scholarly journals Evidence for involvement of glycoprotein-CD45 phosphatase in reversing glycoprotein-CD3-induced microtubule-associated protein-2 kinase activity in Jurkat T-cells

1991 ◽  
Vol 276 (2) ◽  
pp. 481-485 ◽  
Author(s):  
S Pollack ◽  
J A Ledbetter ◽  
R Katz ◽  
K Williams ◽  
B Akerley ◽  
...  
Keyword(s):  
T Cells ◽  
Kinase Activity ◽  
Jurkat Cells ◽  
Serine Kinase ◽  
Jurkat T Cells ◽  
Receptor Aggregation ◽  
Transient Activation ◽  
The Common

Ligation of CD3/TCR on T-cells induces transient activation of lymphoid MAP-2 kinase (MAP-2K), a 43 kDa serine kinase which itself is a substrate of an unidentified tyrosine kinase (pp43). The reversibility of the MAP-2K response agrees with removal of tyrosine phosphates from pp43. Since both activity as well as tyrosine phosphorylation of MAP-2K could be prolonged by Na3VO4, a phosphotyrosine phosphatase inhibitor, we studied the effect of the common CD45 isoform, which is a member of the CD45 phosphatase family, on MAP-2K activity in vivo and in vitro. We demonstrate the ability of purified CD45 phosphatase to remove tyrosine phosphates from partially purified lymphoid MAP-2K. Utilizing the approach of heterologous receptor aggregation, we also showed that CD45 could inhibit the induction of MAP-2K activity in intact Jurkat cells during CD3 or CD3 + CD4 stimulation. We therefore suggest that this phosphatase may control the activity of lymphoid MAP-2K in vivo.

scholarly journals Complexing of the CD-3 subunit by a monoclonal antibody activates a microtubule-associated protein 2 (MAP-2) serine kinase in Jurkat cells

1989 ◽  
Vol 262 (2) ◽  
pp. 449-456 ◽  
Author(s):  
C Hanekom ◽  
A Nel ◽  
C Gittinger ◽  
A Rheeder ◽  
G Landreth
Keyword(s):  
T Cells ◽  
Time Course ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Jurkat Cells ◽  
Serine Kinase ◽  
Transient Activation ◽  
Normal Human ◽  
Dose Dependent

Treatment of Jurkat T-cells with anti-CD-3 monoclonal antibodies resulted in the rapid and transient activation of a serine kinase which utilized the microtubule-associated protein, MAP-2, as a substrate in vitro. The kinase was also activated on treatment of Jurkat cells with phytohaemagglutinin, but with a different time course. The activation of the MAP-2 kinase by anti-CD-3 antibodies was dose-dependent, with maximal activity observed at concentrations of greater than 500 ng/ml. Normal human E-rosette-positive T-cells also exhibited induction of MAP-2 kinase activity during anti-CD-3 treatment. The enzyme was optimally active in the presence of 2 mM-Mn2+; lower levels of activity were observed with Mg2+, even at concentrations up to 20 mM. The kinase was partially purified by passage over DE-52 Sephacel with the activity eluting as a single peak at 0.25 M-NaCl. The molecular mass was estimated to be 45 kDa by gel filtration. The activation of the MAP-2 kinase was probably due to phosphorylation of this enzyme as treatment with alkaline phosphatase diminished its activity. These data demonstrate that the stimulation of T-cells through the CD-3 complex results in the activation of a novel serine kinase which may be critically involved in signal transduction in these cells.

scholarly journals Modulating p56Lck in T-Cells by a Chimeric Peptide Comprising Two Functionally Different Motifs of Tip fromHerpesvirus saimiri

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Jean-Paul Vernot ◽  
Ana María Perdomo-Arciniegas ◽  
Luis Alberto Pérez-Quintero ◽  
Diego Fernando Martínez
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lipid Rafts ◽  
T Cell Activation ◽  
Cell Activation ◽  
Jurkat Cells ◽  
Chimeric Peptide ◽  
Vector Targeting

The Lck interacting protein Tip ofHerpesvirus saimiriis responsible for T-cell transformation bothin vitroandin vivo. Here we designed the chimeric peptide hTip-CSKH, comprising the Lck specific interacting motif CSKH of Tip and its hydrophobic transmembrane sequence (hTip), the latter as a vector targeting lipid rafts. We found that hTip-CSKH can induce a fivefold increase in proliferation of human andAotussp. T-cells. Costimulation with PMA did not enhance this proliferation rate, suggesting that hTip-CSKH is sufficient and independent of further PKC stimulation. We also found that human Lck phosphorylation was increased earlier after stimulation when T-cells were incubated previously with hTip-CSKH, supporting a strong signalling and proliferative effect of the chimeric peptide. Additionally, Lck downstream signalling was evident with hTip-CSKH but not with control peptides. Importantly, hTip-CSKH could be identified in heavy lipid rafts membrane fractions, a compartment where important T-cell signalling molecules (LAT, Ras, and Lck) are present during T-cell activation. Interestingly, hTip-CSKH was inhibitory to Jurkat cells, in total agreement with the different signalling pathways and activation requirements of this leukemic cell line. These results provide the basis for the development of new compounds capable of modulating therapeutic targets present in lipid rafts.

scholarly journals Interactions of Cbl with Grb2 and phosphatidylinositol 3'-kinase in activated Jurkat cells.

1995 ◽  
Vol 15 (7) ◽  
pp. 3571-3578 ◽  
Author(s):  
H Meisner ◽  
B R Conway ◽  
D Hartley ◽  
M P Czech
Keyword(s):  
T Cells ◽  
Kinase Activity ◽  
Cell Receptor ◽  
Sh2 Domain ◽  
Jurkat Cells ◽  
Cross Linking ◽  
Jurkat T Cells ◽  
Son Of Sevenless ◽  
Src Homology ◽  
Tcr Activation

T-cell receptor (TCR) cross-linking increases tyrosine phosphorylation of multiple proteins, only a few of which have been identified. One of the most rapidly tyrosine-phosphorylated polypeptides is the 120-kDa product of the proto-oncogene c-cbl, a cytosolic and cytoskeletal protein containing multiple proline-rich motifs that are potential binding sites for proteins containing Src homology 3 (SH3) domains. We report here that in cultured Jurkat T cells, Cbl is coprecipitated with antibody against the adapter protein Grb2. Upon activation of Jurkat T cells via the TCR-CD3 complex, we find that high-affinity binding of Cbl requires the N-terminal SH3 domain of GST-Grb2 fusion protein but after cross-linking of the TCR-CD3 and CD4 receptors, Cbl binds equally to its SH2 domain. Grb2 antisera also precipitated p85 from serum-starved cells, while TCR activation increased p85 and tyrosine-phosphorylated Cbl but not Cbl protein in Grb2 immunocomplexes. Phosphatidylinositol (PI) 3-kinase activity was immunoprecipitated from serum-starved cells with Cbl and to a lesser extent with Grb2 antisera, and TCR cross-linking increased this activity severalfold. The PI 3-kinase activity associated with Cbl amounted to 5 to 10% of the total cellular activity that could be precipitated by p85 antisera. The Ras exchange factor Son-of-sevenless 1 (Sos-1) was not found in anti-Cbl immunoprecipitates from activated cells, and Cbl was not detectable in anti-Sos-1 precipitates, supporting the likelihood that Sos-Grb2 and Cbl-Grb2 are present as distinct complexes. Taken together, these data suggest that Cbl function in Jurkat T cells involves its constitutive association with Grb2 and its recruitment of PI 3-kinase in response to TCR activation.

scholarly journals PD-L1 chimeric costimulatory receptor improves the efficacy of CAR-T cells for PD-L1-positive solid tumors and reduces toxicity in vivo

2020 ◽  
Author(s):  
Qibin Liao ◽  
Yunyu Mao ◽  
Huan He ◽  
Xiangqing Ding ◽  
Xiaoyan Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
Solid Tumors ◽  
Jurkat T Cells ◽  
Costimulatory Receptor ◽  
Car T Cells ◽  
Car T ◽  
Engineered T Cells ◽  
Therapeutic Safety

Abstract Background: On-target off-tumor toxicity impedes the clinical application of chimeric antigen receptor-modified T cells (CAR-T cells) in the treatment of solid tumors. The combinatorial antigen recognition strategy can improve the therapeutic safety of CAR-T cells by targeting two different tumor-associated antigens (TAAs) using a CAR and a chimeric costimulatory receptor (CCR). Although programmed death-ligand 1 (PD-L1, also known as B7-H1) is expressed on multiple tumors, the potential of PD-L1 as a universal target for designing CCR remains unknown.Methods: A first-generation CD19 or HER2 CAR and a PD-L1 CCR containing the CD28 signaling domain were constructed and delivered into Jurkat T cells or primary T cells by a pseudotyped lentivirus. The release of cytokines, including IL-2, IFN-γ and TNF-α, was quantified using enzyme-linked immunosorbent assay (ELISA) kits or a cytometric bead array (CBA). The in vitro cytotoxicity of CAR-T cells was detected with a luciferase-based killing assay. The in vitro proliferation of CAR-T cells was assessed by flow cytometry. The therapeutic safety and efficacy of CAR-T cells was evaluated using a subcutaneous dual-tumor model in vivo.Results: Jurkat T cells or primary T cells expressing both the CD19/HER2 CAR and PD-L1 CCR produced higher levels of cytokines in the presence of CD19/HER2 and PD-L1 than in the presence of HER2/CD19. Compared to HER2-z-engineered T cells, HER2-z-PD-L1-28-engineered T cells had higher in vitro cytotoxicity potential against PD-L1-positive tumor cells. CD19/HER2-z-PD-L1-28-engineered T cells showed higher proliferation potential in the presence of CD19/HER2 and PD-L1 than in the absence of PD-L1. CD19/HER2-z-PD-L1-28-engineered T cells preferably destroyed xenograft tumors expressing CD19/HER2 and PD-L1 in vivo and did not significantly affect CD19/HER2-expressing tumors. The PD-L1 CCR improved the antitumor efficacy of low-affinity HER2 CAR-T cells against PD-L1-positive tumors expressing high levels of HER2.Conclusion: Our findings confirmed that PD-L1 can be used as a universal target antigen for designing CCR, improving the efficacy of CAR-T cells in the treatment of PD-L1-positive solid tumors but reducing toxicity within PD-L1-negative normal tissues expressing low levels of TAA in vivo.

scholarly journals Inhibition of Bcr serine kinase by tyrosine phosphorylation.

1996 ◽  
Vol 16 (3) ◽  
pp. 998-1005 ◽  
Author(s):  
J Liu ◽  
Y Wu ◽  
G Z Ma ◽  
D Lu ◽  
L Haataja ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
Kinase Activity ◽  
Philadelphia Chromosome ◽  
Wild Type ◽  
Serine Kinase ◽  
Serine Threonine Kinase ◽  
Threonine Kinase

The first exon of the BCR gene encodes a new serine/threonine protein kinase. Abnormal fusion of the BCR and ABL genes, resulting from the formation of the Philadelphia chromosome (Ph), is the hallmark of Ph-positive leukemia. We have previously demonstrated that the Bcr protein is tyrosine phosphorylated within first-exon sequences by the Bcr-Abl oncoprotein. Here we report that in addition to tyrose 177 (Y-177), Y-360 and Y283 are phosphorylated in Bcr-Abl proteins in vitro. Moreover, Bcr tyrosine 360 is phosphorylated in vivo within both Bcr-Abl and Bcr. Bcr mutant Y177F had a greatly reduced ability to transphosphorylate casein and histone H1, whereas Bcr mutants Y177F and Y283F had wild-type activities. In contrast, the Y360F mutation had little effect on Bcr's autophosphorylation activity. Tyrosine-phosphorylated Bcr, phosphorylated in vitro by Bcr-Abl, was greatly inhibited in its serine/threonine kinase activity, impairing both auto- and transkinase activities of Bcr. Similarly, the isolation of Bcr from cells expressing Bcr-Abl under conditions that preserve phosphotyrosine residues also reduced Bcr's kinase activity. These results indicate that tyrosine 360 of Bcr is critical for the transphosphorylation activity of Bcr and that in Ph-positive leukemia, Bcr serine/threonine kinase activity is seriously impaired.

scholarly journals A tightly associated serine/threonine protein kinase regulates phosphoinositide 3-kinase activity.

1993 ◽  
Vol 13 (3) ◽  
pp. 1657-1665 ◽  
Author(s):  
C L Carpenter ◽  
K R Auger ◽  
B C Duckworth ◽  
W M Hou ◽  
B Schaffhausen ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Protein Phosphatase 2A ◽  
T Antigen ◽  
Serine Kinase ◽  
Phosphatase 2A ◽  
Phosphoinositide 3 Kinase

We identified a serine/threonine protein kinase that is associated with and phosphorylates phosphoinositide 3-kinase (PtdIns 3-kinase). The serine kinase phosphorylates both the 85- and 110-kDa subunits of PtdIns 3-kinase and purifies with it from rat liver and immunoprecipitates with antibodies raised to the 85-kDa subunit. Tryptic phosphopeptide maps indicate that p85 from polyomavirus middle T-transformed cells is phosphorylated in vivo at three sites phosphorylated in vitro by the associated serine kinase. The 85-kDa subunit of PtdIns 3-kinase is phosphorylated in vitro on serine at a stoichiometry of approximately 1 mol of phosphate per mol of p85. This phosphorylation results in a three- to sevenfold decrease in PtdIns 3-kinase activity. Dephosphorylation with protein phosphatase 2A reverses the inhibition. This suggests that the association of protein phosphatase 2A with middle T antigen may function to activate PtdIns 3-kinase.

scholarly journals Interdomain B in ZAP-70 Regulates but Is Not Required for ZAP-70 Signaling Function in Lymphocytes

1999 ◽  
Vol 19 (1) ◽  
pp. 948-956 ◽  
Author(s):  
Qihong Zhao ◽  
Brandi L. Williams ◽  
Robert T. Abraham ◽  
Arthur Weiss
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Kinase Activity ◽  
Dominant Negative ◽  
Jurkat Cells ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Function

ABSTRACT The protein tyrosine kinase ZAP-70 plays an important role in T-cell activation and development. After T-cell receptor stimulation, ZAP-70 associates with the receptor and is phosphorylated on many tyrosines, including Y292, Y315, and Y319 within interdomain B. Previously, we demonstrated that Y292 negatively regulates ZAP-70 function and that Y315 positively regulates ZAP-70 function by interacting with Vav. Recent studies have suggested that Y319 also positively regulate ZAP-70 function. Paradoxically, removal of interdomain B (to create the construct designated Δ), containing the Y292, Y315, and Y319 sites, did not eliminate the ability of ZAP-70 to induce multiple gene reporters in Syk-deficient DT-40 B cells and ZAP-70/Syk-deficient Jurkat cells. Here we show that Δ still utilizes the same pathways as wild-type ZAP-70 to mediate NF-AT induction. This is manifested by the ability of Δ to restore induction of calcium fluxes and mitogen-activated protein kinase activation and by the ability of dominant negative Ras and FK506 to block the induction of NF-AT activity mediated by Δ. Biochemically we show that the stimulated tyrosine phosphorylation of Vav, Shc, and ZAP-70 itself is diminished, whereas that of Slp-76 is increased in cells reconstituted with Δ. Deletion of interdomain B did not affect the ability of ZAP-70 to bind to the receptor. The in vitro kinase activity of ZAP-70 lacking interdomain B was markedly reduced, but the kinase activity was still required for the protein’s in vivo activity. Based on these data, we concluded that interdomain B regulates but is not required for ZAP-70 signaling function leading to cellular responses.

scholarly journals Regulation of Phosphoinositide 3-Kinase by Its Intrinsic Serine Kinase Activity In Vivo

2004 ◽  
Vol 24 (3) ◽  
pp. 966-975 ◽  
Author(s):  
Lazaros C. Foukas ◽  
Caroline A. Beeton ◽  
Jorgen Jensen ◽  
Wayne A. Phillips ◽  
Peter R. Shepherd
Keyword(s):  
Growth Factor ◽  
Kinase Activity ◽  
Catalytic Subunit ◽  
Protein Kinase Activity ◽  
Growth Factor Signaling ◽  
Serine Kinase ◽  
Lipid Kinase ◽  
Phosphoinositide 3 Kinase

ABSTRACT One potentially important mechanism for regulating class Ia phosphoinositide 3-kinase (PI 3-kinase) activity is autophosphorylation of the p85α adapter subunit on Ser608 by the intrinsic protein kinase activity of the p110 catalytic subunit, as this downregulates the lipid kinase activity in vitro. Here we investigate whether this phosphorylation can occur in vivo. We find that p110α phosphorylates p85α Ser608 in vivo with significant stoichiometry. However, p110β is far less efficient at phosphorylating p85α Ser608, identifying a potential difference in the mechanisms by which these two isoforms are regulated. The p85α Ser608 phosphorylation was increased by treatment with insulin, platelet-derived growth factor, and the phosphatase inhibitor okadaic acid. The functional effects of this phosphorylation are highlighted by mutation of Ser608, which results in reduced lipid kinase activity and reduced association of the p110α catalytic subunit with p85α. The importance of this phosphorylation was further highlighted by the finding that autophosphorylation on Ser608 was impaired, while lipid kinase activity was increased, in a p85α mutant recently discovered in human tumors. These results provide the first evidence that phosphorylation of Ser608 plays a role as a shutoff switch in growth factor signaling and contributes to the differences in functional properties of different PI 3-kinase isoforms in vivo.

scholarly journals The Effects of Combining Cancer Drugs with Compounds Isolated from Combretum zeyheri Sond. and Combretum platypetalum Welw. ex M.A. Lawson (Combretaceae) on the Viability of Jurkat T Cells and HL-60 Cells

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Morris Wende ◽  
Simbarashe Sithole ◽  
Godloves Fru Chi ◽  
Marc Y. Stevens ◽  
Stanley Mukanganyama
Keyword(s):  
T Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Mammalian Cells ◽  
Cancer Cell Lines ◽  
Jurkat T Cells ◽  
Cytotoxic Effects ◽  
Peritoneal Cells

Combretum zeyheri and Combretum platypetalum have been shown to have anticancer, antibacterial, antituberculosis, and antifungal effects in both in vivo and in vitro studies. This study sought to evaluate the antiproliferative effects of compounds isolated from C. zeyheri and C. platypetalum on Jurkat T and HL-60 cancer cell lines in combination with doxorubicin and/or chlorambucil. At their GI50 concentrations, the isolated compounds were combined with the corresponding GI50 of chlorambucil and doxorubicin. The cytotoxic effects of the combined compounds were determined on BALB/c mouse peritoneal cells. All the 4 isolated compounds had significant cytotoxic effects on Jurkat T cells. Compounds CP 404 (1), CP 409 (2), CZ 453 (3), and CZ 455 (4) had GI50s on Jurkat T cells of 3.98, 19.33, 6.82, and 20.28 μg/ml, respectively. CP 404 (1), CP 409 (2), CZ 453 (3), and CZ 455 (4) showed GI50s of 14.18, 28.69, 29.87, and 16.46 μg/ml on HL-60 cancer cell lines, respectively. The most potent combination against Jurkat T cells was found to be CP 404 (1) and chlorambucil. This combination showed no cytotoxic effects when tested on BALB/c mouse peritoneal cells. It was concluded that the compounds extracted from C. zeyheri and C. platypetalum inhibit the growth of Jurkat T cells in vitro. The combination of the compounds with anticancer drugs enhanced their anticancer effects. The combination of CP 404 (1) and chlorambucil was found not to be toxic to normal mammalian cells. Therefore, CP 404 (1), 3-O-β-L-rrhamnopyranosyl-5,7,3 ′ 4 ′ ,5 ′ -pentahydroxyflavone, has the potential to be a source of lead compounds that can be developed for anticancer therapy. Further structure-activity relationship studies on this compound are warranted.

scholarly journals ADP-dependent glucokinase regulates energy metabolism via ER-localized glucose sensing

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Roland Imle ◽  
Bei-Tzu Wang ◽  
Nicolas Stützenberger ◽  
Jana Birkenhagen ◽  
Amol Tandon ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Energy Metabolism ◽  
Critical Role ◽  
Receptor Activation ◽  
Glucose Sensing ◽  
Model Systems ◽  
Jurkat T Cells

Abstract Modulation of energy metabolism to a highly glycolytic phenotype, i.e. Warburg effect, is a common phenotype of cancer and activated immune cells allowing increased biomass-production for proliferation and cell division. Endoplasmic reticulum (ER)-localized ADP-dependent glucokinase (ADPGK) has been shown to play a critical role in T cell receptor activation-induced remodeling of energy metabolism, however the underlying mechanisms remain unclear. Therefore, we established and characterized in vitro and in vivo models for ADPGK-deficiency using Jurkat T cells and zebrafish. Upon activation, ADPGK knockout Jurkat T cells displayed increased cell death and ER stress. The increase in cell death resulted from a metabolic catastrophe and knockout cells displayed severely disturbed energy metabolism hindering induction of Warburg phenotype. ADPGK knockdown in zebrafish embryos led to short, dorsalized body axis induced by elevated apoptosis. ADPGK hypomorphic zebrafish further displayed dysfunctional glucose metabolism. In both model systems loss of ADPGK function led to defective N- and O-glycosylation. Overall, our data illustrate that ADPGK is part of a glucose sensing system in the ER modulating metabolism via regulation of N- and O-glycosylation.

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