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Duarte F, Teçza M, Gedi V, McGourty K, Hudson SP. C5a peptidase (ScpA) activity towards human type II and type III interferons. Cytokine 2024; 180:156652. [PMID: 38759527 DOI: 10.1016/j.cyto.2024.156652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/04/2024] [Accepted: 05/13/2024] [Indexed: 05/19/2024]
Abstract
C5a peptidase, also known as ScpA, is a surface associated serine protease derived from Streptococcus pyogenes and has been described as an important factor in streptococcus virulence, capable of cleaving complement components C5a, C3 and C3a. Although the interactions of ScpA with complement components is well studied, extensive screening of ScpA activity against other pro-inflammatory cytokines is lacking. Here, ScpA's ability to cleave human pro-inflammatory cytokines was tested, revealing its ability to cleave human IFNγ, IFNλ1, IFNλ2, C5, IL-37 but with significantly reduced activities. The functional consequence of ScpA's cleavage of IFNγ in its signalling through the Jak-Stat pathway has also been evaluated in an in vitro RPE1 cell model. These newly identified targets for ScpA highlight the complexity of streptococcus infections and indeed, the potential for ScpA to have a therapeutic role in the progression of inflammatory diseases involving these cytokines.
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Affiliation(s)
- Francisco Duarte
- Department of Chemical Sciences, SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Bernal Institute, University of Limerick, Ireland
| | - Malgorzata Teçza
- Department of Chemical Sciences, SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Bernal Institute, University of Limerick, Ireland
| | - Vinayakumar Gedi
- Department of Chemical Sciences, SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Bernal Institute, University of Limerick, Ireland
| | - Kieran McGourty
- Department of Chemical Sciences, SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Bernal Institute, University of Limerick, Ireland
| | - Sarah P Hudson
- Department of Chemical Sciences, SSPC, the Science Foundation Ireland Research Centre for Pharmaceuticals, Bernal Institute, University of Limerick, Ireland.
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Shih HP, Ding JY, Sotolongo Bellón J, Lo YF, Chung PH, Ting HT, Peng JJ, Wu TY, Lin CH, Lo CC, Lin YN, Yeh CF, Chen JB, Wu TS, Liu YM, Kuo CY, Wang SY, Tu KH, Ng CY, Lei WT, Tsai YH, Chen JH, Chuang YT, Huang JY, Rey FA, Chen HK, Chang TW, Piehler J, Chi CY, Ku CL. Pathogenic autoantibodies to IFN-γ act through the impedance of receptor assembly and Fc-mediated response. J Exp Med 2022; 219:213354. [PMID: 35833912 PMCID: PMC9287643 DOI: 10.1084/jem.20212126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/21/2022] [Accepted: 06/23/2022] [Indexed: 01/16/2023] Open
Abstract
Anti-interferon (IFN)-γ autoantibodies (AIGAs) are a pathogenic factor in late-onset immunodeficiency with disseminated mycobacterial and other opportunistic infections. AIGAs block IFN-γ function, but their effects on IFN-γ signaling are unknown. Using a single-cell capture method, we isolated 19 IFN-γ-reactive monoclonal antibodies (mAbs) from patients with AIGAs. All displayed high-affinity (KD < 10-9 M) binding to IFN-γ, but only eight neutralized IFN-γ-STAT1 signaling and HLA-DR expression. Signal blockade and binding affinity were correlated and attributed to somatic hypermutations. Cross-competition assays identified three nonoverlapping binding sites (I-III) for AIGAs on IFN-γ. We found that site I mAb neutralized IFN-γ by blocking its binding to IFN-γR1. Site II and III mAbs bound the receptor-bound IFN-γ on the cell surface, abolishing IFN-γR1-IFN-γR2 heterodimerization and preventing downstream signaling. Site III mAbs mediated antibody-dependent cellular cytotoxicity, probably through antibody-IFN-γ complexes on cells. Pathogenic AIGAs underlie mycobacterial infections by the dual blockade of IFN-γ signaling and by eliminating IFN-γ-responsive cells.
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Affiliation(s)
- Han-Po Shih
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Jing-Ya Ding
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Junel Sotolongo Bellón
- Division of Biophysics, Department of Biology, University of Osnabruck, Osnabruck, Germany
| | - Yu-Fang Lo
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | | | - He-Ting Ting
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Jhan-Jie Peng
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Tsai-Yi Wu
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Chia-Hao Lin
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Chia-Chi Lo
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - You-Ning Lin
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Fu Yeh
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Jiun-Bo Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Ting-Shu Wu
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan,Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Yuag-Meng Liu
- Division of Infectious Diseases, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan
| | - Chen-Yen Kuo
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Division of Infectious Diseases, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shang-Yu Wang
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Division of General Surgery, Department of Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Kun-Hua Tu
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Chang Gung University College of Medicine, Taoyuan, Taiwan,Kidney Research Center, Department of Nephrology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chau Yee Ng
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Department of Dermatology, Chang Gung Memorial Hospital, Taipei, Taiwan
| | - Wei-Te Lei
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Department of Pediatrics, Hsinchu MacKay Memorial Hospital, Hsinchu, Taiwan
| | - Yu-Huan Tsai
- Laboratory of Host-Microbe Interactions and Cell Dynamics, Institute of Microbiology and Immunology, College of Life Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jou-Han Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Ya-Ting Chuang
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | | | - Félix A. Rey
- Structural Virology Unit, Department of Virology, Institut Pasteur, Paris, France
| | | | - Tse-Wen Chang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Jacob Piehler
- Division of Biophysics, Department of Biology, University of Osnabruck, Osnabruck, Germany
| | - Chih-Yu Chi
- Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan,School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan,Chih-Yu Chi:
| | - Cheng-Lung Ku
- Laboratory of Human Immunology and Infectious Disease, Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan,Department of Nephrology, Chang Gung Memorial Hospital, Taoyuan, Taiwan,Center for Molecular and Clinical Immunology, Chang Gung University, Taoyuan, Taiwan,Correspondence to Cheng-Lung Ku:
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Luo Y, Liu S, Li H, Hou J, Lin W, Xu Z, Lu T, Li Y, Peng B, Zhang S, Han X, Kuang Z, Wen Y, Cai J, Liu F, Chen XL. Mass Cytometry and Single-Cell Transcriptome Analyses Reveal the Immune Cell Characteristics of Ulcerative Colitis. Front Mol Biosci 2022; 9:859645. [PMID: 35813827 PMCID: PMC9260076 DOI: 10.3389/fmolb.2022.859645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 06/02/2022] [Indexed: 12/31/2022] Open
Abstract
Background: The pathogenesis of ulcerative colitis (UC) is closely related to immunity. The immune characteristic differences between active UC (UCa) and inactive UC (UCin) have not been completely explained. Mass cytometry (CyTOF) and single-cell RNA sequencing (scRNA-seq) were used to analyze the immune cells of UCa, UCin and healthy control (HC) subjects to determine the specific immune characteristics. Methods: The immune cell subsets among UCa, UCin, HC were distinguished using CyTOF analysis. scRNA-seq analysis was used to validate the results of CyTOF. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to understand the roles of differential immune cell subsets. Results: After CyTOF analysis and validation of scRNA-seq analysis, differential immune cell subsets mainly contained TNF+IL-17A++ effector memory (EM) Tregs, CXCR3+CTLA4+ EM Tregs, CXCR3++CCR7+ B cells, HLA-DR+CCR7+ dendritic cells (DCs) and CTLA-4+ natural killer (NK) cells. In comparison to HC, CCR6+TNF+CD161+ EM T cells were highly enriched in UCa and UCin. Besides, UCa was characterized by an increase in CD38+TNF+ EM Tregs, CXCR3+CCR4+ naïve B cells, HLA-DR+CD14+IL21+ macrophages/monocytes, HLA-DR+CCR7+ DCs, AHR+CD14+ cytotoxic NK (cNK) cells and CD8A+IFNG+ cNK cells. Decreases in CD38+CD27+ plasmablasts, CXCR3+CD38+ regulatory NK cells, and CXCR3+CCR7+ tolerant NK cells in UCa were discovered. Conclusions: Novel immune cell subsets which was used to distinguish UCa, UCin and HC were identified. This information might be utilized to distinguish the patients with UCa and UCin.
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Affiliation(s)
- Yongxin Luo
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shiying Liu
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Huibiao Li
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jiangtao Hou
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wenjia Lin
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zewen Xu
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Tianyu Lu
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yanwu Li
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
- Pi-Wei Institute, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bin Peng
- The First Clinical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shijing Zhang
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xue Han
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zuoliang Kuang
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yi Wen
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jiazhong Cai
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
- Pi-Wei Institute, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Fengbin Liu
- The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
- *Correspondence: Fengbin Liu, ; Xin-Lin Chen,
| | - Xin-Lin Chen
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
- *Correspondence: Fengbin Liu, ; Xin-Lin Chen,
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STAT1 transcriptionally regulates the expression of S1PR1 by binding its promoter region. Gene 2020; 736:144417. [PMID: 32006593 DOI: 10.1016/j.gene.2020.144417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 12/19/2022]
Abstract
Sphingosine 1-phosphate receptor 1 (S1PR1) plays a pivotal role in mediating trafficking and migration of immune cells. Previous reports also identify S1PR1 as an important susceptibility gene of asthma and other autoimmune disorders. However, little has been known about the regulatory mechanism of S1PR1 expression. Thus we systematically investigated the transcriptional regulation of S1PR1 in this study. Promoter activity of S1PR1 gene was carefully screened using series of pGL3-Basic reporter vectors, containing full length (range from transcription start site to upstream -1 kb region) or several truncated fragments of S1PR1 promoter. We identified an area (from -29 to -12 bp) of the S1PR1 promoter as the minimal promoter region. Bioinformatics prediction results showed that several transcription factors were recruited to these sites. EMSA and ChIP assays demonstrated the transcriptional factor STAT1 could bind to the region. We also found that the level of S1PR1 level was significantly reduced when STAT1 was knocked-down. Consistent with the reduction of S1PR1 caused by depletion of STAT1, overexpression of STAT1 resulted in up-regulation of S1PR1. In addition, both mRNA and protein levels of S1PR1 were increased when STAT1 was activated by IFN-γ, and decreased when STAT1 was inhibited by fludarabine. Besides, the levels of STAT1 and S1PR1 expression were positively correlated in peripheral blood leukocytes derived from 41 healthy individuals. Our study showed that transcription factor STAT1 could bind to upstream region of -29 bp to -12 bp of the S1PR1 promoter and stimulate the expression of S1PR1.
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Wu S, Wang Y, Zhang M, Wang M, He JQ. Genetic variants in IFNG and IFNGR1 and tuberculosis susceptibility. Cytokine 2019; 123:154775. [PMID: 31310896 DOI: 10.1016/j.cyto.2019.154775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 07/06/2019] [Accepted: 07/08/2019] [Indexed: 02/05/2023]
Abstract
BACKGROUND Tuberculosis (TB) is the type of chronic infectious disease which majorly caused by Mycobacterium tuberculosis (M. TB). Emerging data suggest that interferon gamma (IFNG) and its receptor IFNGR1 may be involved in the risk of TB. METHODS A total of 636 TB patients and 608 healthy controls were selected. The association between single nucleotide polymorphisms (SNPs) and TB was estimated by logistic analyses adjusting for age, gender and smoking status. SNPs genotyping was done by using the improved multiplex ligase detection reaction (iMLDR). RESULTS The IFNG rs1861494 allele C was related to an increased risk for TB (OR = 1.25, 95%CI: 1.06-1.48; P = 0.009). Compared with TT genotype, CT (OR = 1.28, 95%CI: 1.01-1.63; P = 0.040) and CC (OR = 1.51, 95%CI: 1.04-2.19; P = 0.031) were also risk factors for TB. In the subgroup analysis, the association was stronger among participants < 25 years (OR = 2.40, 95%CI: 1.70-3.38; P < 0.001) and male groups (OR = 1.31, 95%CI: 1.03-1.66; P = 0.030). In addition, IFNG rs1861494 was associated with anti-TB treatment outcome (OR = 0.70, 95%CI: 0.52-0.94; P = 0.017). We also detected that IFNGR1 rs2234711 influenced the IFNG production. CONCLUSION IFNG rs1861494 polymorphism was associated with TB, particularly in the younger and male subgroups.
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Affiliation(s)
- Shouquan Wu
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yu Wang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Miaomiao Zhang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Minggui Wang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jian-Qing He
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
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Alspach E, Lussier DM, Schreiber RD. Interferon γ and Its Important Roles in Promoting and Inhibiting Spontaneous and Therapeutic Cancer Immunity. Cold Spring Harb Perspect Biol 2019; 11:a028480. [PMID: 29661791 PMCID: PMC6396335 DOI: 10.1101/cshperspect.a028480] [Citation(s) in RCA: 296] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Originally identified in studies of cellular resistance to viral infection, interferon (IFN)-γ is now known to represent a distinct member of the IFN family and plays critical roles not only in orchestrating both innate and adaptive immune responses against viruses, bacteria, and tumors, but also in promoting pathologic inflammatory processes. IFN-γ production is largely restricted to T lymphocytes and natural killer (NK) cells and can ultimately lead to the generation of a polarized immune response composed of T helper (Th)1 CD4+ T cells and CD8+ cytolytic T cells. In contrast, the temporally distinct elaboration of IFN-γ in progressively growing tumors also promotes a state of adaptive resistance caused by the up-regulation of inhibitory molecules, such as programmed-death ligand 1 (PD-L1) on tumor cell targets, and additional host cells within the tumor microenvironment. This review focuses on the diverse positive and negative roles of IFN-γ in immune cell activation and differentiation leading to protective immune responses, as well as the paradoxical effects of IFN-γ within the tumor microenvironment that determine the ultimate fate of that tumor in a cancer-bearing individual.
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Affiliation(s)
- Elise Alspach
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Danielle M Lussier
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Robert D Schreiber
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
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Sen S, Roy K, Mukherjee S, Mukhopadhyay R, Roy S. Restoration of IFNγR subunit assembly, IFNγ signaling and parasite clearance in Leishmania donovani infected macrophages: role of membrane cholesterol. PLoS Pathog 2011; 7:e1002229. [PMID: 21931549 PMCID: PMC3169561 DOI: 10.1371/journal.ppat.1002229] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/14/2011] [Indexed: 01/10/2023] Open
Abstract
Despite the presence of significant levels of systemic Interferon gamma (IFNγ), the host protective cytokine, Kala-azar patients display high parasite load with downregulated IFNγ signaling in Leishmania donovani (LD) infected macrophages (LD-MØs); the cause of such aberrant phenomenon is unknown. Here we reveal for the first time the mechanistic basis of impaired IFNγ signaling in parasitized murine macrophages. Our study clearly shows that in LD-MØs IFNγ receptor (IFNγR) expression and their ligand-affinity remained unaltered. The intracellular parasites did not pose any generalized defect in LD-MØs as IL-10 mediated signal transducer and activator of transcription 3 (STAT3) phosphorylation remained unaltered with respect to normal. Previously, we showed that LD-MØs are more fluid than normal MØs due to quenching of membrane cholesterol. The decreased rigidity in LD-MØs was not due to parasite derived lipophosphoglycan (LPG) because purified LPG failed to alter fluidity in normal MØs. IFNγR subunit 1 (IFNγR1) and subunit 2 (IFNγR2) colocalize in raft upon IFNγ stimulation of normal MØs, but this was absent in LD-MØs. Oddly enough, such association of IFNγR1 and IFNγR2 could be restored upon liposomal delivery of cholesterol as evident from the fluorescence resonance energy transfer (FRET) experiment and co-immunoprecipitation studies. Furthermore, liposomal cholesterol treatment together with IFNγ allowed reassociation of signaling assembly (phospho-JAK1, JAK2 and STAT1) in LD-MØs, appropriate signaling, and subsequent parasite killing. This effect was cholesterol specific because cholesterol analogue 4-cholestene-3-one failed to restore the response. The presence of cholesterol binding motifs [(L/V)-X(1-5)-Y-X(1-5)-(R/K)] in the transmembrane domain of IFNγR1 was also noted. The interaction of peptides representing this motif of IFNγR1 was studied with cholesterol-liposome and analogue-liposome with difference of two orders of magnitude in respective affinity (K(D): 4.27×10(-9) M versus 2.69×10(-7) M). These observations reinforce the importance of cholesterol in the regulation of function of IFNγR1 proteins. This study clearly demonstrates that during its intracellular life-cycle LD perturbs IFNγR1 and IFNγR2 assembly and subsequent ligand driven signaling by quenching MØ membrane cholesterol.
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Affiliation(s)
- Subha Sen
- Division of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
| | - Koushik Roy
- Division of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
| | - Sandip Mukherjee
- Division of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
| | - Rupkatha Mukhopadhyay
- Division of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
| | - Syamal Roy
- Division of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India
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Fegan A, White B, Carlson JCT, Wagner CR. Chemically controlled protein assembly: techniques and applications. Chem Rev 2010; 110:3315-36. [PMID: 20353181 DOI: 10.1021/cr8002888] [Citation(s) in RCA: 229] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Adrian Fegan
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Najjar I, Fagard R. STAT1 and pathogens, not a friendly relationship. Biochimie 2010; 92:425-44. [PMID: 20159032 PMCID: PMC7117016 DOI: 10.1016/j.biochi.2010.02.009] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 02/09/2010] [Indexed: 12/21/2022]
Abstract
STAT1 belongs to the STAT family of transcription factors, which comprises seven factors: STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B and STAT6. STAT1 is a 91 kDa protein originally identified as the mediator of the cellular response to interferon (IFN) α, and thereafter found to be a major component of the cellular response to IFNγ. STAT1 is, in fact, involved in the response to several cytokines and to growth factors. It is activated by cytokine receptors via kinases of the JAK family. STAT1 becomes phosphorylated and forms a dimer which enters the nucleus and triggers the transcription of its targets. Although not lethal at birth, selective gene deletion of STAT1 in mice leads to rapid death from severe infections, demonstrating its major role in the response to pathogens. Similarly, in humans who do not express STAT1, there is a lack of resistance to pathogens leading to premature death. This indicates a key, non-redundant function of STAT1 in the defence against pathogens. Thus, to successfully infect organisms, bacterial, viral or parasitic pathogens must overcome the activity of STAT1, and almost all the steps of this pathway can be blocked or inhibited by proteins produced in infected cells. Interestingly, some pathogens, like the oncogenic Epstein–Barr virus, have evolved a strategy which uses STAT1 activation.
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Affiliation(s)
- Imen Najjar
- INSERM Unité 978, SMBH, 74 rue Marcel Cachin, Bobigny-cedex 93017, France.
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Altenburg JD, Siddiqui RA. Docosahexaenoic acid downregulates interferon gamma-induced expression of CXCL16 in human aortic smooth muscle cells. Biochem Biophys Res Commun 2010; 391:609-14. [DOI: 10.1016/j.bbrc.2009.11.107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 11/18/2009] [Indexed: 11/28/2022]
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Ogilvie RL, Sternjohn JR, Rattenbacher B, Vlasova IA, Williams DA, Hau HH, Blackshear PJ, Bohjanen PR. Tristetraprolin mediates interferon-gamma mRNA decay. J Biol Chem 2009; 284:11216-23. [PMID: 19258311 DOI: 10.1074/jbc.m901229200] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Tristetraprolin (TTP) regulates expression at the level of mRNA decay of several cytokines, including the T cell-specific cytokine, interleukin-2. We performed experiments to determine whether another T cell-specific cytokine, interferon-gamma (IFN-gamma), is also regulated by TTP and found that T cell receptor-activated T cells from TTP knock-out mice overproduced IFN-gamma mRNA and protein compared with activated T cells from wild-type mice. The half-life of IFN-gamma mRNA was 23 min in anti-CD3-stimulated T cells from wild-type mice, whereas it was 51 min in anti-CD3-stimulated T cells from TTP knock-out mice, suggesting that the overexpression of IFN-gamma mRNA in TTP knock-out mice was due to stabilization of IFN-gamma mRNA. Insertion of a 70-nucleotide AU-rich sequence from the murine IFN-gamma 3'-untranslated region, which contained a high affinity binding site for TTP, into the 3'-untranslated region of a beta-globin reporter transcript conferred TTP-dependent destabilization on the beta-globin transcript. Together these results suggest that TTP binds to a functional AU-rich element in the 3'-untranslated region of IFN-gamma mRNA and mediates rapid degradation of the IFN-gamma transcript. Thus, TTP plays an important role in turning off IFN-gamma expression at the appropriate time during an immune response.
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Affiliation(s)
- Rachel L Ogilvie
- Centers for Infectious Diseases and Microbiology Translational Research and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Honing H, van Rooijen N, van den Berg T. Manipulation of Macrophage Activities Using Liposomes. J Liposome Res 2008. [DOI: 10.3109/08982100009031105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Cooke GS, Campbell SJ, Sillah J, Gustafson P, Bah B, Sirugo G, Bennett S, McAdam KPWJ, Sow O, Lienhardt C, Hill AVS. Polymorphism within the interferon-gamma/receptor complex is associated with pulmonary tuberculosis. Am J Respir Crit Care Med 2006; 174:339-43. [PMID: 16690980 DOI: 10.1164/rccm.200601-088oc] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Interferon-gamma (IFN-gamma) is of central interest in the study of tuberculosis. A number of single-gene mutations have been identified in the IFN-gamma signaling pathway that predispose to severe mycobacterial disease, but the relevance of polymorphism within these genes to the common phenotype of tuberculosis remains unclear. METHODS A total of 1,301 individuals were included in a large, detailed study of West African populations with pulmonary tuberculosis. We investigated disease association with the genes encoding IFN-gamma and its receptor subunits (IFNG, IFNGR1, and IFNGR2). RESULTS Within the IFNG gene, two promoter variants showed evidence of novel disease association: -1616GG (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.11-2.00; p = 0.008) and +3234TT (OR, 1.40; 95% CI, 1.09-1.80; p = 0.009). The +874AA genotype was not significantly more frequent among cases over control subjects (OR, 1.16; 95%CI, 0.89-1.51; p = 0.25). In addition, novel disease association was also found with the -56CC genotype of the IFNGR1 promoter (OR, 0.75; 95% CI, 0.57-0.99; p = 0.041). No disease association was seen with the IFNGR2 locus. CONCLUSIONS These results provide evidence of a significant role for genetic variation at the IFNG locus and provide detailed understanding of the genetic mechanisms underlying this association. The disease association with IFNGR1 is novel, and together these findings support the hypothesis that genetically determined variation in both IFN-gamma production and responsiveness influences the risk of developing tuberculosis.
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Affiliation(s)
- Graham S Cooke
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK.
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14
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Clarke DTW, Irving AT, Lambley EH, Payne E, McMillan NAJ. A novel method for screening viral interferon-resistance genes. J Interferon Cytokine Res 2005; 24:470-7. [PMID: 15320960 DOI: 10.1089/1079990041689610] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Many viruses have evolved mechanisms to antagonize the interferon (IFN) system, targeting all the major components involved in receptor binding and signaling. Although a number of these vital proteins are homologous to cellular proteins involved in IFN downregulation (e.g., viral IFN regulatory factors [vIRFs]), many share little resemblance to known proteins. To determine the IFN-blocking properties of these proteins, functional assays are required. Here, we present a new and rapid functional screening method, based on the 2fTGH cell line, which is able to determine viral gene products that inhibit the IFN-alpha/Jak-Stat signaling pathway. Expression cloning of viral IFN-blocking genes into 2fTGH and consequent selection with IFN-alpha and 6-thioguanine result in the outgrowth of cells that are no longer responsive to IFN-alpha. We also demonstrate that selection occurs if members of the Jak-Stat signaling pathway are lost. To show the utility of our system, we have used a known suppressor of IFN signaling, the human papillomavirus (HPV) E7 gene. Expression of E7 causes the loss of ability of 2fTGH cells to respond to IFN-alpha treatment because of a functional disruption of the signaling pathway. This approach offers a new strategy for identifying novel viral genes or new functions of already described viral genes that have a role in IFN-alpha signaling inhibition.
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Affiliation(s)
- Daniel T W Clarke
- Centre for Immunology and Cancer Research, Princess Alexandra Hospital, University of Queensland, Brisbane, Australia
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15
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Corleto VD, Nasoni S, Panzuto F, Cassetta S, Delle Fave G. Somatostatin receptor subtypes: basic pharmacology and tissue distribution. Dig Liver Dis 2004; 36 Suppl 1:S8-16. [PMID: 15077906 DOI: 10.1016/j.dld.2003.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The heptahelical receptor superfamily constitutes the largest single family of transmembrane-signalling molecules that regulate a wide range of physiological processes. The five somatostatin receptors represent a distinct subgroup of this seven transmembrane receptor superfamily. They range in size from 356 to 391 amino acids with 39-57% protein identity between the subtypes with 100 residues strictly conserved among the somatostatin receptor sequences. A high grade of mRNA homology exists in somatostatin receptor subtypes cloned from different species. Following somatostatin receptor binding and functional activity studies, two alternative models of ligand-binding interaction have been hypothesised. One relies on the presence of a binding pocket within the receptor structure constituted by specific amino acids residues, the other denies the presence of such binding structures and suggests that it is the interaction of agonists with specific extracellular and/or transmembrane domains that determine stable receptor structure conformation. Somatostatin receptors, as, indeed, all G-protein-coupled receptors are able to regulate their responsiveness to agonist exposure. This agonist-specific regulation includes three main events, namely, desensitisation, receptor internalisation and receptor degradation. The cell expression of somatostatin receptor subtypes, at the mRNA level, has been characterised in rodent and in human organs with multiple subtype expression in brain and peripheral tissues.
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Affiliation(s)
- V D Corleto
- Department of Digestive and Liver Diseases, II School of Medicine and Surgery, University of La Sapienza, S. Andrea Hospital, Via di Grottarossa 1035, 00189 Rome, Italy.
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16
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Netea MG, Kullberg BJ, Van der Meer JWM. Proinflammatory Cytokines in the Treatment of Bacterial and Fungal Infections. BioDrugs 2004; 18:9-22. [PMID: 14733604 DOI: 10.2165/00063030-200418010-00002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mortality due to severe bacterial infections has not been markedly effected by the introduction of new antimicrobial drugs over the last 30-40 years. This has emphasized the need for development of new therapeutic strategies to combat sepsis. The outcome of an infection depends on two factors: the growth of the microorganisms (including the effect of antibacterial drugs), and the host's defensive response to the invading organism. It is known that injection of bacterial products into experimental animals leads to enhanced nonspecific resistance to a variety of microorganisms. The discovery of the specific mediators responsible for modulation of host defense has created new possibilities for the development of alternative treatment strategies. Molecules such as interleukins, interferons, tumor necrosis factors and hematopoietic growth factors have become available in recombinant form, and their therapeutic potential in various infectious diseases has been tested in various experimental models of infections. Initial data in various patient groups indicate that adjunctive therapy with recombinant proinflammatory cytokines may have beneficial effects in the treatment of bacterial and fungal infections.
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Affiliation(s)
- Mihai G Netea
- Department of Medicine, University Medical Center St. Radboud, Nijmegen, The Netherlands
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17
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Schroder K, Hertzog PJ, Ravasi T, Hume DA. Interferon-gamma: an overview of signals, mechanisms and functions. J Leukoc Biol 2003; 75:163-89. [PMID: 14525967 DOI: 10.1189/jlb.0603252] [Citation(s) in RCA: 2907] [Impact Index Per Article: 138.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Interferon-gamma (IFN-gamma) coordinates a diverse array of cellular programs through transcriptional regulation of immunologically relevant genes. This article reviews the current understanding of IFN-gamma ligand, receptor, signal transduction, and cellular effects with a focus on macrophage responses and to a lesser extent, responses from other cell types that influence macrophage function during infection. The current model for IFN-gamma signal transduction is discussed, as well as signal regulation and factors conferring signal specificity. Cellular effects of IFN-gamma are described, including up-regulation of pathogen recognition, antigen processing and presentation, the antiviral state, inhibition of cellular proliferation and effects on apoptosis, activation of microbicidal effector functions, immunomodulation, and leukocyte trafficking. In addition, integration of signaling and response with other cytokines and pathogen-associated molecular patterns, such as tumor necrosis factor-alpha, interleukin-4, type I IFNs, and lipopolysaccharide are discussed.
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Affiliation(s)
- Kate Schroder
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Brisbane 4072, Australia.
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18
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Gotoh B, Komatsu T, Takeuchi K, Yokoo J. Paramyxovirus strategies for evading the interferon response. Rev Med Virol 2002; 12:337-57. [PMID: 12410527 DOI: 10.1002/rmv.357] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Two genera, the Respirovirus (Sendai virus (SeV) and human parainfluenza virus (hPIV3) and the Rubulavirus (simian virus (SV) 5, SV41, mumps virus and hPIV2), of the three in the subfamily Paramyxovirinae inhibit interferon (IFN) signalling to circumvent the IFN response. The viral protein responsible for the inhibition is the C protein for respirovirus SeV and the V protein for the rubulaviruses, both of which are multifunctional accessory proteins expressed from the P gene. SeV suppresses IFN-stimulated tyrosine phosphorylation of signal transducers and activators of transcription (STATs) at an early phase of infection and further inhibits the downstream signalling without degrading any of the signalling components in most cell lines. On the contrary, the Rubulavirus V protein targets Stat1 or Stat2 for degradation. Proteasome-mediated degradation appears to be involved in most cases. Studies on the molecular mechanisms by which paramyxoviruses evade the IFN response will offer important information for modulating the JAK-STAT pathway, designing novel antiviral drugs and recombinant live vaccines, and improving paramyxovirus expression vectors for gene therapy.
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Affiliation(s)
- Bin Gotoh
- Department of Microbiology, Fukui Medical University School of Medicine, Shimoaizuki 23-3, Matsuoka-cho, Yoshida-gun, Fukui 910-1193, Japan.
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19
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Krause CD, Mei E, Xie J, Jia Y, Bopp MA, Hochstrasser RM, Pestka S. Seeing the light: preassembly and ligand-induced changes of the interferon gamma receptor complex in cells. Mol Cell Proteomics 2002; 1:805-15. [PMID: 12438563 DOI: 10.1074/mcp.m200065-mcp200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Our experiments were designed to test the hypothesis that the cell surface interferon gamma receptor chains are preassembled rather than associated by ligand and to assess the molecular changes on ligand binding. To accomplish this, we used fluorescence resonance energy transfer, a powerful spectroscopic technique that has been used to determine molecular interactions and distances between the donor and acceptor. However, current commercial instruments do not provide sufficient sensitivity or the full spectra to provide decisive results of interactions between proteins labeled with blue and green fluorescent proteins in living cells. In our experiments, we used the blue fluorescent protein and green fluorescent protein pair, attached a monochrometer and charge-coupled device camera to a modified confocal microscope, reduced background fluorescence with the use of two-photon excitation, and focused on regions of single cells to provide clear spectra of fluorescence resonance energy transfer. In contrast to the prevailing view, the results demonstrate that the receptor chains are preassociated and that the intracellular domains move apart on binding the ligand interferon gamma. Application of this technology should lead to new rapid methods for high throughput screening and delineation of the interactome of cells.
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Affiliation(s)
- Christopher D Krause
- Department of Molecular Genetics, Microbiology and Immunology, Robert Wood Johnson Medical School-University of Medicine and Dentistry of New Jersey, Piscataway 08854-5635, USA
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20
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Symons JA, Tscharke DC, Price N, Smith GL. A study of the vaccinia virus interferon-gamma receptor and its contribution to virus virulence. J Gen Virol 2002; 83:1953-1964. [PMID: 12124459 DOI: 10.1099/0022-1317-83-8-1953] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vaccinia virus (VV) strain Western Reserve gene B8R encodes a 43 kDa glycoprotein that is secreted from infected cells early in infection as a homodimer. This protein has amino acid similarity with the extracellular domain of cellular IFN-gamma receptor (IFN-gammaR) and binds and inhibits IFN-gamma from a wide range of species. Here we demonstrate that the B8R protein also inhibits equine IFN-gamma. The 5' end of the B8R mRNA has been mapped by primer extension analysis and the contribution of IFN-gammaRs to VV virulence was studied by the construction of a deletion mutant lacking the B8R gene (vDeltaB8R) and a revertant virus (vB8R-R) in which the B8R gene was re-inserted into the deletion mutant. A recombinant virus that expressed a soluble form of the mouse IFN-gammaR was also constructed and studied. The virulence of these viruses was tested in rodent models of infection. In mice, the loss of the VV IFN-gammaR did not affect virulence compared with WT and revertant viruses, consistent with the low affinity of the VV IFN-gammaR for mouse IFN-gamma. However, expression of the mouse soluble IFN-gammaR increased virus virulence slightly. In rabbit skin, loss of the VV IFN-gammaR produced lesions with histological differences compared with WT and revertant viruses. Lastly, the affinity constants of the VV IFN-gammaR for human and mouse IFN-gamma were determined by surface plasmon resonance.
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Affiliation(s)
- Julian A Symons
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1
| | - David C Tscharke
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1
| | - Nicola Price
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1
| | - Geoffrey L Smith
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1
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21
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Abstract
A new role of the Paramyxovirus accessory proteins has been uncovered. The P gene of the subfamily Paramyxovirinae encodes accessory proteins including the V and/or C protein by means of pseudotemplated nucleotide addition (RNA editing) or by overlapping open reading frame. The Respirovirus (Sendai virus and human parainfluenza virus (hPIV)3) and Rubulavirus (simian virus (SV)5, SV41, mumps virus and hPIV2) circumvent the interferon (IFN) response by inhibiting IFN signaling. The responsible genes were mapped to the C gene for SeV and the V gene for rubulaviruses. On the other hand, wild type measles viruses isolated from clinical specimens suppress production of IFN, although responsible viral factors remain to be identified. Both human and bovine respiratory syncytial viruses (RSVs) counteract the antiviral effect of IFN with inhibiting neither IFN signaling nor IFN production. Bovine RSV NS1 and NS2 proteins cooperatively antagonize the antiviral effect of IFN. Studies on the molecular mechanism by which viruses circumvent the host IFN response will not only illustrate co-evolution of virus strategies of immune evasion but also provide basic information useful for engineering novel antiviral drugs as well as recombinant live vaccine.
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Affiliation(s)
- B Gotoh
- Department of Microbiology, Fukui Medical University, Japan.
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22
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Abstract
The vaccinia virus (VV) interferon (IFN)-gamma receptor (IFN-gammaR) is a 43 kDa soluble glycoprotein that is secreted from infected cells early during infection. Here we demonstrate that the IFN-gammaR from VV, cowpox virus and camelpox virus exists naturally as a homodimer, whereas the cellular IFN-gammaR dimerizes only upon binding the homodimeric IFN-gamma. The existence of the virus protein as a dimer in the absence of ligand may provide an advantage to the virus in efficient binding and inhibition of IFN-gamma in solution.
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Affiliation(s)
- Antonio Alcamí
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1
| | - Geoffrey L Smith
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK1
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23
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Randal M, Kossiakoff AA. The structure and activity of a monomeric interferon-gamma:alpha-chain receptor signaling complex. Structure 2001; 9:155-63. [PMID: 11250200 DOI: 10.1016/s0969-2126(01)00567-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Interferon-gamma (IFN-gamma) is a homodimeric cytokine that exerts its various activities by inducing the aggregation of two different receptors. The alpha chain receptor (IFN-gammaRalpha) is a high affinity receptor that binds to IFN-gamma in a symmetric bivalent manner to form a stable, intermediate 1:2 complex. This intermediate forms a binding template for the subsequent binding of two copies of the second receptor, beta chain receptor (IFN-gammaRbeta), producing the active 1:2:2 signaling complex. RESULTS A single chain monovalent variant of IFN-gamma (scIFN-gamma) was constructed and complexed to one copy of the extracellular domain (ECD) of IFN-gammaRalpha. The structure of this 1:1 complex was determined and the hormone-receptor interface shown to be characterized by a number of hydrophilic interactions mediated by several highly ordered water networks. The scIFN-gamma interface consists of segments from each of the monomer chains of the homodimer. The principal hydrophobic contact of the receptor involves a tripeptide segment of the receptor having an unusual and high energy conformation. Despite containing only one binding site for IFN-gammaRalpha, the monovalent scIFN-gamma molecule has significant activity in antiviral biological assays. CONCLUSIONS ScIFN-gamma binds the ECD of IFN-gammaRalpha through a highly hydrated interface with an important set of hormone-receptor contacts mediated through structured waters. Although the interface is highly hydrated, it supports tight binding and has a considerable degree of specificity. The biological activity of scIFN-gamma confirms that the scIFN-gamma:IFN-gammaRalpha complex represents a productive intermediate and that it can effectively recruit the other required component, IFN-gammaRbeta, to signal based on the 1:1:1 complex.
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Affiliation(s)
- M Randal
- Graduate Group in Biophysics, University of California, 94000, San Francisco, CA, USA
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24
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Dorman SE, Holland SM. Interferon-gamma and interleukin-12 pathway defects and human disease. Cytokine Growth Factor Rev 2000; 11:321-33. [PMID: 10959079 DOI: 10.1016/s1359-6101(00)00010-1] [Citation(s) in RCA: 231] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A genetic component to human mycobacterial disease susceptibility has long been postulated. Over the past five years, mutations in the interferon-gamma (IFNgamma) receptor, IL-12 receptor beta1 (IL-12Rbeta1), and IL-12 p40 genes have been recognized. These mutations are associated with heightened susceptibility to disease caused by intracellular pathogens including nontuberculous mycobacteria, vaccine-associated bacille Calmette Guerin (BCG), Salmonella species, and some viruses. We describe the genotype-phenotype correlations in IFNgamma receptor, IL-12Rbeta1, and IL-12 p40 deficiency, and discuss how study of these diseases has enhanced knowledge of human host defense against mycobacteria and other intracellular pathogens.
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Affiliation(s)
- S E Dorman
- Laboratory of Host Defenses, National Institutes of Health, NIAID, Building 10, Room 11N103, 10 Center Dr, MSC 1886, Bethesda, MD 20892, USA
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25
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Krause CD, Lunn CA, Izotova LS, Mirochnitchenko O, Kotenko SV, Lundell DJ, Narula SK, Pestka S. Signaling by covalent heterodimers of interferon-gamma. Evidence for one-sided signaling in the active tetrameric receptor complex. J Biol Chem 2000; 275:22995-3004. [PMID: 10811814 DOI: 10.1074/jbc.m909607199] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interferon-gamma (IFN-gamma) and its receptor complex are dimeric and bilaterally symmetric. We created mutants of IFN-gamma that bind only one IFN-gammaR1 chain per dimer molecule (called a monovalent IFN-gamma) to see if the interaction of IFN-gamma with one-half of the receptor complex is sufficient for bioactivity. Mutating a receptor-binding sequence in either AB loop of a covalent dimer of IFN-gamma yielded two monovalent IFN-gammas, gamma(m)-gamma and gamma-gamma(m), which cross-link to only a single soluble IFN-gammaR1 molecule in solution and on the cell surface. Monovalent IFN-gamma competes fully with wild type IFN-gamma for binding to U937 cells but only at a greater than 100-fold higher concentration than wild type IFN-gamma. Monovalent IFN-gamma had anti-vesicular stomatitis virus activity and antiproliferative activity, and it induced major histocompatibility complex class I and class II (HLA-DR) expression. In contrast, the maximal levels of activated Stat1alpha produced by monovalent IFN-gammas after 15 min were never more than half of those produced by either wild type or covalent IFN-gammas in human cell lines. These data indicate that while monovalent IFN-gamma activates only one-half of a four-chain receptor complex, this is sufficient for Stat1alpha activation, major histocompatibility complex class I surface antigen induction, and antiviral and antiproliferative activities. Thus, while interaction with both halves of the receptor complex is required for high affinity binding of IFN-gamma and efficient signal transduction, interaction with only one-half of the receptor complex is sufficient to initiate signal transduction.
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Affiliation(s)
- C D Krause
- Department of Molecular Genetics and Microbiology, The Graduate School of Biomedical Sciences, The University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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26
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Landar A, Curry B, Parker MH, DiGiacomo R, Indelicato SR, Nagabhushan TL, Rizzi G, Walter MR. Design, characterization, and structure of a biologically active single-chain mutant of human IFN-gamma. J Mol Biol 2000; 299:169-79. [PMID: 10860730 DOI: 10.1006/jmbi.2000.3734] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A mutant form of human interferon-gamma (IFN-gamma SC1) that binds one IFN-gamma receptor alpha chain (IFN-gamma R alpha) has been designed and characterized. IFN-gamma SC1 was derived by linking the two peptide chains of the IFN-gamma dimer by a seven-residue linker and changing His111 in the first chain to an aspartic acid residue. Isothermal titration calorimetry shows that IFN-gamma SC1 forms a 1:1 complex with its high-affinity receptor (IFN-gamma R alpha) with an affinity of 27(+/- 9) nM. The crystal structure of IFN-gamma SC1 has been determined at 2.9 A resolution from crystals grown in 1.4 M citrate solutions at pH 7.6. Comparison of the wild-type receptor-binding domain and the Asp111-containing domain of IFN-gamma SC1 show that they are structurally equivalent but have very different electrostatic surface potentials. As a result, surface charge rather than structural changes is likely responsible for the inability of the His111-->Asp domain of to bind IFN-gamma R alpha. The AB loops of IFN-gamma SC1 adopt conformations similar to the ordered loops of IFN-gamma observed in the crystal structure of the IFN-gamma/IFN-gamma R alpha complex. Thus, IFN-gamma R alpha binding does not result in a large conformational change in the AB loop as previously suggested. The structure also reveals the final six C-terminal amino acid residues of IFN-gamma SC1 (residues 253-258) that have not been observed in any other reported IFN-gamma structures. Despite binding to only one IFN-gamma R alpha, IFN-gamma SC1 is biologically active in cell proliferation, MHC class I induction, and anti-viral assays. This suggests that one domain of IFN-gamma is sufficient to recruit IFN-gamma R alpha and IFN-gamma R beta into a complex competent for eliciting biological activity. The current data are consistent with the main role of the IFN-gamma dimer being to decrease the dissociation constant of IFN-gamma for its cellular receptors.
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Affiliation(s)
- A Landar
- Center for Macromolecular Crystallography, University of Alabama, Birmingham 35294, USA
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27
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Rocheville M, Lange DC, Kumar U, Sasi R, Patel RC, Patel YC. Subtypes of the somatostatin receptor assemble as functional homo- and heterodimers. J Biol Chem 2000; 275:7862-9. [PMID: 10713101 DOI: 10.1074/jbc.275.11.7862] [Citation(s) in RCA: 361] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The existence of receptor dimers has been proposed for several G protein-coupled receptors. However, the question of whether G protein-coupled receptor dimers are necessary for activating or modulating normal receptor function is unclear. We address this question with somatostatin receptors (SSTRs) of which there are five distinct subtypes. By using transfected mutant and wild type receptors, as well as endogenous receptors, we provide pharmacological, biochemical, and physical evidence, based on fluorescence resonance energy transfer analysis, that activation by ligand induces SSTR dimerization, both homo- and heterodimerization with other members of the SSTR family, and that dimerization alters the functional properties of the receptor such as ligand binding affinity and agonist-induced receptor internalization and up-regulation. Double label confocal fluorescence microscopy showed that when SSTR1 and SSTR5 subtypes were coexpressed in Chinese hamster ovary-K1 cells and treated with agonist they underwent internalization and were colocalized in cytoplasmic vesicles. SSTR5 formed heterodimers with SSTR1 but not with SSTR4 suggesting that heterodimerization is a specific process that is restricted to some but not all receptor subtype combinations. Direct protein interaction between different members of the SSTR subfamily defines a new level of molecular cross-talk between subtypes of the SSTR and possibly related receptor families.
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Affiliation(s)
- M Rocheville
- Fraser Laboratories, Departments of Medicine, Pharmacology and Therapeutics, and Neurology and Neurosurgery, McGill University and Royal Victoria Hospital, Montreal, Quebec H3A 1A1, Canada
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28
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Abstract
Interferon-gamma (IFN-gamma) is a cytokine that plays an important role in inducing and modulating an array of immune responses. Cellular responses to IFN-gamma are mediated by its heterodimeric cell-surface receptor (IFN-gammaR), which activates downstream signal transduction cascades, ultimately leading to the regulation of gene expression. In order to study the role of IFN-gamma in a number of immune responses and pathways, researchers have generated mice with altered patterns of IFN-gammaR gene expression. These studies, together with analyses of naturally occurring mutations of the IFN-gammaR in man, have been instrumental in elucidating the diverse functions of IFN-gamma, and are the subject of this review.
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Affiliation(s)
- G Tau
- Integrated Program in Cellular, Molecular Biology and Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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29
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Kossiakoff AA, De Vos AM. Structural basis for cytokine hormone-receptor recognition and receptor activation. ADVANCES IN PROTEIN CHEMISTRY 1999; 52:67-108. [PMID: 9917918 DOI: 10.1016/s0065-3233(08)60433-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- A A Kossiakoff
- Department of Protein Engineering, Genentech, Inc., South San Francisco, California 94080, USA
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30
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Abstract
Interferons play key roles in mediating antiviral and antigrowth responses and in modulating immune response. The main signaling pathways are rapid and direct. They involve tyrosine phosphorylation and activation of signal transducers and activators of transcription factors by Janus tyrosine kinases at the cell membrane, followed by release of signal transducers and activators of transcription and their migration to the nucleus, where they induce the expression of the many gene products that determine the responses. Ancillary pathways are also activated by the interferons, but their effects on cell physiology are less clear. The Janus kinases and signal transducers and activators of transcription, and many of the interferon-induced proteins, play important alternative roles in cells, raising interesting questions as to how the responses to the interferons intersect with more general aspects of cellular physiology and how the specificity of cytokine responses is maintained.
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Affiliation(s)
- G R Stark
- Lerner Research Institute, Cleveland Clinic Foundation, Ohio 44195, USA.
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31
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Sadir R, Forest E, Lortat-Jacob H. The heparan sulfate binding sequence of interferon-gamma increased the on rate of the interferon-gamma-interferon-gamma receptor complex formation. J Biol Chem 1998; 273:10919-25. [PMID: 9556569 DOI: 10.1074/jbc.273.18.10919] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interferon-gamma (IFNgamma), in common with a number of growth factors, binds both to heparan sulfate or heparin-related molecules and to a specific high affinity receptor (IFNgammaR). Using surface plasmon resonance technology, kinetic analysis of the IFNgamma. IFNgammaR complex formation was performed with the extracellular part of IFNgammaR immobilized on a sensor chip. At the sensor chip surface, IFNgamma was bound by two IFNgammaR molecules with an affinity in the nanomolar range (0.68 nM). This binding was characterized by an important on rate, kon = 7.3 x 10(6) M-1.s-1, and an off rate, koff = 5 x 10(-3).s-1. This binding assay was used to investigate a possible role of heparin in the IFNgamma.IFNgammaR complex formation. In contrast to growth factors for which binding to heparin is usually required for high affinity receptor interaction, we found in this study that IFNgamma bound to heparin displayed a strongly reduced affinity for its receptor. This is consistent with the fact that a cluster of basic amino acids (KTGKRKR, called the C1 domain) in the carboxyl-terminal sequence of the cytokine was involved both in heparin and receptor recognition. To understand how a single domain of IFNgamma could be implicated in two discrete functions (i.e. binding to heparin and to IFNgammaR), we also analyzed in a detailed manner the role of the IFNgamma carboxyl-terminal sequence in receptor binding. Using forms of IFNgamma, with carboxyl terminus truncations of defined regions of the heparin binding sequence, we found that the C1 domain functioned by increasing the on rate of the IFNgamma.IFNgammaR binding reaction but was not otherwise required for the stability of the complex. Interactions between the IFNgamma carboxyl-terminal domain and IFNgammaR could increased the association rate of the reaction either by increasing the number of encounters between the two molecules or by favoring productive collisions. The mechanisms by which heparan sulfate regulates IFNgamma activity may thus include both control of selective protease cleavage events, which directly affect the cytokine activity, and also an ability to modulate the interaction of IFNgamma with the IFNgammaR via competitive binding to the C1 domain.
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Affiliation(s)
- R Sadir
- Institut Pasteur de Lyon, CNRS URA 1459, Avenue des Martyrs, 38027 Grenoble Cedex 01, France
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32
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Randal M, Kossiakoff AA. Crystallization and preliminary X-ray analysis of a 1:1 complex between a designed monomeric interferon-gamma and its soluble receptor. Protein Sci 1998; 7:1057-60. [PMID: 9568913 PMCID: PMC2143989 DOI: 10.1002/pro.5560070424] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A variant of human interferon-gamma (IFN-gamma) has been created in which the two chains of the homodimeric cytokine were linked N- to C-terminus by an eight residue polypeptide linker. The sequence of this linker was derived from a loop in bira bifunctional protein, and was determined from a structural database search. This "single-chain" variant was used to create an IFN-gamma molecule that binds only a single copy of the alpha-chain receptor, rather than the 2 alpha-chain receptor: 1 IFN-gamma binding stoichiometry observed for the native hormone. Crystals have been grown of a 1:1 complex between this single-chain molecule and the extracellular domain of its alpha-chain receptor. These crystals diffract beyond 2.0 A, significantly better than the 2.9 A observed for the native 2:1 complex. Density calculations suggest these crystals contain two complexes in the asymmetric unit; a self-rotation function confirms this conclusion.
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Affiliation(s)
- M Randal
- Graduate Group in Biophysics, University of California, San Francisco 94000, USA
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33
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Hébert TE, Bouvier M. Structural and functional aspects of G protein-coupled receptor oligomerization. Biochem Cell Biol 1998. [DOI: 10.1139/o98-012] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the single largest family of cell surface receptors involved in signal transduction. It is estimated that several hundred distinct members of this receptor family in humans direct responses to a wide variety of chemical transmitters, including biogenic amines, amino acids, peptides, lipids, nucleosides, and large polypeptides. These transmembrane receptors are key controllers of such diverse physiological processes as neurotransmission, cellular metabolism, secretion, cellular differentiation, and growth as well as inflammatory and immune responses. GPCRs therefore represent major targets for the development of new drug candidates with potential application in all clinical fields. Many currently used therapeutics act by either activating (agonists) or blocking (antagonists) GPCRs. Studies over the past two decades have provided a wealth of information on the biochemical events underlying cellular signalling by GPCRs. However, our understanding of the molecular interactions between ligands and the receptor protein and, particularly, of the structural correlates of receptor activation or inhibition by agonists and inverse agonists, respectively, is still rudimentary. Most of the work in this area has focused on mapping regions of the receptor responsible for drug binding affinity. Although binding of ligand molecules to specific receptors represents the first event in the action of drugs, the efficacy with which this binding is translated into a physiological response remains the only determinant of therapeutic utility. In the last few years, increasing evidence suggested that receptor oligomerization and in particular dimerization may play an important role in the molecular events leading to GPCR activation. In this paper, we review the biochemical and functional evidence supporting this notion.Key words: G proteins, receptors, dimerization, signal transduction, adrenergic.
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34
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De Flora A, Franco L, Guida L, Bruzzone S, Zocchi E. Ectocellular CD38-catalyzed synthesis and intracellular Ca(2+)-mobilizing activity of cyclic ADP-ribose. Cell Biochem Biophys 1997; 28:45-62. [PMID: 9386892 DOI: 10.1007/bf02738309] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CD38 is a type-II transmembrane glycoprotein occurring in several hematopoietic and mature blood cells as well as in other cell types, including neurons. Although classified as an orphan receptor, CD38 is also a bifunctional ectoenzyme that catalyzes both the conversion of NAD+ to nicotinamide and cyclic ADP-ribose (cADPR), via an ADP-ribosyl cyclase reaction, and also the hydrolysis of cADPR to ADP-ribose (hydrolase). Major unresolved questions concern the correlation between receptor and catalytic properties of CD38, and also the apparent contradiction between ectocellular generation and intracellular Ca(2+)-mobilizing activity of cADPR. Results are presented that provide some explanations to this topological paradox in two different cell types. In cultured rat cerebellar granule neurons, extracellular cADPR (either generated by CD38 or directly added) elicited an enhanced intracellular Ca(2+)-response to KCl-induced depolarization, a process that can be qualified as a Ca(2+)-induced Ca2+ release (CICR) mechanism. On the other hand, in the CD38+ human Namalwa B lymphoid cells, NAD+ (and thiol compounds as well) induced a two-step process of self-aggregation followed by endocytosis of CD38, which resulted in a shift of cADPR metabolism from the cell surface to the cytosol. Both distinctive types of cellular responses to extracellular NAD+ seem to be suitable to elicit changes in the intracellular Ca2+ homeostasis.
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Affiliation(s)
- A De Flora
- Institute of Biochemistry, University of Genova, Italy
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35
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Löster K, Josić D. Analysis of protein aggregates by combination of cross-linking reactions and chromatographic separations. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1997; 699:439-61. [PMID: 9392387 DOI: 10.1016/s0378-4347(97)00215-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Chemical cross-linking provides a method that covalently bridges near-neighbour associations within proteins and protein aggregates. Combined with chromatographic separations and protein-chemical methods, it may be used to localize and to investigate three-dimensional relations as present under natural conditions. This paper reviews the chemistry and application of cross-linking reagents and the development of combination experimental approaches in view of chromatographic separations and cross-linking reactions. Investigations of homooligomeric and heterooligomeric protein associations as well as conformational analysis are presented.
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Affiliation(s)
- K Löster
- Institut für Molekularbiologie und Biochemie, Freie Universität Berlin, Berlin-Dahlem, Germany
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36
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De Flora A, Guida L, Franco L, Zocchi E. The CD38/cyclic ADP-ribose system: a topological paradox. Int J Biochem Cell Biol 1997; 29:1149-66. [PMID: 9438379 DOI: 10.1016/s1357-2725(97)00062-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
CD38 was first identified as a lymphocyte differentiation antigen that showed typical properties of an orphan receptor involved in many programs of cell proliferation and activation. However, CD38 proved also to be a bifunctional ectoenzyme that catalyzes the transient formation of cyclic ADP-ribose (cADPR) in a variety of cell types. This property raises many intriguing and so far unanswered questions, since cADPR is a new second messenger molecule directly involved in the control of calcium homeostasis by means of receptor-mediated release of calcium from ryanodine-sensitive intracellular stores. The relationship between receptor-like and enzymatic properties of CD38 is still unknown. The apparent topological paradox of ectocellular synthesis and intracellular activity of cADPR might be explained by: (a) influx of cADPR across the plasma membrane to reach its target stores, as suggested by experiments on cerebellar granule cells; and (b) NAD(+)-induced internalization, following membrane oligomerization, of CD38 with consequent partial import of cADPR metabolism to an intracellular compartment, as recently observed in lymphoid B cells. These two distinct mechanisms and other potential ones (e.g. binding of ectocellularly formed cADPR to cell surface receptors and initiation of signal-transducing pathways across the plasmamembrane) seem to be paradigmatic of processes affecting different types of cells. Although in some biological systems, such as Aplysia and sea urchin egg, cADPR metabolism is restricted to the intracellular environment, in mammalian cells the CD38/cADPR system provides new challenges in terms of subcellular compartmentation and qualifies as an unusual example of "ectobiochemistry" with potential, still unrecognized, properties of cellular regulation.
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Affiliation(s)
- A De Flora
- Institute of Biochemistry, University of Genova, Italy
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37
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Herz JM, Thomsen WJ, Yarbrough GG. Molecular approaches to receptors as targets for drug discovery. J Recept Signal Transduct Res 1997; 17:671-776. [PMID: 9292776 DOI: 10.3109/10799899709044284] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The cloning of a great number of receptors and channels has revealed that many of these targets for drug discovery can be grouped into superfamilies based on sequence and structural similarities. This review presents an overview of how molecular biological approaches have revealed a plethora of receptor subtypes, led to new definitions of subtypes and isoforms, and played a role in the development of high selective drugs. Moreover, the diversity of subtypes has molded current views of the structure and function of receptor families. Practical difficulties and limitations inherent in the characterization of the ligand binding and signaling properties of expressed recombinant receptors are discussed. The importance of evaluating drug-receptor interactions that differ with temporally transient and distinct receptor conformational states is emphasized. Structural motifs and signal transduction features are presented for the following major receptor superfamilies: ligand-gated ion channel, voltage-dependent ion channel, G-protein coupled, receptor tyrosine-kinase, receptor protein tyrosine-phosphatase, cytokine and nuclear hormone. In addition, a prototypic receptor is analyzed to illustrate functional properties of a given family. The review concludes with a discussion of future directions in receptor research that will impact drug discovery, with a specific focus on orphan receptors as targets for drug discovery. Methods for classifying orphan receptors based upon homologies with members of existing superfamilies are presented together with molecular approaches to the greater challenge of defining their physiological roles. Besides revealing new orphan receptors, the human genome sequencing project will result in the identification of an abundance of novel receptors that will be molecular targets for the development of highly selective drugs. These findings will spur the discovery and development of an exciting new generation of receptor-subtype specific drugs with enhanced therapeutic specificity.
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Affiliation(s)
- J M Herz
- Applied Receptor Sciences, Mill Creek, WA 98012, USA
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38
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Pestka S, Kotenko SV, Muthukumaran G, Izotova LS, Cook JR, Garotta G. The interferon gamma (IFN-gamma) receptor: a paradigm for the multichain cytokine receptor. Cytokine Growth Factor Rev 1997; 8:189-206. [PMID: 9462485 DOI: 10.1016/s1359-6101(97)00009-9] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
With the purification and cloning of the interferon gamma (IFN-gamma) receptor chains the mechanism of IFN-gamma action and the resultant signal transduction events were delineated in remarkable detail. The interferon gamma (IFN-gamma) receptor complex consists of two chains: IFN-gammaR1, the ligand-binding chain, and IFN-gammaR2, the accessory chain. Binding of IFN-gamma causes oligomerization of the two IFN-gamma receptor subunits, IFN-gammaR1 and IFN-gammaR2, which initiates the signal transduction events: activation of Jak1 and Jak2 receptor associated protein tyrosine kinases, phosphorylation of the IFN-gammaR1 intracellular domain on Tyr440 followed by phosphorylation and activation of Stat1alpha, the latent transcriptional factor. With all these steps established, the IFN-gamma receptor complex has provided the basic model for understanding the receptors for other members of the family of class II cytokine receptors.
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Affiliation(s)
- S Pestka
- UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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39
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Young DC, Zhan H, Cheng QL, Hou J, Matthews DJ. Characterization of the receptor binding determinants of granulocyte colony stimulating factor. Protein Sci 1997; 6:1228-36. [PMID: 9194183 PMCID: PMC2143731 DOI: 10.1002/pro.5560060611] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We performed a series of experiments using alanine-scanning mutagenesis to locate side chains within human granulocyte colony-stimulating factor (G-CSF) that are involved in human G-CSF receptor binding. We constructed a panel of 28 alanine mutants that examined all surface exposed residues on helices A and D, as well as all charged residues on the surface of G-CSF. The G-CSF mutants were expressed in a transiently transfected mammalian cell line and quantitated by a sensitive biosensor method. We measured the activity of mutant proteins using an in vitro proliferation assay and an ELISA binding competition assay. These studies show that there is a region of five charged residues on helices A and C employed by G-CSF in binding its receptor, with the most important residue in this binding patch being Glu 19. Both wild-type G-CSF and the E19A mutant were expressed in E. coli. The re-folded proteins were found to have proliferative activities similar to the analogous proteins from mammalian cells: furthermore, biophysical analysis indicated that the E19A mutation does not cause gross structural perturbations in G-CSF. Although G-CSF is likely to signal through receptor homo-dimerization, we found no compelling evidence for a second receptor binding region. We also found no evidence of self-antagonism at high G-CSF concentrations, suggesting that, in contrast to human growth hormone (hGH) and erythropoietin (EPO), G-CSF probably does not signal via a pure 2:1 receptor ligand complex. Thus, G-CSF, while having a similar tertiary structure to hGH and EPO, uses different areas of the four helix bundle for high-affinity interaction with its receptor.
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Affiliation(s)
- D C Young
- Department of Molecular Biology, Arris Pharmaceutical Corporation, South San Francisco, California 94080, USA
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40
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Abstract
▪ Abstract During the last several years, the mechanism of IFNγ-dependent signal transduction has been the focus of intense investigation. This research has recently culminated in the elucidation of a comprehensive molecular understanding of the events that underlie IFNγ-induced cellular responses. The structure and function of the IFNγ receptor have been defined. The mechanism of IFNγ signal transduction has been largely elucidated, and the physiologic relevance of this process validated. Most recently, the molecular events that link receptor ligation to signal transduction have been established. Together these insights have produced a model of IFNγ signaling that is nearly complete and that serves as a paradigm for signaling by other members of the cytokine receptor superfamily.
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Affiliation(s)
- Erika A. Bach
- Center for Immunology and Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110
- Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses, CH-1066 Epalinges, Lausanne, Switzerland
| | - Michel Aguet
- Center for Immunology and Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110
- Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses, CH-1066 Epalinges, Lausanne, Switzerland
| | - Robert D. Schreiber
- Center for Immunology and Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110
- Swiss Institute for Experimental Cancer Research (ISREC), Ch. des Boveresses, CH-1066 Epalinges, Lausanne, Switzerland
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41
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Behrmann I, Janzen C, Gerhartz C, Schmitz-Van de Leur H, Hermanns H, Heesel B, Graeve L, Horn F, Tavernier J, Heinrich PC. A single STAT recruitment module in a chimeric cytokine receptor complex is sufficient for STAT activation. J Biol Chem 1997; 272:5269-74. [PMID: 9030599 DOI: 10.1074/jbc.272.8.5269] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We established a system of receptor chimeras that enabled us to induce heterodimerization of different cytoplasmic tails. Fusion constructs were created that are composed of the extracellular parts of the interleukin-5 receptor alpha and beta chains, respectively, and the transmembrane and intracellular parts of gp130, the signal transducing chain of the interleukin-6 receptor complex. In COS-7 transfectants we observed a dose-dependent interleukin-5-inducible STAT1 activation for which the presence of both the alpha and the beta chain chimera was needed. No STAT activity was detected if one of the cytoplasmic tails of the receptor complex was deleted, indicating that STAT activity resulted from a receptor dimer rather than from higher receptor aggregates. We further investigated whether dimerization of STAT1 depends on the juxtaposition of two STAT recruitment modules in a receptor complex. We show that a receptor dimer with only a single STAT1 docking site was still able to lead to STAT1 activation. This indicates that the formation of a paired set of STAT binding sites in a receptor complex is not the prerequisite for STAT factor dimerization. Our findings are discussed in view of alternative STAT dimerization models.
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Affiliation(s)
- I Behrmann
- Institute of Biochemistry, Rheinisch-Westfälische Technische Hochschule Aachen, 52057 Aachen, Germany.
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42
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Muthukumaran G, Kotenko S, Donnelly R, Ihle JN, Pestka S. Chimeric erythropoietin-interferon gamma receptors reveal differences in functional architecture of intracellular domains for signal transduction. J Biol Chem 1997; 272:4993-9. [PMID: 9030561 DOI: 10.1074/jbc.272.8.4993] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Binding of interferon gamma (IFN-gamma) causes oligomerization of the two interferon gamma receptor (IFN-gammaR) subunits, receptor chain 1 (IFN-gammaR1, the ligand-binding chain) and the second chain of the receptor (IFN-gammaR2), and causes activation of two Jak kinases (Jak1 and Jak2). In contrast, the erythropoietin receptor (EpoR) requires only one receptor chain and one Jak kinase (Jak2). Chimeras between the EpoR and the IFN-gammaR1 and IFN-gammaR2 chains demonstrate that the architecture of the EpoR and the IFN-gammaR complexes differ significantly. Although IFN-gammaR1 alone cannot initiate signal transduction, the chimera EpoR/gammaR1 (extracellular/intracellular) generates slight responses characteristic of IFN-gamma in response to Epo and the EpoR/gammaR1. EpoR/gammaR2 heterodimer is a fully functional receptor complex. The results demonstrate that the configuration of the extracellular domains influences the architecture of the intracellular domains.
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Affiliation(s)
- G Muthukumaran
- Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA
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43
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Popko B, Corbin JG, Baerwald KD, Dupree J, Garcia AM. The effects of interferon-gamma on the central nervous system. Mol Neurobiol 1997; 14:19-35. [PMID: 9170099 PMCID: PMC7091409 DOI: 10.1007/bf02740619] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Interferon-gamma (IFN-gamma) is a pleotropic cytokine released by T-lymphocytes and natural killer cells. Normally, these cells do not traverse the blood-brain barrier at appreciable levels and, as such, IFN-gamma is generally undetectable within the central nervous system (CNS). Nevertheless, in response to CNS infections, as well as during certain disorders in which the CNS is affected, T-cell traffic across the blood-brain barrier increases considerably, thereby exposing neuronal and glial cells to the potent effects of IFN-gamma. A larger portion of this article is devoted to the substantial circumstantial and experimental evidence that suggests that IFN-gamma plays an important role in the pathogenesis of the demyelinating disorder multiple sclerosis (MS) and its animal model experimental allergic encephalomyelitis (EAE). Moreover, the biochemical and physiological effects of IFN-gamma are discussed in the context of the potential consequences of such activities on the developing and mature nervous systems.
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Affiliation(s)
- B Popko
- Department of Biochemistry, UNC Neuroscience Center, University of North Carolina, Chapel Hill 27599-7250, USA
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44
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Abstract
During the last several years, the mechanism of IFN gamma-dependent signal transduction has been the focus of intense investigation. This research has recently culminated in the elucidation of a comprehensive molecular understanding of the events that underlie IFN gamma-induced cellular responses. The structure and function of the IFN gamma receptor have been defined. The mechanism of IFN gamma signal transduction has been largely elucidated, and the physiologic relevance of this process validated. Most recently, the molecular events that link receptor ligation to signal transduction have been established. Together these insights have produced a model of IFN gamma signaling that is nearly complete and that serves as a paradigm for signaling by other members of the cytokine receptor superfamily.
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Affiliation(s)
- E A Bach
- Center for Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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45
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Abstract
Interferons are cytokines that play a complex and central role in the resistance of mammalian hosts to pathogens. Type I interferon (IFN-alpha and IFN-beta) is secreted by virus-infected cells. Immune, type II, or gamma-interferon (IFN-gamma) is secreted by thymus-derived (T) cells under certain conditions of activation and by natural killer (NK) cells. Although originally defined as an agent with direct antiviral activity, the properties of IFN-gamma include regulation of several aspects of the immune response, stimulation of bactericidal activity of phagocytes, stimulation of antigen presentation through class I and class II major histocompatibility complex (MHC) molecules, orchestration of leukocyte-endothelium interactions, effects on cell proliferation and apoptosis, as well as the stimulation and repression of a variety of genes whose functional significance remains obscure. The implementation of such a variety of effects by a single cytokine is achieved by complex patterns of cell-specific gene regulation: Several IFN-gamma-regulated genes are themselves components of transcription factors. The IFN-gamma response is itself regulated by interaction with responses to other cytokines including IFN-alpha/beta, TNF-alpha, and IL-4. Over 200 genes are now known to be regulated by IFN-gamma and they are listed in a World Wide Web document that accompanies this review. However, much of the cellular response to IFN-gamma can be described in terms of a set of integrated molecular programs underlying well-defined physiological systems, for example the induction of efficient antigen processing for MHC-mediated antigen presentation, which play clearly defined roles in pathogen resistance. A promising approach to the complexity of the IFN-gamma response is to extend the analysis of the less understood IFN-gamma-regulated genes in terms of molecular programs functional in pathogen resistance.
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Affiliation(s)
- U Boehm
- Institute for Genetics, University of Cologne, Köln, Germany.
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46
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Zocchi E, Franco L, Guida L, Piccini D, Tacchetti C, De Flora A. NAD+-dependent internalization of the transmembrane glycoprotein CD38 in human Namalwa B cells. FEBS Lett 1996; 396:327-32. [PMID: 8915013 DOI: 10.1016/0014-5793(96)01125-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
CD38 is a transmembrane glycoprotein involved as an orphan receptor in many physiological processes of lymphocytes. It is also a bifunctional enzyme that catalyzes at its ectocellular domain the synthesis from NAD+ (cyclase) and the hydrolysis (hydrolase) of the calcium-mobilizing metabolite cyclic ADP-ribose (cADPR). A still unexplained paradox concerns the relationship between ectocellular localization of CD38 and intracellular calcium-releasing activity of its intermediate product cADPR. Incubation of CD38+ human Namalwa B cells with external NAD+ elicited extensive membrane down-regulation of CD38 and its internalization in non-clathrin-coated vesicles. Since the internalized CD38 was demonstrated to be enzymatically active, this NAD+-dependent process is a hitherto unrecognized means for shifting cADPR metabolism from the cell surface to the intracellular environment.
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Affiliation(s)
- E Zocchi
- Institute of Biochemistry, University of Genoa, Italy
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47
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Weber-Nordt RM, Riley JK, Greenlund AC, Moore KW, Darnell JE, Schreiber RD. Stat3 recruitment by two distinct ligand-induced, tyrosine-phosphorylated docking sites in the interleukin-10 receptor intracellular domain. J Biol Chem 1996; 271:27954-61. [PMID: 8910398 DOI: 10.1074/jbc.271.44.27954] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Recent work has shown that IL-10 induces activation of the JAK-STAT signaling pathway. To define the mechanism underlying signal transducer and activator of transcription (STAT) protein recruitment to the interleukin 10 (IL-10) receptor, the STAT proteins activated by IL-10 in different cell populations were first defined using electrophoretic mobility shift assays. In all cells tested, IL-10 activated Stat1 and Stat3 and induced the formation of three distinct DNA binding complexes that contained different combinations of these two transcription factors. IL-10 also activated Stat5 in Ba/F3 cells that stably expressed the murine IL-10 receptor. Using a structure-function mutagenesis approach, two tyrosine residues (Tyr427 and Tyr477) in the intracellular domain of the murine IL-10 receptor were found to be redundantly required for receptor function and for activation of Stat3 but not for Stat1 or Stat5. Twelve amino acid peptides encompassing either of these two tyrosine residues in phosphorylated form coprecipitated Stat3 but not Stat1 and blocked IL-10-induced Stat3 phosphorylation in a cell-free system. In contrast, tyrosine-phosphorylated peptides containing Tyr374 or Tyr396 did not interact with Stat3 or block Stat3 activation. These data demonstrate that Stat3 but not Stat1 or Stat5 is directly recruited to the ligand-activated IL-10 receptor by binding to specific but redundant receptor intracellular domain sequences containing phosphotyrosine. This study thus supports the concept that utilization of distinct STAT proteins by different cytokine receptors is dependent on the expression of particular ligand-activatable, tyrosine-containing STAT docking sites in receptor intracellular domains.
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Affiliation(s)
- R M Weber-Nordt
- Center for Immunology, Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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48
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Windsor WT, Walter LJ, Syto R, Fossetta J, Cook WJ, Nagabhushan TL, Walter MR. Purification and crystallization of a complex between human interferon gamma receptor (extracellular domain) and human interferon gamma. Proteins 1996; 26:108-14. [PMID: 8880934 DOI: 10.1002/(sici)1097-0134(199609)26:1<108::aid-prot10>3.0.co;2-k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
X-ray diffraction quality crystals have been obtained from a complex between interferon gamma and the extracellular domain of its high-affinity cell surface receptor. The crystals were obtained from interferon gamma/interferon gamma receptor complexes purified by size exclusion chromatography. Diffraction quality crystals required analyzing these complex samples by isoelectric focusing gels to select purified complex fractions devoid of unbound interferon gamma. These studies used interferon gamma receptor engineered with an eight amino acid N-terminal deletion to eliminate heterogeneity generated due to proteolytic cleavage. In addition, the receptor was expressed in an E. coli secretion cell line which eliminated the need to refold the protein. Hexagonal crystals were grown from 1.6 M ammonium phosphate solutions and belong to a spacegroup of P6(5)22 with unit cell dimensions a = 145.9 A and c = 180.3 A. These crystals diffract to at least 2.9 A resolution when exposed to synchrotron radiation. SDS PAGE analysis of the crystals demonstrated that both interferon gamma and the receptor were present. Analysis of the x-ray diffraction data revealed that the crystals contain complexes with a stoichiometry of 2:1 receptor: ligand within the crystallographic asymmetric unit and consist of approximately 55% solvent.
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Affiliation(s)
- W T Windsor
- Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
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49
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Kotenko SV, Izotova LS, Pollack BP, Muthukumaran G, Paukku K, Silvennoinen O, Ihle JN, Pestka S. Other kinases can substitute for Jak2 in signal transduction by interferon-gamma. J Biol Chem 1996; 271:17174-82. [PMID: 8663414 DOI: 10.1074/jbc.271.29.17174] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Each cytokine which utilizes the Jak-Stat signal transduction pathway activates a distinct combination of members of the Jak and Stat families. Thus, either the Jaks, the Stats, or both could contribute to the specificity of ligand action. With the use of chimeric receptors involving the interferon gamma receptor (IFN-gammaR) complex as a model system, we demonstrate that Jak2 activation is not an absolute requirement for IFN-gamma signaling. Other members of the Jak family can functionally substitute for Jak2. IFN-gamma can signal through the activation of Jak family members other than Jak2 as measured by Statlalpha homodimerization and major histocompatibility complex class I antigen expression. This indicates that Jaks are interchangeable and indiscriminative in the Jak-Stat signal transduction pathway. The necessity for the activation of one particular kinase during signaling can be overcome by recruiting another kinase to the receptor complex. The results may suggest that the Jaks do not contribute to the specificity of signal transduction in the Jak-Stat pathway to the same degree as Stats.
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Affiliation(s)
- S V Kotenko
- Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA
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50
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Umar S, Malavasi F, Mehta K. Post-translational modification of CD38 protein into a high molecular weight form alters its catalytic properties. J Biol Chem 1996; 271:15922-7. [PMID: 8663150 DOI: 10.1074/jbc.271.27.15922] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Human CD38 is a 45-kDa transmembrane protein that acts as a bifunctional ectoenzyme, catalyzing the synthesis of cyclic ADP-ribose (cADPR) from NAD+ and the hydrolysis of cADPR to ADP-ribose. All-trans-retinoic acid (RA) is a potent and specific inducer of CD38 in myeloid cells. In this report, we demonstrate that RA-induced CD38 protein from human myeloid (HL-60) leukemia cells coimmunoprecipitates with another protein of molecular mass approximately190 kDa (p190). The p190 protein is localized exclusively in the membranes and is a consequence of post-translational cross-linking of CD38 protein. This conclusion was based on the observations that purified CD38 effectively competes with p190, its accumulation is preceded by the accumulation of CD38, it immunoreacted with three different monospecific anti-CD38 antibodies on immunoblots, and its peptide map revealed several peptides in common with CD38. Furthermore, CD38 could serve as a suitable substrate for transglutaminase (TGase)-catalyzed cross-linking reactions in vitro, and the accumulation of p190 in RA-treated HL-60 cells is effectively blocked by the presence of TGase-specific inhibitor. The purified p190 showed at least three times more cyclase activity than CD38. Conversely, p190 was at least 2.5-fold less active than CD38 in hydrolyzing cADPR to ADPR. These results suggest that post-translational modification of CD38 may represent an important mechanism for regulating the two catalytic activities of this bifunctional enzyme.
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Affiliation(s)
- S Umar
- Department of Bioimmunotherapy, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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