SIGNAL TRANSDUCTION IN T LYMPHOCYTE ACTIVATION

Summary

Principal Investigator: Amnon Altman
Affiliation: La Jolla Institute for Allergy and Immunology
Country: USA
Abstract: The importance of PKC? in TCR signals controlling T cell activation and differentiation is well established. The selective requirement of PKC? in allergic and autoimmune diseases, but not in antiviral responses, highlights it as a promising drug target. Realization of this potential requires a clear understanding of the mechanism(s) that regulate the unique, non-redundant functions and highly selective immunological synapse (IS) localization of PKC? in T cells, which remain unknown. Our work during the last funding period revealed that within the large PKC family, PKC? represents a unique paradigm with respect to the mechanisms that regulate these events and, ultimately, lead to the activation of critical transcription factors, which determine T cell fate. We propose to apply a multi-disciplinary approach in order to address the following unresolved questions: Aim 1) Positive regulation of PKC? activation and localization. Using biochemical, genetic, imaging and biophysical approaches, we will address the hypothesis that the localization and activation of PKC? in T cells are positively regulated by specialized mechanisms and plasma membrane interactions owing to the unique properties of its regulatory C1 and V3 domains. We will conduct a detailed structure- function analysis of the C1A, C1B and V3 domains of PKC?, their phosphorylation, and their interaction with binding partners. Aim 2) Autoinhibition by the PKC? C2 domain. Our studies indicate that the PKC? N- terminal C2 domain negatively regulates its function, and that autoinhibition is relieved by TCR-induced phosphorylation of Tyr-90, and, furthermore, that C2 itself is a pTyr- and PIP2-binding domain. We will investigate the mechanisms through which autoinhibition is effected, and characterize C2-binding ligands and their functional significance. We will pursue Aims 1 and 2 as a collaborative consortium with Dr. Wonhwa Cho (U. Illinois), who will provide his expertise in biophysical and two-photon imaging approaches to further elucidate the specialized mechanisms that regulate PKC?. Aim 3) Regulation of Ca2+/NFAT signaling by PKC?. PKC?-/- T cells display a Ca2+/NFAT signaling defect, but the mechanism linking PKC? to Ca2+ signaling is unknown. Based on our recent findings, and given the important role of Ca2+ signaling in determining the balance between productive T cell activation and anergy/apoptosis, we will characterize this pathway. Specifically, we will address the hypothesis that PKC? mediates a positive feedback loop that promotes PLC31 activation and, hence, Ca2+/NFAT signaling, via its functional and/or physical association with Tec family tyrosine kinase(s). Our studies will elucidate novel mechanisms that control the unique membrane localization and function of PKC? in T cells. The new information will likely provide a rational basis for using PKC? as a drug target in autoimmune and allergic diseases, and in T cell malignancies. PUBLIC HEALTH RELEVANCE: Protein kinase C-8 (PKC?), an enzyme expressed in T lymphocytes of the immune system, is important for the activation and survival of these cells and their ability to mount many beneficial as well as pathological immune responses, e.g., protection against certain infections, and autoimmune and allergic diseases. However, the mechanisms, which control the unique functions and intracellular localization of PKC? in T lymphocytes (which are not shared by other related members of the PKC family), are largely unknown. Here we propose to use a complementary set of biochemical, genetic, imaging and biophysical approaches in order to elucidate these mechanisms and the regulatory interactions of PKC? with other proteins and membrane lipids. Understanding of these pathways is likely to establish a more rational basis for the use of PKC? as a drug target in autoimmune and allergic diseases, and in T cell leukemias/lymphomas
Funding Period: -------------------- - --------------------
more information: NIH RePORT

Top Publications

  1. ncbi Impaired activation and localization of LAT in anergic T cells as a consequence of a selective palmitoylation defect
    Matthias Hundt
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA
    Immunity 24:513-22. 2006
  2. pmc TNFR-associated factor 6 regulates TCR signaling via interaction with and modification of LAT adapter
    Ji Ji Xie
    State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of Ministry of Education, School of Life Sciences, Sun Yat Sen University, Guangzhou 510006, China
    J Immunol 190:4027-36. 2013
  3. pmc The yin and yang of protein kinase C-theta (PKCθ): a novel drug target for selective immunosuppression
    Elizabeth Yan Zhang
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
    Adv Pharmacol 66:267-312. 2013
  4. pmc In and out of the bull's eye: protein kinase Cs in the immunological synapse
    Kok Fai Kong
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
    Trends Immunol 34:234-42. 2013
  5. pmc Protein kinase Cθ C2 domain is a phosphotyrosine binding module that plays a key role in its activation
    Robert V Stahelin
    Department of Chemistry, University of Illinois, Chicago, IL 60607, USA
    J Biol Chem 287:30518-28. 2012
  6. pmc Protein kinase C-η controls CTLA-4-mediated regulatory T cell function
    Kok Fai Kong
    1 Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA 2
    Nat Immunol 15:465-72. 2014
  7. pmc PKCdelta acts upstream of SPAK in the activation of NKCC1 by hyperosmotic stress in human airway epithelial cells
    Laura Smith
    Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio 44106, USA
    J Biol Chem 283:22147-56. 2008
  8. ncbi Mechanism of diacylglycerol-induced membrane targeting and activation of protein kinase Ctheta
    Heather R Melowic
    Department of Chemistry, University of Illinois, Chicago, Illinois 60607, USA
    J Biol Chem 282:21467-76. 2007
  9. pmc Protein kinase C theta (PKCtheta): a key player in T cell life and death
    Keitaro Hayashi
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
    Pharmacol Res 55:537-44. 2007
  10. ncbi Filamin A is required for T cell activation mediated by protein kinase C-theta
    Keitaro Hayashi
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA
    J Immunol 177:1721-8. 2006

Scientific Experts

  • Amnon Altman
  • Kok Fai Kong
  • Keitaro Hayashi
  • Robert V Stahelin
  • Heather R Melowic
  • Elizabeth Yan Zhang
  • Ji Ji Xie
  • Takashi Saito
  • Ann J Canonigo-Balancio
  • Tadashi Yokosuka
  • Takanori So
  • Wonhwa Cho
  • Wen Tian
  • Laura Smith
  • Matthias Hundt
  • Javier Casas
  • John R Yates
  • Nicholas R J Gascoigne
  • Stéphane Bécart
  • Yaoyang Zhang
  • Guo Fu
  • Gisen Kim
  • Mitchell Kronenberg
  • Liang Hui Diao
  • Yingqiu Li
  • Jia Qi Liang
  • Katherine E Ward
  • Diana Murray
  • Sumita Raha
  • Michael Croft
  • Pejman Soroosh
  • So Young Eun
  • Noah Isakov
  • Carole M Liedtke
  • Nicole Smallwood
  • Nichole R Blatner
  • Myung Shin Jeon
  • Lauren De Giorgio
  • Yun Cai Liu
  • Hiroki Tabata
  • Yoshihiko Tanaka
  • Roma Krishna
  • Masaki Fukata

Detail Information

Publications13

  1. ncbi Impaired activation and localization of LAT in anergic T cells as a consequence of a selective palmitoylation defect
    Matthias Hundt
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA
    Immunity 24:513-22. 2006
    ....
  2. pmc TNFR-associated factor 6 regulates TCR signaling via interaction with and modification of LAT adapter
    Ji Ji Xie
    State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of Ministry of Education, School of Life Sciences, Sun Yat Sen University, Guangzhou 510006, China
    J Immunol 190:4027-36. 2013
    ....
  3. pmc The yin and yang of protein kinase C-theta (PKCθ): a novel drug target for selective immunosuppression
    Elizabeth Yan Zhang
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
    Adv Pharmacol 66:267-312. 2013
    ..Early progress in developing such drugs is being made, but additional studies on the role of PKCθ in the human immune system are urgently needed...
  4. pmc In and out of the bull's eye: protein kinase Cs in the immunological synapse
    Kok Fai Kong
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
    Trends Immunol 34:234-42. 2013
    ..Further work is needed to identify mechanisms underlying PKC recruitment or exclusion at the IS, potential redundancy among IS-localized PKCs, and the relevance of PKC localization for IS dynamics and lymphocyte activation...
  5. pmc Protein kinase Cθ C2 domain is a phosphotyrosine binding module that plays a key role in its activation
    Robert V Stahelin
    Department of Chemistry, University of Illinois, Chicago, IL 60607, USA
    J Biol Chem 287:30518-28. 2012
    ..Collectively, these studies establish the C2 domain of PKCθ as a Tyr(P)-binding domain and suggest that the domain may play a major role in PKCθ activation via its Tyr(P) binding...
  6. pmc Protein kinase C-η controls CTLA-4-mediated regulatory T cell function
    Kok Fai Kong
    1 Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA 2
    Nat Immunol 15:465-72. 2014
    ..These results reveal a CTLA-4-PKC-η signaling axis required for contact-dependent suppression and implicate this pathway as a potential cancer immunotherapy target. ..
  7. pmc PKCdelta acts upstream of SPAK in the activation of NKCC1 by hyperosmotic stress in human airway epithelial cells
    Laura Smith
    Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio 44106, USA
    J Biol Chem 283:22147-56. 2008
    ..Inhibition of PKCdelta activity with rottlerin blocked the increase in SPAK kinase activity. The results indicate that PKCdelta acts upstream of SPAK to increase activity of NKCC1 during hyperosmotic stress...
  8. ncbi Mechanism of diacylglycerol-induced membrane targeting and activation of protein kinase Ctheta
    Heather R Melowic
    Department of Chemistry, University of Illinois, Chicago, Illinois 60607, USA
    J Biol Chem 282:21467-76. 2007
    ..Collectively, these results show that PKC has a unique membrane binding and activation mechanism that may account for its subcellular targeting properties...
  9. pmc Protein kinase C theta (PKCtheta): a key player in T cell life and death
    Keitaro Hayashi
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
    Pharmacol Res 55:537-44. 2007
    ..Therefore, PKCtheta is a critical enzyme that regulates T cell function at multiple stages, and it represents an attractive drug target for allergic and autoimmune diseases...
  10. ncbi Filamin A is required for T cell activation mediated by protein kinase C-theta
    Keitaro Hayashi
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA
    J Immunol 177:1721-8. 2006
    ....
  11. pmc Antigen-independent signalosome of CARMA1, PKCθ, and TNF receptor-associated factor 2 (TRAF2) determines NF-κB signaling in T cells
    Takanori So
    Divisions of Molecular Immunology and Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
    Proc Natl Acad Sci U S A 108:2903-8. 2011
    ..Thus, by recruiting TCR-related intracellular molecules into the TRAF2 complex, OX40 provides the T cell with a high level of NF-κB activity needed for longevity...
  12. pmc A motif in the V3 domain of the kinase PKC-θ determines its localization in the immunological synapse and functions in T cells via association with CD28
    Kok Fai Kong
    Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
    Nat Immunol 12:1105-12. 2011
    ....