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Sawant KV, Sepuru KM, Lowry E, Penaranda B, Frevert CW, Garofalo RP, Rajarathnam K. Neutrophil recruitment by chemokines Cxcl1/KC and Cxcl2/MIP2: Role of Cxcr2 activation and glycosaminoglycan interactions. J Leukoc Biol 2021; 109:777-791. [PMID: 32881070 PMCID: PMC8296306 DOI: 10.1002/jlb.3a0820-207r] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
Chemokines play a crucial role in combating microbial infection by recruiting blood neutrophils to infected tissue. In mice, the chemokines Cxcl1/KC and Cxcl2/MIP2 fulfill this role. Cxcl1 and Cxcl2 exist as monomers and dimers, and exert their function by activating the Cxcr2 receptor and binding glycosaminoglycans (GAGs). Here, we characterized Cxcr2 G protein and β-arrestin activities, and GAG heparan sulfate (HS) interactions of Cxcl1 and Cxcl2 and of the trapped dimeric variants. To understand how Cxcr2 and GAG interactions impact in vivo function, we characterized their neutrophil recruitment activity to the peritoneum, Cxcr2 and CD11b levels on peritoneal and blood neutrophils, and transport profiles out of the peritoneum. Cxcl2 variants compared with Cxcl1 variants were more potent for Cxcr2 activity. Native Cxcl1 compared with native Cxcl2 and dimers compared with native proteins bound HS with higher affinity. Interestingly, recruitment activity between native Cxcl1 and Cxcl2, between dimers, and between the native protein and the dimer could be similar or very different depending on the dose or the time point. These data indicate that peritoneal neutrophil recruitment cannot be solely attributed to Cxcr2 or GAG interactions, and that the relationship between recruited neutrophils, Cxcr2 activation, GAG interactions, and chemokine levels is complex and highly context dependent. We propose that the ability of Cxcl1 and Cxcl2 to reversibly exist as monomers and dimers and differences in their Cxcr2 activity and GAG interactions coordinate neutrophil recruitment and activation, which play a critical role for successful resolution of inflammation.
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Affiliation(s)
- Kirti V. Sawant
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Emily Lowry
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Brigith Penaranda
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Charles W. Frevert
- Department of Comparative Medicine and Center for Lung Biology, University of Washington, Seattle, WA, USA
| | - Roberto P. Garofalo
- Department of Pediatrics, The University of Texas Medical Branch, Galveston, Texas, USA
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
- Department of Pediatrics, The University of Texas Medical Branch, Galveston, Texas, USA
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, Texas, USA
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Rajarathnam K, Desai UR. Structural Insights Into How Proteoglycans Determine Chemokine-CXCR1/CXCR2 Interactions: Progress and Challenges. Front Immunol 2020; 11:660. [PMID: 32391006 PMCID: PMC7193095 DOI: 10.3389/fimmu.2020.00660] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/23/2020] [Indexed: 01/01/2023] Open
Abstract
Proteoglycans (PGs), present in diverse environments, such as the cell membrane surface, extracellular milieu, and intracellular granules, are fundamental to life. Sulfated glycosaminoglycans (GAGs) are covalently attached to the core protein of proteoglycans. PGs are complex structures, and are diverse in terms of amino acid sequence, size, shape, and in the nature and number of attached GAG chains, and this diversity is further compounded by the phenomenal diversity in GAG structures. Chemokines play vital roles in human pathophysiology, from combating infection and cancer to leukocyte trafficking, immune surveillance, and neurobiology. Chemokines mediate their function by activating receptors that belong to the GPCR class, and receptor interactions are regulated by how, when, and where chemokines bind GAGs. GAGs fine-tune chemokine function by regulating monomer/dimer levels and chemotactic/haptotactic gradients, which are also coupled to how they are presented to their receptors. Despite their small size and similar structures, chemokines show a range of GAG-binding geometries, affinities, and specificities, indicating that chemokines have evolved to exploit the repertoire of chemical and structural features of GAGs. In this review, we summarize the current status of research on how GAG interactions regulate ELR-chemokine activation of CXCR1 and CXCR2 receptors, and discuss knowledge gaps that must be overcome to establish causal relationships governing the impact of GAG interactions on chemokine function in human health and disease.
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Affiliation(s)
- Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch at Galveston, Galveston, TX, United States.,Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch at Galveston, Galveston, TX, United States.,Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, TX, United States
| | - Umesh R Desai
- Department of Medicinal Chemistry, Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, United States
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Gulati K, Gangele K, Kumar D, Poluri KM. An inter-switch between hydrophobic and charged amino acids generated druggable small molecule binding pocket in chemokine paralog CXCL3. Arch Biochem Biophys 2018; 662:121-128. [PMID: 30528777 DOI: 10.1016/j.abb.2018.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/29/2018] [Accepted: 12/04/2018] [Indexed: 12/27/2022]
Abstract
Multigene families such as chemokines arose as a result of gene duplication events, followed by mutations and selection. GRO chemokines are three duplicated CXCL genes, comprising of CXCL1, CXCL2 and CXCL3 proteins. Comparative structural analysis of the two closely related paralog chemokines CXCL2 and CXCL3 in the current study indicated a variable electrostatic surface between them, and a specific hydrophobic pocket on the surface of CXCL3 that can bind naphthalene derivatives. Combined fluorescence and NMR analyses revealed that CXCL3 monomer can specifically bind to ANS (8-Anilinonaphthalene-1-sulfonic acid) with a stoichiometry of 1:1 by involving the residues belonging to the structural elements 310 helix and the α-helix. A close observation of the surfaces of these paralogs suggested that such a hydrophobic pocket is a resultant of inter-switch between a charged and a hydrophobic residue on the primary sequence of the two paralog proteins. Interestingly, the hydrophobic pocket is in the vicinity of GAG binding region of CXCL3, a molecular determinant in leukocyte trafficking. Such unique pockets/patches on specific chemokine surfaces can be exploited to design the naphthalene/small molecule based inhibitors against GAG binding to regulate their molecular interactions during the onset and progression of various types of cancers and inflammatory diseases.
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Affiliation(s)
- Khushboo Gulati
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India
| | - Krishnakant Gangele
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India
| | - Dinesh Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow, 226014, Uttar Pradesh, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India; Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
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4
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Sepuru KM, Nagarajan B, Desai UR, Rajarathnam K. Structural basis, stoichiometry, and thermodynamics of binding of the chemokines KC and MIP2 to the glycosaminoglycan heparin. J Biol Chem 2018; 293:17817-17828. [PMID: 30257866 DOI: 10.1074/jbc.ra118.004866] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/10/2018] [Indexed: 01/21/2023] Open
Abstract
Keratinocyte-derived chemokine (KC or mCXCL1) and macrophage inflammatory protein 2 (MIP2 or mCXCL2) play nonredundant roles in trafficking blood neutrophils to sites of infection and injury. The functional responses of KC and MIP2 are intimately coupled to their interactions with glycosaminoglycans (GAGs). GAG interactions orchestrate chemokine concentration gradients and modulate receptor activity, which together regulate neutrophil trafficking. Here, using NMR, molecular dynamics (MD) simulations, and isothermal titration calorimetry (ITC), we characterized the molecular basis of KC and MIP2 binding to the GAG heparin. Both chemokines reversibly exist as monomers and dimers, and the NMR analysis indicates that the dimer binds heparin with higher affinity. The ITC experiments indicate a stoichiometry of two GAGs per KC or MIP2 dimer and that the enthalpic and entropic contributions vary significantly between the two chemokine-heparin complexes. NMR-based structural models of heparin-KC and heparin-MIP2 complexes reveal that different combinations of residues from the N-loop, 40s turn, β3-strand, and C-terminal helix form a binding surface within a monomer and that both conserved residues and residues unique to a particular chemokine mediate the binding interactions. MD simulations indicate significant residue-specific differences in their contribution to binding and affinity for a given chemokine and between chemokines. On the basis of our observations that KC and MIP2 bind to GAG via distinct molecular interactions, we propose that the differences in these GAG interactions lead to differences in neutrophil recruitment and play nonoverlapping roles in resolution of inflammation.
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Affiliation(s)
- Krishna Mohan Sepuru
- From the Departments of Biochemistry and Molecular Biology; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
| | - Balaji Nagarajan
- Department of Medicinal Chemistry and Institute for Structural Biology, and Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219
| | - Umesh R Desai
- Department of Medicinal Chemistry and Institute for Structural Biology, and Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219
| | - Krishna Rajarathnam
- From the Departments of Biochemistry and Molecular Biology; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555; Microbiology and Immunology.
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5
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Gulati K, Gangele K, Agarwal N, Jamsandekar M, Kumar D, Poluri KM. Molecular cloning and biophysical characterization of CXCL3 chemokine. Int J Biol Macromol 2017; 107:575-584. [PMID: 28928065 DOI: 10.1016/j.ijbiomac.2017.09.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/17/2017] [Accepted: 09/12/2017] [Indexed: 02/07/2023]
Abstract
CXCL3 is a neutrophil activating chemokine that belongs to GRO subfamily of CXC chemokines. GRO chemokine family comprises of three chemokines GRO α (CXCL1), GROβ (CXCL2), and GRO γ (CXCL3), which arose as a result of gene duplication events during the course of chemokine evolution. Although primary sequences of GRO chemokines are highly similar, they performs several protein specific functions in addition to their common property of neutrophil trafficking. However, the molecular basis for their differential functions has not well understood. Although structural details are available for CXCL1 and CXCL2, no such information regarding CXCL3 is available till date. In the present study, we have successfully cloned, expressed, and purified the recombinant CXCL3. Around 15mg/L of pure recombinant CXCL3 protein was obtained. Further, we investigated its functional divergence and biophysical characteristics such as oligomerization, thermal stability and heparin binding etc., and compared all these features with its closest paralog CXCL2. Our studies revealed that, although overall structural and oligomerization features of CXCL3 and CXCL2 are similar, prominent differences were observed in their surface characteristics, thus implicating for a functional divergence.
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Affiliation(s)
- Khushboo Gulati
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 Uttarakhand, India
| | - Krishnakant Gangele
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 Uttarakhand, India
| | - Nipanshu Agarwal
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 Uttarakhand, India
| | - Minal Jamsandekar
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 Uttarakhand, India
| | - Dinesh Kumar
- Centre for Biomedical Research, SGPGIMS Campus, Lucknow 226014, Uttar Pradesh, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 Uttarakhand, India; Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 Uttarakhand, India.
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6
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Brown AJ, Sepuru KM, Rajarathnam K. Structural Basis of Native CXCL7 Monomer Binding to CXCR2 Receptor N-Domain and Glycosaminoglycan Heparin. Int J Mol Sci 2017; 18:ijms18030508. [PMID: 28245630 PMCID: PMC5372524 DOI: 10.3390/ijms18030508] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/14/2017] [Accepted: 02/21/2017] [Indexed: 11/23/2022] Open
Abstract
CXCL7, a chemokine highly expressed in platelets, orchestrates neutrophil recruitment during thrombosis and related pathophysiological processes by interacting with CXCR2 receptor and sulfated glycosaminoglycans (GAG). CXCL7 exists as monomers and dimers, and dimerization (~50 μM) and CXCR2 binding (~10 nM) constants indicate that CXCL7 is a potent agonist as a monomer. Currently, nothing is known regarding the structural basis by which receptor and GAG interactions mediate CXCL7 function. Using solution nuclear magnetic resonance (NMR) spectroscopy, we characterized the binding of CXCL7 monomer to the CXCR2 N-terminal domain (CXCR2Nd) that constitutes a critical docking site and to GAG heparin. We found that CXCR2Nd binds a hydrophobic groove and that ionic interactions also play a role in mediating binding. Heparin binds a set of contiguous basic residues indicating a prominent role for ionic interactions. Modeling studies reveal that the binding interface is dynamic and that GAG adopts different binding geometries. Most importantly, several residues involved in GAG binding are also involved in receptor interactions, suggesting that GAG-bound monomer cannot activate the receptor. Further, this is the first study that describes the structural basis of receptor and GAG interactions of a native monomer of the neutrophil-activating chemokine family.
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Affiliation(s)
- Aaron J Brown
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Krishna Rajarathnam
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA.
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7
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Gulati K, Poluri KM. Deciphering the in vitro homo and hetero oligomerization characteristics of CXCL1/CXCL2 chemokines. RSC Adv 2016. [DOI: 10.1039/c6ra01884j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Murine GRO chemokines CXCL1(mKC)/CXCL2(MIP2) forms heterodimers and thus adding another layer of regulatory mechanism for leukocyte trafficking during infection/inflammation.
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Affiliation(s)
- Khushboo Gulati
- Department of Biotechnology
- Indian Institute of Technology Roorkee
- Roorkee-247667
- India
| | - Krishna Mohan Poluri
- Department of Biotechnology
- Indian Institute of Technology Roorkee
- Roorkee-247667
- India
- Centre for Nanotechnology
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8
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Poluri KM, Joseph PRB, Sawant KV, Rajarathnam K. Molecular basis of glycosaminoglycan heparin binding to the chemokine CXCL1 dimer. J Biol Chem 2013; 288:25143-25153. [PMID: 23864653 DOI: 10.1074/jbc.m113.492579] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycosaminoglycan (GAG)-bound and soluble chemokine gradients in the vasculature and extracellular matrix mediate neutrophil recruitment to the site of microbial infection and sterile injury in the host tissue. However, the molecular principles by which chemokine-GAG interactions orchestrate these gradients are poorly understood. This, in part, can be directly attributed to the complex interrelationship between the chemokine monomer-dimer equilibrium and binding geometry and affinities that are also intimately linked to GAG length. To address some of this missing knowledge, we have characterized the structural basis of heparin binding to the murine CXCL1 dimer. CXCL1 is a neutrophil-activating chemokine and exists as both monomers and dimers (Kd = 36 μm). To avoid interference from monomer-GAG interactions, we designed a trapped dimer (dCXCL1) by introducing a disulfide bridge across the dimer interface. We characterized the binding of GAG heparin octasaccharide to dCXCL1 using solution NMR spectroscopy. Our studies show that octasaccharide binds orthogonally to the interhelical axis and spans the dimer interface and that heparin binding enhances the structural integrity of the C-terminal helical residues and stability of the dimer. We generated a quadruple mutant (H20A/K22A/K62A/K66A) on the basis of the binding data and observed that this mutant failed to bind heparin octasaccharide, validating our structural model. We propose that the stability enhancement of dimers upon GAG binding regulates in vivo neutrophil trafficking by increasing the lifetime of "active" chemokines, and that this structural knowledge could be exploited for designing inhibitors that disrupt chemokine-GAG interactions and neutrophil homing to the target tissue.
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Affiliation(s)
- Krishna Mohan Poluri
- From the Department of Biochemistry and Molecular Biology,; Sealy Center for Structural Biology and Molecular Biophysics, and
| | - Prem Raj B Joseph
- From the Department of Biochemistry and Molecular Biology,; Sealy Center for Structural Biology and Molecular Biophysics, and
| | - Kirti V Sawant
- From the Department of Biochemistry and Molecular Biology
| | - Krishna Rajarathnam
- From the Department of Biochemistry and Molecular Biology,; Sealy Center for Structural Biology and Molecular Biophysics, and; Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas 77555.
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9
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Rajasekaran D, Keeler C, Syed MA, Jones MC, Harrison JK, Wu D, Bhandari V, Hodsdon ME, Lolis EJ. A model of GAG/MIP-2/CXCR2 interfaces and its functional effects. Biochemistry 2012; 51:5642-54. [PMID: 22686371 DOI: 10.1021/bi3001566] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
MIP-2/CXCL2 is a murine chemokine related to human chemokines that possesses the Glu-Leu-Arg (ELR) activation motif and activates CXCR2 for neutrophil chemotaxis. We determined the structure of MIP-2 to 1.9 Å resolution and created a model with its murine receptor CXCR2 based on the coordinates of human CXCR4. Chemokine-induced migration of cells through specific G-protein coupled receptors is regulated by glycosaminoglycans (GAGs) that oligomerize chemokines. MIP-2 GAG-binding residues were identified that interact with heparin disaccharide I-S by NMR spectroscopy. A model GAG/MIP-2/CXCR2 complex that supports a 2:2 complex between chemokine and receptor was created. Mutants of these disaccharide-binding residues were made and tested for heparin binding, in vitro neutrophil chemotaxis, and in vivo neutrophil recruitment to the mouse peritoneum and lung. The mutants have a 10-fold decrease in neutrophil chemotaxis in vitro. There is no difference in neutrophil recruitment between wild-type MIP-2 and mutants in the peritoneum, but all activity of the mutants is lost in the lung, supporting the concept that GAG regulation of chemokines is tissue-dependent.
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Affiliation(s)
- Deepa Rajasekaran
- Departments of Pharmacology, Yale University School of Medicine, New Haven, CT 06520-8066, USA
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10
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Tamarozzi MB, Soares SG, Sá-Nunes A, Paiva HH, Saggioro FP, Garcia AB, Lucena-Araujo AR, Falcão RP, Bordin JO, Rego EM. Comparative analysis of the pathological events involved in immune and non-immune TRALI models. Vox Sang 2012; 103:309-21. [DOI: 10.1111/j.1423-0410.2012.01613.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Zhao B, Liwang PJ. Characterization of the interactions of vMIP-II, and a dimeric variant of vMIP-II, with glycosaminoglycans. Biochemistry 2010; 49:7012-22. [PMID: 20712376 DOI: 10.1021/bi100549y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemokines are important immune proteins, carrying out their function by binding to glycosaminoglycans (GAGs) on the endothelial surface and to cell surface chemokine receptors. A unique viral chemokine analogue, viral macrophage inflammatory protein-II (vMIP-II), encoded by human herpesvirus-8, has garnered interest because of its ability to bind to multiple chemokine receptors, including both HIV coreceptors. In addition, vMIP-II binds to cell surface GAGs much more tightly than most human chemokines, which may be the key to its anti-inflammatory function in vivo. The goal of this work was to determine the mechanism of binding of GAG by vMIP-II. The interaction of vMIP-II with a heparin-derived disaccharide was characterized using NMR. Important binding sites were further analyzed by mutagenesis studies, in which corresponding vMIP-II mutants were tested for GAG binding ability using heparin chromatography and NMR. We found that despite having many more basic residues than some chemokines, vMIP-II shares a characteristic binding site similar to that of its human analogues, utilizing basic residues R18, R46, and R48. Interestingly, a particular mutation (Leu13Phe) caused vMIP-II to form a pH-dependent CC chemokine-type dimer as determined by analytical ultracentrifugation and NMR. To the best of our knowledge, this is the first example of engineering a naturally predominantly monomeric chemokine into a dissociable dimer by a single mutation. This dimeric vMIP-II mutant binds to heparin much more tightly than wild-type vMIP-II and provides a new model for studying the relationship between chemokine quaternary structure and various aspects of function. Structural differences between monomeric and dimeric vMIP-II upon GAG binding were characterized by NMR and molecular docking.
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Affiliation(s)
- Bo Zhao
- University of California, 5200 North Lake Road, Merced, California 95343, USA
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Landsberg J, Gaffal E, Cron M, Kohlmeyer J, Renn M, Tüting T. Autochthonous primary and metastatic melanomas in Hgf-Cdk4R24C mice evade T-cell-mediated immune surveillance. Pigment Cell Melanoma Res 2010; 23:649-60. [DOI: 10.1111/j.1755-148x.2010.00744.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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13
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Woods RJ, Brower JO, Castellanos E, Hashemzadeh M, Khakshoor O, Russu WA, Nowick JS. Cyclic modular beta-sheets. J Am Chem Soc 2007; 129:2548-58. [PMID: 17295482 PMCID: PMC2597679 DOI: 10.1021/ja0667965] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of peptide beta-hairpins is problematic, because folding depends on the amino acid sequence and changes to the sequence can significantly decrease folding. Robust beta-hairpins that can tolerate such changes are attractive tools for studying interactions involving protein beta-sheets and developing inhibitors of these interactions. This paper introduces a new class of peptide models of protein beta-sheets that addresses the problem of separating folding from the sequence. These model beta-sheets are macrocyclic peptides that fold in water to present a pentapeptide beta-strand along one edge; the other edge contains the tripeptide beta-strand mimic Hao [JACS 2000, 122, 7654] and two additional amino acids. The pentapeptide and Hao-containing peptide strands are connected by two delta-linked ornithine (deltaOrn) turns [JACS 2003, 125, 876]. Each deltaOrn turn contains a free alpha-amino group that permits the linking of individual modules to form divalent beta-sheets. These "cyclic modular beta-sheets" are synthesized by standard solid-phase peptide synthesis of a linear precursor followed by solution-phase cyclization. Eight cyclic modular beta-sheets 1a-1h containing sequences based on beta-amyloid and macrophage inflammatory protein 2 were synthesized and characterized by 1H NMR. Linked cyclic modular beta-sheet 2, which contains two modules of 1b, was also synthesized and characterized. 1H NMR studies show downfield alpha-proton chemical shifts, deltaOrn delta-proton magnetic anisotropy, and NOE cross-peaks that establish all compounds but 1c and 1g to be moderately or well folded into a conformation that resembles a beta-sheet. Pulsed-field gradient NMR diffusion experiments show little or no self-association at low (=2 mM) concentrations. Changes to the residues in the Hao-containing strands of 1c and 1g improve folding and show that folding of the structures can be enhanced without altering the sequence of the pentapeptide strand. Well-folded cyclic modular beta-sheets 1a, 1b, and 1f each have a phenylalanine directly across from Hao, suggesting that cyclic modular beta-sheets containing aromatic residues across from Hao are better folded.
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Affiliation(s)
- R. Jeremy Woods
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
| | - Justin O. Brower
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
| | - Elena Castellanos
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
| | - Mehrnoosh Hashemzadeh
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
| | - Omid Khakshoor
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
| | - Wade A. Russu
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
| | - James S. Nowick
- Department of Chemistry, University of California, Irvine, Irvine, CA 92697-2025, Phone: 949-824-6091, FAX: 949-824-9920
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14
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Jin H, Hayes GL, Darbha NS, Meyer E, LiWang PJ. Investigation of CC and CXC chemokine quaternary state mutants. Biochem Biophys Res Commun 2005; 338:987-99. [PMID: 16256937 DOI: 10.1016/j.bbrc.2005.10.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Accepted: 10/07/2005] [Indexed: 11/29/2022]
Abstract
The chemokine family forms two different types of homodimer despite members sharing nearly identical folds. To study the formation of quaternary structure in this family, rational mutagenesis was employed on a representative member of each subfamily (MIP-1beta and IL-8). The variants were studied by analytical ultracentrifugation and NMR, and it was determined that formation of a folded monomer from a natural chemokine dimer is reasonably facile, while conversion between dimer types is not. Monomeric variants of MIP-1beta and IL-8 were randomly mutated and a lambda phage-based selection system was employed in a novel way to screen for dimerization. A total of 6,000,000 random mutants were screened, but no dimers were formed, suggesting again that the chemokine fold is robust and amenable to sequence variation, while the chemokine dimer is much more difficult to attain. This work represents a biophysical analysis of an array of chemokine quaternary state variants.
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Affiliation(s)
- Hongjun Jin
- Department of Biochemistry and Biophysics, Texas A&M University, TAMU 2128, College Station, TX 77843-2128, USA
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15
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Luz JG, Yu M, Su Y, Wu Z, Zhou Z, Sun R, Wilson IA. Crystal structure of viral macrophage inflammatory protein I encoded by Kaposi's sarcoma-associated herpesvirus at 1.7A. J Mol Biol 2005; 352:1019-28. [PMID: 16140327 DOI: 10.1016/j.jmb.2005.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 08/03/2005] [Accepted: 08/11/2005] [Indexed: 10/25/2022]
Abstract
Viral macrophage inflammatory protein I (vMIP-I) is a chemokine encoded by the Kaposi's sarcoma-associated herpesvirus (KSHV) that selectively activates the CC chemokine receptor 8 (CCR8), for which the endogenous ligand is CCL1. The crystal structure of vMIP-I was determined at 1.7A for comparison with other chemokines, especially those that bind CCR8, such as vMIP-II from KSHV, a CCR8 antagonist and the closest homolog (40% identical). vMIP-I has a typical chemokine fold consisting of an extended N-terminal loop, followed by a three-stranded antiparallel beta-sheet and a C-terminal alpha-helix. The four molecules in the asymmetric unit comprise two MIP-1beta-like dimers. Electrostatic surface representations of CCR8-binding chemokines reveal only minor areas of correlating surface potential, which must be reconciled with promiscuity in receptor and glycosaminoglycan (GAG) binding. In addition, the biological relevance of chemokine oligomerization is examined by comparing the oligomeric states of all chemokine structures deposited to date in the RCSB PDB.
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Affiliation(s)
- John G Luz
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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16
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Springael JY, Urizar E, Parmentier M. Dimerization of chemokine receptors and its functional consequences. Cytokine Growth Factor Rev 2005; 16:611-23. [PMID: 15979374 DOI: 10.1016/j.cytogfr.2005.05.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 05/17/2005] [Indexed: 12/15/2022]
Abstract
It became clear over the recent years that most, if not all, G protein-coupled receptors (GPCR) are able to form dimers or higher order oligomers. Chemokine receptors make no exception to this new rule and both homo- and heterodimerization were demonstrated for CC and CXC receptors. Functional analyses demonstrated negative binding cooperativity between the two subunits of a dimer. The consequence is that only one chemokine can bind with high affinity onto a receptor dimer. In the context of receptor activation, this implies that the motions of helical domains triggered by the binding of agonists induce correlated changes in the other protomer. The impact of the chemokine dimerization process in terms of co-receptor function and drug development is discussed.
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Affiliation(s)
- Jean-Yves Springael
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, B-1070 Brussels, Belgium
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17
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Schountz T, Green R, Davenport B, Buniger A, Richens T, Root JJ, Davidson F, Calisher CH, Beaty BJ. Cloning and characterization of deer mouse (Peromyscus maniculatus) cytokine and chemokine cDNAs. BMC Immunol 2004; 5:1. [PMID: 14720307 PMCID: PMC331403 DOI: 10.1186/1471-2172-5-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Accepted: 01/13/2004] [Indexed: 12/04/2022] Open
Abstract
Background Sin Nombre virus (SNV) establishes a persistent infection in the deer mouse, Peromyscus maniculatus. A strong antibody response occurs in response to SNV infection, but the role of the innate immune response is unclear. To address this issue, we have initiated an effort to identify and characterize deer mouse cytokine and chemokine genes. Such cytokines and chemokines are involved in various aspects of immunity, including the transition from innate to adaptive responses, type I and type II responses, recruitment of leukocytes to sites of infection, and production of mature cells from bone marrow progenitors. Results We established a colony of SNV antibody-negative deer mice and cloned 11 cytokine and chemokine partial cDNA sequences using directed PCR. Most of the deer mouse sequences were highly conserved with orthologous sequences from other rodent species and functional domains were identified in each putative polypeptide. Conclusions The availability of these sequences will allow the examination of the role of these cytokines in deer mouse responses to infection with Sin Nombre virus.
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Affiliation(s)
- Tony Schountz
- Department of Biological Sciences, Mesa State College, 1100 North Ave., Grand Junction, CO 81501, USA
- Saccomanno Research Institute, 2530 N. 8Street, Wellington Bldg. 4, Ste. 100, Grand Junction, CO 81501, USA
| | - Renata Green
- Department of Biological Sciences, Mesa State College, 1100 North Ave., Grand Junction, CO 81501, USA
| | - Bennett Davenport
- Department of Biological Sciences, Mesa State College, 1100 North Ave., Grand Junction, CO 81501, USA
| | - Amie Buniger
- Department of Biological Sciences, Mesa State College, 1100 North Ave., Grand Junction, CO 81501, USA
| | - Tiffany Richens
- Department of Biological Sciences, Mesa State College, 1100 North Ave., Grand Junction, CO 81501, USA
- Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - J Jeffrey Root
- Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Forbes Davidson
- Department of Biological Sciences, Mesa State College, 1100 North Ave., Grand Junction, CO 81501, USA
| | - Charles H Calisher
- Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Barry J Beaty
- Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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18
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Suetomi K, Rojo D, Navarro J. Identification of a signal transduction switch in the chemokine receptor CXCR1. J Biol Chem 2002; 277:31563-6. [PMID: 12077146 DOI: 10.1074/jbc.m204713200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chemokine receptors belong to the superfamily of G protein-coupled receptors, which regulate the trafficking and activation of leukocytes, and operate as coreceptors in the entry of HIV-1. To investigate the early steps in the signal transmission from the chemokine-binding site to the G protein-coupling region we engineered metal ion-binding sites at putative extracellular sites in the chemokine receptor CXCR1. We introduced histidines into sites located in the second and third putative extracellular loops of CXCR1, creating single, double, and triple mutant receptors: R199H, R203H, D265H, R199H/R203H, R199H/D265H, R203H/D265H, R203H/H207Q, and R199H/R203H/D265H. Cells expressing the double mutants R199H/D265H and R203H/D265H and the triple mutant R199H/R203H/D265H failed to trigger interleukin 8-dependent calcium responses. Interestingly, calcium responses mediated by the single mutant R203H and the double mutants R199H/R203H and R203H/H207Q were blocked by Zn(II), indicating the creation of a functional metal ion-binding site. On the other hand, cells expressing all single, double, or triple histidine-substituted CXCR1 demonstrated high affinity binding to interleukin 8 in the presence and absence of metal ions. These findings indicate that occupation of the engineered metal-binding site uncouples the chemokine-binding site from the activation mechanism in CXCR1. Most importantly, we identify for the first time elements of an early signal transduction switch of chemokine receptors before the activation of cytoplasmic G proteins.
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Affiliation(s)
- Katsutoshi Suetomi
- Membrane Protein Laboratory, Department of Physiology and Biophysics and Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston, Texas 77555-0437, USA
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19
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Kuloğlu ES, McCaslin DR, Markley JL, Volkman BF. Structural rearrangement of human lymphotactin, a C chemokine, under physiological solution conditions. J Biol Chem 2002; 277:17863-70. [PMID: 11889129 PMCID: PMC4451178 DOI: 10.1074/jbc.m200402200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
NMR spectra of human lymphotactin (hLtn), obtained under various solution conditions, have revealed that the protein undergoes a major conformational rearrangement dependent on temperature and salt concentration. At high salt (200 mm NaCl) and low temperature (10 degrees C), hLtn adopts a chemokine-like fold, which consists of a three-stranded antiparallel beta-sheet and a C-terminal alpha-helix (Kuloğlu, E. S., McCaslin, D. R., Kitabwalla, M., Pauza, C. D., Markley, J. L., and Volkman, B. F. (2001) Biochemistry 40, 12486-12496). We have used NMR spectroscopy, sedimentation equilibrium, and intrinsic fluorescence to monitor the reversible conformational change undergone by hLtn as a function of temperature and ionic strength. We have used two-, three- and four-dimensional NMR spectroscopy of isotopically enriched protein samples to determine structural properties of the conformational state stabilized at 45 degrees C and 0 mm NaCl. Patterns of NOEs and (1)H(alpha) and (13)C chemical shifts show that hLtn rearranges under these conditions to form a four-stranded, antiparallel beta-sheet with a pattern of hydrogen bonding that is completely different from that of the chemokine fold stabilized at 10 degrees C and 200 mm NaCl. The C-terminal alpha-helix observed at 10 degrees C and 200 mm NaCl, which is conserved in other chemokines, is absent at 45 degrees C and no salt, and the last 38 residues of the protein are completely disordered, as indicated by heteronuclear (15)N-(1)H NOEs. Temperature dependence of the tryptophan fluorescence of hLtn in low and high salt confirmed that the chemokine conformation is stabilized by increased ionic strength. Sedimentation equilibrium analytical ultracentrifugation showed that hLtn at 40 degrees C in the presence of 100 mm NaCl exists mainly as a dimer. Under near physiological conditions of temperature, pH, and ionic strength, both the chemokine-like and non-chemokine-like conformations of hLtn are significantly populated. The functional relevance of this structural interconversion remains to be elucidated.
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Affiliation(s)
- E. Sonay Kuloğlu
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Darrell R. McCaslin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
- Biophysics Instrumentation Facility, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - John L. Markley
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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20
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Bone-Larson CL, Hogaboam CM, Evanhoff H, Strieter RM, Kunkel SL. IFN-gamma-inducible protein-10 (CXCL10) is hepatoprotective during acute liver injury through the induction of CXCR2 on hepatocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:7077-83. [PMID: 11739529 DOI: 10.4049/jimmunol.167.12.7077] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IFN-gamma-inducible protein-10 (IP-10/CXCL10) is a non-ELR-CXC chemokine that is present during various forms of acute and chronic liver injury. The purpose of this study was to explore the role of IP-10 during acute liver injury induced by acetaminophen (APAP). After a 400 mg/kg APAP challenge in fasted CD-1 mice, immunoreactive levels of IP-10 were dramatically elevated in the serum within 8 h. CXCR3, the receptor for IP-10, was up-regulated in the liver. Mice that received an i.v. injection of rIP-10 10 h after APAP challenge exhibited a dramatic reduction in alanine aminotransferase 8 h later. Histologic analysis confirmed that the delayed IP-10 therapy dramatically improved the appearance of the liver when examined 48 h after APAP. The therapeutic effect of IP-10 was associated with a marked increase in CXCR2 expression on hepatocytes. Neutralization of CXCR2 during IP-10 therapy resulted in an abrogation of the hepatoprotective effect of IP-10. Furthermore, IP-10 treatment of cultured hepatocytes stimulated a CXCR2-dependent proliferative response. In conclusion, IP-10 has a hepatoregenerative effect in a murine model of acute liver injury that is dependent on its up-regulation of CXCR2 on hepatocytes.
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MESH Headings
- Acetaminophen
- Animals
- Antibodies/pharmacology
- Blotting, Western
- Cells, Cultured
- Chemokine CXCL10
- Chemokines, CXC/genetics
- Chemokines, CXC/pharmacology
- Chemokines, CXC/physiology
- Female
- Hepatocytes/drug effects
- Hepatocytes/immunology
- Immunohistochemistry
- Kinetics
- Liver Failure, Acute/chemically induced
- Liver Failure, Acute/drug therapy
- Liver Failure, Acute/immunology
- Liver Failure, Acute/pathology
- Mice
- RNA, Messenger/biosynthesis
- Receptors, Interleukin-8B/biosynthesis
- Receptors, Interleukin-8B/genetics
- Receptors, Interleukin-8B/immunology
- Up-Regulation
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Affiliation(s)
- C L Bone-Larson
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
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21
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Shao W, Fernandez E, Sachpatzidis A, Wilken J, Thompson DA, Schweitzer BI, Lolis E. CCR2 and CCR5 receptor-binding properties of herpesvirus-8 vMIP-II based on sequence analysis and its solution structure. ACTA ACUST UNITED AC 2001; 268:2948-59. [PMID: 11358512 DOI: 10.1046/j.1432-1327.2001.02184.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human herpesvirus-8 (HHV-8) is the infectious agent responsible for Kaposi's sarcoma and encodes a protein, macrophage inflammatory protein-II (vMIP-II), which shows sequence similarity to the human CC chemokines. vMIP-II has broad receptor specificity that crosses chemokine receptor subfamilies, and inhibits HIV-1 viral entry mediated by numerous chemokine receptors. In this study, the solution structure of chemically synthesized vMIP-II was determined by nuclear magnetic resonance. The protein is a monomer and possesses the chemokine fold consisting of a flexible N-terminus, three antiparallel beta strands, and a C-terminal alpha helix. Except for the N-terminal residues (residues 1-13) and the last two C-terminal residues (residues 73-74), the structure of vMIP-II is well-defined, exhibiting average rmsd of 0.35 and 0.90 A for the backbone heavy atoms and all heavy atoms of residues 14-72, respectively. Taking into account the sequence differences between the various CC chemokines and comparing their three-dimensional structures allows us to implicate residues that influence the quaternary structure and receptor binding and activation of these proteins in solution. The analysis of the sequence and three-dimensional structure of vMIP-II indicates the presence of epitopes involved in binding two receptors CCR2 and CCR5. We propose that vMIP-II was initially specific for CCR5 and acquired receptor-binding properties to CCR2 and other chemokine receptors.
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MESH Headings
- Amino Acid Sequence
- Animals
- Binding Sites
- Chemokines/chemistry
- Chemokines/metabolism
- Chemokines, CC/chemistry
- Dimerization
- Epitopes
- Magnetic Resonance Spectroscopy
- Models, Chemical
- Models, Molecular
- Molecular Sequence Data
- Peptide Biosynthesis
- Protein Binding
- Protein Conformation
- Protein Folding
- Protein Structure, Secondary
- Receptors, CCR2
- Receptors, CCR5/chemistry
- Receptors, CCR5/metabolism
- Receptors, Chemokine/chemistry
- Receptors, Chemokine/metabolism
- Sequence Analysis, Protein
- Sequence Homology, Amino Acid
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Affiliation(s)
- W Shao
- Walt Disney Memorial Cancer Institute at Florida Hospital, Orlando, FL, USA
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22
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Pérez-Cañadillas JM, Zaballos A, Gutiérrez J, Varona R, Roncal F, Albar JP, Márquez G, Bruix M. NMR solution structure of murine CCL20/MIP-3alpha, a chemokine that specifically chemoattracts immature dendritic cells and lymphocytes through its highly specific interaction with the beta-chemokine receptor CCR6. J Biol Chem 2001; 276:28372-9. [PMID: 11373289 DOI: 10.1074/jbc.m103121200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CCL20/MIP-3alpha is a beta-chemokine expressed in the thymus, skin, and intestinal epithelial cells that exclusively binds and activates the CCR6 receptor in both mice and humans. The strict receptor binding specificity of CCL20 is exceptional; other chemokines and their receptors bind promiscuously with multiple partners. Toward determining the structural basis for the selective receptor specificity of CCL20, we have determined its three-dimensional structure by 1H NMR spectroscopy. CCL20 exhibits the same monomeric structure previously described for other chemokines: a three-stranded beta-sheet and an overlying alpha-helix. The CCL20 receptor selectivity could arise from the rigid conformation of the N-terminal DCCL motif as well as the groove between the N-loop and the beta2-beta3 hairpin, which is significantly narrower in CCL20 than in other chemokines. Similar structural features are seen in human beta-defensin 2, a small nonchemokine polypeptide reported to selectively bind and activate CCR6, which stresses their importance for the specific binding of both CCL20 and beta-defensin 2 to CCR6. CCL20's structure will be useful to design tools aimed to modulate its important biological functions.
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Affiliation(s)
- J M Pérez-Cañadillas
- Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 119, 28006 Madrid, Spain
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23
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Abstract
Chemokines are a family of proteins involved in inflammatory and immune response. They share a common fold, made up of a three-stranded beta-sheet, and an overlaying alpha-helix. Chemokines are mainly categorized into two subfamilies distinguished by the presence or absence of a residue between two conserved cysteines in the N-terminus. Although dimers and higher-order quaternary structures are common in chemokines, they are known to function as monomers. Yet, there is quite a bit of controversy on how the actual function takes place. The mechanisms of binding and activation in the chemokine family are investigated using the gaussian network model of proteins, a low-resolution model that monitors the collective motions in proteins. It is particularly suitable for elucidating the global dynamic characteristics of large proteins or the common properties of a group of related proteins such as the chemokine family presently investigated. A sample of 16 proteins that belong to the CC, CXC, or CX(3)C subfamilies are inspected. Local packing density and packing order of residues are used to determine the type and range of motions on a global scale, such as those occurring between various loop regions. The 30s-loop, although not directly involved in the binding interface like the N-terminus and the N-loop, is identified as having a prominent role in both binding/activation and dimerization. Two mechanisms are distinguished based on the communication among the three flexible regions. In these two-step mechanisms, the 30s-loop assists either the N-loop or the N-terminus during binding and activation. The findings are verified by molecular mechanics and molecular dynamics simulations carried out on the detailed structure of representative proteins from each mechanism type. A basis for the construction of hybrids of chemokines to bind and/or activate various chemokine receptors is presented. Proteins 2001;43:150-160.
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Affiliation(s)
- C Baysal
- Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla 81474, Istanbul, Turkey.
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24
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Guan E, Wang J, Norcross MA. Identification of human macrophage inflammatory proteins 1alpha and 1beta as a native secreted heterodimer. J Biol Chem 2001; 276:12404-9. [PMID: 11278300 DOI: 10.1074/jbc.m006327200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chemokines are secreted proteins that function as chemoattractants for leukocytes. The chemokines macrophage inflammatory protein 1alpha and 1beta (MIP-1alpha and MIP-1beta) now have been shown to be secreted from activated human monocytes and peripheral blood lymphocytes (PBLs) as a heterodimer. Immunoprecipitation and immunoblot analysis revealed that antibodies to either MIP-1alpha or MIP-1beta precipitated a protein complex containing both MIP-1alpha and MIP-1beta under normal conditions from culture supernatants and lysates of these cells. Mass spectrometry of the complexes, precipitated from the culture supernatants of monocytes and PBLs, revealed the presence of NH(2)-terminal truncated MIP-1alpha (residues 5-70) together with either intact MIP-1beta or NH(2)-terminal truncated MIP-1beta (residues 3-69), respectively. The secreted MIP-1alpha/beta heterodimers were dissociated into their component monomers under acidic conditions. Exposure of monocytes or PBLs to monensin induced the accumulation of heterodimers composed of NH(2)-terminal truncated MIP-1alpha and full-length MIP-1beta in the Golgi complex. The mixing of recombinant chemokines in vitro demonstrated that heterodimerization of MIP-1alpha and MIP-1beta is specific and that it occurs at physiological conditions, pH 7.4, and in the range of nanomolar concentrations. The data presented here provide the first biochemical evidence for the existence of chemokine heterodimers under natural conditions. Formation of heterodimers of MIP-1alpha/beta may have an impact on intracellular signaling events that contribute to CCR5 and possibly to other chemokine receptor functions.
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Affiliation(s)
- E Guan
- Laboratory of Gene Regulation, Division of Therapeutic Proteins, Center for Biologics Evaluation and Research, Food and Drug Administration, National Institutes of Health, Bethesda, Maryland 20892, USA
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25
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Holmes WD, Consler TG, Dallas WS, Rocque WJ, Willard DH. Solution studies of recombinant human stromal-cell-derived factor-1. Protein Expr Purif 2001; 21:367-77. [PMID: 11281710 DOI: 10.1006/prep.2001.1402] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stromal-cell-derived factor-1 (SDF-1alpha) is an 8-kDa chemokine that is constitutively expressed in bone-marrow-derived stromal cells and has been identified as a ligand for the CXCR4 receptor. We produced the chemokine recombinantly as methionine-SDF-1alpha in Escherichia coli without the leader peptide sequence. The protein was denatured, refolded, and further purified by reversed-phase HPLC. SDF-1alpha was shown to be >95% pure as judged by SDS-PAGE. The final yield of purified and refolded SDF-1alpha was 1-2 mg per gram of wet cell paste. The refolded protein is a ligand for the CXCR4 receptor and has been used to block HIV-mediated cell fusion and downmodulates the CXCR4 receptor. Our ability to purify hundreds of milligrams of refolded protein allowed us to conduct detailed studies of the biophysical properties of the protein. We have used a combination of biophysical techniques to study the solution properties of SDF-1alpha. The average mass of SDF-1alpha, as determined by static light scattering, gave us the first indications that the chemokine may self-associate. Further investigation with sedimentation velocity ultracentrifugation confirmed the existence of two species. The measured s(20, W) values defined two masses corresponding to monomer and dimer. Finally, sedimentation equilibrium ultracentrifugation and dynamic light scattering yielded a composite value of 150 +/- 30 microM for the dimerization constant. We conclude that SDF-1alpha exists in a monomer-dimer equilibrium.
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Affiliation(s)
- W D Holmes
- Department of Molecular Sciences, GlaxoWellcome Research and Development, Research Triangle Park, NC 27709, USA.
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26
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Metzler DE, Metzler CM, Sauke DJ. Biochemical Defense Mechanisms. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50034-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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Biedermann T, Kneilling M, Mailhammer R, Maier K, Sander CA, Kollias G, Kunkel SL, Hültner L, Röcken M. Mast cells control neutrophil recruitment during T cell-mediated delayed-type hypersensitivity reactions through tumor necrosis factor and macrophage inflammatory protein 2. J Exp Med 2000; 192:1441-52. [PMID: 11085746 PMCID: PMC2193186 DOI: 10.1084/jem.192.10.1441] [Citation(s) in RCA: 320] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Polymorphonuclear leukocytes (PMNs) characterize the pathology of T cell-mediated autoimmune diseases and delayed-type hypersensitivity reactions (DTHRs) in the skin, joints, and gut, but are absent in T cell-mediated autoimmune diseases of the brain or pancreas. All of these reactions are mediated by interferon gamma-producing type 1 T cells and produce a similar pattern of cytokines. Thus, the cells and mediators responsible for the PMN recruitment into skin, joints, or gut during DTHRs remain unknown. Analyzing hapten-induced DTHRs of the skin, we found that mast cells determine the T cell-dependent PMN recruitment through two mediators, tumor necrosis factor (TNF) and the CXC chemokine macrophage inflammatory protein 2 (MIP-2), the functional analogue of human interleukin 8. Extractable MIP-2 protein was abundant during DTHRs in and around mast cells of wild-type (WT) mice but absent in mast cell-deficient WBB6F(1)-Kit(W)/Kit(W-)(v) (Kit(W)/Kit(W)(-v)) mice. T cell-dependent PMN recruitment was reduced >60% by anti-MIP-2 antibodies and >80% in mast cell-deficient Kit(W)/Kit(W)(-v) mice. Mast cells from WT mice efficiently restored DTHRs and MIP-2-dependent PMN recruitment in Kit(W)/Kit(W)-(v) mice, whereas mast cells from TNF(-/)- mice did not. Thus, mast cell-derived TNF and MIP-2 ultimately determine the pattern of infiltrating cells during T cell-mediated DTHRs.
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Affiliation(s)
- T Biedermann
- Department of Dermatology and Allergology, Ludwig-Maximilians-University Munich, 80337 Munich, Germany
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28
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Liwang AC, Wang ZX, Sun Y, Peiper SC, Liwang PJ. The solution structure of the anti-HIV chemokine vMIP-II. Protein Sci 1999; 8:2270-80. [PMID: 10595530 PMCID: PMC2144214 DOI: 10.1110/ps.8.11.2270] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
We report the solution structure of the chemotactic cytokine (chemokine) vMIP-II. This protein has unique biological activities in that it blocks infection by several different human immunodeficiency virus type 1 (HIV-1) strains. This occurs because vMIP-II binds to a wide range of chemokine receptors, some of which are used by HJV to gain cell entry. vMIP-II is a monomeric protein, unlike most members of the chemokine family, and its structure consists of a disordered N-terminus, followed by a helical turn (Gln25-Leu27), which leads into the first strand of a three-stranded antiparallel beta-sheet (Ser29-Thr34; Gly42-Thr47; Gln52-Asp56). Following the sheet is a C-terminal alpha-helix, which extends from residue Asp60 until Gln68. The final five residues beyond the C-terminal helix (Pro70-Arg74) are in an extended conformation, but several of these C-terminal residues contact the first beta-strand. The structure of vMIP-II is compared to other chemokines that also block infection by HIV-1, and the structural basis of its lack of ability to form a dimer is discussed.
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Affiliation(s)
- A C Liwang
- Texas A&M University, Department of Biochemistry and Biophysics, College Station 77843-2128, USA
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29
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Shao W, Fernandez E, Wilken J, Thompson DA, Siani MA, West J, Lolis E, Schweitzer BI. Accessibility of selenomethionine proteins by total chemical synthesis: structural studies of human herpesvirus-8 MIP-II. FEBS Lett 1998; 441:77-82. [PMID: 9877169 DOI: 10.1016/s0014-5793(98)01520-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The determination of high resolution three-dimensional structures by X-ray crystallography or nuclear magnetic resonance (NMR) is a time-consuming process. Here we describe an approach to circumvent the cloning and expression of a recombinant protein as well as screening for heavy atom derivatives. The selenomethionine-modified chemokine macrophage inflammatory protein-II (MIP-II) from human herpesvirus-8 has been produced by total chemical synthesis, crystallized, and characterized by NMR. The protein has a secondary structure typical of other chemokines and forms a monomer in solution. These results indicate that total chemical synthesis can be used to accelerate the determination of three-dimensional structures of new proteins identified in genome programs.
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Affiliation(s)
- W Shao
- Walt Disney Memorial Cancer Institute at Florida Hospital, Orlando 32826, USA
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