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Liongue C, Ratnayake T, Basheer F, Ward AC. Janus Kinase 3 (JAK3): A Critical Conserved Node in Immunity Disrupted in Immune Cell Cancer and Immunodeficiency. Int J Mol Sci 2024; 25:2977. [PMID: 38474223 DOI: 10.3390/ijms25052977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
The Janus kinase (JAK) family is a small group of protein tyrosine kinases that represent a central component of intracellular signaling downstream from a myriad of cytokine receptors. The JAK3 family member performs a particularly important role in facilitating signal transduction for a key set of cytokine receptors that are essential for immune cell development and function. Mutations that impact JAK3 activity have been identified in a number of human diseases, including somatic gain-of-function (GOF) mutations associated with immune cell malignancies and germline loss-of-function (LOF) mutations associated with immunodeficiency. The structure, function and impacts of both GOF and LOF mutations of JAK3 are highly conserved, making animal models highly informative. This review details the biology of JAK3 and the impact of its perturbation in immune cell-related diseases, including relevant animal studies.
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Affiliation(s)
- Clifford Liongue
- School of Medicine, Deakin University, Geelong, VIC 3216, Australia
- The Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC 3216, Australia
| | | | - Faiza Basheer
- School of Medicine, Deakin University, Geelong, VIC 3216, Australia
- The Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC 3216, Australia
| | - Alister C Ward
- School of Medicine, Deakin University, Geelong, VIC 3216, Australia
- The Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC 3216, Australia
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In vivo impact of JAK3 A573V mutation revealed using zebrafish. Cell Mol Life Sci 2022; 79:322. [PMID: 35622134 PMCID: PMC9142468 DOI: 10.1007/s00018-022-04361-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/19/2022] [Accepted: 05/09/2022] [Indexed: 12/16/2022]
Abstract
Background Janus kinase 3 (JAK3) acts downstream of the interleukin-2 (IL-2) receptor family to play a pivotal role in the regulation of lymphoid cell development. Activating JAK3 mutations are associated with a number of lymphoid and other malignancies, with mutations within the regulatory pseudokinase domain common. Methods The pseudokinase domain mutations A572V and A573V were separately introduced into the highly conserved zebrafish Jak3 and transiently expressed in cell lines and zebrafish embryos to examine their activity and impact on early T cells. Genome editing was subsequently used to introduce the A573V mutation into the zebrafish genome to study the effects of JAK3 activation on lymphoid cells in a physiologically relevant context throughout the life-course. Results Zebrafish Jak3 A573V produced the strongest activation of downstream STAT5 in vitro and elicited a significant increase in T cells in zebrafish embryos. Zebrafish carrying just a single copy of the Jak3 A573V allele displayed elevated embryonic T cells, which continued into adulthood. Hematopoietic precursors and NK cells were also increased, but not B cells. The lymphoproliferative effects of Jak3 A573V in embryos was shown to be dependent on zebrafish IL-2Rγc, JAK1 and STAT5B equivalents, and could be suppressed with the JAK3 inhibitor Tofacitinib. Conclusions This study demonstrates that a single JAK3 A573V allele expressed from the endogenous locus was able to enhance lymphopoiesis throughout the life-course, which was mediated via an IL-2Rγc/JAK1/JAK3/STAT5 signaling pathway and was sensitive to Tofacitinib. This extends our understanding of oncogenic JAK3 mutations and creates a novel model to underpin further translational investigations. Supplementary Information The online version contains supplementary material available at 10.1007/s00018-022-04361-8.
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Abstract
Genomic DNA sequencing technologies have been one of the great advances of the 21st century, having decreased in cost by seven orders of magnitude and opening up new fields of investigation throughout research and clinical medicine. Genomics coupled with biochemical investigation has allowed the molecular definition of a growing number of new genetic diseases that reveal new concepts of immune regulation. Also, defining the genetic pathogenesis of these diseases has led to improved diagnosis, prognosis, genetic counseling, and, most importantly, new therapies. We highlight the investigational journey from patient phenotype to treatment using the newly defined XMEN disease, caused by the genetic loss of the MAGT1 magnesium transporter, as an example. This disease illustrates how genomics yields new fundamental immunoregulatory insights as well as how research genomics is integrated into clinical immunology. At the end, we discuss two other recently described diseases, CHAI/LATAIE (CTLA-4 deficiency) and PASLI (PI3K dysregulation), as additional examples of the journey from unknown immunological diseases to new precision medicine treatments using genomics.
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Affiliation(s)
- Michael Lenardo
- Molecular Development of the Immune System Section, Laboratory of Immunology, and Clinical Genomics Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland;
| | - Bernice Lo
- Molecular Development of the Immune System Section, Laboratory of Immunology, and Clinical Genomics Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland;
| | - Carrie L Lucas
- Molecular Development of the Immune System Section, Laboratory of Immunology, and Clinical Genomics Program, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland;
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Tan W, Yu S, Lei J, Wu B, Wu C. A novel common gamma chain mutation in a Chinese family with X-linked severe combined immunodeficiency (X-SCID; T(-)NK(-)B(+)). Immunogenetics 2015; 67:629-39. [PMID: 26409833 DOI: 10.1007/s00251-015-0871-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 09/10/2015] [Indexed: 01/04/2023]
Abstract
X-linked severe combined immunodeficiency (X-SCID) is one of the most common causes of primary immunodeficiencies in humans. A 4-month-old boy with recurrent pulmonary infection had decreased numbers of CD3(+), CD4(+), CD8(+) T lymphocytes, and NK cells and increased levels of CD19(+) B cells but no memory B cells or plasma cells. The production of cytokines by T cells and the activation of T and B cells were either absent or inefficient. While B cell levels were high, they were all IgM-positive, and the secretion of all Ig isotypes by activated B cells in vitro was defective. Genomic DNA sequencing revealed that the patient had missense mutations in the IL2RG (exon 5, 718 T > C) and IL7R genes (exon 2, 197 T > C; exon 4, 412G > A). Although the patient's father and one of his sisters have the same missense homozygous mutations of the IL7R gene, neither of them exhibited the immunological phenotype of SCID. The results indicate that the IL2RG gene mutation or a combination of the IL7R and IL2RG mutations in the sick boy had resulted in T(-)NK(-)B(+) SCID.
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Affiliation(s)
- Weiping Tan
- Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yang jiang Xi Road, 74 Zhongshan 2nd Road, Guangzhou, 510120, People's Republic of China
| | - Sifei Yu
- Institute of Immunology, Zhongshan School of Medicine, Key Laboratory of Tropical Disease Control Research of Ministry of Education, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou, 510080, People's Republic of China
| | - Jiaying Lei
- Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yang jiang Xi Road, 74 Zhongshan 2nd Road, Guangzhou, 510120, People's Republic of China
| | - Baojing Wu
- Department of Pediatrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yang jiang Xi Road, 74 Zhongshan 2nd Road, Guangzhou, 510120, People's Republic of China
| | - Changyou Wu
- Institute of Immunology, Zhongshan School of Medicine, Key Laboratory of Tropical Disease Control Research of Ministry of Education, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou, 510080, People's Republic of China.
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Zand MS. Tofacitinab in renal transplantation. Transplant Rev (Orlando) 2014; 27:85-9. [PMID: 23849222 DOI: 10.1016/j.trre.2013.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 04/29/2013] [Indexed: 12/24/2022]
Abstract
Tofacitinib (tositinib, CP-690,550) is a small molecule inhibitor of Janus associated kinases, primarily JAK3 and JAK2, which inhibits cytokine signaling through the IL-2Rγ chain. In this article, we review the mechanism of action of tofacitinib, and pre-clinical and clinical data regarding its use in solid organ transplantation thus far. It is hoped that tofacitinib may form the basis for calcineurin-free immunosuppression, improving renal function while eliminating calcineurin inhibitor renal toxicity. Current studies suggest that tofacitinib is an effective immunosuppressive agent for renal transplantation, but it's use in current protocols carries an increased risk of CMV, BK, and EBV viral infection, anemia and leukopenia, and post-transplant lymphoproliferative disorder.
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Affiliation(s)
- Martin S Zand
- Department of Medicine, Division of Nephrology, University of Rochester Medical Center, Box 675, Rochester, NY 14642, USA.
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Pesu M, Candotti F, Husa M, Hofmann SR, Notarangelo LD, O'Shea JJ. Jak3, severe combined immunodeficiency, and a new class of immunosuppressive drugs. Immunol Rev 2005; 203:127-42. [PMID: 15661026 DOI: 10.1111/j.0105-2896.2005.00220.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The recent elucidation of the multiple molecular mechanisms underlying severe combined immunodeficiency (SCID) is an impressive example of the power of molecular medicine. Analysis of patients and the concomitant generation of animal models mimicking these disorders have quickly provided great insights into the pathophysiology of these potentially devastating illnesses. In this review, we summarize the discoveries that led to the understanding of the role of cytokine receptors and a specific tyrosine kinase, Janus kinase 3 (Jak3), in the pathogenesis of SCID. We discuss how the identification of mutations of Jak3 in autosomal recessive SCID has facilitated the diagnosis of these disorders, offered new insights into the biology of this kinase, permitted new avenues for therapy, and provided the rationale for a generation of a new class of immunosuppressants.
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Affiliation(s)
- Marko Pesu
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD 20892-1820, USA
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Aringer M, Hofmann SR, Frucht DM, Chen M, Centola M, Morinobu A, Visconti R, Kastner DL, Smolen JS, O'Shea JJ. Characterization and analysis of the proximal Janus kinase 3 promoter. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:6057-64. [PMID: 12794134 DOI: 10.4049/jimmunol.170.12.6057] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Janus kinase 3 (Jak3) is a nonreceptor tyrosine kinase essential for signaling via cytokine receptors that comprise the common gamma-chain (gammac), i.e., the receptors for IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. Jak3 is preferentially expressed in hemopoietic cells and is up-regulated upon cell differentiation and activation. Despite the importance of Jak3 in lymphoid development and immune function, the mechanisms that govern its expression have not been defined. To gain insight into this issue, we set out to characterize the Jak3 promoter. The 5'-untranslated region of the Jak3 gene is interrupted by a 3515-bp intron. Upstream of this intron and the transcription initiation site, we identified an approximately 1-kb segment that exhibited lymphoid-specific promoter activity and was responsive to TCR signals. Truncation of this fragment revealed that core promoter activity resided in a 267-bp fragment that contains putative Sp-1, AP-1, Ets, Stat, and other binding sites. Mutation of the AP-1 sites significantly diminished, whereas mutation of the Ets sites abolished, the inducibility of the promoter construct. Chromatin immunoprecipitation assays showed that histone acetylation correlates with mRNA expression and that Ets-1/2 binds this region. Thus, transcription factors that bind these sites, especially Ets family members, are likely to be important regulators of Jak3 expression.
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Affiliation(s)
- Martin Aringer
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Vihinen M, Villa A, Mella P, Schumacher RF, Savoldi G, O'Shea JJ, Candotti F, Notarangelo LD. Molecular modeling of the Jak3 kinase domains and structural basis for severe combined immunodeficiency. Clin Immunol 2000; 96:108-18. [PMID: 10900158 DOI: 10.1006/clim.2000.4880] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hereditary severe combined immunodeficiency (SCID) includes a heterogeneous group of diseases that profoundly affect both cellular and humoral immune responses and require treatment by bone marrow transplantation. Characterization of the cellular and molecular bases of SCID is essential to provide accurate genetic counseling and prenatal diagnosis, and it may offer the grounds for alternative forms of treatment. The Jak3 gene is mutated in most cases of autosomal recessive T(-)B(+) SCID in humans. Jak3 belongs to the family of intracellular Janus tyrosine kinases. It is physically and functionally coupled to the common gamma chain, gammac, shared by several cytokine receptors. We have established the JAK3base registry for disease and mutation information. In order to study the structural consequences of the Jak3 mutations, the structure of the human Jak3 kinase and pseudokinase domains was modeled. Residues involved in ATP and Mg(2+) binding were highly conserved in the kinase domain whereas the substrate binding region is somewhat different compared to other kinases. We have identified the first naturally occurring mutations disrupting the function of the human Jak3 kinase domain. The structural basis of all of the known Jak3 mutations reported so far is discussed based on the modeled structure. The model of the Jak3 protein also permits us to study Jak3 phosphorylation at the structural level and may thus serve in the design of novel immune suppressive drugs.
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Affiliation(s)
- M Vihinen
- Institute of Medical Technology, University of Tampere, FIN-33014, Finland
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Benbernou N, Muegge K, Durum SK. Interleukin (IL)-7 induces rapid activation of Pyk2, which is bound to Janus kinase 1 and IL-7Ralpha. J Biol Chem 2000; 275:7060-5. [PMID: 10702271 DOI: 10.1074/jbc.275.10.7060] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interleukin-7 (IL-7) receptor signaling begins with activation of the Janus tyrosine kinases Jak1 and Jak3, which are associated with the receptor complex. To identify potential targets of these kinases, we examined Pyk2 (a member of the focal adhesion kinase family) using an IL-7-dependent murine thymocyte line, D1. We demonstrate that stimulation of D1 (or normal pro-T) cells by IL-7 rapidly increased tyrosine phosphorylation and enzymatic activity of Pyk2, with kinetics slightly lagging that of Jak1 and Jak3 phosphorylation. Conversely, IL-7 withdrawal resulted in a marked decrease of Pyk2 phosphorylation. Pyk2 was found to be physically associated with Jak1 prior to IL-7 stimulation and to increase its association with IL-7Ralpha chain following IL-7 stimulation. Pyk2 appeared to be involved in cell survival, because antisense Pyk2 accelerated the cell death process. Activation of Pyk2 via the muscarinic and nicotinic receptors using carbachol or via intracellular Ca(2+) rise using ionomycin/phorbol myristate acetate promoted survival in the absence of IL-7. These data support a role for Pyk2 in coupling Jak signaling to the trophic response.
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Affiliation(s)
- N Benbernou
- Intramural Research Support Program, SAIC Frederick, NCI-Frederick Cancer Research and Development Center, Frederick, Maryland 21702, USA
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Di Santo JP. SEVERE COMBINED IMMUNODEFICIENCY CAUSED BY DEFECTS IN COMMON CYTOKINE RECEPTOR γc SIGNALING PATHWAYS. Immunol Allergy Clin North Am 2000. [DOI: 10.1016/s0889-8561(05)70131-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Chen M, Cheng A, Candotti F, Zhou YJ, Hymel A, Fasth A, Notarangelo LD, O'Shea JJ. Complex effects of naturally occurring mutations in the JAK3 pseudokinase domain: evidence for interactions between the kinase and pseudokinase domains. Mol Cell Biol 2000; 20:947-56. [PMID: 10629052 PMCID: PMC85212 DOI: 10.1128/mcb.20.3.947-956.2000] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The structure of Janus kinases (JAKs) is unique among protein tyrosine kinases in having tandem, nonidentical kinase and pseudokinase domains. Despite its conservation in evolution, however, the function of the pseudokinase domain remains poorly understood. Lack of JAK3 expression results in severe combined immunodeficiency (SCID). In this study, we analyze two SCID patients with mutations in the JAK3 pseudokinase domain, which allows for protein expression but disrupts the regulation of the kinase activity. Specifically, these mutant forms of JAK3 had undetectable kinase activity in vitro but were hyperphosphorylated both in patients' Epstein-Barr virus-transformed B cells and when overexpressed in COS7 cells. Moreover, reconstitution of cells with these mutants demonstrated that, although they were constitutively phosphorylated basally, they were unable to transmit cytokine-dependent signals. Further analysis showed that the isolated catalytic domain of JAK3 was functional whereas either the addition of the pseudokinase domain or its deletion from the full-length molecule reduced catalytic activity. Through coimmunoprecipitation of the isolated pseudokinase domain with the isolated catalytic domain, we provide the first evidence that these two domains interact. Furthermore, whereas the wild-type pseudokinase domain modestly inhibited kinase domain-mediated STAT5 phosphorylation, the patient-derived mutants markedly inhibited this phosphorylation. We thus conclude that the JAK3 pseudokinase domain is essential for JAK3 function by regulating its catalytic activity and autophosphorylation. We propose a model in which this occurs via intramolecular interaction with the kinase domain and that increased inhibition of kinase activity by the pseudokinase domain likely contributes to the disease pathogenesis in these two patients.
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Affiliation(s)
- M Chen
- Lymphocyte Cell Biology Section, Arthritis and Rheumatism Branch, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Di Santo JP. SEVERE COMBINED IMMUNODEFICIENCY CAUSED BY DEFECTS IN COMMON CYTOKINE RECEPTOR γc SIGNALING PATHWAYS. Radiol Clin North Am 2000. [DOI: 10.1016/s0033-8389(22)00176-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Complex effects of naturally occurring mutations in the JAK3 pseudokinase domain: evidence for interactions between the kinase and pseudokinase domains. Mol Cell Biol 2000. [PMID: 10629052 DOI: 10.1128/mcb.20.3.947‐956.2000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The structure of Janus kinases (JAKs) is unique among protein tyrosine kinases in having tandem, nonidentical kinase and pseudokinase domains. Despite its conservation in evolution, however, the function of the pseudokinase domain remains poorly understood. Lack of JAK3 expression results in severe combined immunodeficiency (SCID). In this study, we analyze two SCID patients with mutations in the JAK3 pseudokinase domain, which allows for protein expression but disrupts the regulation of the kinase activity. Specifically, these mutant forms of JAK3 had undetectable kinase activity in vitro but were hyperphosphorylated both in patients' Epstein-Barr virus-transformed B cells and when overexpressed in COS7 cells. Moreover, reconstitution of cells with these mutants demonstrated that, although they were constitutively phosphorylated basally, they were unable to transmit cytokine-dependent signals. Further analysis showed that the isolated catalytic domain of JAK3 was functional whereas either the addition of the pseudokinase domain or its deletion from the full-length molecule reduced catalytic activity. Through coimmunoprecipitation of the isolated pseudokinase domain with the isolated catalytic domain, we provide the first evidence that these two domains interact. Furthermore, whereas the wild-type pseudokinase domain modestly inhibited kinase domain-mediated STAT5 phosphorylation, the patient-derived mutants markedly inhibited this phosphorylation. We thus conclude that the JAK3 pseudokinase domain is essential for JAK3 function by regulating its catalytic activity and autophosphorylation. We propose a model in which this occurs via intramolecular interaction with the kinase domain and that increased inhibition of kinase activity by the pseudokinase domain likely contributes to the disease pathogenesis in these two patients.
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Stenberg KA, Riikonen PT, Vihinen M. KinMutBase, a database of human disease-causing protein kinase mutations. Nucleic Acids Res 2000; 28:369-71. [PMID: 10592276 PMCID: PMC102425 DOI: 10.1093/nar/28.1.369] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
KinMutBase (http://www.uta.fi/imt/bioinfo/KinMutBase/) is a registry of mutations in human protein kinases related to disorders. Kinases are essential cellular signaling molecules, in which mutations can lead to diseases, including immunodeficiencies, cancers and endocrine disorders. The first release of KinMutBase contained information for protein tyrosine kinases. The current release includes also serine/threonine protein kinases, as well as an update of the tyrosine kinases. There are 251 entries altogether, representing 337 families and 621 patients. Mutations appear both in conserved hallmark residues of the kinases as well as in non-homologous sites. The KinMutBase WWW pages provide plenty of information, namely mutation statistics and display, clickable sequences with mutations and changes to restriction enzyme patterns.
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Affiliation(s)
- K A Stenberg
- Department of Biosciences, Division of Biochemistry, FIN-00014 University of Helsinki, Finland
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Cacalano NA, Johnston JA. Interleukin-2 signaling and inherited immunodeficiency. Am J Hum Genet 1999; 65:287-93. [PMID: 10417270 PMCID: PMC1377926 DOI: 10.1086/302518] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- N A Cacalano
- DNAX Research Institute, Palo Alto, CA 94304-1104, USA
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Cacalano NA, Migone TS, Bazan F, Hanson EP, Chen M, Candotti F, O'Shea JJ, Johnston JA. Autosomal SCID caused by a point mutation in the N-terminus of Jak3: mapping of the Jak3-receptor interaction domain. EMBO J 1999; 18:1549-58. [PMID: 10075926 PMCID: PMC1171243 DOI: 10.1093/emboj/18.6.1549] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Signaling through the hematopoietic receptors requires activation of receptor-associated Janus (Jak) kinases. For example, Jak1 and Jak3 bind specifically to the IL-2 receptor beta (IL-2Rbeta) and common gamma (gammac) chains, respectively, and initiate biochemical signals critical in controlling immune responses. The region of Jak responsible for receptor interactions, however, is not well characterized. Here we describe a naturally occurring Jak3 mutation from a patient with autosomal severe combined immunodeficiency (SCID), where a single amino acid substitution, Y100C, in Janus homology domain 7 (JH7) prevents kinase-receptor interaction. This mutation also results in a loss of IL-2-induced signaling in a B-cell line derived from this patient. Using mutational analysis we have identified a region of Jak3, including portions of JH6 and JH7, that is sufficient for kinase-receptor contact and show that this segment interacts with the proline-rich Box1 region of the receptor. Furthermore, a Jak3-Jak1 chimera containing only the JH6 and JH7 domains of Jak3 interacts with gammac and can reconstitute IL-2-dependent responses, including receptor phosphorylation and activation of signal transducer and activator of transcription (STAT) 5b. Our results suggest that the N-terminus of Jak kinases is critical for receptor binding, and is therefore likely to determine specificity of Jak kinase-receptor interactions.
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Affiliation(s)
- N A Cacalano
- DNAX Research Institute, 901 California Avenue, Palo Alto, CA 94304, USA
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