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García-Solís B, Van Den Rym A, Martinez-Martínez L, Franco T, Pérez-Caraballo JJ, Markle J, Cubillos-Zapata C, Marín AV, Recio MJ, Regueiro JR, Navarro-Zapata A, Mestre-Durán C, Ferreras C, Martín Cotázar C, Mena R, de la Calle-Fabregat C, López-Lera A, Fernández Arquero M, Pérez-Martínez A, López-Collazo E, Sánchez-Ramón S, Casanova JL, Martínez-Barricarte R, de la Calle-Martín O, Pérez de Diego R. Inherited human ezrin deficiency impairs adaptive immunity. J Allergy Clin Immunol 2023; 152:997-1009.e11. [PMID: 37301410 PMCID: PMC11009781 DOI: 10.1016/j.jaci.2023.05.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/31/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023]
Abstract
BACKGROUND Inborn errors of immunity (IEI) are a group of monogenic diseases that confer susceptibility to infection, autoimmunity, and cancer. Despite the life-threatening consequences of some IEI, their genetic cause remains unknown in many patients. OBJECTIVE We investigated a patient with an IEI of unknown genetic etiology. METHODS Whole-exome sequencing identified a homozygous missense mutation of the gene encoding ezrin (EZR), substituting a threonine for an alanine at position 129. RESULTS Ezrin is one of the subunits of the ezrin, radixin, and moesin (ERM) complex. The ERM complex links the plasma membrane to the cytoskeleton and is crucial for the assembly of an efficient immune response. The A129T mutation abolishes basal phosphorylation and decreases calcium signaling, leading to complete loss of function. Consistent with the pleiotropic function of ezrin in myriad immune cells, multidimensional immunophenotyping by mass and flow cytometry revealed that in addition to hypogammaglobulinemia, the patient had low frequencies of switched memory B cells, CD4+ and CD8+ T cells, MAIT, γδ T cells, and centralnaive CD4+ cells. CONCLUSIONS Autosomal-recessive human ezrin deficiency is a newly recognized genetic cause of B-cell deficiency affecting cellular and humoral immunity.
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Affiliation(s)
- Blanca García-Solís
- Laboratory of Immunogenetics of Human Diseases, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Interdepartmental Group of Immunodeficiencies, Madrid, Spain
| | - Ana Van Den Rym
- Laboratory of Immunogenetics of Human Diseases, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Interdepartmental Group of Immunodeficiencies, Madrid, Spain
| | | | - Teresa Franco
- Immunology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Jareb J Pérez-Caraballo
- Division of Genetic Medicine, Department of Medicine, Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, Tenn; Division of Molecular Pathogenesis, Department of Pathology, Microbiology, and Immunology, Vanderbilt Center for Immunobiology, Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tenn
| | - Janet Markle
- Division of Genetic Medicine, Department of Medicine, Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, Tenn; Division of Molecular Pathogenesis, Department of Pathology, Microbiology, and Immunology, Vanderbilt Center for Immunobiology, Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tenn
| | - Carolina Cubillos-Zapata
- Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Centre for Biomedical Research Network, CIBEres, Madrid, Spain
| | - Ana V Marín
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - María J Recio
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain; Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - José R Regueiro
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Alfonso Navarro-Zapata
- Translational Research in Paediatric Oncology, Haematopoietic Transplantation and Cell Therapy, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Carmen Mestre-Durán
- Translational Research in Paediatric Oncology, Haematopoietic Transplantation and Cell Therapy, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Cristina Ferreras
- Translational Research in Paediatric Oncology, Haematopoietic Transplantation and Cell Therapy, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Carla Martín Cotázar
- Translational Research in Paediatric Oncology, Haematopoietic Transplantation and Cell Therapy, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Roció Mena
- Institute of Medical and Molecular Genetics (INGEMM), Hospital Universitario La Paz, Universidad Autónoma de Madrid, IdiPAZ, Madrid, Spain
| | | | - Alberto López-Lera
- IdiPAZ Institute for Health Research, La Paz University Hospital, CIBERER U-754, Madrid, Spain
| | - Miguel Fernández Arquero
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain; Clinical Immunology Department, San Carlos Clinical Hospital, Madrid, Spain
| | - Antonio Pérez-Martínez
- Translational Research in Paediatric Oncology, Haematopoietic Transplantation and Cell Therapy, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Eduardo López-Collazo
- Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
| | - Silvia Sánchez-Ramón
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain; Clinical Immunology Department, San Carlos Clinical Hospital, Madrid, Spain
| | - Jean-Laurent Casanova
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de la Santé et de la Recherche Médicale U1163, Paris, France; St Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, NY; Imagine Institute, University Paris Descartes, Paris, France; Howard Hughes Medical Institute, New York, NY
| | - Rubén Martínez-Barricarte
- Division of Genetic Medicine, Department of Medicine, Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, Tenn; Division of Molecular Pathogenesis, Department of Pathology, Microbiology, and Immunology, Vanderbilt Center for Immunobiology, Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tenn
| | | | - Rebeca Pérez de Diego
- Laboratory of Immunogenetics of Human Diseases, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain; Interdepartmental Group of Immunodeficiencies, Madrid, Spain.
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Holms RD, Ataullakhanov RI. Ezrin Peptide Therapy from HIV to COVID: Inhibition of Inflammation and Amplification of Adaptive Anti-Viral Immunity. Int J Mol Sci 2021; 22:11688. [PMID: 34769119 PMCID: PMC8584018 DOI: 10.3390/ijms222111688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 11/30/2022] Open
Abstract
Human Ezrin Peptides (HEPs) are inhibitors of expression of IL-6 and other inflammatory cytokines, amplifiers of adaptive B cell and T cell immunity and enhancers of tissue repair. The mutation stable C-terminus of HIV gp120, mimics 69% of the "Hep-receptor", a zipped α-helical structure in the middle of the α domain of human ezrin protein. Synthetic peptides homologous to the Hep-receptor of ezrin of five to fourteen amino acids, activate anti-viral immunity against a wide range of viruses (HIV, HCV, herpes, HPV, influenza and other human respiratory viruses). Human Ezrin Peptide One (HEP1) TEKKRRETVEREKE (brand name Gepon, registered for human use in Russia from 2001) is a successful treatment for opportunistic infections in HIV-infected patients. That treats HEP1and prevents mucosal candidiasis, herpes zoster outbreaks and infection-induced chronic diarrhea. There are clinical publications in Russian on the successful treatments of chronic recurrent vaginal candidiasis, acute and chronic enterocolitis and dysbacteriosis, which are accompanied by normalization of the mucosal microbiome, and the decline or disappearance of inflammation. HEP1 is also an effective treatment and prevention for recurrent inflammation and ulceration in the stomach, duodenum and colon. HEP1 and RepG3 GEKKRRETVEREGG (a derivative of HEP1) have been used successfully as an inhaled spray peptide solution to treat a small number of human volunteers with mild-to-moderate COVID, resulting from SARS-CoV-2 infection, based on earlier successes in treating acute viral respiratory disease with inflammatory complications. Ezrin peptides seem to correct a dysregulation of innate immune responses to SARS-CoV-2. They are also adjuvants of B cell adaptive immunity and increase antibody titres, resulting in protection from lethal virus infection of mice. In a clinical study in Moscow, orally administered HEP1 was shown to enhance antibody-titres produced in response to hepatitis-B vaccination. These very preliminary but promising results with ezrin peptide treatment of COVID must be replicated in large-scale randomised placebo controlled clinical studies, to be verified.
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Pohlmeyer CW, Shang C, Han P, Cui ZH, Jones RM, Clarke AS, Murray BP, Lopez DA, Newstrom DW, Inzunza MD, Matzkies FG, Currie KS, Di Paolo JA. Characterization of the mechanism of action of lanraplenib, a novel spleen tyrosine kinase inhibitor, in models of lupus nephritis. BMC Rheumatol 2021; 5:15. [PMID: 33781343 PMCID: PMC8008554 DOI: 10.1186/s41927-021-00178-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 01/22/2021] [Indexed: 12/19/2022] Open
Abstract
Background B cells are critical mediators of systemic lupus erythematosus (SLE) and lupus nephritis (LN), and antinuclear antibodies can be found in the serum of approximately 98% of patients with SLE. Spleen tyrosine kinase (SYK) is a nonreceptor tyrosine kinase that mediates signaling from immunoreceptors, including the B cell receptor. Active, phosphorylated SYK has been observed in tissues from patients with SLE or cutaneous lupus erythematosus, and its inhibition is hypothesized to ameliorate disease pathogenesis. We sought to evaluate the efficacy and characterize the mechanism of action of lanraplenib, a selective oral SYK inhibitor, in the New Zealand black/white (NZB/W) murine model of SLE and LN. Methods Lanraplenib was evaluated for inhibition of primary human B cell functions in vitro. Furthermore, the effect of SYK inhibition on ameliorating LN-like disease in vivo was determined by treating NZB/W mice with lanraplenib, cyclophosphamide, or a vehicle control. Glomerulopathy and immunoglobulin G (IgG) deposition were quantified in kidneys. The concentration of proinflammatory cytokines was measured in serum. Splenocytes were analyzed by flow cytometry for B cell maturation and T cell memory maturation, and the presence of T follicular helper and dendritic cells. Results In human B cells in vitro, lanraplenib inhibited B cell activating factor-mediated survival as well as activation, maturation, and immunoglobulin M production. Treatment of NZB/W mice with lanraplenib improved overall survival, prevented the development of proteinuria, and reduced blood urea nitrogen concentrations. Kidney morphology was significantly preserved by treatment with lanraplenib as measured by glomerular diameter, protein cast severity, interstitial inflammation, vasculitis, and frequency of glomerular crescents; treatment with lanraplenib reduced glomerular IgG deposition. Mice treated with lanraplenib had reduced concentrations of serum proinflammatory cytokines. Lanraplenib blocked disease-driven B cell maturation and T cell memory maturation in the spleen. Conclusions Lanraplenib blocked the progression of LN-like disease in NZB/W mice. Human in vitro and murine in vivo data suggest that lanraplenib may be efficacious in preventing disease progression in patients with LN at least in part by inhibiting B cell maturation. These data provide additional rationale for the use of lanraplenib in the treatment of SLE and LN. Supplementary Information The online version contains supplementary material available at 10.1186/s41927-021-00178-3.
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Affiliation(s)
| | - Ching Shang
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
| | - Pei Han
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
| | - Zhi-Hua Cui
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
| | - Randall M Jones
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
| | - Astrid S Clarke
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
| | - Bernard P Murray
- Department of Drug Metabolism, Gilead Sciences, Inc., Foster City, CA, USA
| | - David A Lopez
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
| | - David W Newstrom
- Department of Nonclinical Safety and Pathobiology, Gilead Sciences, Inc., Foster City, CA, USA
| | - M David Inzunza
- Department of Nonclinical Safety and Pathobiology, Gilead Sciences, Inc., Foster City, CA, USA
| | | | - Kevin S Currie
- Department of Chemistry, Gilead Sciences, Inc., Foster City, CA, USA
| | - Julie A Di Paolo
- Department of Biology, Gilead Sciences, Inc., 333 Lakeside Dr, Foster City, CA, 94404, USA
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Ivetic A, Hoskins Green HL, Hart SJ. L-selectin: A Major Regulator of Leukocyte Adhesion, Migration and Signaling. Front Immunol 2019; 10:1068. [PMID: 31139190 PMCID: PMC6527602 DOI: 10.3389/fimmu.2019.01068] [Citation(s) in RCA: 230] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
L-selectin (CD62L) is a type-I transmembrane glycoprotein and cell adhesion molecule that is expressed on most circulating leukocytes. Since its identification in 1983, L-selectin has been extensively characterized as a tethering/rolling receptor. There is now mounting evidence in the literature to suggest that L-selectin plays a role in regulating monocyte protrusion during transendothelial migration (TEM). The N-terminal calcium-dependent (C-type) lectin domain of L-selectin interacts with numerous glycans, including sialyl Lewis X (sLex) for tethering/rolling and proteoglycans for TEM. Although the signals downstream of L-selectin-dependent adhesion are poorly understood, they will invariably involve the short 17 amino acid cytoplasmic tail. In this review we will detail the expression of L-selectin in different immune cell subsets, and its influence on cell behavior. We will list some of the diverse glycans known to support L-selectin-dependent adhesion, within luminal and abluminal regions of the vessel wall. We will describe how each domain within L-selectin contributes to adhesion, migration and signal transduction. A significant focus on the L-selectin cytoplasmic tail and its proposed contribution to signaling via the ezrin-radixin-moesin (ERM) family of proteins will be outlined. Finally, we will discuss how ectodomain shedding of L-selectin during monocyte TEM is essential for the establishment of front-back cell polarity, bestowing emigrated cells the capacity to chemotax toward sites of damage.
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Affiliation(s)
- Aleksandar Ivetic
- King's College London, School of Cardiovascular Medicine and Sciences, BHF Center of Research Excellence, London, United Kingdom
| | - Hannah Louise Hoskins Green
- King's College London, School of Cardiovascular Medicine and Sciences, BHF Center of Research Excellence, London, United Kingdom
| | - Samuel James Hart
- King's College London, School of Cardiovascular Medicine and Sciences, BHF Center of Research Excellence, London, United Kingdom
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5
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Huang L, Zhang Y, Xu C, Gu X, Niu L, Wang J, Sun X, Bai X, Xuan X, Li Q, Shi C, Yu B, Miller H, Yang G, Westerberg LS, Liu W, Song W, Zhao X, Liu C. Rictor positively regulates B cell receptor signaling by modulating actin reorganization via ezrin. PLoS Biol 2017; 15:e2001750. [PMID: 28821013 PMCID: PMC5562439 DOI: 10.1371/journal.pbio.2001750] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 07/25/2017] [Indexed: 01/13/2023] Open
Abstract
As the central hub of the metabolism machinery, the mammalian target of rapamycin complex 2 (mTORC2) has been well studied in lymphocytes. As an obligatory component of mTORC2, the role of Rictor in T cells is well established. However, the role of Rictor in B cells still remains elusive. Rictor is involved in B cell development, especially the peripheral development. However, the role of Rictor on B cell receptor (BCR) signaling as well as the underlying cellular and molecular mechanism is still unknown. This study used B cell-specfic Rictor knockout (KO) mice to investigate how Rictor regulates BCR signaling. We found that the key positive and negative BCR signaling molecules, phosphorylated Brutons tyrosine kinase (pBtk) and phosphorylated SH2-containing inositol phosphatase (pSHIP), are reduced and enhanced, respectively, in Rictor KO B cells. This suggests that Rictor positively regulates the early events of BCR signaling. We found that the cellular filamentous actin (F-actin) is drastically increased in Rictor KO B cells after BCR stimulation through dysregulating the dephosphorylation of ezrin. The high actin-ezrin intensity area restricts the lateral movement of BCRs upon stimulation, consequently reducing BCR clustering and BCR signaling. The reduction in the initiation of BCR signaling caused by actin alteration is associated with a decreased humoral immune response in Rictor KO mice. The inhibition of actin polymerization with latrunculin in Rictor KO B cells rescues the defects of BCR signaling and B cell differentiation. Overall, our study provides a new pathway linking cell metablism to BCR activation, in which Rictor regulates BCR signaling via actin reorganization.
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Affiliation(s)
- Lu Huang
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Yongjie Zhang
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Chenguang Xu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Xiaomei Gu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Linlin Niu
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Jinzhi Wang
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoyu Sun
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoming Bai
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Xingtian Xuan
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Qubei Li
- Children’s Hospital Respiratory Center of Chongqing Medical University, Chongqing, China
| | - Chunwei Shi
- Department of Pathogen Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Bing Yu
- Department of Pathogen Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Heather Miller
- Department of Intracellular Pathogens, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Gangyi Yang
- Department of Endocrinology, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Lisa S. Westerberg
- Department of Microbiology Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Wanli Liu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Wenxia Song
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Xiaodong Zhao
- Chongqing Key Laboratory of Child Infection and Immunity, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Department of Pediatric Research Institute, Children’s Hospital of Chongqing Medical University, Chongqing, China
- Ministry of Education Key Laboratory of Child Development and Disorders, Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Chaohong Liu
- Department of Pathogen Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
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PSGL-1: A New Player in the Immune Checkpoint Landscape. Trends Immunol 2017; 38:323-335. [PMID: 28262471 DOI: 10.1016/j.it.2017.02.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/02/2017] [Accepted: 02/08/2017] [Indexed: 02/07/2023]
Abstract
P-selectin glycoprotein ligand-1 (PSGL-1) has long been studied as an adhesion molecule involved in immune cell trafficking and is recognized as a regulator of many facets of immune responses by myeloid cells. PSGL-1 also regulates T cell migration during homeostasis and inflammatory settings. However, recent findings indicate that PSGL-1 can also negatively regulate T cell function. Because T cell differentiation is finely tuned by multiple positive and negative regulatory signals that appropriately scale the magnitude of the immune response, PSGL-1 has emerged as an important checkpoint during this process. We summarize what is known regarding PSGL-1 structure and function and highlight how it may act as an immune checkpoint inhibitor in T cells.
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Matsui K, Parameswaran N, Bagheri N, Willard B, Gupta N. Proteomics analysis of the ezrin interactome in B cells reveals a novel association with Myo18aα. J Proteome Res 2011; 10:3983-92. [PMID: 21751808 DOI: 10.1021/pr200577d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The molecular regulation of recruitment and assembly of signalosomes near the B cell receptor (BCR) is poorly understood. We have previously demonstrated a role for the ERM family protein ezrin in regulating antigen-dependent lipid raft coalescence in B cells. In this study, we addressed the possibility that ezrin may collaborate with other adaptor proteins to regulate signalosome dynamics at the membrane. Using mass spectrometry-based proteomics analysis, we identified Myo18aα as a novel binding partner of ezrin. Myo18aα is an attractive candidate as it has several protein-protein interaction domains and an intrinsic motor activity. The expression of Myo18aα varied during B cell development in the bone marrow and in mature B cell subsets suggesting functional differences. Interestingly, BCR stimulation increased the association between ezrin and Myo18aα, and induced co-segregation of Myo18aα with the BCR and phosphotyrosine-containing proteins. Our data raise an intriguing possibility that the Myo18aα/ezrin complex may facilitate BCR-mediated signaling by recruiting signaling proteins that are in close proximity of the antigen receptor. Our study is not only significant with respect to understanding the molecular regulation of BCR signaling but also provides a broader basis for understanding the mechanism of action of ezrin in other cellular systems.
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Affiliation(s)
- Ken Matsui
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, United States
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8
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Zarbock A, Ley K. Protein tyrosine kinases in neutrophil activation and recruitment. Arch Biochem Biophys 2011; 510:112-9. [PMID: 21338576 DOI: 10.1016/j.abb.2011.02.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 02/03/2011] [Accepted: 02/10/2011] [Indexed: 12/30/2022]
Abstract
Migration of leukocytes into tissue is a key element of innate and adaptive immunity. The first contact of leukocytes with endothelial cells is mediated by engagement of selectins with their counter-receptors which results in leukocyte rolling. During rolling, leukocytes collect different inflammatory signals that activate intracellular signaling pathways. Integration of these signals induces leukocyte activation, firm arrest, post-adhesion strengthening, intravascular crawling, and transmigration. In neutrophils, like in T-cells and platelets, both G-protein-coupled receptor-dependent and -independent activation pathways exist that lead to integrin activation. Accumulating evidence suggests that different protein tyrosine kinases play key roles in signal transduction pathways regulating neutrophil activation and recruitment to inflammatory sites. This review focuses on the role of protein tyrosine kinases of the Src, Syk, and Tec families for neutrophil activation and recruitment.
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Affiliation(s)
- Alexander Zarbock
- Department of Anesthesiology and Intensive Care Medicine, University of Münster, Germany.
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9
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Yang J, Reth M. The dissociation activation model of B cell antigen receptor triggering. FEBS Lett 2010; 584:4872-7. [PMID: 20920502 DOI: 10.1016/j.febslet.2010.09.045] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 09/27/2010] [Accepted: 09/27/2010] [Indexed: 11/19/2022]
Abstract
To detect its cognate antigen, each B lymphocyte contains up to 120000 B cell antigen receptor (BCR) complexes on its cell surface. How these abundant receptors remain silent on resting B cells and how they can be activated by a molecularly diverse set of ligands is poorly understood. The antigen-specific activation of the BCR is currently explained by the cross-linking model (CLM). This model predicts that the many BCR complexes on the surface of a B cell are dispersed signalling-inert monomers and that it is BCR dimerization that initiates signalling from the receptor. The finding that the BCR forms auto-inhibited oligomers on the surface of resting B cells falsifies these predictions of the CLM. We propose the dissociation activation model (DAM), which fits better with the existing body of experimental data.
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Affiliation(s)
- Jianying Yang
- Centre of Biological Signalling Studies BIOSS, University Freiburg, Freiburg, Germany
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Zarbock A, Müller H, Kuwano Y, Ley K. PSGL-1-dependent myeloid leukocyte activation. J Leukoc Biol 2009; 86:1119-24. [PMID: 19703898 DOI: 10.1189/jlb.0209117] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cell-cell interactions mediating leukocyte recruitment and inflammation are crucial for host defense. Leukocyte recruitment into injured tissue proceeds in a multistep process. The first contact of leukocytes with endothelial cells ("capturing" or "tethering") is mediated by selectins and their counter-receptor P-selectin glyco-protein ligand (PSGL)-1. During capture and rolling, leukocytes collect different inflammatory signals, which can activate various pathways. Integration of these signals leads to leukocyte activation, integrin-mediated arrest, cytoskeleton rearrangement, polarization, and transmigration. PSGL-1 on leukocytes also binds to activated platelets, where P-selectin is expressed at locally high site densities following alpha-granule fusion with the plasma membrane. Here, we review the signaling functions of PSGL-1 and speculate how the different known signaling events might relate to different phases of leukocyte recruitment.
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Affiliation(s)
- Alexander Zarbock
- Department of Anesthesiology and Critical Care Medicine, University of Münster, Albert-Schweitzer Str. 33, 48149 Münster, Germany.
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11
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Coffey GP, Rajapaksa R, Liu R, Sharpe O, Kuo CC, Krauss SW, Sagi Y, Davis RE, Staudt LM, Sharman JP, Robinson WH, Levy S. Engagement of CD81 induces ezrin tyrosine phosphorylation and its cellular redistribution with filamentous actin. J Cell Sci 2009; 122:3137-44. [PMID: 19654214 DOI: 10.1242/jcs.045658] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
CD81 is a tetraspanin family member involved in diverse cellular interactions in the immune and nervous systems and in cell fusion events. However, the mechanism of action of CD81 and of other tetraspanins has not been defined. We reasoned that identifying signaling molecules downstream of CD81 would provide mechanistic clues. We engaged CD81 on the surface of B-lymphocytes and identified the induced tyrosine-phosphorylated proteins by mass spectrometry. This analysis showed that the most prominent tyrosine phosphorylated protein was ezrin, an actin-binding protein and a member of the ezrin-radixin-moesin family. We also found that CD81 engagement induces spleen tyrosine kinase (Syk) and that Syk was involved in tyrosine phosphorylation of ezrin. After engagement of CD81, it colocalized with ezrin and F-actin, and this association was disrupted when Syk activation was blocked. Taken together, these studies suggest a model in which CD81 interfaces between the plasma membrane and the cytoskeleton by activating Syk, mobilizing ezrin, and recruiting F-actin to facilitate cytoskeletal reorganization and cell signaling. This mechanism might explain the pleiotropic effects induced in response to stimulation of cells by anti-CD81 antibodies or by the hepatitis C virus, which uses this molecule as its key receptor.
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Affiliation(s)
- Greg P Coffey
- Stanford University, School of Medicine, Division of Oncology, Stanford, CA 94305, USA
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12
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Geahlen RL. Syk and pTyr'd: Signaling through the B cell antigen receptor. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1115-27. [PMID: 19306898 DOI: 10.1016/j.bbamcr.2009.03.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 03/06/2009] [Indexed: 11/18/2022]
Abstract
The B cell receptor (BCR) transduces antigen binding into alterations in the activity of intracellular signaling pathways through its ability to recruit and activate the cytoplasmic protein-tyrosine kinase Syk. The recruitment of Syk to the receptor, its activation and its subsequent interactions with downstream effectors are all regulated by its phosphorylation on tyrosine. This review discusses our current understanding of how this phosphorylation regulates the activity of Syk and its participation in signaling through the BCR.
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Affiliation(s)
- Robert L Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.
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13
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Lau C, Wang X, Song L, North M, Wiehler S, Proud D, Chow CW. Syk associates with clathrin and mediates phosphatidylinositol 3-kinase activation during human rhinovirus internalization. THE JOURNAL OF IMMUNOLOGY 2008; 180:870-80. [PMID: 18178826 DOI: 10.4049/jimmunol.180.2.870] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human rhinovirus (HRV) causes the common cold. The most common acute infection in humans, HRV is a leading cause of exacerbations of asthma and chronic obstruction pulmonary disease because of its ability to exacerbate airway inflammation by altering epithelial cell biology upon binding to its receptor, ICAM-1. ICAM-1 regulates not only viral entry and replication but also signaling pathways that lead to inflammatory mediator production. We recently demonstrated the Syk tyrosine kinase to be an important mediator of HRV-ICAM-1 signaling: Syk regulates replication-independent p38 MAPK activation and IL-8 expression. In leukocytes, Syk regulates receptor-mediated internalization via PI3K. Although PI3K has been shown to regulate HRV-induced IL-8 expression and clathrin-mediated endocytosis of HRV, the role of airway epithelial Syk in this signaling pathway is not known. We postulated that Syk regulates PI3K activation and HRV endocytosis in the airway epithelium. Using confocal microscopy and immunoprecipitation, we demonstrated recruitment of the normally cytosolic Syk to the plasma membrane upon HRV16-ICAM-1 binding, along with Syk-clathrin coassociation. Subsequent incubation at 37 degrees C to permit internalization revealed redistribution of Syk to punctate structures resembling endosomes and colocalization with HRV16. Internalized HRV was not detected in cells overexpressing the kinase inactive Syk(K396R) mutant, indicating that kinase activity was necessary for endocytosis. HRV-induced PI3K activation was dependent on Syk; Syk knockdown by small interfering RNA significantly decreased phosphorylation of the PI3K substrate Akt. Together, these data reveal Syk to be an important mediator of HRV endocytosis and HRV-induced PI3K activation.
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Affiliation(s)
- Christine Lau
- Division of Respirology, Multi-Organ Transplantation Programme, University Health Network, Department of Medicine, University of Toronto, Ontario, Canada
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14
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Zarbock A, Ley K. Mechanisms and consequences of neutrophil interaction with the endothelium. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 172:1-7. [PMID: 18079440 DOI: 10.2353/ajpath.2008.070502] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Leukocyte recruitment into inflamed tissue proceeds in a cascade-like fashion. The first contact of neutrophils with the endothelium is mediated by selectins and their counterreceptors, followed by rolling of neutrophils along the endothelial wall of postcapillary venules and integrin-mediated arrest. While rolling, neutrophils collect different inflammatory signals that can activate several pathways. In addition to activation of neutrophils by ligation of G-protein-coupled receptors with chemokines and other chemoattractants, integrins and selectin ligands are also able to signal into the cell, where they initiate neutrophil extravasation, promote cytoskeletal rearrangement, and ultimately induce superoxide production and degranulation. These signaling pathways may be targeted by therapeutic interventions to inhibit specific functions of neutrophils without affecting others. This Review is focused on the signaling events during the interaction of neutrophils with the endothelium.
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Affiliation(s)
- Alexander Zarbock
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, USA
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15
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Wang X, Lau C, Wiehler S, Pow A, Mazzulli T, Gutierrez C, Proud D, Chow CW. Syk is downstream of intercellular adhesion molecule-1 and mediates human rhinovirus activation of p38 MAPK in airway epithelial cells. THE JOURNAL OF IMMUNOLOGY 2007; 177:6859-70. [PMID: 17082600 DOI: 10.4049/jimmunol.177.10.6859] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The airway epithelium is the primary target of inhaled pathogens such as human rhinovirus (HRV). Airway epithelial cells express ICAM-1, the major receptor for HRV. HRV binding to ICAM-1 mediates not only viral entry and replication but also a signaling cascade that leads to enhanced inflammatory mediator production. The specific signaling molecules and pathways activated by HRV-ICAM-1 interactions are not well characterized, although studies in human airway epithelia implicate a role for the p38 MAPK in HRV-induced cytokine production. In the current study, we report that Syk, an important immunoregulatory protein tyrosine kinase, is highly expressed by primary and cultured human airway epithelial cells and is activated in response to infection with HRV16. Biochemical studies revealed that ICAM-1 engagement by HRV and cross-linking Abs enhanced the coassociation of Syk with ICAM-1 and ezrin, a cytoskeletal linker protein. In polarized airway epithelial cells, Syk is diffusely distributed in the cytosol under basal conditions but, following engagement of ICAM-1 by cross-linking Abs, is recruited to the plasma membrane. The enhanced Syk-ICAM-1 association following HRV exposure is accompanied by Syk phosphorylation. ICAM-1 engagement by HRV and cross-linking Abs also induced phosphorylation of p38 in a Syk-dependent manner, and conversely, knockdown of Syk by short interfering (si)RNA substantially diminished p38 activation and IL-8 gene expression. Taken together, these observations identify Syk as an important mediator of the airway epithelial cell inflammatory response by modulating p38 phosphorylation and IL-8 gene expression following ICAM-1 engagement by HRV.
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Affiliation(s)
- Xiaomin Wang
- Division of Respirology, University Health Network, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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16
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Huang SY, Chen YH, Teng SH, Chen IC, Ho LL, Tu CF. Protein expression of lymphocytes in HLA-DR transgenic pigs by a proteomic approach. Proteomics 2006; 6:5815-25. [PMID: 17022099 DOI: 10.1002/pmic.200600054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Matching donor and recipient human leucocyte antigen (HLA-II) could conquer cell-mediated rejection following transplantation. Transgenic pigs carrying HLA genes that "humanize" porcine organs, tissues, and cells were successfully generated. This study further clarifies the effect of HLA-DR transgenes on lymphocyte protein expression, via a proteomic approach. Lymphocytes were isolated from two HLA-DR transgenic pigs and three nontransgenic littermates on 157 d after birth. Soluble protein of 1x10(7) cells was separated using 2-DE. In total, 301 colloidal CBB-stained protein spots detected on all five 2-D gels were quantified. Thirty-three proteins were differentially expressed by a factor of 1.5. These proteins were subsequently identified by MALDI-TOF MS and MALDI-TOF/TOF MS/MS. These proteins were sorted into the following categories: chaperones, T-lymphocyte function, DNA/RNA processing, cytoskeleton-associated proteins, signal transduction, enzymes, and unknown. Previous studies have suggested that some of the identified proteins are associated with lymphocyte activation/proliferation. The identities of the unidentified spots and the systematic effect of these up- and down-regulated proteins on T-cell function in HLA-DR transgenic pigs require further exploration.
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Affiliation(s)
- San-Yuan Huang
- Division of Biotechnology, Animal Technology Institute Taiwan, Miaoli, Taiwan
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Ross SR, Schmidt JW, Katz E, Cappelli L, Hultine S, Gimotty P, Monroe JG. An immunoreceptor tyrosine activation motif in the mouse mammary tumor virus envelope protein plays a role in virus-induced mammary tumors. J Virol 2006; 80:9000-8. [PMID: 16940512 PMCID: PMC1563925 DOI: 10.1128/jvi.00788-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mouse mammary tumor virus (MMTV) induces breast cancer with almost 100% efficiency in susceptible strains through insertional activation of protooncogenes, such as members of the wnt and fibroblast growth factor (fgf) families. We previously showed that expression of the MMTV envelope protein (Env) in normal immortalized mammary epithelial cells grown in three-dimensional cultures caused their morphological transformation, and that this phenotype depended on an immunoreceptor tyrosine-based activation motif (ITAM) present in Env and signaling through the Syk tyrosine kinase (E. Katz, M. H. Lareef, J. C. Rassa, S. M. Grande, L. B. King, J. Russo, S. R. Ross, and J. G. Monroe, J. Exp. Med. 201:431-439, 2005). Here, we examined the role of the Env protein in virus-induced mammary tumorigenesis in vivo. Similar to the effect seen in vitro, Env expression in the mammary glands of transgenic mice bearing either full-length wild-type provirus or only Env transgenes showed increased lobuloalveolar budding. Introduction of the ITAM mutation into the env of an infectious, replication-competent MMTV or into MMTV/murine leukemia virus pseudotypes had no effect on incorporation of Env into virus particles or on in vitro infectivity. Moreover, replication-competent MMTV bearing the ITAM mutation in Env infected lymphoid and mammary tissue at the same level as wild-type MMTV and was transmitted through milk. However, mammary tumor induction was greatly attenuated, and the pattern of oncogene activation was altered. Taken together, these studies indicate that the MMTV Env protein participates in mammary epithelial cell transformation in vivo and that this requires a functional ITAM in the envelope protein.
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Affiliation(s)
- Susan R Ross
- University of Pennsylvania, 313BRBII/III, 421 Curie Blvd., Philadelphia, PA 19104, USA.
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18
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Fodor S, Jakus Z, Mócsai A. ITAM-based signaling beyond the adaptive immune response. Immunol Lett 2005; 104:29-37. [PMID: 16332394 DOI: 10.1016/j.imlet.2005.11.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 10/29/2005] [Accepted: 11/08/2005] [Indexed: 01/26/2023]
Abstract
Classical immunoreceptors like lymphocyte antigen receptors and Fc-receptors (FcR) are central players of the adaptive immune response. These receptors utilize a common signal transduction mechanism, which relies on immunoreceptor tyrosine-based activation motifs (ITAMs) present in the receptor complex. Upon ligand binding to the receptors, tyrosines within the ITAM sequence are phosphorylated by Src-family kinases, leading to an SH2-domain mediated recruitment and activation of the Syk or the related ZAP-70 tyrosine kinase. These kinases then initiate further downstream signaling events. Here we review recent evidence indicating that components of this ITAM-based signaling machinery are also present in a number of non-lymphoid or even non-immune cell types and they participate in diverse biological functions beyond the adaptive immune response, including innate immune mechanisms, platelet activation, bone resorption or tumor development. These results suggest that the ITAM-based signaling paradigm has much wider implications than previously anticipated.
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Affiliation(s)
- Szabina Fodor
- Department of Computer Science, Corvinus University, Budapest, Hungary
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19
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Srivastava J, Elliott BE, Louvard D, Arpin M. Src-dependent ezrin phosphorylation in adhesion-mediated signaling. Mol Biol Cell 2005; 16:1481-90. [PMID: 15647376 PMCID: PMC551509 DOI: 10.1091/mbc.e04-08-0721] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In addition to providing a regulated linkage between the membrane and the actin cytoskeleton, ezrin participates in signal transduction pathways. Here we describe that expression of the ezrin Y145F mutant delays epithelial cell spreading on fibronectin by inhibiting events leading to FAK activation. The defect in spreading was rescued by the overexpression of catalytically functional Src. We demonstrate that ezrin Y145 is phosphorylated in A431 cells stimulated with epidermal growth factor (EGF) and in v-Src-transformed cells. Moreover in cells devoid of Src, SYF-/- fibroblasts, ezrin Y145 phosphorylation could only be detected upon the introduction of an active form of Src. The phosphorylation of ezrin at Y145 required prior binding of the Src SH2 domain to ezrin. Our results further show that Src activity influences its binding to ezrin and a positive feedback mechanism for Src-mediated Y145 phosphorylation is implied. Interestingly, cells expressing ezrin Y145F did not proliferate when cultured in a 3D collagen gel. Collectively, our results demonstrate a key signaling input of Src-dependent ezrin phosphorylation in adhesion-mediated events in epithelial cells.
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Affiliation(s)
- J Srivastava
- Morphogenèse et Signalisation Cellulaires, UMR144 CNRS-Institut Curie, 75248 Paris Cedex 05, France
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20
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Abstract
After a brief overview of the themes and variations that occur in the family of receptors containing immunoreceptor tyrosine-based activation motifs (ITAMs), and of recent structural data on the ligand-binding subunits of these receptors, we use these data to revisit how information on the state and quality of occupancy of the binding site of the T cell antigen receptor (TCR) is conveyed to the proximal components of the TCR transduction cassette.
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Affiliation(s)
- Bernard Malissen
- Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, Marseille, France.
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21
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Urzainqui A, Serrador JM, Viedma F, Yáñez-Mó M, Rodríguez A, Corbí AL, Alonso-Lebrero JL, Luque A, Deckert M, Vázquez J, Sánchez-Madrid F. ITAM-based interaction of ERM proteins with Syk mediates signaling by the leukocyte adhesion receptor PSGL-1. Immunity 2002; 17:401-12. [PMID: 12387735 DOI: 10.1016/s1074-7613(02)00420-x] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
P-selectin glycoprotein ligand 1 (PSGL-1) is a leukocyte adhesion molecule involved in cell tether and rolling on activated endothelium. Our work shows that PSGL-1 associates with Syk. This association is mediated by the actin-linking proteins moesin and ezrin, which directly interact with Syk in an ITAM-dependent manner. PSGL-1 engagement induces tyrosine phosphorylation of Syk and SRE-dependent transcriptional activity. Treatment of cells with the Syk inhibitor piceatannol and overexpression of either a Syk dead kinase mutant or an ITAM-mutated moesin abrogated PSGL-1-induced transcriptional activation. These data unveil a new functional role for the ERMs (ezrin/radixin/moesin) as adaptor molecules in the interactions of adhesion receptors and intracellular tyrosine kinases and show that PSGL-1 is a signaling molecule in leukocytes.
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Affiliation(s)
- Ana Urzainqui
- Servicio de Inmunología, Hospital de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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Abstract
The complex formation of murine CD44 with the src-like protein tyrosine kinases, lck and lyn, was investigated. In accordance with previous observations, stable CD44-lck and CD44-lyn complexes were detected in nonstimulated lymphoid T- and B-cells, respectively. In addition, a direct modulation of lck and lyn by CD44 was observed as revealed by the CD44-dependent translocation of these enzymes to the Triton X-100 resistant cell fraction. To clarify which receptor domain is responsible for the association, peptide binding assays were performed. Interestingly, the synthetic peptide pCD44 (ILAVCIAVNSRRR), which corresponds to the plasma membrane-cytoplasmic interface region of murine CD44, exhibited a high capacity to bind lck and lyn. A single amino acid modification in the position of the cysteine residue completely abolished this interaction, while the truncation of the three tandem arginines significantly decreased it. Remarkably, similar sequences were found in a number of other molecules including subunits of receptors recognizing antigens, immunoglobulins, extracellular matrix components, accessory molecules, cytokines and also in certain viral gene products. Synthetic peptides corresponding to the homologous regions found in CD28 and FcepsilonRIbeta were also studied and comparable lck-lyn-binding potentials were detected. These data suggest a novel interaction between src-family kinases and CD44, CD28, FcepsilonRIbeta, and provide a simple model for the association of src-like kinases with transmembrane proteins.
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Affiliation(s)
- Z Rozsnyay
- Department of Tumor Progression and Immune Defense, German Cancer Research Center, Heidelberg.
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