Related Experiment Videos
Protein kinase C theta affects Ca2+ mobilization and NFAT cell activation in primary mouse T cells
Christa Pfeifhofer1, Kurt Kofler, Thomas Gruber
1Institute of Medical Biology and Human Genetics, University of Innsbruck, Schoepfstrasse 41, A-6020 Innsbruck, Austria.
Abstract:
Protein kinase C (PKC)theta is an established component of the immunological synapse and has been implicated in the control of AP-1 and NF-kappaB. To study the physiological function of PKCtheta, we used gene targeting to generate a PKCtheta null allele in mice. Consistently, interleukin 2 production and T cell proliferative responses were strongly reduced in PKCtheta-deficient T cells. Surprisingly, however, we demonstrate that after CD3/CD28 engagement, deficiency of PKCtheta primarily abrogates NFAT transactivation. In contrast, NF-kappaB activation was only partially reduced. This NFAT transactivation defect appears to be secondary to reduced inositol 1,4,5-trisphosphate generation and intracellular Ca2+ mobilization. Our finding suggests that PKCtheta plays a critical and nonredundant role in T cell receptor-induced NFAT activation.
Insights
Protein kinase C theta (PKCtheta) is crucial for T cell activation. PKCtheta deficiency impairs NFAT transactivation by affecting calcium signaling, highlighting its nonredundant role in T cell receptor signaling.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Protein kinase C theta (PKCtheta) is involved in T cell activation and signaling pathways like AP-1 and NF-kappaB.
- The precise physiological role of PKCtheta in T cell receptor (TCR) signaling requires further elucidation.
Purpose of the Study:
- To investigate the physiological function of PKCtheta in T cell activation using a gene-targeting approach.
- To determine the specific signaling pathways affected by PKCtheta deficiency in T cells.
Main Methods:
- Generation of PKCtheta-deficient mice using gene targeting.
- Analysis of T cell responses, including interleukin-2 production and proliferation.
- Assessment of NFAT and NF-kappaB transactivation following CD3/CD28 stimulation.
- Investigation of inositol 1,4,5-trisphosphate generation and intracellular calcium mobilization.
Main Results:
- PKCtheta-deficient T cells exhibited significantly reduced interleukin-2 production and proliferative responses.
- PKCtheta deficiency primarily abrogated NFAT transactivation after CD3/CD28 engagement.
- NF-kappaB activation was only partially reduced in the absence of PKCtheta.
- The defect in NFAT transactivation was linked to reduced inositol 1,4,5-trisphosphate generation and calcium mobilization.
Conclusions:
- PKCtheta plays a critical and nonredundant role in T cell receptor-induced NFAT activation.
- PKCtheta is essential for efficient calcium signaling and subsequent NFAT-dependent gene expression in T cells.
- These findings reveal a specific function for PKCtheta in regulating key T cell activation pathways.