ZAP-70: an essential kinase in T-cell signaling.
Ontology highlight
ABSTRACT:
SUBMITTER: Wang H
PROVIDER: S-EPMC2857167 | biostudies-literature | 2010 May
REPOSITORIES: biostudies-literature
Publications
ZAP-70: an essential kinase in T-cell signaling.
Wang Haopeng H Kadlecek Theresa A TA Au-Yeung Byron B BB Goodfellow Hanna E Sjölin HE Hsu Lih-Yun LY Freedman Tanya S TS Weiss Arthur A
Cold Spring Harbor perspectives in biology 20100501 5
ZAP-70 is a cytoplasmic protein tyrosine kinase that plays a critical role in the events involved in initiating T-cell responses by the antigen receptor. Here we review the structure of ZAP-70, its regulation, its role in development and in disease. We also describe a model experimental system in which ZAP-70 function can be interrupted by a small chemical inhibitor. ...[more]
Similar Datasets
Project description:HIV efficiently spreads in lymphocytes, likely through virological synapses (VSs). These cell-cell junctions share some characteristics with immunological synapses, but cellular proteins required for their constitution remain poorly characterized. We have examined here the role of ZAP-70, a key kinase regulating T-cell activation and immunological synapse formation, in HIV replication. In lymphocytes deficient for ZAP-70, or expressing a kinase-dead mutant of the protein, HIV replication was strikingly delayed. We have characterized further this replication defect. ZAP-70 was dispensable for the early steps of viral cycle, from entry to expression of viral proteins. However, in the absence of ZAP-70, intracellular Gag localization was impaired. ZAP-70 was required in infected donor cells for efficient cell-to-cell HIV transmission to recipients and for formation of VSs. These results bring novel insights into the links that exist between T-cell activation and HIV spread, and suggest that HIV usurps components of the immunological synapse machinery to ensure its own spread through cell-to-cell contacts.
| S-EPMC1783460 | biostudies-literature
Project description:The zeta chain-associated 70-kDa protein (ZAP-70) of tyrosine kinase plays a critical role in T cell receptor-mediated signal transduction and the immune response. A high level of ZAP-70 expression is observed in leukemia, which suggests ZAP-70 as a logical target for immunomodulatory therapies. (-)-Epigallocatechin gallate (EGCG) is one of the major green tea catechins that is suggested to have a role as a preventive agent in cancer, obesity, diabetes, and cardiovascular disease. Here we identified ZAP-70 as an important and novel molecular target of EGCG in leukemia cells. ZAP-70 and EGCG displayed high binding affinity (Kd = 0.6207 micromol/liter), and additional results revealed that EGCG effectively suppressed ZAP-70, linker for the activation of T cells, phospholipase Cgamma1, extracellular signaling-regulated kinase, and MAPK kinase activities in CD3-activated T cell leukemia. Furthermore, the activation of activator protein-1 and interleukin-2 induced by CD3 was dose-dependently inhibited by EGCG treatment. Notably, EGCG dose-dependently induced caspase-mediated apoptosis in P116.cl39 ZAP-70-expressing leukemia cells, whereas P116 ZAP-70-deficient cells were resistant to EGCG treatment. Molecular docking studies, supported by site-directed mutagenesis experiments, showed that EGCG could form a series of intermolecular hydrogen bonds and hydrophobic interactions within the ATP binding domain, which may contribute to the stability of the ZAP-70-EGCG complex. Overall, these results strongly indicated that ZAP-70 activity was inhibited specifically by EGCG, which contributed to suppressing the CD3-mediated T cell-induced pathways in leukemia cells.
| S-EPMC2568917 | biostudies-literature
Project description:ZAP-70 is a cytoplasmic protein tyrosine kinase that is required for T cell antigen receptor (TCR) signaling. Both mice and humans deficient in ZAP-70 fail to develop functional T cells, thus demonstrating its necessity for T cell development and function. There is currently no highly specific, cell-permeable, small molecule inhibitor for ZAP-70; therefore, we generated a mutant ZAP-70 allele that retains kinase activity but is sensitive to inhibition by a mutant-specific inhibitor. We validated the chemical genetic inhibitor system in Jurkat T cell lines, where the inhibitor blocked ZAP-70-dependent TCR signaling in cells expressing the analog-sensitive allele. Interestingly, the inhibitor also ablated CD28 superagonist signaling, thereby demonstrating the utility of this system in dissecting the requirement for ZAP-70 in alternative mechanisms of T cell activation. Thus, we have developed the first specific chemical means of inhibiting ZAP-70 in cells, which serves as a valuable tool for studying the function of ZAP-70 in T cells.
| S-EPMC2397475 | biostudies-literature
Project description:T cell activation by antigens binding to the T cell receptor (TCR) must be properly regulated to ensure normal T cell development and effective immune responses to pathogens and transformed cells while avoiding autoimmunity. The Src family kinase Lck and the Syk family kinase ZAP-70 (ζ chain-associated protein kinase of 70 kD) are sequentially activated in response to TCR engagement and serve as critical components of the TCR signaling machinery that leads to T cell activation. We performed a mass spectrometry-based phosphoproteomic study comparing the quantitative differences in the temporal dynamics of phosphorylation in stimulated and unstimulated T cells with or without inhibition of ZAP-70 catalytic activity. The data indicated that the kinase activity of ZAP-70 stimulates negative feedback pathways that target Lck and thereby modulate the phosphorylation patterns of the immunoreceptor tyrosine-based activation motifs (ITAMs) of the CD3 and ζ chain components of the TCR and of signaling molecules downstream of Lck, including ZAP-70. We developed a computational model that provides a mechanistic explanation for the experimental findings on ITAM phosphorylation in wild-type cells, ZAP-70-deficient cells, and cells with inhibited ZAP-70 catalytic activity. This model incorporated negative feedback regulation of Lck activity by the kinase activity of ZAP-70 and predicted the order in which tyrosines in the ITAMs of TCR ζ chains must be phosphorylated to be consistent with the experimental data.
| S-EPMC4445242 | biostudies-literature
Project description:RhoH is an hematopoietic-specific, GTPase-deficient Rho GTPase that plays a role in T development. We investigated the mechanisms of RhoH function in TCR signaling. We found that the association between Lck and CD3? was impaired in RhoH-deficient T cells, due to defective translocation of both Lck and ZAP-70 to the immunological synapse. RhoH with Lck and ZAP-70 localizes in the detergent-soluble membrane fraction where the complex is associated with CD3? phosphorylation. To determine if impaired translocation of ZAP-70 was a major determinant of defective T cell development, Rhoh(-/-) bone marrow cells were transduced with a chimeric myristoylation-tagged ZAP-70. Myr-ZAP-70 transduced cells partially reversed the in vivo defects of RhoH-associated thymic development and TCR signaling. Together, our results suggest that RhoH regulates TCR signaling via recruitment of ZAP-70 and Lck to CD3? in the immunological synapse. Thus, we define a new function for a RhoH GTPase as an adaptor molecule in TCR signaling pathway.
| S-EPMC2980477 | biostudies-literature
Project description:Chronic lymphocytic leukemia (CLL) can be divided into groups based on biomarkers of poor prognosis. The expression of the tyrosine kinase ZAP-70 (member of the Syk tyrosine kinase family) in CLL cells is associated with shorter overall survival in CLL patients. Currently, there is a lack of targeted therapies for patients with ZAP-70 expression in CLL cells. The tyrosine kinase inhibitor gefitinib has been shown to be effective at induce apoptosis in acute myeloid leukemia through inhibition of Syk. In this study, we sought to test the efficacy of gefitinib in primary human ZAP-70+ CLL cells. We demonstrate that gefitinib preferentially induces cell death in ZAP-70-expressing CLL cells with a median IC50 of 4.5 μM. In addition, gefitinib decreases the viability of ZAP-70+ Jurkat T leukemia cells but fails to affect T cells from CLL patients. Western blot analysis shows gefitinib reduces both basal and B-cell receptor (BCR)-stimulated phosphorylation of Syk/ZAP-70, ERK, and Akt in ZAP-70+ CLL cells. Moreover, gefitinib inhibits the pro-survival response from BCR stimulation and decreases pro-survival proteins such as Mcl-1. Finally, ZAP-70 expression sensitizes Raji cells to gefitinib treatment. These results demonstrate that gefitinib specifically targets ZAP-70+ CLL cells and inhibits the BCR cell survival pathway leading to apoptosis. This represents the likelihood of tyrosine kinase inhibitors being effective targeted treatments for ZAP-70+ CLL cells.
| S-EPMC4649506 | biostudies-literature
Project description:ZAP-70 (Zeta-chain-associated protein kinase 70) is a tyrosine kinase that interacts directly with the activated T-cell receptor to transduce downstream signals, and is hence a major player in the regulation of the adaptive immune response. Dysfunction of ZAP-70 causes selective T cell deficiency that in turn results in persistent infections. ZAP-70 is activated by a variety of signals including phosphorylation of the kinase domain (KD), and binding of its regulatory tandem Src homology 2 (SH2) domains to the T cell receptor. The present study investigates molecular mechanisms of activation and inhibition of ZAP-70 via atomically detailed molecular dynamics simulation approaches. We report microsecond timescale simulations of five distinct states of the ZAP-70 KD, comprising apo, inhibited and three phosphorylated variants. Extensive analysis of local flexibility and correlated motions reveal crucial transitions between the states, thus elucidating crucial steps in the activation mechanism of the ZAP-70 KD. Furthermore, we rationalize previously observed staurosporine-bound crystal structures, suggesting that whilst the KD superficially resembles an "active-like" conformation, the inhibitor modulates the underlying protein dynamics and restricts it in a compact, rigid state inaccessible to ligands or cofactors. Finally, our analysis reveals a novel, potentially druggable pocket in close proximity to the activation loop of the kinase, and we subsequently use its structure in fragment-based virtual screening to develop a pharmacophore model. The pocket is distinct from classical type I or type II kinase pockets, and its discovery offers promise in future design of specific kinase inhibitors, whilst mutations in residues associated with this pocket are implicated in immunodeficiency in humans.
| S-EPMC4608720 | biostudies-literature
Project description:B-cell chronic lymphocytic leukemia (B-CLL) is a heterogenous disease with a highly variable clinical course and analysis of ZAP-70 and CD38 expression on B-CLL cells allowed for identification of patients with good (ZAP-70-CD38-), intermediate (discordant expression of ZAP-70 and CD38) and poor (ZAP-70+CD38+) prognosis. In an attempt to identify a molecular basis that may underly this diverse clinical behaviour DNA microarray technology was employed to compare eight ZAP-70+CD38+ with eight ZAP-70-CD38- B-CLL cases. We used microarrays to detail the global programme of gene expression distinguising B-CLL from patient with good (samples 1 to 8) and poor prognosis (sample 9 to 16) and identified distinct classes of up- and down-regulated genes. Keywords: Disease progression
2006-09-22 | GSE4392 | GEO
Project description:The tyrosine kinase Zap-70 is a key regulator of T cell receptor (TCR) signaling downstream of antigen presentation, with coordinated regulation of Zap-70 kinase activity critical for proper T cell proliferation, differentiation, and effector function during an immune response. Zap-70 is cytosolic in unstimulated T cells, but is rapidly recruited to the TCR complex following receptor stimulation. Its activity is regulated both by binding to subunits of the TCR and by phosphorylation on multiple tyrosine residues. Zap-70 also has been reported to be ubiquitinated following TCR stimulation. Herein, we confirm the ubiquitination of Zap-70 in T cell lines and in primary human and mouse T cells, and report the identification of nine novel Zap-70 ubiquitination sites. Three sites, including Lys-193, Lys-217, and Lys-376, displayed greater than 20-fold increase in modification levels following TCR stimulation. Abrogation of Lys-217 ubiquitination results in increased kinase activation, enhanced activation of downstream signaling pathways, and elevated IL-2 production following TCR stimulation. These data suggest that Zap-70 ubiquitination contributes to the regulation of Zap-70 signaling following TCR stimulation.
| S-EPMC4902731 | biostudies-literature
Project description:Although ZAP-70 is required for T-cell development, it's unclear how this kinase controls both positive and negative selection.Using OT-I pre-selection thymocytes and a panel of peptide major histocompatibility complex (pMHC) ligands of defined affinity, the recruitment, phosphorylation and activity of ZAP-70 was determined at the interface with antigen-presenting cells (APCs).pMHC ligands promoting negative selection induce a discrete elevation of ZAP-70 recruitment, phosphorylation and enzymatic activity in the thymocyte:APCs interface.The quantity of ZAP-70 kinase activity per cell is a key parameter controlling the fate of a developing thymocyte since partial inhibition of ZAP-70 kinase activity converted negative into positive selection. Surprisingly, the amount of ZAP-70 enzymatic activity observed during negative selection is not controlled by differential phosphorylation of the ZAP-70 protein but rather by the total amount of T-cell receptor and co-associated ZAP-70 recruited to the thymocyte:APC interface.These data provide evidence that a burst of ZAP-70 activity initiates the signaling pathways for negative selection.
| S-EPMC3056388 | biostudies-literature