1
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Kästle M, Merten C, Hartig R, Plaza-Sirvent C, Schmitz I, Bommhardt U, Schraven B, Simeoni L. Type of PaperY192 within the SH2 Domain of Lck Regulates TCR Signaling Downstream of PLC-γ1 and Thymic Selection. Int J Mol Sci 2022; 23:ijms23137271. [PMID: 35806279 PMCID: PMC9267008 DOI: 10.3390/ijms23137271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 06/24/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023] Open
Abstract
Signaling via the TCR, which is initiated by the Src-family tyrosine kinase Lck, is crucial for the determination of cell fates in the thymus. Because of its pivotal role, ablation of Lck results in a profound block of T-cell development. Here, we show that, in addition to its well-known function in the initiation of TCR signaling, Lck also acts at a more downstream level. This novel function of Lck is determined by the tyrosine residue (Y192) located in its SH2 domain. Thymocytes from knock-in mice expressing a phosphomimetic Y192E mutant of Lck initiate TCR signaling upon CD3 cross-linking up to the level of PLC-γ1 phosphorylation. However, the activation of downstream pathways including Ca2+ influx and phosphorylation of Erk1/2 are impaired. Accordingly, positive and negative selections are blocked in LckY192E knock-in mice. Collectively, our data indicate that Lck has a novel function downstream of PLCγ-1 in the regulation of thymocyte differentiation and selection.
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Affiliation(s)
- Matthias Kästle
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
| | - Camilla Merten
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
| | - Roland Hartig
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
| | - Carlos Plaza-Sirvent
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
- Department of Molecular Immunology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Ingo Schmitz
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
- Department of Molecular Immunology, Ruhr-University Bochum, 44801 Bochum, Germany
| | - Ursula Bommhardt
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
- Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Health and Medical Prevention (CHaMP), Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Burkhart Schraven
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
- Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Health and Medical Prevention (CHaMP), Otto-von-Guericke University, 39120 Magdeburg, Germany
- Correspondence: (B.S.); (L.S.)
| | - Luca Simeoni
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (M.K.); (C.M.); (R.H.); (C.P.-S.); (I.S.); (U.B.)
- Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Health and Medical Prevention (CHaMP), Otto-von-Guericke University, 39120 Magdeburg, Germany
- Correspondence: (B.S.); (L.S.)
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2
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Chapman NM, Connolly SF, Reinl EL, Houtman JCD. Focal adhesion kinase negatively regulates Lck function downstream of the T cell antigen receptor. THE JOURNAL OF IMMUNOLOGY 2013; 191:6208-21. [PMID: 24227778 DOI: 10.4049/jimmunol.1301587] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Focal adhesion kinase (FAK) is a critical regulator of signal transduction in multiple cell types. Although this protein is activated upon TCR engagement, the cellular function that FAK plays in mature human T cells is unknown. By suppressing the function of FAK, we revealed that FAK inhibits TCR-mediated signaling by recruiting C-terminal Src kinase to the membrane and/or receptor complex following TCR activation. Thus, in the absence of FAK, the inhibitory phosphorylation of Lck and/or Fyn is impaired. Together, these data highlight a novel role for FAK as a negative regulator TCR function in human T cells. These results also suggest that changes in FAK expression could modulate sensitivity to TCR stimulation and contribute to the progression of T cell malignancies and autoimmune diseases.
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Affiliation(s)
- Nicole M Chapman
- Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA 52242
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3
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Abstract
The development of T cell in the thymus and the activation of mature T cells in the secondary lymphoid tissues require T cell to make adaptive responses to signaling molecules of environment. The activation of T cell receptor (TCR) signaling pathway could be induced by the interaction of the TCR and its co-receptor CD4 and CD8 with MHC/peptide complex. This process involves co-stimulatory molecules and signals mediated by cytokine receptors, which eventually leads to the occurrence of T cell immune response. The Src-family kinases lymphocyte-specific protein tyrosine kinase (Lck) and proto-oncogene tyrosine-protein kinase (Fyn) are expressed in T cells and serve as the signaling molecules that are activated downstream of TCR. These signaling molecules play key roles in development, positive selection, and peripheral maintenance of naive T cells and lymphopenia-induced proliferation of peripheral T cells. Both Lck and Fyn are required for each of these TCR-based signaling pathways, and Lck seems to be the major contributor, while Fyn can only supplement some functions of Lck. In this review, we discussed the mechanisms by which these two proteins perform functions in T cell development based on our current understanding.
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4
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Dooley J, Erickson M, Larochelle WJ, Gillard GO, Farr AG. FGFR2IIIb signaling regulates thymic epithelial differentiation. Dev Dyn 2008; 236:3459-71. [PMID: 17969154 DOI: 10.1002/dvdy.21364] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Heterogeneous epithelial populations comprising the thymic environment influence early and late stages of T-cell development. The processes that regulate the differentiation of thymic epithelium and that are responsible for this heterogeneity are not well understood, although mesenchymal/epithelial interactions are clearly involved. Here, we show that targeted expression by thymocytes of an fibroblast growth factor receptor-2IIIb (FGFR2IIIb) ligand, FGF10, profoundly alters the differentiation and function of thymic epithelium (TE). Reconstitution of irradiated lckFGF10 mice with normal bone marrow restores normal thymic organization and function, while wild-type mice reconstituted with lckFGF10 bone marrow recapitulates some of the thymic alterations seen in lckFGF10 mice. We also demonstrate that interference with FGFR2IIIb signaling in the thymus with a soluble FGFR2IIIb dominant-negative fusion protein leads to precocious reductions in thymic size and cellularity that resemble age-related thymic involution. These findings indicate that TE compartments are dynamically maintained and that FGF signals are involved in this process.
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Affiliation(s)
- James Dooley
- Department of Biological Structure, University of Washington, Seattle, Washington 98195-7420, USA
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5
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Zhao R, Oxley D, Smith TS, Follows GA, Green AR, Alexander DR. DNA damage-induced Bcl-xL deamidation is mediated by NHE-1 antiport regulated intracellular pH. PLoS Biol 2007; 5:e1. [PMID: 17177603 PMCID: PMC1702560 DOI: 10.1371/journal.pbio.0050001] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Accepted: 10/25/2006] [Indexed: 12/30/2022] Open
Abstract
The pro-survival protein Bcl-xL is critical for the resistance of tumour cells to DNA damage. We have previously demonstrated, using a mouse cancer model, that oncogenic tyrosine kinase inhibition of DNA damage–induced Bcl-xL deamidation tightly correlates with T cell transformation in vivo, although the pathway to Bcl-xL deamidation remains unknown and its functional consequences unclear. We show here that rBcl-xL deamidation generates an iso-Asp52/iso-Asp66 species that is unable to sequester pro-apoptotic BH3-only proteins such as Bim and Puma. DNA damage in thymocytes results in increased expression of the NHE-1 Na/H antiport, an event both necessary and sufficient for subsequent intracellular alkalinisation, Bcl-xL deamidation, and apoptosis. In murine thymocytes and tumour cells expressing an oncogenic tyrosine kinase, this DNA damage–induced cascade is blocked. Enforced intracellular alkalinisation mimics the effects of DNA damage in murine tumour cells and human B-lineage chronic lymphocytic leukaemia cells, thereby causing Bcl-xL deamidation and increased apoptosis. Our results define a signalling pathway leading from DNA damage to up-regulation of the NHE-1 antiport, to intracellular alkalanisation to Bcl-xL deamidation, to apoptosis, representing the first example, to our knowledge, of how deamidation of internal asparagine residues can be regulated in a protein in vivo. Our findings also suggest novel approaches to cancer therapy. Cell survival and cell death (apoptosis) are controlled by a finely tuned ensemble of pro-survival and pro-apoptotic proteins. When the two types of protein are balanced, cells survive. But if the pro-survival proteins dominate, there is a danger that cells with damaged DNA will stay alive, leading to malignancy. One of the key pro-survival proteins, Bcl-xL, acts by blocking the actions of pro-apoptotic proteins. We show here that DNA damage results in an important modification of Bcl-xL. Specifically, when the amide groups are removed from two critical asparagine (amino acid) residues, Bcl-xL can no longer block pro-apoptotic proteins, leading to cell death. Surprisingly, Bcl-xL deamidation is catalysed not by an enzyme, but by increased pH inside the cell due to the up-regulation of an NHE-1 transporter that moves positive ions across the cell membrane. Indeed, artificially increasing pH causes Bcl-xL deamidation and apoptosis in the absence of initial DNA damage. Exploring this novel pathway may ultimately suggest approaches to cancer therapy, especially when malignant cells are resistant to chemotherapy or radiotherapy. Until now, the mechanisms and functional implications for DNA damage-induced Bcl-xL deamidation were unknown. Here the authors provide important new insights into this phenomenon and its impact on cell survival.
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Affiliation(s)
- Rui Zhao
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Babraham, Cambridge, United Kingdom
| | - David Oxley
- Protein Technologies Laboratory, The Babraham Institute, Babraham, Cambridge, United Kingdom
| | - Trevor S Smith
- Protein Technologies Laboratory, The Babraham Institute, Babraham, Cambridge, United Kingdom
| | - George A Follows
- Department of Haematology, University of Cambridge, Hills Road, Cambridge, United Kingdom
| | - Anthony R Green
- Department of Haematology, University of Cambridge, Hills Road, Cambridge, United Kingdom
| | - Denis R Alexander
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Babraham, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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6
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Nowak D, Boehrer S, Hochmuth S, Trepohl B, Hofmann W, Hoelzer D, Hofmann WK, Mitrou PS, Ruthardt M, Chow KU. Src kinase inhibitors induce apoptosis and mediate cell cycle arrest in lymphoma cells. Anticancer Drugs 2007; 18:981-95. [PMID: 17704648 DOI: 10.1097/cad.0b013e3281721ff6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Src kinases are involved in multiple cellular contexts such as proliferation, adhesion, tumor invasiveness, angiogenesis, cell cycle control and apoptosis. We here demonstrate that three newly developed dual selective Src/Abl kinase inhibitors (SrcK-I) (AZM559756, AZD0530 and AZD0424) are able to induce apoptosis and cell cycle arrest in BCR-ABL, c-KIT and platelet-derived growth factor-negative lymphoma cell lines. Treatment of DOHH-2, WSU-NHL, Raji, Karpas-299, HUT78 and Jurkat cells with SrcK-I revealed that the tested substances were effective on these parameters in the cell lines DOHH-2 and WSU-NHL, whereas the other tested cell lines remained unaffected. Phosphorylation of Lyn and in particular Lck were affected most heavily by treatment with the SrcK-I. Extrinsic as well as intrinsic apoptosis pathways were activated and elicited unique expressional patterns of apoptosis-relevant proteins such as downregulation of survivin, Bcl-XL and c-FLIP. Protein levels of c-abl were downregulated and Akt phosphorylation was decreased by treatment with SrcK-I. Basal expression levels of c-Myc were notably lower in sensitive cell lines as compared with nonsensitive cell lines, possibly providing an explanation for sensitivity versus resistance against these novel substances. This study provides the first basis for establishing novel SrcK-I as weapons in the arsenal against lymphoma cells.
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Affiliation(s)
- Daniel Nowak
- Department of Internal Medicine II, Hematology and Oncology, University Hospital, Theodor-Stern-Kai Germany
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7
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Rudd ML, Tua-Smith A, Straus DB. Lck SH3 domain function is required for T-cell receptor signals regulating thymocyte development. Mol Cell Biol 2006; 26:7892-900. [PMID: 16923964 PMCID: PMC1636743 DOI: 10.1128/mcb.00968-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thymocyte development is shaped by signals from the T-cell antigen receptor. The strength of receptor signaling determines developmental progression as well as deletion of self-reactive T cells. Receptor stimulation of the extracellular signal-regulated kinase (ERK) pathway plays an important regulatory role during thymocyte development. However, it is unclear how differences in receptor signaling are translated into distinctive activation of the ERK pathway. We have investigated the potential role of the Lck tyrosine kinase in regulating intracellular signaling during thymocyte development. While Lck is known to be critical for initial T-cell receptor signaling events, it may have an independent role in regulating intracellular signaling through the function of its SH3 domain. To determine whether such a regulatory mechanism functions during thymocyte development, we generated mice in which the normal lck allele is replaced with an lck SH3 domain mutant. Analysis of these mice revealed that both early thymocyte development and maturation of CD4(+) and CD8(+) lineages is impaired. Investigation of thymocyte responses to antigen receptor stimulation showed a significant reduction in proliferation and ERK pathway activation, although initial signaling events were intact. These findings indicate that Lck SH3 domain function may provide a means to independently couple receptor signaling to regulation of the ERK pathway during thymocyte development.
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Affiliation(s)
- Meghan L Rudd
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA
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8
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Zhao Y, Ramakrishnan A, Kim KE, Rabson AB. Regulation of Bcl-3 through interaction with the Lck tyrosine kinase. Biochem Biophys Res Commun 2005; 335:865-73. [PMID: 16099425 DOI: 10.1016/j.bbrc.2005.07.162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 07/27/2005] [Indexed: 11/20/2022]
Abstract
bcl-3 is a protooncogene which undergoes chromosomal translocation in a subset of chronic B-cell lymphocytic leukemia cells. Bcl-3 is a unique IkappaB family protein that regulates transcription of a number of NF-kappaB target genes through interactions with NF-kappaB dimers. Based on previous studies, suggesting that Bcl-3 interacts with the Fyn tyrosine kinase in platelets, we investigated possible interactions of Bcl-3 with Lck, a related tyrosine kinase important in lymphoid cells. Protein-protein interactions between Bcl-3 and the Lck tyrosine kinase were identified both in vitro and in vivo. Lck enhanced Bcl-3-mediated activation of a p52/Bcl-3-responsive promoter in reporter gene assays independent of its tyrosine kinase activity, but requiring the Lck SH3 protein interaction domain. These studies suggest that Bcl-3 might participate in oncogenic pathways involving Lck.
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Affiliation(s)
- Yujie Zhao
- Center for Advanced Biotechnology and Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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9
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McGargill MA, Sharp LL, Bui JD, Hedrick SM, Calbo S. Active Ca2+/calmodulin-dependent protein kinase II gamma B impairs positive selection of T cells by modulating TCR signaling. THE JOURNAL OF IMMUNOLOGY 2005; 175:656-64. [PMID: 16002660 DOI: 10.4049/jimmunol.175.2.656] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
T cell development is regulated at two critical checkpoints that involve signaling events through the TCR. These signals are propagated by kinases of the Src and Syk families, which activate several adaptor molecules to trigger Ca(2+) release and, in turn, Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activation. In this study, we show that a constitutively active form of CaMKII antagonizes TCR signaling and impairs positive selection of thymocytes in mice. Following TCR engagement, active CaMKII decreases TCR-mediated CD3zeta chain phosphorylation and ZAP70 recruitment, preventing further downstream events. Therefore, we propose that CaMKII belongs to a negative-feedback loop that modulates the strength of the TCR signal through the tyrosine phosphatase Src homology 2 domain-containing phosphatase 2 (SHP-2).
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MESH Headings
- Animals
- CD3 Complex/metabolism
- Calcium/metabolism
- Calcium/physiology
- Calcium-Calmodulin-Dependent Protein Kinase Type 2
- Calcium-Calmodulin-Dependent Protein Kinases/biosynthesis
- Calcium-Calmodulin-Dependent Protein Kinases/genetics
- Calcium-Calmodulin-Dependent Protein Kinases/physiology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Line, Tumor
- Female
- Humans
- Intracellular Fluid/enzymology
- Intracellular Fluid/metabolism
- Intracellular Signaling Peptides and Proteins/metabolism
- Isoenzymes/biosynthesis
- Isoenzymes/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Phosphorylation
- Protein Phosphatase 2
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatases/metabolism
- Receptors, Antigen, T-Cell/antagonists & inhibitors
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell/physiology
- SH2 Domain-Containing Protein Tyrosine Phosphatases
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/enzymology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Tyrosine/antagonists & inhibitors
- Tyrosine/metabolism
- src Homology Domains/genetics
- src Homology Domains/immunology
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Affiliation(s)
- Maureen A McGargill
- Department of Biology and Cancer Center, University of California-San Diego, La Jolla, CA 92093, USA
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10
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Chong YP, Mulhern TD, Cheng HC. C-terminal Src kinase (CSK) and CSK-homologous kinase (CHK)--endogenous negative regulators of Src-family protein kinases. Growth Factors 2005; 23:233-44. [PMID: 16243715 DOI: 10.1080/08977190500178877] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
C-terminal Src kinase (CSK) and CSK-homologous kinase (CHK) are endogenous inhibitors of the Src-family protein tyrosine kinases (SFKs). Since constitutive activation of SFKs contributes to cancer formation and progression, to prevent excessive activation of SFKs, their activity in normal cells is kept at the basal level by CSK and CHK. CSK and CHK inactivate SFKs by specifically phosphorylating a consensus tyrosine (called Y(T)) near their C-termini. Upon phosphorylation, the phospho-Y(T) engages in intramolecular interactions that lock the SFK molecule in an inactive conformation. SFKs are anchored to the plasma membrane, while CSK and CHK are localized predominantly in the cytosol. To inhibit SFKs, CSK and CHK need to translocate to the plasma membrane. Recruitment of CSK and CHK to the plasma membrane is mediated by the binding of their SH2, SH3 and/or kinase domains to specific transmembrane proteins, G-proteins and adaptor proteins located near the plasma membrane. For CSK, membrane recruitment often accompanies activation. CSK and CHK employ two types of direct interactions with SFKs to achieve efficient Y(T) phosphorylation: (i) short-range interactions involving binding of the active sites of CSK and CHK to specific residues near Y(T), (ii) long-range non-catalytic interactions involving binding of SFKs to motifs located distally from the active sites of CSK and CHK. The interactions between CSK and SFKs are transient in nature. Unlike CSK, CHK binds tightly to SFKs to form stable protein complexes. The binding is non-catalytic as it is independent of Y(T). More importantly, the tight binding alone is sufficient to completely inhibit SFKs. This non-catalytic inhibitory binding represents a novel mechanism employed by CHK to inhibit SFKs. Given that SFKs are implicated in cancer development, compounds mimicking the non-catalytic inhibitory mechanism of CHK are potential anti-cancer therapeutics.
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Affiliation(s)
- Yuh-Ping Chong
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Department of Biochemistry and Molecular Biology, Parkville, Victoria, Australia
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11
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Huntington ND, Tarlinton DM. CD45: direct and indirect government of immune regulation. Immunol Lett 2005; 94:167-74. [PMID: 15275963 DOI: 10.1016/j.imlet.2004.05.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Revised: 05/17/2004] [Accepted: 05/18/2004] [Indexed: 12/24/2022]
Abstract
The protein tyrosine phosphatase (PTP) CD45 is abundantly expressed on all nucleated hematopoietic cells and is critical for classical antigen receptor signalling indicated by the arrested development of B and T cells in mice deficient for CD45. Despite its clear role in positive regulation of signalling through the activation of the Src family of tyrosine kinases, many reports have shown CD45 to also negatively regulate this process. Given such a dichotomy in CD45 function and a poor understanding of the mechanism underlying the phenotype of CD45(-/-) lymphocytes, we considered it timely to review the existing data and attempt to determine whether aspects of the CD45(-/-) phenotype result from excessive positive or negative kinase activity and the target molecules that may mediate such effects.
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Affiliation(s)
- Nicholas D Huntington
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Vic. 3050, Australia.
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12
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Woods CC, Banks KE, Lebsack TW, White TC, Anderson GA, Maccallum T, Gruener R, DeLuca D. Use of a microgravity organ culture dish system to demonstrate the signal dampening effects of modeled microgravity during T cell development. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2005; 29:565-582. [PMID: 15752552 DOI: 10.1016/j.dci.2004.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 09/11/2004] [Accepted: 09/16/2004] [Indexed: 05/24/2023]
Abstract
Recently, we have shown that exposure of fetal thymus organ cultures (FTOC) to modeled microgravity (MMG) using a clinostat with a microgravity organ culture dish system (MOCDS) blocks T cell development in a manner independent of steroid stress hormones present in vivo. In this study, we describe the development of the MOCDS system, as well as its use in attempting to understand the mechanism by which T cell development is inhibited in MMG. We show that after MMG exposure FTOC exhibited a significant reduction in CD4+CD8+ double positive (DP) cell production, but those DP cells which remained expressed higher levels of the T cell receptor (TCR) associated molecule, CD3. Interestingly, CD4-CD8- double negative (DN) cells expressed lower levels of CD3 on their surface. DN, as well as immature single positive (ISP) cells, also expressed reduced levels of the IL-7 receptor alpha chain (CD127). These changes in CD3 and CD127 expression were concomitantly associated with an increased production of tumor necrosis factor (TNF)-alpha. We were also able to show that addition of an exogenous signal (anti-CD3epsilon monoclonal antibody) to these cultures effectively mitigated the MMG-induced effects, suggesting that MMG-exposure causes a signal dampening effect on developing thymocytes.
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Affiliation(s)
- Chris C Woods
- Department of Microbiology and Immunology, University of Arizona, 1501 N Campbell Ave., PO Box 245049, Tucson, AZ 85724, USA
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13
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Palacios EH, Weiss A. Function of the Src-family kinases, Lck and Fyn, in T-cell development and activation. Oncogene 2004; 23:7990-8000. [PMID: 15489916 DOI: 10.1038/sj.onc.1208074] [Citation(s) in RCA: 505] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The function of the Src-family kinases (SFKs) Lck and Fyn in T cells has been intensively studied over the past 15 years. Animal models and cell line studies both indicate a critical role for Lck and Fyn in proximal T-cell antigen receptor (TCR) signal transduction. Recruited SFKs phosphorylate TCR ITAMs (immunoreceptor tyrosine-based activation motifs) in the CD3 and zeta chains, which then serve as docking sites for Syk-family kinases. SFKs then phosphorylate and activate the recruited Syk-family kinase. Lck and Fyn are spatially segregated in cell membranes due to differential lipid raft localization, and may undergo sequential activation. In addition to the CD4 and CD8 coreceptors, a recently described adaptor, Unc119, may link SFKs to the TCR. CD45 and Csk provide positive and negative regulatory control of SFK functions, respectively, and Csk is constitutively bound to the transmembrane adapter protein, PAG/Cbp. TCR-based signaling is required at several stages of T-cell development, including at least pre-TCR signaling, positive selection, peripheral maintenance of naive T cells, and lymphopenia-induced proliferation. SFKs are required for each of these TCR-based signals, and Lck seems to be the major contributor.
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Affiliation(s)
- Emil H Palacios
- Rosalind Russell Medical Research Center for Arthritis, Department of Medicine and The Howard Hughes Medical Institute, University of California, San Francisco 94143-0795, USA
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14
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Yu XZ, Levin SD, Madrenas J, Anasetti C. Lck Is Required for Activation-Induced T Cell Death after TCR Ligation with Partial Agonists. THE JOURNAL OF IMMUNOLOGY 2004; 172:1437-43. [PMID: 14734719 DOI: 10.4049/jimmunol.172.3.1437] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
TCR engagement can induce either T cell proliferation and differentiation or activation-induced T cell death (AICD) through apoptosis. The intracellular signaling pathways that dictate such a disparate fate after TCR engagement have only been partially elucidated. Non-FcR-binding anti-CD3 mAbs induce a partial agonist TCR signaling pattern and cause AICD on Ag-activated, cycling T cells. In this study, we examined TCR signaling during the induction of AICD by anti-CD3 fos, a non-FcR-binding anti-CD3 mAb. This mAb activates Fyn, Lck, and extracellular signal-regulated kinase, and induces phosphorylation of Src-like adapter protein, despite the inability to cause calcium mobilization or TCR polarization. Anti-CD3 fos also fails to effectively activate zeta-associated protein of 70 kDa or NF-kappaB. Using Ag-specific T cells deficient for Fyn or Lck, we provide compelling evidence that activation of Lck is required for the induction of AICD. Our data indicate that a selective and distinct TCR signaling pattern is required for AICD by TCR partial agonist ligands.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/pharmacology
- Antigens/pharmacology
- Apoptosis/genetics
- Apoptosis/immunology
- CD3 Complex/immunology
- Calcium/metabolism
- Calcium/physiology
- Cells, Cultured
- Enzyme Activation/immunology
- Fas Ligand Protein
- Immunoglobulin Fab Fragments/genetics
- Ligands
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/deficiency
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/immunology
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/physiology
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/physiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred MRL lpr
- Mice, Knockout
- Mice, Transgenic
- Mitogen-Activated Protein Kinases/metabolism
- Molecular Sequence Data
- NF-kappa B/metabolism
- Ovalbumin/pharmacology
- Peptide Fragments/pharmacology
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-fyn
- Receptors, Antigen, T-Cell/agonists
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Solubility
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/enzymology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Up-Regulation/immunology
- fas Receptor/physiology
- src-Family Kinases/metabolism
- src-Family Kinases/physiology
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Affiliation(s)
- Xue-Zhong Yu
- Human Immunogenetics Program, Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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15
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Hosea HJ, Rector ES, Taylor CG. Zinc-Deficient Rats Have Fewer Recent Thymic Emigrant (CD90+) T Lymphocytes in Spleen and Blood. J Nutr 2003; 133:4239-42. [PMID: 14652378 DOI: 10.1093/jn/133.12.4239] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It has been hypothesized that increased expression of the signaling protein p56(lck) disrupts maturation of T lymphocytes, leading to the lymphopenia associated with dietary zinc deficiency and malnutrition. Our objective was to examine p56(lck) protein levels, flow cytometric markers of T cell development (CD4, CD8, TCRalphabeta, TCRgammadelta and CD90) and absolute cell numbers in thymus, spleen and blood of zinc-deficient (ZD), diet-restricted (DR) and control (CTL) rats. Recent thymic emigrant (CD90+) T lymphocytes were also investigated after dietary repletion. P56(lck) protein levels were one- to twofold greater in thymocytes than splenocytes, and ZD rats had more thymocyte p56(lck) protein than CTL rats. In the thymus and blood, the proportions of T lymphocyte subpopulations (CD4-CD8-, CD4+CD8+ and CD4+CD- or CD4-CD8+) were unchanged, except for a higher percentage of TCRalphabeta+CD-CD8+ thymocytes in ZD rats. The 15-29% fewer CD90+ T cells in the blood and spleen of ZD rats were reversed after dietary repletion for 7 and 23 d, respectively. In summary, T-cell numbers were proportional to thymus and spleen weights and unaltered per unit blood volume, despite elevated thymocyte p56(lck) protein in ZD rats. In zinc deficiency, the decreased percentages of CD90+ cells in the blood and spleen could adversely affect the T-cell repertoire.
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Affiliation(s)
- Heather J Hosea
- Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
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16
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Schrum AG, Turka LA, Palmer E. Surface T-cell antigen receptor expression and availability for long-term antigenic signaling. Immunol Rev 2003; 196:7-24. [PMID: 14617194 DOI: 10.1046/j.1600-065x.2003.00083.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
It is important to understand how T-cell antigen receptor (TCR) engagement and signaling are regulated throughout an immune response. This review examines the dynamics of surface TCR expression and signaling capacity during thymic and effector T-cell development. Although the TCR can undergo vast changes in surface expression, T cells remain capable of sustaining TCR engagement for long periods of time. This may be achieved by a combination of mechanisms that involve (a) controlling the quantity of surface TCR available for ligand interaction and (b) controlling the quality of surface TCR expression during T-cell activation. TCR signaling itself appears to be one of the main quantitative modulators of surface TCR expression, and it can cause both downregulation and upregulation at different times of T-cell activation. Recent studies indicate that the degree of upregulation is tunable by the strength of antigenic stimulation. There is evidence that qualitatively distinct forms of the TCR exist, and their potential role in sustained antigenic signaling is also discussed. A goal of future studies will be to better characterize these modulations in surface TCR expression and to clarify their impact on the regulation of immune responses.
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Affiliation(s)
- Adam G Schrum
- Laboratory of Transplantation Immunology and Nephrology, Department of Research, University Hospital-Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland.
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17
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Denzel A, Hare KJ, Zhang C, Shokat K, Jenkinson EJ, Anderson G, Hayday A. Cutting edge: a chemical genetic system for the analysis of kinases regulating T cell development. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:519-23. [PMID: 12847211 DOI: 10.4049/jimmunol.171.2.519] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To understand the regulatory activities of kinases in vivo requires their study across a biologically relevant window of activity. To this end, ATP analog-sensitive kinase alleles (ASKAs) specifically sensitive to a competitive inhibitor have been developed. This article tests whether ASKA technology can be applied to complex immunological systems, such as lymphoid development. The results show that when applied to reaggregate thymic organ culture, novel p56(Lck) ASKAs readily expose a dose-dependent correlation of thymocyte development with a range of p56(Lck) activity. By regulating kinase activity, rather than amounts of RNA or protein, ASKA technology offers a general means for assessing the quantitative contributions to immunology of numerous kinases emerging from genomics analyses. It can obviate the generation of multiple lines of mice expressing different levels of kinase transgenes and should permit specific biological effects to be associated with defined biochemical activities.
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Affiliation(s)
- Angela Denzel
- Department of Immunobiology, New Guy's House, Guy's, King's and St. Thomas's School of Medicine, London, United Kingdom
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18
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Haks MC, Belkowski SM, Ciofani M, Rhodes M, Lefebvre JM, Trop S, Hugo P, Zúñiga-Pflücker JC, Wiest DL. Low activation threshold as a mechanism for ligand-independent signaling in pre-T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:2853-61. [PMID: 12626535 DOI: 10.4049/jimmunol.170.6.2853] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Pre-TCR complexes are thought to signal in a ligand-independent manner because they are constitutively targeted to lipid rafts. We report that ligand-independent signaling is not a unique capability of the pre-TCR complex. Indeed, the TCR alpha subunit restores development of pT alpha-deficient thymocytes to the CD4(+)CD8(+) stage even in the absence of conventional MHC class I and class II ligands. Moreover, we found that pre-TCR and alpha beta TCR complexes exhibit no appreciable difference in their association with lipid rafts, suggesting that ligand-independence is a function of the CD4(-)CD8(-) (DN) thymocytes in which pre-TCR signaling occurs. In agreement, we found that only CD44(-)CD25(+) DN thymocytes (DN3) enabled activation of extracellular signal-regulated kinases by the pre-TCR complex. DN thymocytes also exhibited a lower signaling threshold relative to CD4(+)CD8(+) thymocytes, which was associated with both the markedly elevated lipid raft content of their plasma membranes and more robust capacitative Ca(2+) entry. Taken together these data suggest that cell-autonomous, ligand-independent signaling is primarily a property of the thymocytes in which pre-TCR signaling occurs.
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MESH Headings
- Animals
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Enzyme Activation/immunology
- Ligands
- Lymphocyte Activation/genetics
- Membrane Glycoproteins/deficiency
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Membrane Microdomains/immunology
- Membrane Microdomains/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, SCID
- Mice, Transgenic
- Mitogen-Activated Protein Kinases/metabolism
- Organ Culture Techniques
- Receptors, Antigen, T-Cell, alpha-beta/deficiency
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Stem Cells/enzymology
- Stem Cells/immunology
- Stem Cells/metabolism
- T-Lymphocyte Subsets/enzymology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/enzymology
- Thymus Gland/immunology
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Affiliation(s)
- Mariëlle C Haks
- Division of Basic Sciences, Immunobiology Working Group, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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19
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Takaki S, Tezuka Y, Sauer K, Kubo C, Kwon SM, Armstead E, Nakao K, Katsuki M, Perlmutter RM, Takatsu K. Impaired lymphopoiesis and altered B cell subpopulations in mice overexpressing Lnk adaptor protein. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:703-10. [PMID: 12517931 DOI: 10.4049/jimmunol.170.2.703] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Lnk is an adaptor protein expressed primarily in lymphocytes and hemopoietic precursor cells. Marked expansion of B lineage cells occurs in lnk(-/-) mice, indicating that Lnk regulates B cell production by negatively controlling pro-B cell expansion. In addition, lnk(-/-) hemopoietic precursors have an advantage in repopulating the hemopoietic system of irradiated host animals. In this study, we show that Lnk overexpression results in impaired expansion of lymphoid precursor cells and altered mature B cell subpopulations. The representation of both B lineage and T lineage cells was reduced in transgenic mice overexpressing Lnk under the control of a lymphocyte-specific expression vector. Whereas the overall number of B and T cells was correlated with Lnk protein expression levels, marginal zone B cells in spleen and B1 cells in the peritoneal cavity were relatively resistant to Lnk overexpression. The C-terminal tyrosine residue, conserved among Lnk family adaptor proteins, was dispensable for the negative regulatory roles of Lnk in lymphocyte development. Our results illuminate the novel negative regulatory mechanism mediated by the Lnk adaptor protein in controlling lymphocyte production and function.
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Affiliation(s)
- Satoshi Takaki
- Division of Immunology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Japan.
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20
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Iritani BM, Delrow J, Grandori C, Gomez I, Klacking M, Carlos LS, Eisenman RN. Modulation of T-lymphocyte development, growth and cell size by the Myc antagonist and transcriptional repressor Mad1. EMBO J 2002; 21:4820-30. [PMID: 12234922 PMCID: PMC126288 DOI: 10.1093/emboj/cdf492] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Activated lymphocytes must increase in size and duplicate their contents (cell growth) before they can divide. The molecular events that control cell growth in proliferating lymphocytes and other metazoan cells are still unclear. Here, we utilized transgenesis to provide evidence suggesting that the basic helix-loop- helix-zipper (bHLHZ) transcriptional repressor Mad1, considered to be an antagonist of Myc function, inhibits lymphocyte expansion, maturation and growth following pre-T-cell receptor (pre-TCR) and TCR stimulation. Furthermore, we utilized cDNA microarray technology to determine that, of the genes repressed by Mad1, the majority (77%) are involved in cell growth, which correlates with a decrease in size of Mad1 transgenic thymocytes. Over 80% of the genes repressed by Mad1 have previously been found to be induced by Myc. These results suggest that a balance between Myc and Mad levels may normally modulate lymphocyte proliferation and development in part by controlling expression of growth-regulating genes.
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Affiliation(s)
- Brian M. Iritani
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
| | - Jeffrey Delrow
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
| | - Carla Grandori
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
| | - Ivan Gomez
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
| | - Meredith Klacking
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
| | - Leni Sue Carlos
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
| | - Robert N. Eisenman
- Division of Basic Sciences and DNA Array Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., PO Box 19024, Seattle, WA 98109-1024 and Department of Comparative Medicine, University of Washington, Seattle, WA 98195-7190, USA Corresponding author e-mail:
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21
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Vaillant F, Blyth K, Andrew L, Neil JC, Cameron ER. Enforced expression of Runx2 perturbs T cell development at a stage coincident with beta-selection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:2866-74. [PMID: 12218099 DOI: 10.4049/jimmunol.169.6.2866] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of T cells in the thymus is regulated by a series of stage-specific transcription factors. Deregulated expression of these factors can lead to alterations in thymocyte development with the production of aberrant cell subsets and predispose to tumor formation. The three genes of the Runx family are multilineage regulators of differentiation that have been reported to be expressed in the T cell lineage. However, their roles in thymocyte development and T cell function are largely unknown. While the Runx2/Cbfa1/AML3/Pebp2alphaa gene plays a primary role in osteogenesis and regulates a number of key bone regulatory genes, we show here that Runx2 is also expressed during the earliest phase of thymic development, in the double-negative subset. Furthermore, enforced expression of Runx2 in transgenic mice under the CD2 promoter was found to affect T cell development at a stage coincident with beta-selection, resulting in an expansion of double-negative CD4 and CD8 immature single-positive cells. Unlike wild-type controls this preselection population (CD4-CD8+heat-stable Ag+TCR-) is in a nonproliferative state, but appears to be primed for further transformation events. Overall the data suggest that Runx2 accelerates development to the CD8 immature single-positive stage, but retards subsequent differentiation to the double-positive stage. Thus, Runx2 joins a small group of transcription factors that can interfere with early T cell development, cause an expansion of a specific subset, and predispose to lymphoma.
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Affiliation(s)
- François Vaillant
- Molecular Oncology Laboratory, Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow, United Kingdom.
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22
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Nakayama T, Kasprowicz DJ, Yamashita M, Schubert LA, Gillard G, Kimura M, Didierlaurent A, Koseki H, Ziegler SF. The generation of mature, single-positive thymocytes in vivo is dysregulated by CD69 blockade or overexpression. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:87-94. [PMID: 11751950 DOI: 10.4049/jimmunol.168.1.87] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During development in the thymus, mature CD4+ or CD8+ cells are derived from immature CD4+CD8+ cells through a series of selection events. One of the hallmarks of this maturation process is the expression of CD69, which first appears on thymocytes as they begin positive selection. We have used blockade and overexpression of CD69 to determine the role of CD69 in thymocyte development. Blockade of CD69 led to a reduction in single-positive cells and a concomitant increase in double-positive cells in the thymus. Overexpression of a CD69 transgene in the thymus resulted in a dramatic increase in both CD8SP and CD4SP cells. Coexpression with a TCR transgene demonstrated that both positive and negative selection were enhanced by the increased levels of CD69 on thymocytes. Finally, mice overexpressing CD69 displayed a sharp reduction in the number of T cells in the spleen and lymph node. Taken as a whole, these data suggest the involvement of CD69 in the process of selection and maturation during the trafficking of thymocytes to the medulla.
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MESH Headings
- Animals
- Animals, Newborn
- Antibodies, Monoclonal/pharmacology
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Antigens, Differentiation, T-Lymphocyte/genetics
- Antigens, Differentiation, T-Lymphocyte/metabolism
- Antigens, Differentiation, T-Lymphocyte/physiology
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Cell Lineage
- Flow Cytometry
- Immunophenotyping
- Lectins, C-Type
- Lymph Nodes/immunology
- Lymphocyte Count
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Sequence Deletion
- Spleen/immunology
- T-Lymphocyte Subsets/classification
- T-Lymphocyte Subsets/immunology
- Thymus Gland/growth & development
- Thymus Gland/immunology
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Affiliation(s)
- Toshinori Nakayama
- Department of Molecular Immunology, Graduate School of Medicine, Chiba University, Inohana, Chiba, Japan
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23
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Abstract
To investigate the signaling function of the Src-family protein tyrosine kinase Lck in mature T cells, we generated transgenic mice that expressed Lck in thymocytes but not in peripheral lymphocytes. We compared the phenotype and signaling capacity of Lck-deficient T cells with T cells from mice expressing a dominant inhibitory form of Lck and found that both mouse strains have diminished numbers of mature CD8(+) T cells and respond poorly to CD28 costimulation. However, while T cells that lack Lck fail to mobilize Ca(2+) after stimulation, those expressing the dominant negative protein do so normally. Our data demonstrate that Lck plays several unique roles in mature lymphocyte signaling.
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Affiliation(s)
- P A Trobridge
- Department of Immunology, University of Washington, Seattle, WA 98195, USA
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24
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Voice JK, Dorsam G, Lee H, Kong Y, Goetzl EJ. Allergic diathesis in transgenic mice with constitutive T cell expression of inducible vasoactive intestinal peptide receptor. FASEB J 2001; 15:2489-96. [PMID: 11689474 DOI: 10.1096/fj.01-0671com] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vasoactive intestinal peptide (VIP) and its G-protein-coupled receptors (VPAC1 and VPAC2 Rs) are prominent in the immune system. In T cells, VPAC1 R is expressed constitutively whereas VPAC2 R is induced only after stimulation of the T cell receptor (TCR) or exposure to some cytokines. VPAC1 R and VPAC2 R also transduce different effects of VIP on T cells. Constitutive expression of VPAC2 R selectively in CD4+ T cells (helper-inducer Th cells) of transgenic (TG) C57BL/6 mice directed by the lck tyrosine kinase promoter is now shown to evoke production of more Th2-type interleukins 4 and 5, and less Th1-type interferon gamma after TCR activation. VPAC2 R TG mice consequently have significant elevations of blood IgE, IgG1, and eosinophils. VPAC2 R TG mice also show increased IgE antibody responses, which mediate heightened cutaneous allergic reactions, and have depressed delayed-type hypersensitivity. VIP enhancement of the ratio of Th2 cell to Th1 cell cytokines thus evokes an allergic state in normally nonallergic mice, which suggests the possibility of neuropeptide contributions to immune phenotypic alterations in human hypersensitivity diseases.
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Affiliation(s)
- J K Voice
- Departments of Medicine and Microbiology-Immunology, University of California Medical Center, San Francisco, California 94143-0711, USA
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25
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Gibbons D, Douglas NC, Barber DF, Liu Q, Sullo R, Geng L, Fehling HJ, von Boehmer H, Hayday AC. The biological activity of natural and mutant pTalpha alleles. J Exp Med 2001; 194:695-703. [PMID: 11535637 PMCID: PMC2195948 DOI: 10.1084/jem.194.5.695] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
beta selection is a major checkpoint in early thymocyte differentiation, mediated by successful expression of the pre-T cell receptor (TCR) comprising the TCRbeta chain, CD3 proteins, and a surrogate TCRalpha chain, pTalpha. The mechanism of action of the pre-TCR is unresolved. In humans and mice, the pTalpha gene encodes two RNAs, pTalpha(a), and a substantially truncated form, pTalpha(b). This study shows that both are biologically active in their capacity to rescue multiple thymocyte defects in pTalpha(-/-) mice. Further active alleles of pTalpha include one that lacks both the major ectodomain and much of the long cytoplasmic tail (which is unique among antigen receptor chains), and another in which the cytoplasmic tail is substituted with the short tail of TCR Calpha. Thus, very little of the pTalpha chain is required for function. These data support a hypothesis that the primary role of pTalpha is to stabilize the pre-TCR, and that much of the conserved structure of pTalpha probably plays a critical regulatory role.
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MESH Headings
- Animals
- Base Sequence
- DNA Primers
- Flow Cytometry
- Genes, T-Cell Receptor alpha
- Mice
- Mice, Knockout
- Mice, Transgenic
- Molecular Sequence Data
- Mutagenesis
- Phenotype
- Polymerase Chain Reaction
- Protein Kinase C/metabolism
- Receptor-CD3 Complex, Antigen, T-Cell/genetics
- Receptor-CD3 Complex, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Recombinant Proteins/immunology
- Sequence Deletion
- T-Lymphocytes/immunology
- Thymus Gland/immunology
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Affiliation(s)
- Deena Gibbons
- Guy's King's St. Thomas' Medical School, Guy's Hospital, London Bridge, London SE1 9RT, United Kingdom
| | - Nataki C. Douglas
- Yale University, Department of Molecular, Cell and Developmental Biology, New Haven, CT 06520
| | - Domingo F. Barber
- Yale University, Department of Molecular, Cell and Developmental Biology, New Haven, CT 06520
| | - Qiang Liu
- Guy's King's St. Thomas' Medical School, Guy's Hospital, London Bridge, London SE1 9RT, United Kingdom
| | - Renee Sullo
- Yale University, Department of Molecular, Cell and Developmental Biology, New Haven, CT 06520
| | - Liping Geng
- Yale University, Department of Molecular, Cell and Developmental Biology, New Haven, CT 06520
| | - Hans-Joerg Fehling
- Department of Immunology, Medical Faculty/University Clinics Ulm, D-89070 Ulm, Germany
| | | | - Adrian C. Hayday
- Guy's King's St. Thomas' Medical School, Guy's Hospital, London Bridge, London SE1 9RT, United Kingdom
- Yale University, Department of Molecular, Cell and Developmental Biology, New Haven, CT 06520
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26
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Yamada A, Takaki S, Hayashi F, Georgopoulos K, Perlmutter RM, Takatsu K. Identification and characterization of a transcriptional regulator for the lck proximal promoter. J Biol Chem 2001; 276:18082-9. [PMID: 11278409 DOI: 10.1074/jbc.m008387200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lck gene encodes a protein-tyrosine kinase that plays a key role in signaling mediated through T cell receptor (TCR) and pre-TCR complexes. Transcription of the lck gene is regulated by two independent promoter elements: the proximal and distal promoters. Previous studies employing transgenic mice demonstrated that the sequence between -584 and -240 from the transcription start site in the mouse lck proximal promoter is required for its tissue-specific expression in the thymus. In this study, we demonstrate that a Krüppel-like zinc finger protein, mtbeta (BFCOL1, BERF-1, ZBP-89, ZNF148), previously cloned as a protein that binds to the CD3delta gene enhancer, binds to the -365 to -328 region of the lck proximal promoter. mtbeta is ubiquitously expressed in various cell lines and mouse tissues. Overexpressed mtbeta is more active in T-lineage cells than B-lineage cells for transactivating an artificial promoter consisting of the mtbeta binding site and a TATA box. Activity of the lck proximal promoter was significantly impaired by mutating the mtbeta binding site or by reducing mtbeta protein expression level by using antisense mRNA. Our results indicate that mtbeta activity is regulated in a tissue-specific manner and that mtbeta is a critical transactivator for the lck proximal promoter.
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Affiliation(s)
- A Yamada
- Division of Immunology, Department of Microbiology and Immunology, the Institute of Medical Science, the University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
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27
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Sohn SJ, Forbush KA, Pan XC, Perlmutter RM. Activated p56lck directs maturation of both CD4 and CD8 single-positive thymocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:2209-17. [PMID: 11160274 DOI: 10.4049/jimmunol.166.4.2209] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
p56(lck) is a protein tyrosine kinase expressed throughout T cell development. It associates noncovalently with the cytoplasmic domains of the CD4 and CD8 coreceptor molecules and has been implicated in TCR signaling in mature T cells. Its role in early thymocyte differentiation has been demonstrated in vivo, both by targeted gene disruption and by transgene expression. Previously, we showed that expression of a dominant-negative form of p56(lck) in double-positive thymocytes inhibits positive selection. We now demonstrate that expression of constitutively activated p56(lck) (p56(lck)F505) accelerates the transition from the double-positive to the single-positive stage. Importantly, p56(lck)F505 drives survival and lineage commitment of thymocytes in the absence of TCR engagement by appropriate MHC molecules. These results indicate that activation of p56(lck) constitutes an early step in conveying maturational signals after TCR ligation by a positively selecting ligand. Our study provides direct in vivo evidence for the role of p56(lck) in regulating TCR signaling.
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Affiliation(s)
- S J Sohn
- Department of Immunology, University of Washington, Seattle, WA 98195, USA.
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28
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Trobridge PA, Forbush KA, Levin SD. Positive and negative selection of thymocytes depends on Lck interaction with the CD4 and CD8 coreceptors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:809-18. [PMID: 11145654 DOI: 10.4049/jimmunol.166.2.809] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Considerable evidence supports a role for the Src family protein tyrosine kinase Lck in regulating multiple aspects of thymocyte development. In this report, we establish that early events in T lymphopoiesis are restored to Lck-deficient mice by provision of a transgene encoding a version of Lck that cannot interact with the coreceptors CD4 and CD8. In addition, we demonstrate that later events in thymocyte development, specifically, the processes of positive and negative selection, are compromised in mice where the only Lck available cannot associate with either CD4 or CD8. We conclude that not only is Lck activity required for positive and negative selection, but that that activity must be coupled to the CD4 and CD8 coreceptors.
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Affiliation(s)
- P A Trobridge
- Department of Immunology, University of Washington, Seattle, WA 98195, USA
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29
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Abstract
Transgenic mice expressing a T-cell-specific dominant interfering allele (MEnT) of the c-Myb transcription factor have a pronounced block in CD4(-)CD8(-) (DN) development. In this study we show that differentiation of DN MEnT thymocytes is blocked due to the failure of cells to enter the cell cycle following beta-selection, the process by which productive rearrangement of the T-cell receptor (TCR) beta-chain permits maturation of cells into CD4(+)CD8(+) (DP) thymocytes. c-myb mRNA continues to be expressed in DN cells in mice lacking a functional pre-TCR signalling pathway, implying that its transcriptional regulation is independent of the signalling events regulating beta-selection. It is also expressed in the absence of cytokine signalling. However, we show that c-Myb protein is required for the function in beta-selection of its known upstream activator, the serine/threonine kinase Pim1: MEnT expression inhibits the cell cycle in Pim1 transgenic DN thymocytes and prevents Pim1-mediated rescue of a RAG1(-/-) developmental block. Super activation of c-Myb by Pim1 may therefore be required for beta-selection.
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Affiliation(s)
- R Pearson
- CRC Centre for Cell and Molecular Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
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30
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Baker M, Gamble J, Tooze R, Higgins D, Yang FT, O'Brien PC, Coleman N, Pingel S, Turner M, Alexander DR. Development of T-leukaemias in CD45 tyrosine phosphatase-deficient mutant lck mice. EMBO J 2000; 19:4644-54. [PMID: 10970857 PMCID: PMC302076 DOI: 10.1093/emboj/19.17.4644] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The CD45 tyrosine phosphatase lowers T-cell antigen receptor signalling thresholds by its positive actions on p56(lck) tyrosine kinase function. We now show that mice expressing active lck(F505) at non-oncogenic levels develop aggressive thymic lymphomas on a CD45(-/-) background. CD45 suppresses the tumorigenic potential of the kinase by dephosphorylation of the Tyr394 autophosphorylation site. In CD45(-/-) thymocytes the kinase is switched to a hyperactive oncogenic state, resulting in increased resistance to apoptosis. Transformation occurs in early CD4(-)CD8(-) thymocytes during the process of TCR-beta chain rearrangement by a recombinase-independent mechanism. Our findings represent the first example in which a tyrosine phosphatase in situ prevents the oncogenic actions of a SRC: family tyrosine kinase.
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Affiliation(s)
- M Baker
- Laboratory of Lymphocyte Signalling and Development, Programme of Molecular Immunology, The Babraham Institute, Cambridge CB2 4AT, UK
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31
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Basson MA, Wilson TJ, Legname GA, Sarner N, Tomlinson PD, Tybulewicz VL, Zamoyska R. Early growth response (Egr)-1 gene induction in the thymus in response to TCR ligation during early steps in positive selection is not required for CD8 lineage commitment. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2444-50. [PMID: 10946269 DOI: 10.4049/jimmunol.165.5.2444] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The early growth response gene 1 (Egr-1) is induced during positive selection in the thymus and has been implicated in the differentiation of CD4+ thymocytes. Here, we show that signals that specifically direct CD8 lineage commitment also induce Egr-1 DNA-binding activity in the nucleus. However, we find that pharmacological inhibition of mitogen-activated protein kinase/extracellular signal-related kinase kinase activity potently inhibits Egr-1 DNA-binding function at concentrations that promote differentiation of CD8+ thymocytes, suggesting Egr-1 activity is not essential for CD8 commitment. To further determine the role of Egr-1 in thymocyte development, we compare steady-state Egr-1 DNA-binding activity in thymocytes from mice with defined defects in positive selection. The data indicate that the appearance of functional Egr-1 is downstream of signals induced by TCR/MHC engagement, whereas it is less sensitive to alterations in Lck-mediated signals, and does not correlate directly with proficient positive selection. Egr-1 is one of the earliest transcription factors induced upon TCR ligation on immature thymocytes, and plays a potential role in the transcription of genes involved in thymocyte selection.
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Affiliation(s)
- M A Basson
- Division of Molecular Immunology, National Institute for Medical Research, The Ridgeway, Mill Hill, London, United Kingdom
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32
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Spicuglia S, Payet D, Tripathi RK, Rameil P, Verthuy C, Imbert J, Ferrier P, Hempel WM. TCRalpha enhancer activation occurs via a conformational change of a pre-assembled nucleo-protein complex. EMBO J 2000; 19:2034-45. [PMID: 10790370 PMCID: PMC305700 DOI: 10.1093/emboj/19.9.2034] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The TCR alpha enhancer (Ealpha) has served as a paradigm for studying how enhancers organize trans-activators into nucleo-protein complexes thought to recruit and synergistically stimulate the transcriptional machinery. Little is known, however, of either the extent or dynamics of Ealpha occupancy by nuclear factors during T cell development. Using dimethyl sulfate (DMS) in vivo footprinting, we demonstrate extensive Ealpha occupancy, encompassing both previously identified and novel sites, not only in T cells representing a developmental stage where Ealpha is known to be active (CD4(+)CD8(+)-DP cells), but surprisingly, also in cells at an earlier developmental stage where Ealpha is not active (CD4(-)CD8(-)-DN cells). Partial occupancy was also established in B-lymphoid but not non-lymphoid cells. In vivo DNase I footprinting, however, implied developmentally induced changes in nucleo-protein complex topography. Stage-specific differences in factor composition at Ealpha sequences were also suggested by EMSA analysis. These results, which indicate that alterations in the structure of a pre-assembled nucleo-protein complex correlate with the onset of Ealpha activity, may exemplify one mechanism by which enhancers can rapidly respond to incoming stimuli.
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Affiliation(s)
- S Spicuglia
- Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, Case 906, 13288 Marseille and INSERM U119, 27 boulevard Leï Roure, 13009 Marseille, France
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33
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Yorgin PD, Hartson SD, Fellah AM, Scroggins BT, Huang W, Katsanis E, Couchman JM, Matts RL, Whitesell L. Effects of geldanamycin, a heat-shock protein 90-binding agent, on T cell function and T cell nonreceptor protein tyrosine kinases. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:2915-23. [PMID: 10706677 DOI: 10.4049/jimmunol.164.6.2915] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The benzoquinoid ansamycins geldanamycin (GA), herbimycin, and their derivatives are emerging as novel therapeutic agents that act by inhibiting the 90-kDa heat-shock protein hsp90. We report that GA inhibits the proliferation of mitogen-activated T cells. GA is actively toxic to both resting and activated T cells; activated T cells appear to be especially vulnerable. The mechanism by which GA acts is reflected by its effects on an essential hsp90-dependent protein, the T cell-specific nonreceptor tyrosine kinase lck. GA treatment depletes lck levels in cultured T cells by a kinetically slow dose-dependent process. Pulse-chase analyses indicate that GA induces the very rapid degradation of newly synthesized lck molecules. GA also induces a slower degradation of mature lck populations. These results correlate with global losses in protein tyrosine kinase activity and an inability to respond to TCR stimuli, but the activity of mature lck is not immediately compromised. Although the specific proteasome inhibitor lactacystin provides marginal protection against GA-induced lck depletion, proteasome inhibition also induces changes in lck detergent solubility independent of GA application. There is no other evidence for the involvement of the proteosome. Lysosome inhibition provides quantitatively superior protection against degradation. These results indicate that pharmacologic inhibition of hsp90 chaperone function may represent a novel immunosuppressant strategy, and elaborate on the appropriate context in which to interpret losses of lck as a reporter for the pharmacology of GA in whole organisms.
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Affiliation(s)
- P D Yorgin
- Department of Pediatrics, Steele Memorial Children's Research Center, University of Arizona, Tucson, AZ 85724, USA.
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34
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Hernández-Hoyos G, Sohn SJ, Rothenberg EV, Alberola-Ila J. Lck activity controls CD4/CD8 T cell lineage commitment. Immunity 2000; 12:313-22. [PMID: 10755618 DOI: 10.1016/s1074-7613(00)80184-3] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Thymocytes carrying MHC class I-restricted TCRs differentiate into CD8 T cells, while those recognizing MHC class II become CD4 T cells. The mechanisms underlying how MHC class recognition, coreceptor expression, and effector function are coordinated are not well understood. Since the tyrosine kinase Lck binds with more affinity to CD4 than CD8, it has been proposed as a candidate to mediate this process. By using transgenic mice with altered Lck activity, we show that thymocytes carrying a class II-restricted TCR develop into functional CD8 T cells when Lck activity is reduced. Conversely, thymocytes carrying a class I-restricted TCR develop into functional CD4 T cells when Lck activity is increased. These results directly show that quantitative differences in the Lck signal control the CD4/CD8 lineage decision.
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Affiliation(s)
- G Hernández-Hoyos
- Division of Biology, California Institute of Technology, Pasadena 91125, USA
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35
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Lin K, Longo NS, Wang X, Hewitt JA, Abraham KM. Lck domains differentially contribute to pre-T cell receptor (TCR)- and TCR-alpha/beta-regulated developmental transitions. J Exp Med 2000; 191:703-16. [PMID: 10684862 PMCID: PMC2195836 DOI: 10.1084/jem.191.4.703] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Maturational changes at the CD4(-)CD8(-) double negative (DN) to CD4(+)CD8(+) double positive (DP) transition are dependent on signals generated via the pre-T cell receptor (TCR) and the nonreceptor protein tyrosine kinase p56(lck) (Lck). How Lck activities are stimulated or relayed after pre-TCR formation remains obscure. Our structure-function mapping of Lck thymopoietic properties reveals that the noncatalytic domains of Lck are specialized to signal efficient cellular expansion at DN to DP transition. Moreover, although substitution of the Lck catalytic domain with FynT sequences minimally impacts DP development, single positive thymocytes are most efficiently produced in the presence of kinases containing both the NH(2)-terminal and catalytic regions of Lck. These findings demonstrate that the Lck structure is uniquely adapted to mediate signals at both major transitions in thymopoiesis.
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MESH Headings
- Animals
- CD4-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/immunology
- Catalytic Domain
- Cell Differentiation
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/deficiency
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism
- Mice
- Mice, Knockout
- Mice, Transgenic
- Proto-Oncogene Proteins/deficiency
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-fyn
- Receptors, Antigen, T-Cell, alpha-beta/deficiency
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Recombinant Fusion Proteins/immunology
- Signal Transduction
- Thymus Gland/cytology
- Thymus Gland/immunology
- Transfection
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Affiliation(s)
- Kui Lin
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Graduate Program in Molecular and Cellular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Nancy S. Longo
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Xin Wang
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Judy A. Hewitt
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Kristin M. Abraham
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Graduate Program in Molecular and Cellular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
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36
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Sharp LL, Hedrick SM. Commitment to the CD4 Lineage Mediated by Extracellular Signal-Related Kinase Mitogen-Activated Protein Kinase and Lck Signaling. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.12.6598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
The development of T cells results in a concordance between the specificity of the TCR for MHC class I and class II molecules and the expression of CD8 and CD4 coreceptors. Based on analogy to simple metazoan models of organ development and lineage commitment, we sought to determine whether extracellular signal-related kinase (Erk) mitogen-activated protein (MAP) kinase pathway signaling acts as an inductive signal for the CD4 lineage. Here, we show that, by altering the intracellular signaling involving the Erk/MAP kinase pathway, T cells with specificity for MHC class I can be diverted to express CD4, and, conversely, T cells with specificity for MHC class II can be diverted to express CD8. Furthermore, we find that activation of the src-family tyrosine kinase, p56lck is an upstream mediator of lineage commitment. These results suggest a simple mechanism for lineage commitment in T cell development.
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Affiliation(s)
- Leslie L. Sharp
- Department of Biology and Cancer Center, University of California at San Diego, La Jolla, CA 92093. E-mail address:
| | - Stephen M. Hedrick
- Department of Biology and Cancer Center, University of California at San Diego, La Jolla, CA 92093. E-mail address:
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37
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Carter JD, Neel BG, Lorenz U. The tyrosine phosphatase SHP-1 influences thymocyte selection by setting TCR signaling thresholds. Int Immunol 1999; 11:1999-2014. [PMID: 10590266 DOI: 10.1093/intimm/11.12.1999] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Modulation of the strength of signals from the TCR determines the outcome of positive and negative selection in thymocyte development. Previous studies have demonstrated that SHP-1 plays a role in determining signal strength from the TCR. Here, we have taken a genetic approach to test whether SHP-1 plays a role in T cell selection in the thymus. Experiments in which a dominant negative mutant of SHP-1 was expressed in the BYDP hybridoma cell line confirmed that SHP-1 regulated TCR signaling in a cell-autonomous manner and suggested that Lck is one of its targets. To examine the role of SHP-1 in T cell development, we crossed the ovalbumin-specific DO11.10 TCR transgene onto the motheaten background, which lacks SHP-1 expression. Analysis of the progeny of these crosses provided evidence that SHP-1 regulates thymocyte selection: (i) flow cytometric analyses revealed alterations in the percentages of thymocyte subpopulations in the me/me background; (ii) ex vivo deletion experiments demonstrated that me/me:Tg thymocytes undergo negative selection at lower concentrations of OVA peptide compared to +/+:Tg thymocytes; and (iii) ex vivo proliferation analyses indicated that me/me:Tg thymocytes were hyper-sensitive to stimulation by the specific OVA peptide. Our observation that the absence of SHP-1 leads to altered selection of TCR transgenic thymocytes demonstrates that SHP-1 regulates the strength of TCR-mediated signals in vivo and, in turn, helps to set the threshold for thymocyte selection.
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Affiliation(s)
- J D Carter
- Department of Microbiology, University of Virginia, HSC, 1300 Jefferson Park Avenue, Charlottesville, VA 22908, USA
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38
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Majolini MB, Boncristiano M, Baldari CT. Dysregulation of the protein tyrosine kinase LCK in lymphoproliferative disorders and in other neoplasias. Leuk Lymphoma 1999; 35:245-54. [PMID: 10706447 DOI: 10.3109/10428199909145727] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Initially identified as a T-cell specific member of the Src family of protein tyrosine kinases, Lck has become the object of intensive investigations which have revealed a key role for this kinase in the central processes controlling T-cell development, activation, proliferation and survival. Experimental evidence of the oncogenic potential of Lck, together with the identification of defects in the regulation of Lck expression or activity in T-cell leukemias, suggests that dysregulation of Lck might play a role in neoplastic transformation. Here we review the data documenting a potential role for this kinase in the initiation and maintenance of the transformed state in human cancers.
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Affiliation(s)
- M B Majolini
- Department of Evolutionary Biology, University of Siena, Italy
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39
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Longo NS, Wang X, Wildin RS, Abraham KM. Regulation of Src-family protein tyrosine kinase transcription during lymphocyte ontogeny. Mol Immunol 1999; 36:979-92. [PMID: 10698302 DOI: 10.1016/s0161-5890(99)00134-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The distribution and quantity of cellular signaling elements influence response patterns to a variety of stimuli. As protein tyrosine phosphorylation is a requisite event induced by a majority of surface receptors, and protein tyrosine kinases of the src-family (src-PTKs) act as proximal transducers for many hematopoietic receptors, we have designed a quantitative RT-PCR assay to measure src-family PTK expression during critical stages of lymphocyte ontogeny. With this assay we demonstrate that the distal promoter element regulating expression of lck, a src-PTK essential for T-cell development and activation, is similarly regulated during ontogeny of T and B cells. However, lck transcript abundance is drastically reduced in B lineage cells, suggesting that transcriptional elements influencing lck promoter activity are modulated in these cells. Moreover, although transcripts encoding the src-PTK fyn accumulate at 0.1% of lck mRNA levels in thymocytes, diminished activity of the lck distal promoter in the B-cell background brings lck and fyn transcript levels to near equivalence in this population. Importantly, transcripts arising from the lck distal promoter element and the fyn locus are similarly upregulated during developmental transitions associated with antigen-receptor expression in both B and T cells. These findings suggest that although the magnitude of lck and fyn expression is differentially regulated in B and T cells, expression at these loci is similarly developmentally programmed during ontogeny of both lymphocyte lineages.
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Affiliation(s)
- N S Longo
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore 21201-1559, USA
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40
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Ashwell JD, D'Oro U. CD45 and Src-family kinases: and now for something completely different. IMMUNOLOGY TODAY 1999; 20:412-6. [PMID: 10462741 DOI: 10.1016/s0167-5699(99)01505-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- J D Ashwell
- Laboratory of Immune Cell Biology, National Cancer Institute, Room 1B-40, Building 10, 9000 Rockville Pike, National Institutes of Health, Bethesda, MD 20892, USA.
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41
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Pingel S, Baker M, Turner M, Holmes N, Alexander DR. The CD45 tyrosine phosphatase regulates CD3-induced signal transduction and T cell development in recombinase-deficient mice: restoration of pre-TCR function by active p56(lck). Eur J Immunol 1999; 29:2376-84. [PMID: 10458749 DOI: 10.1002/(sici)1521-4141(199908)29:08<2376::aid-immu2376>3.0.co;2-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The pre-TCR complex regulates the transition from CD4(-)CD8(-) double-negative (DN) to CD4(+)CD8(+) double-positive (DP) thymocytes during T cell development. In CD45(-/-) mice there is an accumulation of DN cells, suggesting a possible role for CD45 in pre-TCR signaling. We therefore crossed CD45(-/-) with Rag-1(-/-) mice to investigate the signaling functions of the CD3 complex in DN thymocytes. Remarkably, treatment of Rag-1(-/-)/CD45(-/-) mice with a CD3 mAb caused maturation to the DP stage at only 3% of the level measured in Rag-1(-/-) mice. Furthermore, ligation of the CD3 complex on Rag-1(-/-) /CD45(-/-) thymocytes in vitro induced less tyrosine phosphorylation in specific proteins when compared to Rag-1(-/-) thymocytes. CD45(-/-) mice were also crossed with pLGFA mice expressing a constitutively active form of the lck tyrosine kinase which restored the DN to DP transition to near normal levels. Our results are consistent with a model in which CD45-activated p56(lck) is critical for pre-TCR signal transduction.
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Affiliation(s)
- S Pingel
- Laboratory of Lymphocyte Signalling and Development Programme of Molecular Immunology, The Babraham Institute, Cambridge, GB
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42
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Haks MC, Krimpenfort P, van den Brakel JH, Kruisbeek AM. Pre-TCR signaling and inactivation of p53 induces crucial cell survival pathways in pre-T cells. Immunity 1999; 11:91-101. [PMID: 10435582 DOI: 10.1016/s1074-7613(00)80084-9] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Signaling through the pre-TCR is essential for early T cell development and is severely impaired in mice lacking the CD3 gamma chain of the pre-TCR. We here address the molecular mechanisms underlying this defect. Impaired pre-TCR signaling is shown to be associated with a profound increase in the number of apoptotic CD4- CD8- (DN) thymocytes. Introduction of p53 deficiency into CD3 gamma-deficient mice completely reverses the cell survival defect in CD3 gamma-deficient DN thymocytes and rescues the block in pre-T cell differentiation. In addition, the CD4+ CD8+ (DP) compartment is expanded to its normal size. These findings suggest that the pre-TCR regulates progression through the DNA-damage checkpoint of the DN to DP transition by inactivating p53.
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Affiliation(s)
- M C Haks
- Division of Immunology, The Netherlands Cancer Institute, Amsterdam
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43
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Bubeck-Wardenburg J, Wong J, Fütterer K, Pappu R, Fu C, Waksman G, Chan AC. Regulation of antigen receptor function by protein tyrosine kinases. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1999; 71:373-92. [PMID: 10354705 DOI: 10.1016/s0079-6107(98)00060-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J Bubeck-Wardenburg
- Departments of Internal Medicine and Pathology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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44
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Morrow MA, Mayer EW, Perez CA, Adlam M, Siu G. Overexpression of the Helix-Loop-Helix protein Id2 blocks T cell development at multiple stages. Mol Immunol 1999; 36:491-503. [PMID: 10475604 DOI: 10.1016/s0161-5890(99)00071-1] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Id proteins are inhibitors of basic-Helix-Loop-Helix transcription factor function that have been implicated in the control of cell differentiation and proliferation. To study the role of Id proteins in the control of T cell development, we generated transgenic mice that overexpress the Id2 protein in thymocytes. We detect a significant expansion of the early CD4(-)CD8(+)TCR(-) thymocyte stage and a depletion of the thymocytes of the subsequent developmental stages. These data indicate that the overexpression of Id2 leads to a stage-specific developmental block early in thymopoiesis. In addition, progeny mice from five of the six Id2 transgenic founder lines succumb to aggressive T cell hyperproliferation that resembles lymphoma. Thus, overexpression of the Id2 protein has profound effects on T cell development and oncogenesis, consistent with the hypothesis that the bHLH proteins play critical roles in these processes.
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Affiliation(s)
- M A Morrow
- Department of Biology, State University of New York, New Paltz 12561-2499, USA.
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45
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Seavitt JR, White LS, Murphy KM, Loh DY, Perlmutter RM, Thomas ML. Expression of the p56(Lck) Y505F mutation in CD45-deficient mice rescues thymocyte development. Mol Cell Biol 1999; 19:4200-8. [PMID: 10330160 PMCID: PMC104379 DOI: 10.1128/mcb.19.6.4200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/1999] [Accepted: 03/23/1999] [Indexed: 11/20/2022] Open
Abstract
Mice deficient in the transmembrane protein tyrosine phosphatase CD45 exhibit a block in thymocyte development. To determine whether the block in thymocyte development was due to the inability to dephosphorylate the inhibitory phosphorylation site (Y505) in p56(lck) (Lck), we generated CD45-deficient mice that express transgenes for the Lck Y505F mutation and the DO11.10 T-cell antigen receptor (TCR). CD4 single-positive T cells developed and accumulated in the periphery. Treatment with antigen resulted in thymocyte apoptosis and the loss of transgenic-TCR-bearing cells. Peripheral CD45-deficient T cells from the mice expressing both transgenes responded to antigen by increasing CD69 expression, interleukin-2 production, and proliferation. These results indicate that thymocyte development requires the dephosphorylation of the inhibitory site in Lck by CD45.
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Affiliation(s)
- J R Seavitt
- Center for Immunology, Department of Pathology and Howard Hughes Medical Institute, Washington University, St. Louis, Missouri 63110, USA
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Iritani BM, Alberola-Ila J, Forbush KA, Perimutter RM. Distinct signals mediate maturation and allelic exclusion in lymphocyte progenitors. Immunity 1999; 10:713-22. [PMID: 10403646 PMCID: PMC5310940 DOI: 10.1016/s1074-7613(00)80070-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Successful in-frame rearrangement of immunoglobulin heavy chain genes or T cell antigen receptor (TCR) beta chain genes in lymphocyte progenitors results in formation of pre-BCR and pre-TCR complexes. These complexes signal progenitor cells to mature, expand in cell number, and suppress further rearrangements at the immunoglobulin heavy chain or TCRbeta chain loci, thereby ensuring allelic exclusion. We used transgenic expression of a constitutively active form of c-Raf-1 (Raf-CAAX) to demonstrate that activation of the Map kinase pathway can stimulate both maturation and expansion of B and T lymphocytes, even in the absence of pre-TCR or pre-BCR formation. However, the same Raf signal did not mediate allelic exclusion. We conclude that maturation of lymphocyte progenitors and allelic exclusion require distinct signals.
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Affiliation(s)
- B M Iritani
- Department of Immunology, Howard Hughes Medical Institute, University of Washington, Seattle 98195, USA.
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47
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Abstract
Recent studies have identified several populations of progenitor cells in the human thymus. The hematopoietic precursor activity of these populations has been determined. The most primitive human thymocytes express high levels of CD34 and lack CD1a. These cells acquire CD1a and differentiate into CD4+CD8+ through CD3−CD4+CD8− and CD3−CD4+CD8+β− intermediate populations. The status of gene rearrangements in the various TCR loci, in particular of TCRδ and TCRγ, has not been analyzed in detail. In the present study we have determined the status of TCR gene rearrangements of early human postnatal thymocyte subpopulations by Southern blot analysis. Our results indicate that TCRδ rearrangements initiate in CD34+CD1a− cells preceding those in the TCRγ and TCRβ loci that commence in CD34+CD1a+ cells. Furthermore, we have examined at which cellular stage TCRβ selection occurs in humans. We analyzed expression of cytoplasmic TCRβ and cell-surface CD3 on thymocytes that lack a mature TCRβ. In addition, we overexpressed a constitutive-active mutant of p56lckF505 by retrovirus-mediated gene transfer in sequential stages of T-cell development and analyzed the effect in a fetal thymic organ culture system. Evidence is presented that TCRβ selection in humans is initiated at the transition of the CD3−CD4+CD8− into the CD4+CD8+β− stage.
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48
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Gärtner F, Alt FW, Monroe R, Chu M, Sleckman BP, Davidson L, Swat W. Immature thymocytes employ distinct signaling pathways for allelic exclusion versus differentiation and expansion. Immunity 1999; 10:537-46. [PMID: 10367899 DOI: 10.1016/s1074-7613(00)80053-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
T cell receptor (TCR) beta chain allelic exclusion occurs at the thymocyte CD4- 8- (double-negative, or DN) to CD4+ 8+ (double-positive, or DP) transition, concurrently with differentiation and cellular expansion, and is imposed by a negative feedback loop in which a product of the first rearranged TCRbeta allele arrests further recombination in the TCRbeta locus. All of the major events associated with the development of DP cells can be induced by the introduction of TCRbeta or activated Lck transgenes. Here, we present evidence that the signaling pathways that promote thymocyte differentiation and expansion of RAG-deficient DN cells but not those that suppress rearrangements of endogenous TCRbeta genes in normal DN cells are engaged by activated Ras. We propose that TCRbeta allelic exclusion is mediated by effector pathways downstream of Lck but independent of Ras.
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Affiliation(s)
- F Gärtner
- Howard Hughes Medical Institute, The Children's Hospital, and The Center for Blood Research, Harvard Medical School, Boston, Massachusetts 02115, USA
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49
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TCR Gene Rearrangements and Expression of the Pre-T Cell Receptor Complex During Human T-Cell Differentiation. Blood 1999. [DOI: 10.1182/blood.v93.9.3033] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Recent studies have identified several populations of progenitor cells in the human thymus. The hematopoietic precursor activity of these populations has been determined. The most primitive human thymocytes express high levels of CD34 and lack CD1a. These cells acquire CD1a and differentiate into CD4+CD8+ through CD3−CD4+CD8− and CD3−CD4+CD8+β− intermediate populations. The status of gene rearrangements in the various TCR loci, in particular of TCRδ and TCRγ, has not been analyzed in detail. In the present study we have determined the status of TCR gene rearrangements of early human postnatal thymocyte subpopulations by Southern blot analysis. Our results indicate that TCRδ rearrangements initiate in CD34+CD1a− cells preceding those in the TCRγ and TCRβ loci that commence in CD34+CD1a+ cells. Furthermore, we have examined at which cellular stage TCRβ selection occurs in humans. We analyzed expression of cytoplasmic TCRβ and cell-surface CD3 on thymocytes that lack a mature TCRβ. In addition, we overexpressed a constitutive-active mutant of p56lckF505 by retrovirus-mediated gene transfer in sequential stages of T-cell development and analyzed the effect in a fetal thymic organ culture system. Evidence is presented that TCRβ selection in humans is initiated at the transition of the CD3−CD4+CD8− into the CD4+CD8+β− stage.
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50
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Bhandoola A, Cibotti R, Punt JA, Granger L, Adams AJ, Sharrow SO, Singer A. Positive selection as a developmental progression initiated by alpha beta TCR signals that fix TCR specificity prior to lineage commitment. Immunity 1999; 10:301-11. [PMID: 10204486 DOI: 10.1016/s1074-7613(00)80030-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During positive selection, immature thymocytes commit to either the CD4+ or CD8+ T cell lineage ("commitment") and convert from short-lived thymocytes into long-lived T cells ("rescue"). By formal precursor-progeny analysis, we now identify what is likely to be the initial positive selection step signaled by alpha beta TCR, which we have termed "induction". During induction, RAG mRNA expression is downregulated, but lineage commitment does not occur. Rather, lineage commitment (which depends upon the MHC class specificity of the alpha beta TCR) only occurs after downregulation of RAG expression and the consequent fixation of alpha beta TCR specificity. We propose that positive selection can be viewed as a sequence of increasingly selective developmental steps (induction-->commitment-->rescue) that are signaled by alpha beta TCR engagements of intrathymic ligands.
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MESH Headings
- Animals
- CD3 Complex/physiology
- CD5 Antigens/physiology
- Cell Differentiation/immunology
- Cell Lineage/immunology
- Clonal Deletion/immunology
- DNA-Binding Proteins/antagonists & inhibitors
- DNA-Binding Proteins/biosynthesis
- Down-Regulation/immunology
- Epitopes, T-Lymphocyte/metabolism
- Hematopoietic Stem Cells/immunology
- Hematopoietic Stem Cells/metabolism
- Histocompatibility Antigens Class I/immunology
- Homeodomain Proteins/antagonists & inhibitors
- Homeodomain Proteins/biosynthesis
- Mice
- Mice, Congenic
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Receptors, Antigen, T-Cell, alpha-beta/analysis
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Signal Transduction/immunology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocytes/chemistry
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- A Bhandoola
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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