-proliferative phenotype is accompanied by increased activation of signaling pathways downstream of the TCR, elevated levels of cytokine production, and increased susceptibility of Sts-1/2-/- mice to autoimmunity in a mouse model of multiple sclerosis. In our ongoing effort to characterize the functions of the Sts proteins, we recently discovered that Sts-1 has a novel and potent enzyme activity. This activity derives from an evolutionarily conserved region within the protein and our recent data indicates that it plays an essential role in the ability of Sts-1 to regulate TCR signaling pathways. Sts-1 is sufficiently dissimilar to other known enzymes to make it a novel and unique phosphatase. In addition, the connection between Sts-1 catalytic activity and regulation of T cell activation in unknown and unexplored. The experiments outlined in this proposal are designed to shed light on these areas.
Our Specific Aims are: 1. To determine the structural features that define and regulate Sts-1 catalytic activity. 2. To determine the role of Sts-1 phosphatase activity in regulating Zap-70 signaling. We will use some recently developed protocols to accomplish our goals. Completion of the studies described herein will help us build a model of how Sts-1 cooperates with Sts-2 and other intracellular signaling mechanisms to control T cell reactivity. It is our hope that a broad, integrated understanding of all the mechanisms that control T cell activation will translate into therapies that prevent the onset of a variety of autoimmune diseases. Autoimmune diseases arise when normal regulatory mechanisms within the immune system fail. Developing therapies that will prevent or cure autoimmune diseases will require a thorough and integrated understanding of the mechanisms that control the immune response. This project focuses on understanding the function of a novel protein that participates in the regulation of T cell activation. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI075176-01
Application #
7297150
Study Section
Cellular and Molecular Immunology - B Study Section (CMIB)
Program Officer
Mallia, Conrad M
Project Start
2007-09-20
Project End
2009-08-31
Budget Start
2007-09-20
Budget End
2008-08-31
Support Year
1
Fiscal Year
2007
Total Cost
$193,750
Indirect Cost
Name
State University New York Stony Brook
Department
Genetics
Type
Schools of Medicine
DUNS #
804878247
City
Stony Brook
State
NY
Country
United States
Zip Code
11794
Luis, Boris S; Carpino, Nick (2014) Insights into the suppressor of T-cell receptor (TCR) signaling-1 (Sts-1)-mediated regulation of TCR signaling through the use of novel substrate-trapping Sts-1 phosphatase variants. FEBS J 281:696-707
San Luis, Boris; Nassar, Nicolas; Carpino, Nick (2013) New insights into the catalytic mechanism of histidine phosphatases revealed by a functionally essential arginine residue within the active site of the Sts phosphatases. Biochem J 453:27-35
San Luis, Boris; Sondgeroth, Ben; Nassar, Nicolas et al. (2011) Sts-2 is a phosphatase that negatively regulates zeta-associated protein (ZAP)-70 and T cell receptor signaling pathways. J Biol Chem 286:15943-54
Carpino, Nick; Chen, Yunting; Nassar, Nicolas et al. (2009) The Sts proteins target tyrosine phosphorylated, ubiquitinated proteins within TCR signaling pathways. Mol Immunol 46:3224-31
Chen, Yunting; Jakoncic, Jean; Parker, Kathlyn A et al. (2009) Structures of the phosphorylated and VO(3)-bound 2H-phosphatase domain of Sts-2. Biochemistry 48:8129-35
Chen, Yunting; Jakoncic, Jean; Carpino, Nick et al. (2009) Structural and functional characterization of the 2H-phosphatase domain of Sts-2 reveals an acid-dependent phosphatase activity. Biochemistry 48:1681-90
Chen, Yunting; Jakoncic, Jean; Wang, Jin et al. (2008) Structural and functional characterization of the c-terminal domain of the ecdysteroid phosphate phosphatase from bombyx mori reveals a new enzymatic activity. Biochemistry 47:12135-45
Mikhailik, Anatoly; Ford, Bradley; Keller, James et al. (2007) A phosphatase activity of Sts-1 contributes to the suppression of TCR signaling. Mol Cell 27:486-97