The Tec family tyrosine kinases Itk, Tec and Rlk are expressed in T cells. Previous studies have established that these kinases are critical for TCR signaling, leading to the activation of PLCγ1. To further understand the functions of Tec kinases in T cell activation, we took three different approaches. First, we performed a thorough analysis of CD28-mediated signaling events and functional responses with purified naïve T cells from Itk-/- mice and a highly controlled stimulation system. Data from this set of studies definitively demonstrate that CD28 costimulation functions efficiently in naïve CD4+ T cells in the absence of Itk. Second, in order to further study the functions of Tec kinases in vivo, we generated transgenic mouse lines expressing a kinase-dead (KD) mutant of Tec on the Itk-/-Rlk-/- background, hoping to study mice that are functionally deficient for all three Tec kinases. The results hint the importance of the Tec kinases in T cell development and/or survival. Finally, in order to identify potential transcriptional targets of Itk, we used microarray technology to compare global gene expression profiles of naïve and stimulated Itk-/- versus Itk+/- CD4+ T cells. This analysis provided a short list of differentially expressed genes in Itk-/- versus Itk+/- CD4 T cells, providing a starting point for further studies of Itk in T cell activation. Collectively, these studies clarified the role of Itk in CD28 signaling, revealed some unexpected aspects of Tec family kinases in T cells, and indicated potential targets of Itk-dependent signaling pathways in T cells.
| Identifer | oai:union.ndltd.org:umassmed.edu/oai:escholarship.umassmed.edu:gsbs_diss-1004 |
| Date | 27 October 2005 |
| Creators | Li, Cheng-Rui Michael |
| Publisher | eScholarship@UMMS |
| Source Sets | University of Massachusetts Medical School |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | GSBS Dissertations and Theses |
| Rights | Copyright is held by the author, with all rights reserved., select |
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