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Knapp BD, Ward MD, Bowman GR, Shi H, Huang KC. Multiple conserved states characterize the twist landscape of the bacterial actin homolog MreB. Comput Struct Biotechnol J 2022; 20:5838-5846. [PMID: 36382191 PMCID: PMC9627593 DOI: 10.1016/j.csbj.2022.10.008] [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: 08/04/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 12/01/2022] Open
Abstract
Filament formation by cytoskeletal proteins is critical to their involvement in myriad cellular processes. The bacterial actin homolog MreB, which is essential for cell-shape determination in many rod-shaped bacteria, has served as a model system for studying the mechanics of cytoskeletal filaments. Previous molecular dynamics (MD) simulations revealed that the twist of MreB double protofilaments is dependent on the bound nucleotide, as well as binding to the membrane or the accessory protein RodZ, and MreB mutations that modulate twist also affect MreB spatial organization and cell shape. Here, we show that MreB double protofilaments can adopt multiple twist states during microsecond-scale MD simulations. A deep learning algorithm trained only on high- and low-twist states robustly identified all twist conformations across most perturbations of ATP-bound MreB, suggesting the existence of a conserved set of states whose occupancy is affected by each perturbation to MreB. Simulations replacing ATP with ADP indicated that twist states were generally stable after hydrolysis. These findings suggest a rich twist landscape that could provide the capacity to tune MreB activity and therefore its effects on cell shape.
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Affiliation(s)
| | - Michael D. Ward
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63130, USA
- Center for the Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Gregory R. Bowman
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63130, USA
- Center for the Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Corresponding authors at: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Kerwyn Casey Huang
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
- Corresponding authors at: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Jørgensen AS, Brandum EP, Mikkelsen JM, Orfin KA, Boilesen DR, Egerod KL, Moussouras NA, Vilhardt F, Kalinski P, Basse P, Chen YH, Yang Z, Dwinell MB, Volkman BF, Veldkamp CT, Holst PJ, Lahl K, Goth CK, Rosenkilde MM, Hjortø GM. The C-terminal peptide of CCL21 drastically augments CCL21 activity through the dendritic cell lymph node homing receptor CCR7 by interaction with the receptor N-terminus. Cell Mol Life Sci 2021; 78:6963-6978. [PMID: 34586443 PMCID: PMC8558179 DOI: 10.1007/s00018-021-03930-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 08/04/2021] [Accepted: 08/20/2021] [Indexed: 12/11/2022]
Abstract
The endogenous chemokines CCL19 and CCL21 signal via their common receptor CCR7. CCL21 is the main lymph node homing chemokine, but a weak chemo-attractant compared to CCL19. Here we show that the 41-amino acid positively charged peptide, released through C-terminal cleavage of CCL21, C21TP, boosts the immune cell recruiting activity of CCL21 by up to 25-fold and the signaling activity via CCR7 by ~ 100-fold. Such boosting is unprecedented. Despite the presence of multiple basic glycosaminoglycan (GAG) binding motifs, C21TP boosting of CCL21 signaling does not involve interference with GAG mediated cell-surface retention. Instead, boosting is directly dependent on O-glycosylations in the CCR7 N-terminus. As dictated by the two-step binding model, the initial chemokine binding involves interaction of the chemokine fold with the receptor N-terminus, followed by insertion of the chemokine N-terminus deep into the receptor binding pocket. Our data suggest that apart from a role in initial chemokine binding, the receptor N-terminus also partakes in a gating mechanism, which could give rise to a reduced ligand activity, presumably through affecting the ligand positioning. Based on experiments that support a direct interaction of C21TP with the glycosylated CCR7 N-terminus, we propose that electrostatic interactions between the positively charged peptide and sialylated O-glycans in CCR7 N-terminus may create a more accessible version of the receptor and thus guide chemokine docking to generate a more favorable chemokine-receptor interaction, giving rise to the peptide boosting effect.
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Affiliation(s)
- Astrid Sissel Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Room 18.5.32., 2200, Copenhagen, Denmark
| | - Emma Probst Brandum
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Room 18.5.32., 2200, Copenhagen, Denmark
| | - Jeppe Malthe Mikkelsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Room 18.5.32., 2200, Copenhagen, Denmark
| | - Klaudia A Orfin
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Ditte Rahbæk Boilesen
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer Lihme Egerod
- Novo Nordisk Foundation, Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Natasha A Moussouras
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Frederik Vilhardt
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Pawel Kalinski
- Department of Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Per Basse
- Department of Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - Yen-Hsi Chen
- Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
| | - Zhang Yang
- Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen, Denmark
| | - Michael B Dwinell
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Peter Johannes Holst
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Katharina Lahl
- Immunology Section, Lund University, 221 84, Lund, Sweden
- Section for Experimental and Translational Immunology, Department of Health Technology, Technical University of Denmark (DTU), Lyngby, Denmark
| | - Christoffer Knak Goth
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Room 18.5.32., 2200, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Room 18.5.32., 2200, Copenhagen, Denmark
| | - Gertrud Malene Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, Room 18.5.32., 2200, Copenhagen, Denmark.
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Jørgensen AS, Larsen O, Uetz-von Allmen E, Lückmann M, Legler DF, Frimurer TM, Veldkamp CT, Hjortø GM, Rosenkilde MM. Biased Signaling of CCL21 and CCL19 Does Not Rely on N-Terminal Differences, but Markedly on the Chemokine Core Domains and Extracellular Loop 2 of CCR7. Front Immunol 2019; 10:2156. [PMID: 31572374 PMCID: PMC6753178 DOI: 10.3389/fimmu.2019.02156] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/28/2019] [Indexed: 12/27/2022] Open
Abstract
Chemokine receptors play important roles in the immune system and are linked to several human diseases. Targeting chemokine receptors have so far shown very little success owing to, to some extent, the promiscuity of the immune system and the high degree of biased signaling within it. CCR7 and its two endogenous ligands display biased signaling and here we investigate the differences between the two ligands, CCL21 and CCL19, with respect to their biased activation of CCR7. We use bystander bioluminescence resonance energy transfer (BRET) based signaling assays and Transwell migration assays to determine (A) how swapping of domains between the two ligands affect their signaling patterns and (B) how receptor mutagenesis impacts signaling. Using chimeric ligands we find that the chemokine core domains are central for determining signaling outcome as the lack of β-arrestin-2 recruitment displayed by CCL21 is linked to its core domain and not N-terminus. Through a mutagenesis screen, we identify the extracellular domains of CCR7 to be important for both ligands and show that the two chemokines interact differentially with extracellular loop 2 (ECL-2). By using in silico modeling, we propose a link between ECL-2 interaction and CCR7 signal transduction. Our mutagenesis study also suggests a lysine in the top of TM3, K1303.26, to be important for G protein signaling, but not β-arrestin-2 recruitment. Taken together, the bias in CCR7 between CCL19 and CCL21 relies on the chemokine core domains, where interactions with ECL-2 seem particularly important. Moreover, TM3 selectively regulates G protein signaling as found for other chemokine receptors.
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Affiliation(s)
- Astrid S Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Olav Larsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Edith Uetz-von Allmen
- Biotechnology Institute Thurgau (BITg), University of Konstanz, Kreuzlingen, Switzerland
| | - Michael Lückmann
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg), University of Konstanz, Kreuzlingen, Switzerland
| | - Thomas M Frimurer
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Christopher T Veldkamp
- Department of Chemistry, University of Wisconsin-Whitewater, Whitewater, WI, United States
| | - Gertrud M Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Jørgensen AS, Adogamhe PE, Laufer JM, Legler DF, Veldkamp CT, Rosenkilde MM, Hjortø GM. CCL19 with CCL21-tail displays enhanced glycosaminoglycan binding with retained chemotactic potency in dendritic cells. J Leukoc Biol 2018; 104:401-411. [PMID: 29768676 DOI: 10.1002/jlb.2vma0118-008r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 12/23/2022] Open
Abstract
CCL19 is more potent than CCL21 in inducing chemotaxis of human dendritic cells (DC). This difference is attributed to 1) a stronger interaction of the basic C-terminal tail of CCL21 with acidic glycosaminoglycans (GAGs) in the environment and 2) an autoinhibitory function of this C-terminal tail. Moreover, different receptor docking modes and tissue expression patterns of CCL19 and CCL21 contribute to fine-tuned control of CCR7 signaling. Here, we investigate the effect of the tail of CCL21 on chemokine binding to GAGs and on CCR7 activation. We show that transfer of CCL21-tail to CCL19 (CCL19CCL21-tail ) markedly increases binding of CCL19 to human dendritic cell surfaces, without impairing CCL19-induced intracellular calcium release or DC chemotaxis, although it causes reduced CCR7 internalization. The more potent chemotaxis induced by CCL19 and CCL19CCL21-tail compared to CCL21 is not transferred to CCL21 by replacing its N-terminus with that of CCL19 (CCL21CCL19-N-term ). Measurements of cAMP production in CHO cells uncover that CCL21-tail transfer (CCL19CCL21-tail ) negatively affects CCL19 potency, whereas removal of CCL21-tail (CCL21tailless ) increases signaling compared to full-length CCL21, indicating that the tail negatively affects signaling via cAMP. Similar to chemokine-driven calcium mobilization and chemotaxis, the potency of CCL21 in cAMP is not improved by transfer of the CCL19 N-terminus to CCL21 (CCL21CCL19-N-term ). Together these results indicate that ligands containing CCL21 core and C-terminal tail (CCL21 and CCL21CCL19-N-term ) are most restricted in their cAMP signaling; a phenotype attributed to a stronger GAG binding of CCL21 and defined structural differences between CCL19 and CCL21.
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Affiliation(s)
- Astrid S Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Pontian E Adogamhe
- Department of Chemistry, University of Wisconsin-Whitewater, Whitewater, Wisconsin, USA
| | - Julia M Laufer
- Biotechnology Institute Thurgau (BITg), at the University of Konstanz, Kreuzlingen, Switzerland
| | - Daniel F Legler
- Biotechnology Institute Thurgau (BITg), at the University of Konstanz, Kreuzlingen, Switzerland
| | | | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Gertrud M Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
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Jørgensen AS, Rosenkilde MM, Hjortø GM. Biased signaling of G protein-coupled receptors - From a chemokine receptor CCR7 perspective. Gen Comp Endocrinol 2018; 258:4-14. [PMID: 28694053 DOI: 10.1016/j.ygcen.2017.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/03/2017] [Accepted: 07/06/2017] [Indexed: 12/22/2022]
Abstract
Chemokines (chemotactic cytokines) and their associated G protein-coupled receptors (GPCRs) work in a concerted manner to govern immune cell positioning in time and space. Promiscuity of both ligands and receptors, but also biased signaling within the chemokine system, adds to the complexity of how the cell-based immune system is controlled. Bias comes in three forms; ligand-, receptor- and tissue-bias. Biased signaling is increasingly being recognized as playing an important role in contributing to the fine-tuned coordination of immune cell chemotaxis. In the current review we discuss the recent findings related to ligand- and tissue-biased signaling of CCR7 and summarize what is known about bias at other chemokine receptors. CCR7 is expressed by a subset of T-cells and by mature dendritic cells (DCs). Together with its two endogenous ligands CCL19 and CCL21, of which the carboxy terminal tail of CCL21 displays an extraordinarily strong glycosaminoglycan (GAG) binding, CCR7 plays a central role in coordinating the meeting between mature antigen presenting DCs and naïve T-cells which normally takes place in the lymph nodes (LNs). This process is a prerequisite for the initiation of an antigen-specific T-cell mediated immune response. Thus CCR7 and its ligands are key players in initiating cell-based immune responses. CCL19 and CCL21 display differential interaction- and docking-modes for CCR7 leading to stabilization of different CCR7 conformations and hereby preferential activation of distinct intracellular signaling pathways (i.e. ligand bias). In general CCL19 seems to generate a strong temporal signal, whereas CCL21 generates a weaker, but more persistent signal. Tissue differential expression of these two ligands, and the generation of a third ligand "tailless-CCL21", through DC specific protease activity (tissue bias), orchestrates DC and T-cell LN homing and priming, with each ligand serving overlapping, but also distinct roles.
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Affiliation(s)
- Astrid Sissel Jørgensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Gertrud M Hjortø
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.
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