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Fernández-Aguilar LM, Vico-Barranco I, Arbulo-Echevarria MM, Aguado E. A Story of Kinases and Adaptors: The Role of Lck, ZAP-70 and LAT in Switch Panel Governing T-Cell Development and Activation. BIOLOGY 2023; 12:1163. [PMID: 37759563 PMCID: PMC10525366 DOI: 10.3390/biology12091163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/29/2023]
Abstract
Specific antigen recognition is one of the immune system's features that allows it to mount intense yet controlled responses to an infinity of potential threats. T cells play a relevant role in the host defense and the clearance of pathogens by means of the specific recognition of peptide antigens presented by antigen-presenting cells (APCs), and, to do so, they are equipped with a clonally distributed antigen receptor called the T-cell receptor (TCR). Upon the specific engagement of the TCR, multiple intracellular signals are triggered, which lead to the activation, proliferation and differentiation of T lymphocytes into effector cells. In addition, this signaling cascade also operates during T-cell development, allowing for the generation of cells that can be helpful in the defense against threats, as well as preventing the generation of autoreactive cells. Early TCR signals include phosphorylation events in which the tyrosine kinases Lck and ZAP70 are involved. The sequential activation of these kinases leads to the phosphorylation of the transmembrane adaptor LAT, which constitutes a signaling hub for the generation of a signalosome, finally resulting in T-cell activation. These early signals play a relevant role in triggering the development, activation, proliferation and apoptosis of T cells, and the negative regulation of these signals is key to avoid aberrant processes that could generate inappropriate cellular responses and disease. In this review, we will examine and discuss the roles of the tyrosine kinases Lck and ZAP70 and the membrane adaptor LAT in these cellular processes.
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Grants
- PY20_01297 Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain
- PID2020-113943RB-I00 Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación, Spain
- PR2022-037 University of Cádiz
- PAIDI2020/DOC_01433 Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain
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Affiliation(s)
- Luis M. Fernández-Aguilar
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Inmaculada Vico-Barranco
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Mikel M. Arbulo-Echevarria
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Enrique Aguado
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
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2
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Arbulo-Echevarria MM, Vico-Barranco I, Zhang F, Fernandez-Aguilar LM, Chotomska M, Narbona-Sánchez I, Zhang L, Malissen B, Liang Y, Aguado E. Mutation of the glycine residue preceding the sixth tyrosine of the LAT adaptor severely alters T cell development and activation. Front Immunol 2022; 13:1054920. [PMID: 36569841 PMCID: PMC9768323 DOI: 10.3389/fimmu.2022.1054920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
The LAT transmembrane adaptor is essential to transduce intracellular signals triggered by the TCR. Phosphorylation of its four C-terminal tyrosine residues (136, 175, 195, and 235 in mouse LAT) recruits several proteins resulting in the assembly of the LAT signalosome. Among those tyrosine residues, the one found at position 136 of mouse LAT plays a critical role for T cell development and activation. The kinetics of phosphorylation of this residue is delayed as compared to the three other C-terminal tyrosines due to a conserved glycine residue found at position 135. Mutation of this glycine into an aspartate residue (denoted LATG135D) increased TCR signaling and altered antigen recognition in human Jurkat T cells and ex vivo mouse T cells. Here, using a strain of LATG135D knockin mice, we showed that the LATG135D mutation modifies thymic development, causing an increase in the percentage of CD4+CD8+ double-positive cells, and a reduction in the percentage of CD4+ and CD8+ single-positive cells. Interestingly, the LATG135D mutation alters thymic development even in a heterozygous state. In the periphery, the LATG135D mutation reduces the percentage of CD8+ T cells and results in a small increment of γδ T cells. Remarkably, the LATG135D mutation dramatically increases the percentage of central memory CD8+ T cells. Finally, analysis of the proliferation and activation of T lymphocytes shows increased responses of T cells from mutant mice. Altogether, our results reinforce the view that the residue preceding Tyr136 of LAT constitutes a crucial checkpoint in T cell development and activation.
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Affiliation(s)
- Mikel M. Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Universidad de Cádiz, Cádiz, Spain,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Inmaculada Vico-Barranco
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Universidad de Cádiz, Cádiz, Spain,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Fanghui Zhang
- Centre d’Immunologie de Marseille-Luminy (CIML), Aix Marseille Université, INSERM, CNRS, Marseille, France,Henan Key Laboratory for Immunology and Targeted Therapy, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Luis M. Fernandez-Aguilar
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Universidad de Cádiz, Cádiz, Spain,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Martyna Chotomska
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Universidad de Cádiz, Cádiz, Spain
| | - Isaac Narbona-Sánchez
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Universidad de Cádiz, Cádiz, Spain,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Lichen Zhang
- Henan Key Laboratory for Immunology and Targeted Therapy, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Bernard Malissen
- Centre d’Immunologie de Marseille-Luminy (CIML), Aix Marseille Université, INSERM, CNRS, Marseille, France,Laboratory of Immunophenomics, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Yinming Liang
- Henan Key Laboratory for Immunology and Targeted Therapy, School of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Enrique Aguado
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Universidad de Cádiz, Cádiz, Spain,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain,*Correspondence: Enrique Aguado,
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3
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A Novel, LAT/Lck Double Deficient T Cell Subline J.CaM1.7 for Combined Analysis of Early TCR Signaling. Cells 2021; 10:cells10020343. [PMID: 33562083 PMCID: PMC7915312 DOI: 10.3390/cells10020343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 11/21/2022] Open
Abstract
Intracellular signaling through the T cell receptor (TCR) is essential for T cell development and function. Proper TCR signaling requires the sequential activities of Lck and ZAP-70 kinases, which result in the phosphorylation of tyrosine residues located in the CD3 ITAMs and the LAT adaptor, respectively. LAT, linker for the activation of T cells, is a transmembrane adaptor protein that acts as a scaffold coupling the early signals coming from the TCR with downstream signaling pathways leading to cellular responses. The leukemic T cell line Jurkat and its derivative mutants J.CaM1.6 (Lck deficient) and J.CaM2 (LAT deficient) have been widely used to study the first signaling events upon TCR triggering. In this work, we describe the loss of LAT adaptor expression found in a subline of J.CaM1.6 cells and analyze cis-elements responsible for the LAT expression defect. This new cell subline, which we have called J.CaM1.7, can re-express LAT adaptor after Protein Kinase C (PKC) activation, which suggests that activation-induced LAT expression is not affected in this new cell subline. Contrary to J.CaM1.6 cells, re-expression of Lck in J.CaM1.7 cells was not sufficient to recover TCR-associated signals, and both LAT and Lck had to be introduced to recover activatory intracellular signals triggered after CD3 crosslinking. Overall, our work shows that the new LAT negative J.CaM1.7 cell subline could represent a new model to study the functions of the tyrosine kinase Lck and the LAT adaptor in TCR signaling, and their mutual interaction, which seems to constitute an essential early signaling event associated with the TCR/CD3 complex.
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Arbulo-Echevarria MM, Vico-Barranco I, Narbona-Sánchez I, García-Cózar F, Miazek A, Aguado E. Increased Protein Stability and Interleukin-2 Production of a LAT G131D Variant With Possible Implications for T Cell Anergy. Front Cell Dev Biol 2020; 8:561503. [PMID: 33042995 PMCID: PMC7517355 DOI: 10.3389/fcell.2020.561503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/13/2020] [Indexed: 11/13/2022] Open
Abstract
The adaptor LAT plays a crucial role in the transduction of signals coming from the TCR/CD3 complex. Phosphorylation of some of its tyrosines generates recruitment sites for other cytosolic signaling molecules. Tyrosine 132 in human LAT is essential for PLC-γ activation and calcium influx generation. It has been recently reported that a conserved glycine residue preceding tyrosine 132 decreases its phosphorylation kinetics, which constitutes a mechanism for ligand discrimination. Here we confirm that a LAT mutant in which glycine 131 has been substituted by an aspartate (LATG131D) increases phosphorylation of Tyr132, PLC-γ activation and calcium influx generation. Interestingly, the LATG131D mutant has a slower protein turnover while being equally sensitive to Fas-mediated protein cleavage by caspases. Moreover, J.CaM2 cells expressing LATG131D secrete greater amounts of interleukin-2 (IL-2) in response to CD3/CD28 engagement. However, despite this increased IL-2 secretion, J.CaM2 cells expressing the LATG131D mutant are more sensitive to inhibition of IL-2 production by pre-treatment with anti-CD3, which points to a possible role of this residue in the generation of anergy. Our results suggest that the increased kinetics of LAT Tyr132 phosphorylation could contribute to the establishment of T cell anergy, and thus constitutes an earliest known intracellular event responsible for the induction of peripheral tolerance.
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Affiliation(s)
| | | | | | - Francisco García-Cózar
- Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain.,Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Arkadiusz Miazek
- Department of Biochemistry and Molecular Biology, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Enrique Aguado
- Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain.,Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
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5
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Arbulo-Echevarria MM, Narbona-Sánchez I, Fernandez-Ponce CM, Vico-Barranco I, Rueda-Ygueravide MD, Dustin ML, Miazek A, Duran-Ruiz MC, García-Cózar F, Aguado E. A Stretch of Negatively Charged Amino Acids of Linker for Activation of T-Cell Adaptor Has a Dual Role in T-Cell Antigen Receptor Intracellular Signaling. Front Immunol 2018; 9:115. [PMID: 29456532 PMCID: PMC5801411 DOI: 10.3389/fimmu.2018.00115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/15/2018] [Indexed: 11/13/2022] Open
Abstract
The adaptor protein linker for activation of T cells (LAT) has an essential role transducing activatory intracellular signals coming from the TCR/CD3 complex. Previous reports have shown that upon T-cell activation, LAT interacts with the tyrosine kinase Lck, leading to the inhibition of its kinase activity. LAT-Lck interaction seemed to depend on a stretch of negatively charged amino acids in LAT. Here, we have substituted this segment of LAT between amino acids 113 and 126 with a non-charged segment and expressed the mutant LAT (LAT-NIL) in J.CaM2 cells in order to analyze TCR signaling. Substitution of this segment in LAT prevented the activation-induced interaction with Lck. Moreover, cells expressing this mutant form of LAT showed a statistically significant increase of proximal intracellular signals such as phosphorylation of LAT in tyrosine residues 171 and 191, and also enhanced ZAP70 phosphorylation approaching borderline statistical significance (p = 0.051). Nevertheless, downstream signals such as Ca2+ influx or MAPK pathways were partially inhibited. Overall, our data reveal that LAT-Lck interaction constitutes a key element regulating proximal intracellular signals coming from the TCR/CD3 complex.
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Affiliation(s)
- Mikel M Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Isaac Narbona-Sánchez
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Cecilia M Fernandez-Ponce
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | - Inmaculada Vico-Barranco
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain
| | | | - Michael L Dustin
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, The Kennedy Institute of Rheumatology, The University of Oxford, Headington, United Kingdom
| | - Arkadiusz Miazek
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Mª Carmen Duran-Ruiz
- Department of Biomedicine, Biotechnology and Public Health (Biochemistry), University of Cádiz, Cádiz, Spain.,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Francisco García-Cózar
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain.,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
| | - Enrique Aguado
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Cádiz, Spain.,Institute of Biomedical Research Cadiz (INIBICA), Cádiz, Spain
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6
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Bacchelli C, Moretti FA, Carmo M, Adams S, Stanescu HC, Pearce K, Madkaikar M, Gilmour KC, Nicholas AK, Woods CG, Kleta R, Beales PL, Qasim W, Gaspar HB. Mutations in linker for activation of T cells (LAT) lead to a novel form of severe combined immunodeficiency. J Allergy Clin Immunol 2016; 139:634-642.e5. [PMID: 27522155 DOI: 10.1016/j.jaci.2016.05.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/17/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Signaling through the T-cell receptor (TCR) is critical for T-cell development and function. Linker for activation of T cells (LAT) is a transmembrane adaptor signaling molecule that is part of the TCR complex and essential for T-cell development, as demonstrated by LAT-deficient mice, which show a complete lack of peripheral T cells. OBJECTIVE We describe a pedigree affected by a severe combined immunodeficiency phenotype with absent T cells and normal B-cell and natural killer cell numbers. A novel homozygous frameshift mutation in the gene encoding for LAT was identified in this kindred. METHODS Genetic, molecular, and functional analyses were used to identify and characterize the LAT defect. Clinical and immunologic analysis of patients was also performed and reported. RESULTS Homozygosity mapping was used to identify potential defective genes. Sanger sequencing of the LAT gene showed a mutation that resulted in a premature stop codon and protein truncation leading to complete loss of function and loss of expression of LAT in the affected family members. We also demonstrate loss of LAT expression and lack of TCR signaling restoration in LAT-deficient cell lines reconstituted with a synthetic LAT gene bearing this severe combined immunodeficiency mutation. CONCLUSION For the first time, the results of this study show that inherited LAT deficiency should be considered in patients with combined immunodeficiency with T-cell abnormalities.
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Affiliation(s)
- Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Federico A Moretti
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Marlene Carmo
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Stuart Adams
- Bone Marrow Transplantation, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - Horia C Stanescu
- Centre for Nephrology, University College London Royal Free Hospital, London, United Kingdom
| | - Kerra Pearce
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Manisha Madkaikar
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Pediatric Immunology and Leukocyte Biology, National Institute of Immunohematology, ICMR, Mumbai, India
| | - Kimberly C Gilmour
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - Adeline K Nicholas
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - C Geoffrey Woods
- Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Robert Kleta
- Centre for Nephrology, University College London Royal Free Hospital, London, United Kingdom
| | - Phil L Beales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Waseem Qasim
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom
| | - H Bobby Gaspar
- Infection, Immunity, Inflammation and Physiological Medicine, UCL Institute of Child Health, London, United Kingdom; Department of Clinical Immunology, Great Ormond Street Hospital NHS Trust, London, United Kingdom.
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7
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Arbulo-Echevarria MM, Muñoz-Miranda JP, Caballero-García A, Poveda-Díaz JL, Fernández-Ponce C, Durán-Ruiz MC, Miazek A, García-Cózar F, Aguado E. Non-T cell activation linker (NTAL) proteolytic cleavage as a terminator of activatory intracellular signals. J Leukoc Biol 2016; 100:351-60. [PMID: 26830332 DOI: 10.1189/jlb.2a0715-318r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/21/2016] [Indexed: 12/13/2022] Open
Abstract
Non-T cell activation linker is an adaptor protein that is tyrosine phosphorylated upon cross-linking of immune receptors expressed on B lymphocytes, NK cells, macrophages, basophils, or mast cells, allowing the recruitment of cytosolic mediators for downstream signaling pathways. Fas receptor acts mainly as a death receptor, and when cross-linked with Fas ligand, many proteins are proteolytically cleaved, including several signaling molecules in T and B cells. Fas receptor triggering also interferes with TCR intracellular signals, probably by means of proteolytic cleavage of several adaptor proteins. We have previously found that the adaptor linker for activation of T cells, evolutionarily related to non-T cell activation linker, is cleaved upon proapoptotic stimuli in T lymphocytes and thymocytes, in a tyrosine phosphorylation-dependent fashion. Here, we describe non-T cell activation linker proteolytic cleavage triggered in human B cells and monocytes by Fas cross-linking and staurosporine treatment. Non-T cell activation linker is cleaved, producing an N-terminal fragment of ∼22 kDa, and such cleavage is abrogated in the presence of caspase 8/granzyme B and caspase 3 inhibitors. Moreover, we have identified an aspartic acid residue at which non-T cell activation linker is cleaved, which similar to linker for activation of T cells, this aspartic acid residue is located close to tyrosine and serine residues, suggesting an interdependence of phosphorylation and proteolytic cleavage. Consistently, induction of non-T cell activation linker phosphorylation by pervanadate inhibits its cleavage. Interestingly, the truncated isoform of non-T cell activation linker, generated after cleavage, has a decreased signaling ability when compared with the full-length molecule. Altogether, our results suggest that cleavage of transmembrane adaptors constitutes a general mechanism for signal termination of immune receptors.
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Affiliation(s)
- Mikel M Arbulo-Echevarria
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Juan Pedro Muñoz-Miranda
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Andrés Caballero-García
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - José L Poveda-Díaz
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Cecilia Fernández-Ponce
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - M Carmen Durán-Ruiz
- Department of Biomedicine, Biotechnology and Public Health (Biochemistry), University of Cádiz, Cádiz, Spain
| | - Arkadiusz Miazek
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
| | - Francisco García-Cózar
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain
| | - Enrique Aguado
- Core Research Facility for Health Sciences, University of Cádiz and Puerto Real University Hospital Research Unit, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cádiz, Spain,
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8
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Kłossowicz M, Marek-Bukowiec K, Arbulo-Echevarria MM, Ścirka B, Majkowski M, Sikorski AF, Aguado E, Miazek A. Identification of functional, short-lived isoform of linker for activation of T cells (LAT). Genes Immun 2014; 15:449-56. [PMID: 25008862 DOI: 10.1038/gene.2014.35] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 05/04/2014] [Accepted: 05/23/2014] [Indexed: 12/13/2022]
Abstract
Linker for activation of T cells (LAT) is a transmembrane adaptor protein playing a key role in the development, activation and maintenance of peripheral homeostasis of T cells. In this study we identified a functional isoform of LAT. It originates from an intron 6 retention event generating an in-frame splice variant of LAT mRNA denoted as LATi6. Comparison of LATi6 expression in peripheral blood leukocytes of human and several other mammalian species revealed that it varied from being virtually absent in the mouse to being predominant in the cow. Analysis of LAT isoform frequency expressed from minigene splicing reporters carrying loss- or gain-of-function point mutations within intronic polyguanine sequences showed that these elements are critical for controlling the intron 6 removal. The protein product of LATi6 isoform (LATi6) ectopically expressed in LAT-deficient JCam 2.5 cell line localized correctly to subcellular compartments and supported T-cell receptor signaling but differed from the canonical LAT protein by displaying a shorter half-life and mediating an increased interleukin-2 secretion upon prolonged CD3/CD28 crosslinking. Altogether, our data suggest that the appearance of LATi6 isoform is an evolutionary innovation that may contribute to a more efficient proofreading control of effector T-cell response.
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Affiliation(s)
- M Kłossowicz
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - K Marek-Bukowiec
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - M M Arbulo-Echevarria
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cadiz and Puerto Real University Hospital Research Unit, School of Medicine, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cadiz, Spain
| | - B Ścirka
- Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - M Majkowski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wroclaw, Poland
| | - A F Sikorski
- Laboratory of Cytobiochemistry, Biotechnology Faculty, University of Wrocław, Wroclaw, Poland
| | - E Aguado
- Department of Biomedicine, Biotechnology and Public Health (Immunology), Core Research Facility for Health Sciences, University of Cadiz and Puerto Real University Hospital Research Unit, School of Medicine, Department of Biomedicine, Biotechnology and Public Health (Immunology), Cadiz, Spain
| | - A Miazek
- 1] Laboratory of Tumor Immunology, Department of Tumor Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland [2] Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
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