PKC-theta is a component of the immunological synapse that plays an essential role in mature T cell activation by integrating T cell receptor (TCR)/CD28 costimulatory signals that activate transcription factors NF-kappaB and AP-1. These events are defective in anergic T cells. This application is based on the following hypotheses: a) Proper function of PKC-theta in antigen-specific T cells depends upon its selective localization to the T cell synapse and is important for preventing T cell anergy. b) A scaffold protein links PKC-theta to specific membrane and/or cytoskeleton compartments and selectively recruits it to the T cell synapse. The following Aims will address these hypotheses: 1 ) We will map the critical residues/regions in the regulatory domain of PKC-theta that are responsible for its selective translocation to the T cell synapse and co-localized lipid rafts. 2) We will determine whether either one of two candidate PDZ proteins, hDLG or p55, represents the PKC-theta-selective scaffold and, if not, embark on a broad search to isolate the putative PKC-theta scaffold. We will then conduct a detailed structure-function analysis to determine the functional significance of the interaction between PKC-theta and its scaffold in antigen-induced T cell activation. 3) We will establish T cell lines expressing beta-lactamase-based AP-1 and CD28RE reporter genes. These lines will be used as sensitive biosensors in a high throughput screen of compound libraries in order to isolate and functionally characterize compounds that selectively interfere with PKC-theta function and its selective recruitment to the T cell synapse. The proposed studies directly address one goal of this RFA, i.e., """"""""identification and characterization of promising new T or B cell molecular targets for tolerance induction"""""""". They offer the potential for developing novel therapeutic strategies, which may be useful for modulating CD28 costimulation in disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AI049888-01
Application #
6353270
Study Section
Special Emphasis Panel (ZAI1-NN-I (M1))
Program Officer
Quill, Helen R
Project Start
2001-09-30
Project End
2004-08-31
Budget Start
2001-09-30
Budget End
2002-08-31
Support Year
1
Fiscal Year
2001
Total Cost
$282,000
Indirect Cost
Name
La Jolla Institute
Department
Type
DUNS #
603880287
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Li, Yingqiu; Sedwick, Caitlin E; Hu, Junru et al. (2005) Role for protein kinase Ctheta (PKCtheta) in TCR/CD28-mediated signaling through the canonical but not the non-canonical pathway for NF-kappaB activation. J Biol Chem 280:1217-23
Altman, Amnon; Kaminski, Sandra; Busuttil, Valere et al. (2004) Positive feedback regulation of PLCgamma1/Ca(2+) signaling by PKCtheta in restimulated T cells via a Tec kinase-dependent pathway. Eur J Immunol 34:2001-11
Sedwick, Caitlin E; Altman, Amnon (2004) Perspectives on PKCtheta in T cell activation. Mol Immunol 41:675-86
Salek-Ardakani, Shahram; So, Takanori; Halteman, Beth S et al. (2004) Differential regulation of Th2 and Th1 lung inflammatory responses by protein kinase C theta. J Immunol 173:6440-7
Li, Yingqiu; Hu, Junru; Vita, Randi et al. (2004) SPAK kinase is a substrate and target of PKCtheta in T-cell receptor-induced AP-1 activation pathway. EMBO J 23:1112-22
Altman, Amnon; Villalba, Martin (2003) Protein kinase C-theta (PKCtheta): it's all about location, location, location. Immunol Rev 192:53-63
Altman, Amnon; Villalba, Martin (2002) Protein kinase C-theta (PKC theta): a key enzyme in T cell life and death. J Biochem 132:841-6
Isakov, Noah; Altman, Amnon (2002) Protein kinase C(theta) in T cell activation. Annu Rev Immunol 20:761-94