1
|
Narayanan KK, Amaya M, Tsang N, Yin R, Jays A, Broder CC, Shukla D, Procko E. Sequence basis for selectivity of ephrin-B2 ligand for Eph receptors and pathogenic henipavirus G glycoproteins. J Virol 2023; 97:e0062123. [PMID: 37931130 PMCID: PMC10688352 DOI: 10.1128/jvi.00621-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/13/2023] [Indexed: 11/08/2023] Open
Abstract
IMPORTANCE Ephrin-B2 (EFNB2) is a ligand for six Eph receptors in humans and regulates multiple cell developmental and signaling processes. It also functions as the cell entry receptor for Nipah virus and Hendra virus, zoonotic viruses that can cause respiratory and/or neurological symptoms in humans with high mortality. Here, we investigate the sequence basis of EFNB2 specificity for binding the Nipah virus attachment G glycoprotein over Eph receptors. We then use this information to engineer EFNB2 as a soluble decoy receptor that specifically binds the attachment glycoproteins of the Nipah virus and other related henipaviruses to neutralize infection. These findings further mechanistic understanding of protein selectivity and may facilitate the development of diagnostics or therapeutics against henipavirus infection.
Collapse
Affiliation(s)
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - Natalie Tsang
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | - Randy Yin
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Alka Jays
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois, USA
- Cancer Center at Illinois, University of Illinois, Urbana, Illinois, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
- Cancer Center at Illinois, University of Illinois, Urbana, Illinois, USA
- Cyrus Biotechnology, Seattle, Washington, USA
| |
Collapse
|
2
|
Gill KS, Mehta K, Heredia JD, Krishnamurthy VV, Zhang K, Procko E. Multiple mechanisms of self-association of chemokine receptors CXCR4 and CCR5 demonstrated by deep mutagenesis. J Biol Chem 2023; 299:105229. [PMID: 37690681 PMCID: PMC10551899 DOI: 10.1016/j.jbc.2023.105229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 08/24/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023] Open
Abstract
Chemokine receptors are members of the rhodopsin-like class A GPCRs whose signaling through G proteins drives the directional movement of cells in response to a chemokine gradient. Chemokine receptors CXCR4 and CCR5 have been extensively studied due to their roles in leukocyte development and inflammation and their status as coreceptors for HIV-1 infection, among other roles. Both receptors form dimers or oligomers of unclear function. While CXCR4 has been crystallized in a dimeric arrangement, available atomic resolution structures of CCR5 are monomeric. To investigate their dimerization interfaces, we used a bimolecular fluorescence complementation (BiFC)-based screen and deep mutational scanning to find mutations that change how the receptors self-associate, either via specific oligomer assembly or alternative mechanisms of clustering in close proximity. Many disruptive mutations promoted self-associations nonspecifically, suggesting they aggregated in the membrane. A mutationally intolerant region was found on CXCR4 that matched the crystallographic dimer interface, supporting this dimeric arrangement in living cells. A mutationally intolerant region was also observed on the surface of CCR5 by transmembrane helices 3 and 4. Mutations predicted from the scan to reduce BiFC were validated and were localized in the transmembrane domains as well as the C-terminal cytoplasmic tails where they reduced lipid microdomain localization. A mutation in the dimer interface of CXCR4 had increased binding to the ligand CXCL12 and yet diminished calcium signaling. There was no change in syncytia formation with cells expressing HIV-1 Env. The data highlight that multiple mechanisms are involved in self-association of chemokine receptor chains.
Collapse
Affiliation(s)
- Kevin S Gill
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | - Kritika Mehta
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | - Jeremiah D Heredia
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | | | - Kai Zhang
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, Illinois, USA; Cyrus Biotechnology, Seattle, Washington, USA.
| |
Collapse
|
3
|
Havranek B, Lindsey GW, Higuchi Y, Itoh Y, Suzuki T, Okamoto T, Hoshino A, Procko E, Islam SM. A computationally designed ACE2 decoy has broad efficacy against SARS-CoV-2 omicron variants and related viruses in vitro and in vivo. Commun Biol 2023; 6:513. [PMID: 37173421 PMCID: PMC10177734 DOI: 10.1038/s42003-023-04860-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023] Open
Abstract
SARS-CoV-2, especially B.1.1.529/omicron and its sublineages, continues to mutate to evade monoclonal antibodies and antibodies elicited by vaccination. Affinity-enhanced soluble ACE2 (sACE2) is an alternative strategy that works by binding the SARS-CoV-2 S protein, acting as a 'decoy' to block the interaction between the S and human ACE2. Using a computational design strategy, we designed an affinity-enhanced ACE2 decoy, FLIF, that exhibited tight binding to SARS-CoV-2 delta and omicron variants. Our computationally calculated absolute binding free energies (ABFE) between sACE2:SARS-CoV-2 S proteins and their variants showed excellent agreement to binding experiments. FLIF displayed robust therapeutic utility against a broad range of SARS-CoV-2 variants and sarbecoviruses, and neutralized omicron BA.5 in vitro and in vivo. Furthermore, we directly compared the in vivo therapeutic efficacy of wild-type ACE2 (non-affinity enhanced ACE2) against FLIF. A few wild-type sACE2 decoys have shown to be effective against early circulating variants such as Wuhan in vivo. Our data suggest that moving forward, affinity-enhanced ACE2 decoys like FLIF may be required to combat evolving SARS-CoV-2 variants. The approach described herein emphasizes how computational methods have become sufficiently accurate for the design of therapeutics against viral protein targets. Affinity-enhanced ACE2 decoys remain highly effective at neutralizing omicron subvariants.
Collapse
Affiliation(s)
- Brandon Havranek
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, 19107, USA
- ComputePharma, LLC., Chicago, IL, USA
| | | | - Yusuke Higuchi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Yumi Itoh
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Tatsuya Suzuki
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Toru Okamoto
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Atsushi Hoshino
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, IL, 61801, USA
- Cyrus Biotechnology, Inc., Seattle, WA, USA
| | - Shahidul M Islam
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, 60607, USA.
- ComputePharma, LLC., Chicago, IL, USA.
- Department of Chemistry, Delaware State University, Dover, DE, 19901, USA.
| |
Collapse
|
4
|
Narayanan KK, Amaya M, Tsang N, Yin R, Jays A, Broder CC, Shukla D, Procko E. The Sequence Basis for Selectivity of Ephrin-B2 Ligand for Eph Receptors and Pathogenic Henipavirus G Glycoproteins: Selective Ephrin-B2 Decoys for Nipah and Hendra Virus. bioRxiv 2023:2023.04.26.538420. [PMID: 37162958 PMCID: PMC10168364 DOI: 10.1101/2023.04.26.538420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Ephrin-B2 (EFNB2) is a ligand for six Eph receptors in humans and functions as a cell entry receptor for several henipaviruses including Nipah virus (NiV), a pathogenic zoonotic virus with pandemic potential. To understand the sequence basis of promiscuity for EFNB2 binding to the attachment glycoprotein of NiV (NiV-G) and Eph receptors, we performed deep mutagenesis on EFNB2 to identify mutations that enhance binding to NiV-G over EphB2, one of the highest affinity Eph receptors. The mutations highlight how different EFNB2 conformations are selected by NiV-G versus EphB2. Specificity mutations are enriched at the base of the G-H binding loop of EFNB2, especially surrounding a phenylalanine hinge upon which the G-H loop pivots, and at a phenylalanine hook that rotates away from the EFNB2 core to engage Eph receptors. One EFNB2 mutant, D62Q, possesses pan-specificity to the attachment glycoproteins of closely related henipaviruses and has markedly diminished binding to the six Eph receptors. However, EFNB2-D62Q has high residual binding to EphB3 and EphB4. A second deep mutational scan of EFNB2 identified combinatorial mutations to further enhance specificity to NiV-G. A triple mutant of soluble EFNB2, D62Q-Q130L-V167L, has minimal binding to Eph receptors but maintains binding, albeit reduced, to NiV-G. Soluble EFNB2 decoy receptors carrying the specificity mutations were potent neutralizers of chimeric henipaviruses. These findings demonstrate how specific residue changes at the shared binding interface of a promiscuous ligand (EFNB2) can influence selectivity for multiple receptors, and may also offer insight towards the development of henipavirus therapeutics and diagnostics.
Collapse
Affiliation(s)
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
| | - Natalie Tsang
- Department of Biochemistry, University of Illinois, Urbana IL, USA
| | - Randy Yin
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda MD, USA
| | - Alka Jays
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda MD, USA
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda MD, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, USA
- Cancer Center at Illinois, University of Illinois, Urbana IL, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana IL, USA
- Cancer Center at Illinois, University of Illinois, Urbana IL, USA
- Cyrus Biotechnology, Seattle WA, USA
| |
Collapse
|
5
|
Gill KS, Mehta K, Heredia JD, Krishnamurthy VV, Zhang K, Procko E. Multiple mechanisms of self-association of chemokine receptors CXCR4 and CCR5 demonstrated by deep mutagenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.25.534231. [PMID: 36993221 PMCID: PMC10055436 DOI: 10.1101/2023.03.25.534231] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Chemokine receptors are members of the rhodopsin-like class A GPCRs whose signaling through G proteins drives the directional movement of cells in response to a chemokine gradient. Chemokine receptors CXCR4 and CCR5 have been extensively studied due to their roles in white blood cell development and inflammation and their status as coreceptors for HIV-1 infection, among other functions. Both receptors form dimers or oligomers but the function/s of self-associations are unclear. While CXCR4 has been crystallized in a dimeric arrangement, available atomic resolution structures of CCR5 are monomeric. To investigate the dimerization interfaces of these chemokine receptors, we used a bimolecular fluorescence complementation (BiFC)-based screen and deep mutational scanning to find mutations that modify receptor self-association. Many disruptive mutations promoted self-associations nonspecifically, suggesting they aggregated in the membrane. A mutationally intolerant region was found on CXCR4 that matched the crystallographic dimer interface, supporting this dimeric arrangement in living cells. A mutationally intolerant region was also observed on the surface of CCR5 by transmembrane helices 3 and 4. Mutations from the deep mutational scan that reduce BiFC were validated and were localized in the transmembrane domains as well as the C-terminal cytoplasmic tails where they reduced lipid microdomain localization. The reduced self-association mutants of CXCR4 had increased binding to the ligand CXCL12 but diminished calcium signaling. There was no change in syncytia formation with cells expressing HIV-1 Env. The data highlight that multiple mechanisms are involved in self-association of chemokine receptor chains.
Collapse
Affiliation(s)
- Kevin S Gill
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Kritika Mehta
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Jeremiah D Heredia
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
- Current affiliation: Codexis, Redwood City, CA 94063
| | | | - Kai Zhang
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
- Cyrus Biotechnology, Seattle, WA 98121, USA
| |
Collapse
|
6
|
Chan MC, Chan KK, Procko E, Shukla D. Machine Learning Guided Design of High-Affinity ACE2 Decoys for SARS-CoV-2 Neutralization. J Phys Chem B 2023; 127:1995-2001. [PMID: 36827526 PMCID: PMC9999943 DOI: 10.1021/acs.jpcb.3c00469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/03/2023] [Indexed: 02/26/2023]
Abstract
A potential therapeutic strategy for neutralizing SARS-CoV-2 infection is engineering high-affinity soluble ACE2 decoy proteins to compete for binding to the viral spike (S) protein. Previously, a deep mutational scan of ACE2 was performed and has led to the identification of a triple mutant variant, named sACE22.v.2.4, that exhibits subnanomolar affinity to the receptor-binding domain (RBD) of S. Using a recently developed transfer learning algorithm, TLmutation, we sought to identify other ACE2 variants that may exhibit similar binding affinity with decreased mutational load. Upon training a TLmutation model on the effects of single mutations, we identified multiple ACE2 double mutants that bind SARS-CoV-2 S with tighter affinity as compared to the wild type, most notably L79V;N90D that binds RBD similarly to ACE22.v.2.4. The experimental validation of the double mutants successfully demonstrates the use of machine learning approaches for engineering protein-protein interactions and identifying high-affinity ACE2 peptides for targeting SARS-CoV-2.
Collapse
Affiliation(s)
- Matthew C. Chan
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61081, USA
| | - Kui. K. Chan
- Cyrus Biotechnology, Inc., Seattle, WA, 98101, USA
| | - Erik Procko
- Cyrus Biotechnology, Inc., Seattle, WA, 98101, USA
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61081, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61081, USA
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL 61081, USA
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL 61081, USA
| |
Collapse
|
7
|
Sun Y, Papadaki GF, Devlin CA, Danon JN, Young MC, Winters TJ, Burslem GM, Procko E, Sgourakis NG. Xeno interactions between MHC-I proteins and molecular chaperones enable ligand exchange on a broad repertoire of HLA allotypes. Sci Adv 2023; 9:eade7151. [PMID: 36827371 PMCID: PMC9956121 DOI: 10.1126/sciadv.ade7151] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/19/2023] [Indexed: 06/01/2023]
Abstract
Immunological chaperones tapasin and TAP binding protein, related (TAPBPR) play key roles in antigenic peptide optimization and quality control of nascent class I major histocompatibility complex (MHC-I) molecules. The polymorphic nature of MHC-I proteins leads to a range of allelic dependencies on chaperones for assembly and cell-surface expression, limiting chaperone-mediated peptide exchange to a restricted set of human leukocyte antigen (HLA) allotypes. Here, we demonstrate and characterize xeno interactions between a chicken TAPBPR ortholog and a complementary repertoire of HLA allotypes, relative to its human counterpart. We find that TAPBPR orthologs recognize empty MHC-I with broader allele specificity and facilitate peptide exchange by maintaining a reservoir of receptive molecules. Deep mutational scanning of human TAPBPR further identifies gain-of-function mutants, resembling the chicken sequence, which can enhance HLA-A*01:01 expression in situ and promote peptide exchange in vitro. These results highlight that polymorphic sites on MHC-I and chaperone surfaces can be engineered to manipulate their interactions, enabling chaperone-mediated peptide exchange on disease-relevant HLA alleles.
Collapse
Affiliation(s)
- Yi Sun
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Georgia F. Papadaki
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Christine A. Devlin
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61820, USA
| | - Julia N. Danon
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Michael C. Young
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - Trenton J. Winters
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
| | - George M. Burslem
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
- Department of Cancer Biology and Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61820, USA
| | - Nikolaos G. Sgourakis
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3501 Civic Center Blvd., Philadelphia, PA 19104, USA
| |
Collapse
|
8
|
Zhang L, Narayanan KK, Cooper L, Chan KK, Skeeters SS, Devlin CA, Aguhob A, Shirley K, Rong L, Rehman J, Malik AB, Procko E. An ACE2 decoy can be administered by inhalation and potently targets omicron variants of SARS-CoV-2. EMBO Mol Med 2022. [PMID: 36094679 DOI: 10.1101/2022.03.28.486075v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Monoclonal antibodies targeting the SARS-CoV-2 spike (S) neutralize infection and are efficacious for the treatment of COVID-19. However, SARS-CoV-2 variants, notably sublineages of B.1.1.529/omicron, have emerged that escape antibodies in clinical use. As an alternative, soluble decoy receptors based on the host entry receptor ACE2 broadly bind and block S from SARS-CoV-2 variants and related betacoronaviruses. The high-affinity and catalytically active decoy sACE22 .v2.4-IgG1 was previously shown to be effective against SARS-CoV-2 variants when administered intravenously. Here, inhalation of aerosolized sACE22 .v2.4-IgG1 increased survival and ameliorated lung injury in K18-hACE2 mice inoculated with P.1/gamma virus. Loss of catalytic activity reduced the decoy's therapeutic efficacy, which was further confirmed by intravenous administration, supporting dual mechanisms of action: direct blocking of S and turnover of ACE2 substrates associated with lung injury and inflammation. Furthermore, sACE22 .v2.4-IgG1 tightly binds and neutralizes BA.1, BA.2, and BA.4/BA.5 omicron and protects K18-hACE2 mice inoculated with a high dose of BA.1 omicron virus. Overall, the therapeutic potential of sACE22 .v2.4-IgG1 is demonstrated by the inhalation route and broad neutralization potency persists against highly divergent SARS-CoV-2 variants.
Collapse
Affiliation(s)
- Lianghui Zhang
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL, USA
| | | | - Laura Cooper
- Department of Microbiology and Immunology, The University of Illinois College of Medicine, Chicago, IL, USA
| | - Kui K Chan
- Cyrus Biotechnology, Inc., Seattle, WA, USA
| | | | | | | | | | - Lijun Rong
- Department of Microbiology and Immunology, The University of Illinois College of Medicine, Chicago, IL, USA
| | - Jalees Rehman
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL, USA
- Department of Biochemistry and Molecular Genetics, The University of Illinois College of Medicine, Chicago, IL, USA
| | - Asrar B Malik
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
- Cyrus Biotechnology, Inc., Seattle, WA, USA
| |
Collapse
|
9
|
Zhang L, Narayanan KK, Cooper L, Chan KK, Skeeters SS, Devlin CA, Aguhob A, Shirley K, Rong L, Rehman J, Malik AB, Procko E. An ACE2 decoy can be administered by inhalation and potently targets omicron variants of SARS-CoV-2. EMBO Mol Med 2022; 14:e16109. [PMID: 36094679 PMCID: PMC9539395 DOI: 10.15252/emmm.202216109] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/09/2022] Open
Abstract
Monoclonal antibodies targeting the SARS-CoV-2 spike (S) neutralize infection and are efficacious for the treatment of COVID-19. However, SARS-CoV-2 variants, notably sublineages of B.1.1.529/omicron, have emerged that escape antibodies in clinical use. As an alternative, soluble decoy receptors based on the host entry receptor ACE2 broadly bind and block S from SARS-CoV-2 variants and related betacoronaviruses. The high-affinity and catalytically active decoy sACE22 .v2.4-IgG1 was previously shown to be effective against SARS-CoV-2 variants when administered intravenously. Here, inhalation of aerosolized sACE22 .v2.4-IgG1 increased survival and ameliorated lung injury in K18-hACE2 mice inoculated with P.1/gamma virus. Loss of catalytic activity reduced the decoy's therapeutic efficacy, which was further confirmed by intravenous administration, supporting dual mechanisms of action: direct blocking of S and turnover of ACE2 substrates associated with lung injury and inflammation. Furthermore, sACE22 .v2.4-IgG1 tightly binds and neutralizes BA.1, BA.2, and BA.4/BA.5 omicron and protects K18-hACE2 mice inoculated with a high dose of BA.1 omicron virus. Overall, the therapeutic potential of sACE22 .v2.4-IgG1 is demonstrated by the inhalation route and broad neutralization potency persists against highly divergent SARS-CoV-2 variants.
Collapse
Affiliation(s)
- Lianghui Zhang
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular BiologyThe University of Illinois College of MedicineChicagoILUSA
- Present address:
Division of Pulmonary, Allergy and Critical Care Medicine, Department of MedicineUniversity of Pittsburgh Medical CenterPittsburghPAUSA
| | | | - Laura Cooper
- Department of Microbiology and ImmunologyThe University of Illinois College of MedicineChicagoILUSA
| | | | | | | | | | | | - Lijun Rong
- Department of Microbiology and ImmunologyThe University of Illinois College of MedicineChicagoILUSA
| | - Jalees Rehman
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular BiologyThe University of Illinois College of MedicineChicagoILUSA
- Department of Biochemistry and Molecular GeneticsThe University of Illinois College of MedicineChicagoILUSA
| | - Asrar B Malik
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular BiologyThe University of Illinois College of MedicineChicagoILUSA
| | - Erik Procko
- Department of BiochemistryUniversity of IllinoisUrbanaILUSA
- Cyrus Biotechnology, Inc.SeattleWAUSA
| |
Collapse
|
10
|
McShan AC, Devlin CA, Papadaki GF, Sun Y, Green AI, Morozov GI, Burslem GM, Procko E, Sgourakis NG. TAPBPR employs a ligand-independent docking mechanism to chaperone MR1 molecules. Nat Chem Biol 2022; 18:859-868. [PMID: 35725941 PMCID: PMC9703140 DOI: 10.1038/s41589-022-01049-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 04/28/2022] [Indexed: 11/08/2022]
Abstract
Chaperones tapasin and transporter associated with antigen processing (TAP)-binding protein related (TAPBPR) associate with the major histocompatibility complex (MHC)-related protein 1 (MR1) to promote trafficking and cell surface expression. However, the binding mechanism and ligand dependency of MR1/chaperone interactions remain incompletely characterized. Here in vitro, biochemical and computational studies reveal that, unlike MHC-I, TAPBPR recognizes MR1 in a ligand-independent manner owing to the absence of major structural changes in the MR1 α2-1 helix between empty and ligand-loaded molecules. Structural characterization using paramagnetic nuclear magnetic resonance experiments combined with restrained molecular dynamics simulations reveals that TAPBPR engages conserved surfaces on MR1 to induce similar adaptations to those seen in MHC-I/TAPBPR co-crystal structures. Finally, nuclear magnetic resonance relaxation dispersion experiments using 19F-labeled diclofenac show that TAPBPR can affect the exchange kinetics of noncovalent metabolites with the MR1 groove, serving as a catalyst. Our results support a role of chaperones in stabilizing nascent MR1 molecules to enable loading of endogenous or exogenous cargo.
Collapse
Affiliation(s)
- Andrew C McShan
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christine A Devlin
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Georgia F Papadaki
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi Sun
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Adam I Green
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Giora I Morozov
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - George M Burslem
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Cancer Biology and Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
11
|
Chan MC, Procko E, Shukla D. Structural Rearrangement of the Serotonin Transporter Intracellular Gate Induced by Thr276 Phosphorylation. ACS Chem Neurosci 2022; 13:933-945. [PMID: 35258286 DOI: 10.1021/acschemneuro.1c00714] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The reuptake of the neurotransmitter serotonin from the synaptic cleft by the serotonin transporter, SERT, is essential for proper neurological signaling. Biochemical studies have shown that Thr276 of transmembrane helix 5 is a site of PKG-mediated SERT phosphorylation, which has been proposed to shift the SERT conformational equilibria to promote inward-facing states, thus enhancing 5-HT transport. Recent structural and simulation studies have provided insights into the conformation transitions during substrate transport but have not shed light on SERT regulation via post-translational modifications. Using molecular dynamics simulations and Markov state models, we investigate how Thr276 phosphorylation impacts the SERT mechanism and its role in enhancing transporter stability and function. Our simulations show that Thr276 phosphorylation alters the hydrogen-bonding network involving residues on transmembrane helix 5. This in turn decreases the free energy barriers for SERT to transition to the inward-facing state, thus facilitating 5-HT import. The results provide atomistic insights into in vivo SERT regulation and can be extended to other pharmacologically important transporters in the solute carrier family.
Collapse
Affiliation(s)
- Matthew C. Chan
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Erik Procko
- Department of Biochemistry, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Neuroscience Program, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Cancer Center at Illinois, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Cancer Center at Illinois, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- National Center for Supercomputing Applications, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
- Department of Bioengineering, University of Illinois Urbana−Champaign, Urbana, Illinois 61801, United States
| |
Collapse
|
12
|
Zhang L, Narayanan KK, Cooper L, Chan KK, Devlin CA, Aguhob A, Shirley K, Rong L, Rehman J, Malik AB, Procko E. An engineered ACE2 decoy receptor can be administered by inhalation and potently targets the BA.1 and BA.2 omicron variants of SARS-CoV-2. bioRxiv 2022. [PMID: 35378764 PMCID: PMC8978935 DOI: 10.1101/2022.03.28.486075] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Monoclonal antibodies targeting the SARS-CoV-2 spike (S) glycoprotein neutralize infection and are efficacious for the treatment of mild-to-moderate COVID-19. However, SARS-CoV-2 variants have emerged that partially or fully escape monoclonal antibodies in clinical use. Notably, the BA.2 sublineage of B.1.1.529/omicron escapes nearly all monoclonal antibodies currently authorized for therapeutic treatment of COVID-19. Decoy receptors, which are based on soluble forms of the host entry receptor ACE2, are an alternative strategy that broadly bind and block S from SARS-CoV-2 variants and related betacoronaviruses. The high-affinity and catalytically active decoy sACE22.v2.4-IgG1 was previously shown to be effective in vivo against SARS-CoV-2 variants when administered intravenously. Here, the inhalation of sACE22.v2.4-IgG1 is found to increase survival and ameliorate lung injury in K18-hACE2 transgenic mice inoculated with a lethal dose of the virulent P.1/gamma virus. Loss of catalytic activity reduced the decoy’s therapeutic efficacy supporting dual mechanisms of action: direct blocking of viral S and turnover of ACE2 substrates associated with lung injury and inflammation. Binding of sACE22.v2.4-IgG1 remained tight to S of BA.1 omicron, despite BA.1 omicron having extensive mutations, and binding exceeded that of four monoclonal antibodies approved for clinical use. BA.1 pseudovirus and authentic virus were neutralized at picomolar concentrations. Finally, tight binding was maintained against S from the BA.2 omicron sublineage, which differs from S of BA.1 by 26 mutations. Overall, the therapeutic potential of sACE22.v2.4-IgG1 is further confirmed by inhalation route and broad neutralization potency persists against increasingly divergent SARS-CoV-2 variants.
Collapse
|
13
|
Zhang L, Dutta S, Xiong S, Chan M, Chan KK, Fan TM, Bailey KL, Lindeblad M, Cooper LM, Rong L, Gugliuzza AF, Shukla D, Procko E, Rehman J, Malik AB. Engineered ACE2 decoy mitigates lung injury and death induced by SARS-CoV-2 variants. Nat Chem Biol 2022; 18:342-351. [PMID: 35046611 PMCID: PMC8885411 DOI: 10.1038/s41589-021-00965-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 12/16/2021] [Indexed: 12/15/2022]
Abstract
Vaccine hesitancy and emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) escaping vaccine-induced immune responses highlight the urgency for new COVID-19 therapeutics. Engineered angiotensin-converting enzyme 2 (ACE2) proteins with augmented binding affinities for SARS-CoV-2 spike (S) protein may prove to be especially efficacious against multiple variants. Using molecular dynamics simulations and functional assays, we show that three amino acid substitutions in an engineered soluble ACE2 protein markedly augmented the affinity for the S protein of the SARS-CoV-2 WA-1/2020 isolate and multiple VOCs: B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.617.2 (Delta). In humanized K18-hACE2 mice infected with the SARS-CoV-2 WA-1/2020 or P.1 variant, prophylactic and therapeutic injections of soluble ACE22.v2.4-IgG1 prevented lung vascular injury and edema formation, essential features of CoV-2-induced SARS, and above all improved survival. These studies demonstrate broad efficacy in vivo of an engineered ACE2 decoy against SARS-CoV-2 variants in mice and point to its therapeutic potential.
Collapse
Affiliation(s)
- Lianghui Zhang
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL, USA.
| | - Soumajit Dutta
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, USA
| | - Shiqin Xiong
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Matthew Chan
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, USA
| | - Kui K Chan
- Cyrus Biotechnology, Inc., Seattle, WA, USA
| | - Timothy M Fan
- Department of Veterinary Clinical Medicine, University of Illinois College of Veterinary Medicine, Urbana, IL, USA
| | - Keith L Bailey
- Department of Veterinary Clinical Medicine, University of Illinois College of Veterinary Medicine, Urbana, IL, USA
| | - Matthew Lindeblad
- Toxicology Research Laboratory, Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Laura M Cooper
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Lijun Rong
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Anthony F Gugliuzza
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, IL, USA.
| | - Jalees Rehman
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL, USA.
- Division of Cardiology, Department of Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
| | - Asrar B Malik
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL, USA.
| |
Collapse
|
14
|
Chan MC, Selvam B, Young HJ, Procko E, Shukla D. The substrate import mechanism of the human serotonin transporter. Biophys J 2022; 121:715-730. [PMID: 35114149 PMCID: PMC8943754 DOI: 10.1016/j.bpj.2022.01.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/18/2021] [Accepted: 01/25/2022] [Indexed: 11/17/2022] Open
Abstract
The serotonin transporter (SERT) initiates the reuptake of extracellular serotonin in the synapse to terminate neurotransmission. The cryogenic electron microscopy structures of SERT bound to ibogaine and the physiological substrate serotonin resolved in different states have provided a glimpse of the functional conformations at atomistic resolution. However, the conformational dynamics and structural transitions to intermediate states are not fully understood. Furthermore, the molecular basis of how serotonin is recognized and transported remains unclear. In this study, we performed unbiased microsecond-long simulations of the human SERT to investigate the structural dynamics to various intermediate states and elucidated the complete substrate import pathway. Using Markov state models, we characterized a sequential order of conformational-driven ion-coupled substrate binding and transport events and calculated the free energy barriers of conformation transitions associated with the import mechanism. We find that the transition from the occluded to inward-facing state is the rate-limiting step for substrate import and that the substrate decreases the free energy barriers to achieve the inward-facing state. Our study provides insights on the molecular basis of dynamics-driven ion-substrate recognition and transport of SERT that can serve as a model for other closely related neurotransmitter transporters.
Collapse
Affiliation(s)
- Matthew C Chan
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Balaji Selvam
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Heather J Young
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois; Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois; Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois; National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois; NIH Center for Macromolecular Modeling and Bioinformatics, University of Illinois at Urbana-Champaign, Urbana, Illinois.
| |
Collapse
|
15
|
Bauer MS, Gruber S, Hausch A, Milles LF, Nicolaus T, Schendel LC, López Navajas P, Procko E, Lietha D, Bernardi RC, Lipfert J, Gaub HE. A tethered ligand assay to probe SARS-CoV-2:ACE2 interactions. Biophys J 2022. [PMCID: PMC8833015 DOI: 10.1016/j.bpj.2021.11.2564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
16
|
Chan MC, Young HJ, Selvam B, Szymanski SK, Procko E, Shukla D. Combining simulations and deep mutagenesis to elucidate structural dynamics of monoamine transporters. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
|
17
|
Islam MS, Havranek B, Procko E, Chan K. Computationally engineered ACE2 decoy binds with nanomolar affinity with the SARS-CoV-2 spike protein. Biophys J 2022. [PMCID: PMC8833049 DOI: 10.1016/j.bpj.2021.11.664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
18
|
Sharma P, Procko E, Kranz DM. Engineering Proteins by Combining Deep Mutational Scanning and Yeast Display. Methods Mol Biol 2022; 2491:117-142. [PMID: 35482188 DOI: 10.1007/978-1-0716-2285-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Protein engineering using display platforms such as yeast display and phage display has allowed discovery of proteins with therapeutic and industrial applications. Antibodies and T cell receptors developed for therapeutic applications are often engineered by constructing libraries of mutations in loops of five to ten residues called complementarity determining regions that are in proximity to the antigen. In the past decade, deep mutational scanning has become a powerful tool in a protein engineer's toolbox, as it allows one to compare the impact of all 20 amino acids at each position, across the length of the protein. Thus, a single experiment can provide a sequence-activity landscape with information about hotspots or suboptimal binding sites in the original proteins. These residues or regions may be overlooked by engineering methods that are driven solely by structures or directed evolution of error-prone PCR libraries. Here, we describe experimental methods to engineer proteins by combining yeast display and deep mutational scanning mutagenesis, using T cell receptors as an example.
Collapse
Affiliation(s)
- Preeti Sharma
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
- Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
- Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - David M Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL, USA.
- Cancer Center at Illinois, University of Illinois, Urbana, IL, USA.
| |
Collapse
|
19
|
Abstract
A potential therapeutic candidate for neutralizing SARS-CoV-2 infection is engineering high-affinity soluble ACE2 decoy proteins to compete for binding of the viral spike (S) protein. Previously, a deep mutational scan of ACE2 was performed and has led to the identification of a triple mutant ACE2 variant, named ACE2 2 .v.2.4, that exhibits nanomolar affinity binding to the RBD domain of S. Using a recently developed transfer learning algorithm, TLmutation, we sought to identified other ACE2 variants, namely double mutants, that may exhibit similar binding affinity with decreased mutational load. Upon training a TLmutation model on the effects of single mutations, we identified several ACE2 double mutants that bind to RBD with tighter affinity as compared to the wild type, most notably, L79V;N90D that binds RBD with similar affinity to ACE2 2 .v.2.4. The successful experimental validation of the double mutants demonstrated the use transfer and supervised learning approaches for engineering protein-protein interactions and identifying high affinity ACE2 peptides for targeting SARS-CoV-2.
Collapse
Affiliation(s)
- Matthew C Chan
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61081
| | - Kui K Chan
- Cyrus Biotechnology, Inc., Seattle, WA, 98101
| | - Erik Procko
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61081
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61081
| |
Collapse
|
20
|
Zhang L, Dutta S, Xiong S, Chan M, Chan KK, Fan TM, Bailey KL, Lindeblad M, Cooper LM, Rong L, Gugliuzza AF, Shukla D, Procko E, Rehman J, Malik AB. Engineered High-Affinity ACE2 Peptide Mitigates ARDS and Death Induced by Multiple SARS-CoV-2 Variants. bioRxiv 2021:2021.12.21.473668. [PMID: 34981059 PMCID: PMC8722596 DOI: 10.1101/2021.12.21.473668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Vaccine hesitancy and continuing emergence of SARS-CoV-2 variants of concern that may escape vaccine-induced immune responses highlight the urgent need for effective COVID-19 therapeutics. Monoclonal antibodies used in the clinic have varying efficacies against distinct SARS-CoV-2 variants; thus, there is considerable interest in engineered ACE2 peptides with augmented binding affinities for SARS-CoV-2 Spike protein. These could have therapeutic benefit against multiple viral variants. Using molecular dynamics simulations, we show how three amino acid substitutions in an engineered soluble ACE2 peptide (sACE2 2 .v2.4-IgG1) markedly increase affinity for the SARS-CoV-2 Spike (S) protein. We demonstrate high binding affinity to S protein of the early SARS-CoV-2 WA-1/2020 isolate and also to multiple variants of concern: B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta) SARS-CoV-2 variants. In humanized K18-hACE2 mice, prophylactic and therapeutic administration of sACE2 2 .v2.4-IgG1 peptide prevented acute lung vascular endothelial injury and lung edema (essential features of ARDS) and significantly improved survival after infection by SARS-CoV-2 WA-1/2020 as well as P.1 variant of concern. These studies demonstrate for the first time broad efficacy in vivo of an ACE2 decoy peptide against multiple SARS-CoV-2 variants and point to its therapeutic potential.
Collapse
Affiliation(s)
- Lianghui Zhang
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Soumajit Dutta
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, USA
| | - Shiqin Xiong
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Matthew Chan
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, USA
| | - Kui K. Chan
- Cyrus Biotechnology, Inc., Seattle, WA 98101, USA
| | - Timothy M. Fan
- Department of Veterinary Clinical Medicine, University of Illinois College of Veterinary Medicine, Urbana, IL 61802, USA
| | - Keith L. Bailey
- Department of Veterinary Clinical Medicine, University of Illinois College of Veterinary Medicine, Urbana, IL 61802, USA
| | - Matthew Lindeblad
- Toxicology Research Laboratory, Department of Pharmacology and Regenerative Medicine, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Laura M. Cooper
- Department of Microbiology and Immunology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Lijun Rong
- Department of Microbiology and Immunology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Anthony F. Gugliuzza
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Jalees Rehman
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
- Division of Cardiology, Department of Medicine, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Asrar B. Malik
- Department of Pharmacology and Regenerative Medicine and the Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| |
Collapse
|
21
|
Havranek B, Chan KK, Wu A, Procko E, Islam SM. Computationally Designed ACE2 Decoy Receptor Binds SARS-CoV-2 Spike (S) Protein with Tight Nanomolar Affinity. J Chem Inf Model 2021; 61:4656-4669. [PMID: 34427448 PMCID: PMC8409145 DOI: 10.1021/acs.jcim.1c00783] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Indexed: 12/25/2022]
Abstract
Even with the availability of vaccines, therapeutic options for COVID-19 still remain highly desirable, especially in hospitalized patients with moderate or severe disease. Soluble ACE2 (sACE2) is a promising therapeutic candidate that neutralizes SARS CoV-2 infection by acting as a decoy. Using computational mutagenesis, we designed a number of sACE2 derivatives carrying three to four mutations. The top-predicted sACE2 decoy based on the in silico mutagenesis scan was subjected to molecular dynamics and free-energy calculations for further validation. After illuminating the mechanism of increased binding for our designed sACE2 derivative, the design was verified experimentally by flow cytometry and BLI-binding experiments. The computationally designed sACE2 decoy (ACE2-FFWF) bound the receptor-binding domain of SARS-CoV-2 tightly with low nanomolar affinity and ninefold affinity enhancement over the wild type. Furthermore, cell surface expression was slightly greater than wild-type ACE2, suggesting that the design is well-folded and stable. Having an arsenal of high-affinity sACE2 derivatives will help to buffer against the emergence of SARS CoV-2 variants. Here, we show that computational methods have become sufficiently accurate for the design of therapeutics for current and future viral pandemics.
Collapse
Affiliation(s)
- Brandon Havranek
- Department of Chemistry, University of
Illinois at Chicago, Chicago, Illinois 60607, United
States
| | - Kui K. Chan
- Orthogonal Biologics Inc.,
Urbana, Illinois 61801, United States
| | - Austin Wu
- Department of Computer Science,
Northwestern University, Evanston, Illinois 60208,
United States
| | - Erik Procko
- Department of Biochemistry and Cancer Center at
Illinois, University of Illinois, Urbana, Illinois 61801,
United States
| | - Shahidul M. Islam
- Department of Chemistry, University of
Illinois at Chicago, Chicago, Illinois 60607, United
States
| |
Collapse
|
22
|
Serrano J, Seflova J, Park J, Pribadi M, Sanematsu K, Shigemura N, Serna V, Yi F, Mari A, Procko E, Pratley RE, Robia SL, Kyriazis GA. The Ile191Val is a partial loss-of-function variant of the TAS1R2 sweet-taste receptor and is associated with reduced glucose excursions in humans. Mol Metab 2021; 54:101339. [PMID: 34509698 PMCID: PMC8476773 DOI: 10.1016/j.molmet.2021.101339] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 10/29/2022] Open
Abstract
OBJECTIVE Sweet taste receptors (STR) are expressed in the gut and other extra-oral tissues, suggesting that STR-mediated nutrient sensing may contribute to human physiology beyond taste. A common variant (Ile191Val) in the TAS1R2 gene of STR is associated with nutritional and metabolic outcomes independent of changes in taste perception. It is unclear whether this polymorphism directly alters STR function and how it may contribute to metabolic regulation. METHODS We implemented a combination of in vitro biochemical approaches to decipher the effects of TAS1R2 polymorphism on STR function. Then, as proof-of-concept, we assessed its effects on glucose homeostasis in apparently healthy lean participants. RESULTS The Ile191Val variant causes a partial loss of function of TAS1R2 through reduced receptor availability in the plasma membrane. Val minor allele carriers have reduced glucose excursions during an OGTT, mirroring effects previously seen in mice with genetic loss of function of TAS1R2. These effects were not due to differences in beta-cell function or insulin sensitivity. CONCLUSIONS Our pilot studies on a common TAS1R2 polymorphism suggest that STR sensory function in peripheral tissues, such as the intestine, may contribute to the regulation of metabolic control in humans.
Collapse
Affiliation(s)
- Joan Serrano
- Department of Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Jihye Park
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Marsha Pribadi
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Keisuke Sanematsu
- Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Noriatsu Shigemura
- Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Vanida Serna
- Department of Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Fanchao Yi
- AdventHealth Translational Research Institute, Orlando, FL, 32804, USA
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padova, Italy
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Richard E Pratley
- AdventHealth Translational Research Institute, Orlando, FL, 32804, USA
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, 60153, USA
| | - George A Kyriazis
- Department of Biological Chemistry & Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, USA.
| |
Collapse
|
23
|
McShan AC, Devlin CA, Morozov GI, Overall SA, Moschidi D, Akella N, Procko E, Sgourakis NG. TAPBPR promotes antigen loading on MHC-I molecules using a peptide trap. Nat Commun 2021; 12:3174. [PMID: 34039964 PMCID: PMC8154891 DOI: 10.1038/s41467-021-23225-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 04/16/2021] [Indexed: 11/08/2022] Open
Abstract
Chaperones Tapasin and TAP-binding protein related (TAPBPR) perform the important functions of stabilizing nascent MHC-I molecules (chaperoning) and selecting high-affinity peptides in the MHC-I groove (editing). While X-ray and cryo-EM snapshots of MHC-I in complex with TAPBPR and Tapasin, respectively, have provided important insights into the peptide-deficient MHC-I groove structure, the molecular mechanism through which these chaperones influence the selection of specific amino acid sequences remains incompletely characterized. Based on structural and functional data, a loop sequence of variable lengths has been proposed to stabilize empty MHC-I molecules through direct interactions with the floor of the groove. Using deep mutagenesis on two complementary expression systems, we find that important residues for the Tapasin/TAPBPR chaperoning activity are located on a large scaffolding surface, excluding the loop. Conversely, loop mutations influence TAPBPR interactions with properly conformed MHC-I molecules, relevant for peptide editing. Detailed biophysical characterization by solution NMR, ITC and FP-based assays shows that the loop hovers above the MHC-I groove to promote the capture of incoming peptides. Our results suggest that the longer loop of TAPBPR lowers the affinity requirements for peptide selection to facilitate peptide loading under conditions and subcellular compartments of reduced ligand concentration, and to prevent disassembly of high-affinity peptide-MHC-I complexes that are transiently interrogated by TAPBPR during editing.
Collapse
Affiliation(s)
- Andrew C McShan
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Christine A Devlin
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Giora I Morozov
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Sarah A Overall
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Danai Moschidi
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Neha Akella
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA.
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
24
|
Abstract
SARS coronavirus 2 is neutralized by proteins that block receptor-binding sites on spikes that project from the viral envelope. In particular, substantial research investment has advanced monoclonal antibody therapies to the clinic where they have shown partial efficacy in reducing viral burden and hospitalization. An alternative is to use the host entry receptor, angiotensin-converting enzyme 2 (ACE2), as a soluble decoy that broadly blocks SARS-associated coronaviruses with limited potential for viral escape. Here, we summarize efforts to engineer higher affinity variants of soluble ACE2 that rival the potency of affinity-matured antibodies. Strategies have also been used to increase the valency of ACE2 decoys for avid spike interactions and to improve pharmacokinetics via IgG fusions. Finally, the intrinsic catalytic activity of ACE2 for the turnover of the vasoconstrictor angiotensin II may directly address COVID-19 symptoms and protect against lung and cardiovascular injury, conferring dual mechanisms of action unachievable by monoclonal antibodies. Soluble ACE2 derivatives therefore have the potential to be next generation therapeutics for addressing the immediate needs of the current pandemic and possible future outbreaks.
Collapse
Affiliation(s)
- Wenyang Jing
- Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, Illinois, USA
| | - Erik Procko
- Center for Biophysics and Quantitative Biology, University of Illinois, Urbana, Illinois, USA.,Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, Illinois, USA
| |
Collapse
|
25
|
Abstract
Deep mutational scanning or deep mutagenesis is a powerful tool for understanding the sequence diversity available to viruses for adaptation in a laboratory setting. It generally involves tracking an in vitro selection of protein sequence variants with deep sequencing to map mutational effects based on changes in sequence abundance. Coupled with any of a number of selection strategies, deep mutagenesis can explore the mutational diversity available to viral glycoproteins, which mediate critical roles in cell entry and are exposed to the humoral arm of the host immune response. Mutational landscapes of viral glycoproteins for host cell attachment and membrane fusion reveal extensive epistasis and potential escape mutations to neutralizing antibodies or other therapeutics, as well as aiding in the design of optimized immunogens for eliciting broadly protective immunity. While less explored, deep mutational scans of host receptors further assist in understanding virus-host protein interactions. Critical residues on the host receptors for engaging with viral spikes are readily identified and may help with structural modeling. Furthermore, mutations may be found for engineering soluble decoy receptors as neutralizing agents that specifically bind viral targets with tight affinity and limited potential for viral escape. By untangling the complexities of how sequence contributes to viral glycoprotein and host receptor interactions, deep mutational scanning is impacting ideas and strategies at multiple levels for combatting circulating and emergent virus strains.
Collapse
Affiliation(s)
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, United States
| |
Collapse
|
26
|
Procko C, Murthy S, Keenan WT, Mousavi SAR, Dabi T, Coombs A, Procko E, Baird L, Patapoutian A, Chory J. Stretch-activated ion channels identified in the touch-sensitive structures of carnivorous Droseraceae plants. eLife 2021; 10:e64250. [PMID: 33724187 PMCID: PMC7963481 DOI: 10.7554/elife.64250] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/18/2021] [Indexed: 12/11/2022] Open
Abstract
In response to touch, some carnivorous plants such as the Venus flytrap have evolved spectacular movements to capture animals for nutrient acquisition. However, the molecules that confer this sensitivity remain unknown. We used comparative transcriptomics to show that expression of three genes encoding homologs of the MscS-Like (MSL) and OSCA/TMEM63 family of mechanosensitive ion channels are localized to touch-sensitive trigger hairs of Venus flytrap. We focus here on the candidate with the most enriched expression in trigger hairs, the MSL homolog FLYCATCHER1 (FLYC1). We show that FLYC1 transcripts are localized to mechanosensory cells within the trigger hair, transfecting FLYC1 induces chloride-permeable stretch-activated currents in naïve cells, and transcripts coding for FLYC1 homologs are expressed in touch-sensing cells of Cape sundew, a related carnivorous plant of the Droseraceae family. Our data suggest that the mechanism of prey recognition in carnivorous Droseraceae evolved by co-opting ancestral mechanosensitive ion channels to sense touch.
Collapse
Affiliation(s)
- Carl Procko
- Plant Biology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
| | - Swetha Murthy
- Department of Neuroscience, Dorris Neuroscience Center, Scripps ResearchSan DiegoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - William T Keenan
- Department of Neuroscience, Dorris Neuroscience Center, Scripps ResearchSan DiegoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Seyed Ali Reza Mousavi
- Department of Neuroscience, Dorris Neuroscience Center, Scripps ResearchSan DiegoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Tsegaye Dabi
- Plant Biology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
| | - Adam Coombs
- Department of Neuroscience, Dorris Neuroscience Center, Scripps ResearchSan DiegoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Lisa Baird
- Department of Biology, University of San DiegoSan DiegoUnited States
| | - Ardem Patapoutian
- Department of Neuroscience, Dorris Neuroscience Center, Scripps ResearchSan DiegoUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Joanne Chory
- Plant Biology Laboratory, Salk Institute for Biological StudiesLa JollaUnited States
| |
Collapse
|
27
|
Chan KK, Tan TJC, Narayanan KK, Procko E. An engineered decoy receptor for SARS-CoV-2 broadly binds protein S sequence variants. Sci Adv 2021; 7:eabf1738. [PMID: 33597251 PMCID: PMC7888922 DOI: 10.1126/sciadv.abf1738] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/31/2020] [Indexed: 05/04/2023]
Abstract
The spike S of SARS-CoV-2 recognizes ACE2 on the host cell membrane to initiate entry. Soluble decoy receptors, in which the ACE2 ectodomain is engineered to block S with high affinity, potently neutralize infection and, because of close similarity with the natural receptor, hold out the promise of being broadly active against virus variants without opportunity for escape. Here, we directly test this hypothesis. We find that an engineered decoy receptor, sACE22v2.4, tightly binds S of SARS-associated viruses from humans and bats, despite the ACE2-binding surface being a region of high diversity. Saturation mutagenesis of the receptor-binding domain followed by in vitro selection, with wild-type ACE2 and the engineered decoy competing for binding sites, failed to find S mutants that discriminate in favor of the wild-type receptor. We conclude that resistance to engineered decoys will be rare and that decoys may be active against future outbreaks of SARS-associated betacoronaviruses.
Collapse
Affiliation(s)
- Kui K Chan
- Orthogonal Biologics, Champaign, IL 61821, USA
| | - Timothy J C Tan
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA
| | - Krishna K Narayanan
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA.
| |
Collapse
|
28
|
Abstract
The spike S of SARS-CoV-2 recognizes ACE2 on the host cell membrane to initiate entry. Soluble decoy receptors, in which the ACE2 ectodomain is engineered to block S with high affinity, potently neutralize infection and, due to close similarity with the natural receptor, hold out the promise of being broadly active against virus variants without opportunity for escape. Here, we directly test this hypothesis. We find an engineered decoy receptor, sACE2 2 .v2.4, tightly binds S of SARS-associated viruses from humans and bats, despite the ACE2-binding surface being a region of high diversity. Saturation mutagenesis of the receptor-binding domain (RBD) followed by in vitro selection, with wild type ACE2 and the engineered decoy competing for binding sites, failed to find S mutants that discriminate in favor of the wild type receptor. Variant N501Y in the RBD, which has emerged in a rapidly spreading lineage (B.1.1.7) in England, enhances affinity for wild type ACE2 20-fold but remains tightly bound to engineered sACE22.v2.4. We conclude that resistance to engineered decoys will be rare and that decoys may be active against future outbreaks of SARS-associated betacoronaviruses.
Collapse
Affiliation(s)
- Kui K Chan
- Orthogonal Biologics, Champaign IL 61821
| | - Timothy J C Tan
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana IL 61801
| | - Krishna K Narayanan
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana IL 61801
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana IL 61801
| |
Collapse
|
29
|
Abstract
INTRODUCTION The spike (S) of SARS coronavirus 2 (SARS-CoV-2) engages angiotensin-converting enzyme 2 (ACE2) on a host cell to trigger viral-cell membrane fusion and infection. The extracellular region of ACE2 can be administered as a soluble decoy to compete for binding sites on the receptor-binding domain (RBD) of S, but it has only moderate affinity and efficacy. The RBD, which is targeted by neutralizing antibodies, may also change and adapt through mutation as SARS-CoV-2 becomes endemic, posing challenges for therapeutic and vaccine development. AREAS COVERED Deep mutagenesis is a Big Data approach to characterizing sequence variants. A deep mutational scan of ACE2 expressed on human cells identified mutations that increase S affinity and guided the engineering of a potent and broad soluble receptor decoy. A deep mutational scan of the RBD displayed on the surface of yeast has revealed residues tolerant of mutational changes that may act as a source for drug resistance and antigenic drift. EXPERT OPINION Deep mutagenesis requires a selection of diverse sequence variants; an in vitro evolution experiment that is tracked with next-generation sequencing. The choice of expression system, diversity of the variant library and selection strategy have important consequences for data quality and interpretation.
Collapse
Affiliation(s)
- Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL, USA
| |
Collapse
|
30
|
Chan KK, Dorosky D, Sharma P, Abbasi SA, Dye JM, Kranz DM, Herbert AS, Procko E. Engineering human ACE2 to optimize binding to the spike protein of SARS coronavirus 2. Science 2020; 369:1261-1265. [PMID: 32753553 PMCID: PMC7574912 DOI: 10.1126/science.abc0870] [Citation(s) in RCA: 427] [Impact Index Per Article: 106.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/05/2020] [Accepted: 07/28/2020] [Indexed: 11/26/2022]
Abstract
For severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to enter human cells, the spike protein on the surface of the virus must bind to the host receptor protein, angiotensin-converting enzyme 2 (ACE2). A soluble version of the receptor is being explored as a therapeutic. Chan et al. used deep mutagenesis to identify ACE2 mutants that bind more tightly to the spike protein and combined mutations to further increase binding affinity (see the Perspective by DeKosky). A promising variant was engineered to be a stable dimer that has a binding affinity for the spike protein; it is comparable with neutralizing antibodies and neutralized both SARS-CoV-2 and SARS-CoV-1 in a cell-based assay. In addition, the similarity to the natural receptor may limit the possibility for viral escape. Science, this issue p. 1261; see also p. 1167 The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds angiotensin-converting enzyme 2 (ACE2) on host cells to initiate entry, and soluble ACE2 is a therapeutic candidate that neutralizes infection by acting as a decoy. By using deep mutagenesis, mutations in ACE2 that increase S binding are found across the interaction surface, in the asparagine 90–glycosylation motif and at buried sites. The mutational landscape provides a blueprint for understanding the specificity of the interaction between ACE2 and S and for engineering high-affinity decoy receptors. Combining mutations gives ACE2 variants with affinities that rival those of monoclonal antibodies. A stable dimeric variant shows potent SARS-CoV-2 and -1 neutralization in vitro. The engineered receptor is catalytically active, and its close similarity with the native receptor may limit the potential for viral escape.
Collapse
Affiliation(s)
- Kui K Chan
- Orthogonal Biologics, Champaign, IL 61821, USA
| | - Danielle Dorosky
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | - Preeti Sharma
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA
| | - Shawn A Abbasi
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | - John M Dye
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | - David M Kranz
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA
| | - Andrew S Herbert
- U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA.,The Geneva Foundation, Tacoma, WA 98402, USA
| | - Erik Procko
- Department of Biochemistry and Cancer Center at Illinois, University of Illinois, Urbana, IL 61801, USA.
| |
Collapse
|
31
|
Park J, Gill KS, Aghajani AA, Heredia JD, Choi H, Oberstein A, Procko E. Engineered receptors for human cytomegalovirus that are orthogonal to normal human biology. PLoS Pathog 2020; 16:e1008647. [PMID: 32559251 PMCID: PMC7329128 DOI: 10.1371/journal.ppat.1008647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 07/01/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022] Open
Abstract
A trimeric glycoprotein complex on the surface of human cytomegalovirus (HCMV) binds to platelet-derived growth factor (PDGF) receptor α (PDGFRα) to mediate host cell recognition and fusion of the viral and cellular membranes. Soluble PDGFRα potently neutralizes HCMV in tissue culture, and its potential use as an antiviral therapeutic has the benefit that any escape mutants will likely be attenuated. However, PDGFRα binds multiple PDGF ligands in the human body as part of developmental programs in embryogenesis and continuing through adulthood. Any therapies with soluble receptor therefore come with serious efficacy and safety concerns, especially for the treatment of congenital HCMV. Soluble virus receptors that are orthogonal to human biology might resolve these concerns. This engineering problem is solved by deep mutational scanning on the D2-D3 domains of PDGFRα to identify variants that maintain interactions with the HCMV glycoprotein trimer in the presence of competing PDGF ligands. Competition by PDGFs is conformation-dependent, whereas HCMV trimer binding is independent of proper D2-D3 conformation, and many mutations at the receptor-PDGF interface are suitable for functionally separating trimer from PDGF interactions. Purified soluble PDGFRα carrying a targeted mutation succeeded in displaying wild type affinity for HCMV trimer with a simultaneous loss of PDGF binding, and neutralizes trimer-only and trimer/pentamer-expressing HCMV strains infecting fibroblasts or epithelial cells. Overall, this work makes important progress in the realization of soluble HCMV receptors for clinical application. Human cytomegalovirus (HCMV) causes severe disease in transplant recipients and immunocompromised patients, and infections in a fetus or neonate are responsible for life-long neurological defects. Cell entry is in part mediated by a trimeric glycoprotein complex on the viral surface, which binds tightly to the host receptor PDGFRα. The soluble extracellular region of PDGFRα can be used as an antiviral agent to potently neutralize the virus in vitro. However, PDGFRα ordinarily binds growth factors in the human body to regulate developmental programs, which will limit the in vivo efficacy and safety of soluble PDGFRα. Using saturation mutagenesis and selections in human cell culture, mutations in PDGFRα are identified that eliminate off-target growth factor interactions while preserving HCMV binding and neutralization.
Collapse
Affiliation(s)
- Jihye Park
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Kevin Sean Gill
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Ali Asghar Aghajani
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Jeremiah Dallas Heredia
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Hannah Choi
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Adam Oberstein
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Erik Procko
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
- Cancer Center at Illinois (CCIL), University of Illinois, Urbana, Illinois, United States of America
- * E-mail:
| |
Collapse
|
32
|
Abstract
The rapid and escalating spread of SARS coronavirus 2 (SARS-CoV-2) poses an immediate public health emergency. The viral spike protein S binds ACE2 on host cells to initiate molecular events that release the viral genome intracellularly. Soluble ACE2 inhibits entry of both SARS and SARS-2 coronaviruses by acting as a decoy for S binding sites, and is a candidate for therapeutic, prophylactic and diagnostic development. Using deep mutagenesis, variants of ACE2 are identified with increased binding to the receptor binding domain of S. Mutations are found across the interface, in the N90-glycosylation motif, and at buried sites where they are predicted to enhance local folding and presentation of the interaction epitope. When single substitutions are combined, large increases in binding can be achieved. The mutational landscape offers a blueprint for engineering high affinity proteins and peptides that block receptor binding sites on S to meet this unprecedented challenge.
Collapse
Affiliation(s)
- Erik Procko
- Department of Biochemistry, University of Illinois, Urbana IL 61801
| |
Collapse
|
33
|
Sgourakis N, McShan AC, Devlin CA, Morozov G, Procko E. Illuminating the Mechanism of MHC-I Folding and Antigen Repertoire Selection Using Deep Mutational Scanning and Biophysical Studies. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.140.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Chaperones Tapasin and TAP-binding protein related (TAPBPR) perform the important functions of stabilizing nascent MHC-I molecules (chaperoning), and selecting high affinity peptide cargo in the MHC-I groove (editing). While X-ray and cryoEM snapshots of MHC-I molecules prepared in complex with TAPBPR and Tapasin, respectively, have provided important insights into the empty MHC-I groove structure, the molecular mechanism through which these chaperones influence the selection of specific amino acid sequences remains incompletely characterized. Of particular importance is a 16 aa loop region in TAPBPR (corresponding to 11 residues in the sequence of Tapasin), which has been suggested to actively compete with incoming peptides by forming direct contacts with the F-pocket of the empty MHC-I groove. Using a deep mutational scanning functional analysis of TAPBPR, we find that important residues for its chaperoning activity are located on the major interaction surfaces with nascent MHC-I molecules, excluding the loop. However, interactions with properly conformed molecules toward editing of their peptide cargo are influenced by loop mutations, in an MHC-I allele- and peptide-dependent manner, as shown in MHC-I tetramer staining experiments using a TAPBPR library expressed on the surface of yeast. Detailed biophysical characterization by NMR and ITC reveal that the loop does not interact with the empty MHC-I groove to compete with incoming peptides, but instead promotes peptide loading by acting as a kinetic “trap”. Our results suggest that, by utilizing a longer loop, TAPBPR lowers the affinity requirements for peptide selection relative to Tapasin to promote loading under conditions of reduced peptide concentration.
Collapse
|
34
|
Zhang J, Kim EC, Chen C, Procko E, Pant S, Lam K, Patel J, Choi R, Hong M, Joshi D, Bolton E, Tajkhorshid E, Chung HJ. Identifying mutation hotspots reveals pathogenetic mechanisms of KCNQ2 epileptic encephalopathy. Sci Rep 2020; 10:4756. [PMID: 32179837 PMCID: PMC7075958 DOI: 10.1038/s41598-020-61697-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 03/02/2020] [Indexed: 11/08/2022] Open
Abstract
Kv7 channels are enriched at the axonal plasma membrane where their voltage-dependent potassium currents suppress neuronal excitability. Mutations in Kv7.2 and Kv7.3 subunits cause epileptic encephalopathy (EE), yet the underlying pathogenetic mechanism is unclear. Here, we used novel statistical algorithms and structural modeling to identify EE mutation hotspots in key functional domains of Kv7.2 including voltage sensing S4, the pore loop and S6 in the pore domain, and intracellular calmodulin-binding helix B and helix B-C linker. Characterization of selected EE mutations from these hotspots revealed that L203P at S4 induces a large depolarizing shift in voltage dependence of Kv7.2 channels and L268F at the pore decreases their current densities. While L268F severely reduces expression of heteromeric channels in hippocampal neurons without affecting internalization, K552T and R553L mutations at distal helix B decrease calmodulin-binding and axonal enrichment. Importantly, L268F, K552T, and R553L mutations disrupt current potentiation by increasing phosphatidylinositol 4,5-bisphosphate (PIP2), and our molecular dynamics simulation suggests PIP2 interaction with these residues. Together, these findings demonstrate that each EE variant causes a unique combination of defects in Kv7 channel function and neuronal expression, and suggest a critical need for both prediction algorithms and experimental interrogations to understand pathophysiology of Kv7-associated EE.
Collapse
Affiliation(s)
- Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Congcong Chen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Shashank Pant
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Kin Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Jaimin Patel
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Rebecca Choi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Mary Hong
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Dhruv Joshi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Eric Bolton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA.
| |
Collapse
|
35
|
Sgourakis N, McShan A, Natarajan K, Jiang J, Park J, Overall S, Toor JS, Kumirov V, Flores-Solis D, Badstubner M, Kovrigin EL, Bagshaw CR, Pallesen J, Procko E, Margulies DH. Getting in the groove: Editing of MHC-I antigen repertoires by molecular chaperones is governed by a network of protein dynamics. The Journal of Immunology 2019. [DOI: 10.4049/jimmunol.202.supp.177.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Molecular chaperones TAPBPR (TAP-binding protein related) and tapasin associate with class-I major histocompatibility complex (MHC-I) molecules to promote optimization (editing) of peptide cargo. Using solution NMR, we investigate the molecular mechanism of peptide exchange performed by the 90 kDa chaperone protein complex. We identify TAPBPR-induced conformational changes on conserved MHC-I surfaces, consistent with our independently determined X-ray structure of the empty complex. Conformational dynamics present in the empty MHC-I are stabilized by TAPBPR in a peptide-deficient complex, and become progressively dampened with increasing peptide occupancy. Incoming peptides are recognized by the chaperoned groove according to the global stability of the final pMHC-I product, and anneal in a native-like conformation. Our results demonstrate an inverse relationship between MHC-I occupancy by peptide and the affinity of TAPBPR for such pMHC-I molecules, where the lifetime of transiently bound peptides controls the dynamic regulation of a conformational switch, located near the TAPBPR binding site, which triggers TAPBPR release. We further discuss the role of protein dynamics in shaping chaperone specificity towards different human and murine class-I MHC allotypes, and present the high-resolution cryoEM structure of a human A*02/TAPBPR complex with novel insights into the antigen editing mechanism. These results suggest a similar mechanism for the editing function of tapasin in the peptide-loading complex, and provide a molecular blueprint for the design of novel chaperones with tailored antigen editing functions.
Collapse
Affiliation(s)
| | | | - Kannan Natarajan
- 2National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Jiansheng Jiang
- 2National Institute of Allergy and Infectious Diseases, National Institutes of Health
| | - Jihye Park
- 3university of Illinois at Urbana-Champaign
| | | | | | | | | | | | | | | | | | | | - David H Margulies
- 2National Institute of Allergy and Infectious Diseases, National Institutes of Health
| |
Collapse
|
36
|
Park J, Selvam B, Sanematsu K, Shigemura N, Shukla D, Procko E. Structural architecture of a dimeric class C GPCR based on co-trafficking of sweet taste receptor subunits. J Biol Chem 2019; 294:4759-4774. [PMID: 30723160 DOI: 10.1074/jbc.ra118.006173] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/24/2019] [Indexed: 01/06/2023] Open
Abstract
Class C G protein-coupled receptors (GPCRs) are obligatory dimers that are particularly important for neuronal responses to endogenous and environmental stimuli. Ligand recognition through large extracellular domains leads to the reorganization of transmembrane regions to activate G protein signaling. Although structures of individual domains are known, the complete architecture of a class C GPCR and the mechanism of interdomain coupling during receptor activation are unclear. By screening a mutagenesis library of the human class C sweet taste receptor subunit T1R2, we enhanced surface expression and identified a dibasic intracellular retention motif that modulates surface expression and co-trafficking with its heterodimeric partner T1R3. Using a highly expressed T1R2 variant, dimerization sites along the entire subunit within all the structural domains were identified by a comprehensive mutational scan for co-trafficking with T1R3 in human cells. The data further reveal that the C terminus of the extracellular cysteine-rich domain needs to be properly folded for T1R3 dimerization and co-trafficking, but not for surface expression of T1R2 alone. These results guided the modeling of the T1R2-T1R3 dimer in living cells, which predicts a twisted arrangement of domains around the central axis, and a continuous folded structure between transmembrane domain loops and the cysteine-rich domains. These insights have implications for how conformational changes between domains are coupled within class C GPCRs.
Collapse
Affiliation(s)
- Jihye Park
- From the Departments of Biochemistry and
| | - Balaji Selvam
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
| | - Keisuke Sanematsu
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriatsu Shigemura
- the Section of Oral Neuroscience, Graduate School of Dental Science, and.,the Division of Sensory Physiology-Medical Application Sensing, Research and Development Center for Five-Sense Devices, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Diwakar Shukla
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
| | | |
Collapse
|
37
|
Kim EC, Zhang J, Pang W, Wang S, Lee KY, Cavaretta JP, Walters J, Procko E, Tsai NP, Chung HJ. Reduced axonal surface expression and phosphoinositide sensitivity in K v7 channels disrupts their function to inhibit neuronal excitability in Kcnq2 epileptic encephalopathy. Neurobiol Dis 2018; 118:76-93. [PMID: 30008368 DOI: 10.1016/j.nbd.2018.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/22/2018] [Accepted: 07/04/2018] [Indexed: 01/08/2023] Open
Abstract
Neuronal Kv7/KCNQ channels are voltage-gated potassium channels composed of Kv7.2/KCNQ2 and Kv7.3/KCNQ3 subunits. Enriched at the axonal membrane, they potently suppress neuronal excitability. De novo and inherited dominant mutations in Kv7.2 cause early onset epileptic encephalopathy characterized by drug resistant seizures and profound psychomotor delay. However, their precise pathogenic mechanisms remain elusive. Here, we investigated selected epileptic encephalopathy causing mutations in calmodulin (CaM)-binding helices A and B of Kv7.2. We discovered that R333W, K526N, and R532W mutations located peripheral to CaM contact sites decreased axonal surface expression of heteromeric channels although only R333W mutation reduced CaM binding to Kv7.2. These mutations also altered gating modulation by phosphatidylinositol 4,5-bisphosphate (PIP2), revealing novel PIP2 binding residues. While these mutations disrupted Kv7 function to suppress excitability, hyperexcitability was observed in neurons expressing Kv7.2-R532W that displayed severe impairment in voltage-dependent activation. The M518 V mutation at the CaM contact site in helix B caused most defects in Kv7 channels by severely reducing their CaM binding, K+ currents, and axonal surface expression. Interestingly, the M518 V mutation induced ubiquitination and accelerated proteasome-dependent degradation of Kv7.2, whereas the presence of Kv7.3 blocked this degradation. Furthermore, expression of Kv7.2-M518V increased neuronal death. Together, our results demonstrate that epileptic encephalopathy mutations in helices A and B of Kv7.2 cause abnormal Kv7 expression and function by disrupting Kv7.2 binding to CaM and/or modulation by PIP2. We propose that such multiple Kv7 channel defects could exert more severe impacts on neuronal excitability and health, and thus serve as pathogenic mechanisms underlying Kcnq2 epileptic encephalopathy.
Collapse
Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Weilun Pang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shuwei Wang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kwan Young Lee
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - John P Cavaretta
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jennifer Walters
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| |
Collapse
|
38
|
Heredia JD, Park J, Brubaker RJ, Szymanski SK, Gill KS, Procko E. Mapping Interaction Sites on Human Chemokine Receptors by Deep Mutational Scanning. J Immunol 2018; 200:3825-3839. [PMID: 29678950 DOI: 10.4049/jimmunol.1800343] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/30/2018] [Indexed: 02/02/2023]
Abstract
Chemokine receptors CXCR4 and CCR5 regulate WBC trafficking and are engaged by the HIV-1 envelope glycoprotein gp120 during infection. We combine a selection of human CXCR4 and CCR5 libraries comprising nearly all of ∼7000 single amino acid substitutions with deep sequencing to define sequence-activity landscapes for surface expression and ligand interactions. After consideration of sequence constraints for surface expression, known interaction sites with HIV-1-blocking Abs were appropriately identified as conserved residues following library sorting for Ab binding, validating the use of deep mutational scanning to map functional interaction sites in G protein-coupled receptors. Chemokine CXCL12 was found to interact with residues extending asymmetrically into the CXCR4 ligand-binding cavity, similar to the binding surface of CXCR4 recognized by an antagonistic viral chemokine previously observed crystallographically. CXCR4 mutations distal from the chemokine binding site were identified that enhance chemokine recognition. This included disruptive mutations in the G protein-coupling site that diminished calcium mobilization, as well as conservative mutations to a membrane-exposed site (CXCR4 residues H792.45 and W1614.50) that increased ligand binding without loss of signaling. Compared with CXCR4-CXCL12 interactions, CCR5 residues conserved for gp120 (HIV-1 BaL strain) interactions map to a more expansive surface, mimicking how the cognate chemokine CCL5 makes contacts across the entire CCR5 binding cavity. Acidic substitutions in the CCR5 N terminus and extracellular loops enhanced gp120 binding. This study demonstrates how comprehensive mutational scanning can define functional interaction sites on receptors, and novel mutations that enhance receptor activities can be found simultaneously.
Collapse
Affiliation(s)
- Jeremiah D Heredia
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jihye Park
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Riley J Brubaker
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Steven K Szymanski
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Kevin S Gill
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| |
Collapse
|
39
|
Berger S, Procko E, Margineantu D, Lee EF, Shen BW, Zelter A, Silva DA, Chawla K, Herold MJ, Garnier JM, Johnson R, MacCoss MJ, Lessene G, Davis TN, Stayton PS, Stoddard BL, Fairlie WD, Hockenbery DM, Baker D. Computationally designed high specificity inhibitors delineate the roles of BCL2 family proteins in cancer. eLife 2016; 5. [PMID: 27805565 PMCID: PMC5127641 DOI: 10.7554/elife.20352] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/01/2016] [Indexed: 01/07/2023] Open
Abstract
Many cancers overexpress one or more of the six human pro-survival BCL2 family proteins to evade apoptosis. To determine which BCL2 protein or proteins block apoptosis in different cancers, we computationally designed three-helix bundle protein inhibitors specific for each BCL2 pro-survival protein. Following in vitro optimization, each inhibitor binds its target with high picomolar to low nanomolar affinity and at least 300-fold specificity. Expression of the designed inhibitors in human cancer cell lines revealed unique dependencies on BCL2 proteins for survival which could not be inferred from other BCL2 profiling methods. Our results show that designed inhibitors can be generated for each member of a closely-knit protein family to probe the importance of specific protein-protein interactions in complex biological processes.
Collapse
Affiliation(s)
- Stephanie Berger
- Department of Bioengineering, University of Washington, Seattle, United States
| | - Erik Procko
- Department of Biochemistry, University of Washington, Seattle, United States.,Department of Biochemistry, University of Illinois, Urbana, United States
| | - Daciana Margineantu
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Erinna F Lee
- Department of Chemistry and Physics, LaTrobe Institute for Molecular Science, Melbourne, Australia.,Olivia Newton-John Cancer Research Institute, Olivia Newton-John Cancer and Wellness Centre, Heidelberg, Australia.,School of Cancer Medicine, La Trobe University, Melbourne, Australia.,The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Betty W Shen
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Alex Zelter
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Daniel-Adriano Silva
- Department of Biochemistry, University of Washington, Seattle, United States.,Institute for Protein Design, University of Washington, Seattle, United States
| | - Kusum Chawla
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Marco J Herold
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Jean-Marc Garnier
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Richard Johnson
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, United States
| | - Guillaume Lessene
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Australia.,Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, Australia
| | - Trisha N Davis
- Department of Biochemistry, University of Washington, Seattle, United States
| | - Patrick S Stayton
- Department of Bioengineering, University of Washington, Seattle, United States
| | - Barry L Stoddard
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - W Douglas Fairlie
- Department of Chemistry and Physics, LaTrobe Institute for Molecular Science, Melbourne, Australia.,Olivia Newton-John Cancer Research Institute, Olivia Newton-John Cancer and Wellness Centre, Heidelberg, Australia.,School of Cancer Medicine, La Trobe University, Melbourne, Australia.,The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - David M Hockenbery
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, United States.,Institute for Protein Design, University of Washington, Seattle, United States.,Howard Hughes Medical Institute, University of Washington, Seattle, United States
| |
Collapse
|
40
|
Harris DT, Wang N, Riley TP, Anderson SD, Singh NK, Procko E, Baker BM, Kranz DM. Deep Mutational Scans as a Guide to Engineering High Affinity T Cell Receptor Interactions with Peptide-bound Major Histocompatibility Complex. J Biol Chem 2016; 291:24566-24578. [PMID: 27681597 DOI: 10.1074/jbc.m116.748681] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/15/2016] [Indexed: 11/06/2022] Open
Abstract
Proteins are often engineered to have higher affinity for their ligands to achieve therapeutic benefit. For example, many studies have used phage or yeast display libraries of mutants within complementarity-determining regions to affinity mature antibodies and T cell receptors (TCRs). However, these approaches do not allow rapid assessment or evolution across the entire interface. By combining directed evolution with deep sequencing, it is now possible to generate sequence fitness landscapes that survey the impact of every amino acid substitution across the entire protein-protein interface. Here we used the results of deep mutational scans of a TCR-peptide-MHC interaction to guide mutational strategies. The approach yielded stable TCRs with affinity increases of >200-fold. The substitutions with the greatest enrichments based on the deep sequencing were validated to have higher affinity and could be combined to yield additional improvements. We also conducted in silico binding analyses for every substitution to compare them with the fitness landscape. Computational modeling did not effectively predict the impacts of mutations distal to the interface and did not account for yeast display results that depended on combinations of affinity and protein stability. However, computation accurately predicted affinity changes for mutations within or near the interface, highlighting the complementary strengths of computational modeling and yeast surface display coupled with deep mutational scanning for engineering high affinity TCRs.
Collapse
Affiliation(s)
- Daniel T Harris
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801 and
| | - Ningyan Wang
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801 and
| | - Timothy P Riley
- the Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, South Bend, Indiana 46557
| | - Scott D Anderson
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801 and
| | - Nishant K Singh
- the Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, South Bend, Indiana 46557
| | - Erik Procko
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801 and
| | - Brian M Baker
- the Department of Chemistry and Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, South Bend, Indiana 46557
| | - David M Kranz
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801 and.
| |
Collapse
|
41
|
Abstract
Protein-protein interfaces regulate many critical processes for cellular function. The ability to accurately control and regulate these molecular interactions is of major interest for biomedical and synthetic biology applications, as well as to address fundamental biological questions. In recent years, computational protein design has emerged as a tool for designing novel protein-protein interactions with functional relevance. Although attractive, these computational tools carry a steep learning curve. In order to make some of these methods more accessible, we present detailed descriptions and examples of ROSETTA computational protocols for the design of functional protein binders using seeded protein interface design. In these protocols, a motif of known structure that interacts with the target site is grafted into a scaffold protein, followed by design of the surrounding interaction surface.
Collapse
Affiliation(s)
| | - Bruno E Correia
- Institute of Bioengineering, Ecole polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Erik Procko
- Department of Biochemistry, University of Illinois, 600 S. Matthews, Urbana, IL, 61801, USA.
| |
Collapse
|
42
|
Procko E, Berguig GY, Shen BW, Song Y, Frayo S, Convertine AJ, Margineantu D, Booth G, Correia BE, Cheng Y, Schief WR, Hockenbery DM, Press OW, Stoddard BL, Stayton PS, Baker D. A computationally designed inhibitor of an Epstein-Barr viral Bcl-2 protein induces apoptosis in infected cells. Cell 2014; 157:1644-1656. [PMID: 24949974 PMCID: PMC4079535 DOI: 10.1016/j.cell.2014.04.034] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 03/13/2014] [Accepted: 04/15/2014] [Indexed: 11/25/2022]
Abstract
Because apoptosis of infected cells can limit virus production and spread, some viruses have co-opted prosurvival genes from the host. This includes the Epstein-Barr virus (EBV) gene BHRF1, a homolog of human Bcl-2 proteins that block apoptosis and are associated with cancer. Computational design and experimental optimization were used to generate a novel protein called BINDI that binds BHRF1 with picomolar affinity. BINDI recognizes the hydrophobic cleft of BHRF1 in a manner similar to other Bcl-2 protein interactions but makes many additional contacts to achieve exceptional affinity and specificity. BINDI induces apoptosis in EBV-infected cancer lines, and when delivered with an antibody-targeted intracellular delivery carrier, BINDI suppressed tumor growth and extended survival in a xenograft disease model of EBV-positive human lymphoma. High-specificity-designed proteins that selectively kill target cells may provide an advantage over the toxic compounds used in current generation antibody-drug conjugates.
Collapse
Affiliation(s)
- Erik Procko
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Geoffrey Y. Berguig
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Betty W. Shen
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Yifan Song
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Shani Frayo
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | | | - Garrett Booth
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | - Yuanhua Cheng
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | | | | | - Oliver W. Press
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | - Patrick S. Stayton
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| |
Collapse
|
43
|
Procko E, Hedman R, Hamilton K, Seetharaman J, Fleishman SJ, Su M, Aramini J, Kornhaber G, Hunt JF, Tong L, Montelione GT, Baker D. Computational design of a protein-based enzyme inhibitor. J Mol Biol 2013; 425:3563-75. [PMID: 23827138 DOI: 10.1016/j.jmb.2013.06.035] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/15/2013] [Accepted: 06/25/2013] [Indexed: 01/30/2023]
Abstract
While there has been considerable progress in designing protein-protein interactions, the design of proteins that bind polar surfaces is an unmet challenge. We describe the computational design of a protein that binds the acidic active site of hen egg lysozyme and inhibits the enzyme. The design process starts with two polar amino acids that fit deep into the enzyme active site, identifies a protein scaffold that supports these residues and is complementary in shape to the lysozyme active-site region, and finally optimizes the surrounding contact surface for high-affinity binding. Following affinity maturation, a protein designed using this method bound lysozyme with low nanomolar affinity, and a combination of NMR studies, crystallography, and knockout mutagenesis confirmed the designed binding surface and orientation. Saturation mutagenesis with selection and deep sequencing demonstrated that specific designed interactions extending well beyond the centrally grafted polar residues are critical for high-affinity binding.
Collapse
Affiliation(s)
- Erik Procko
- Department of Biochemistry and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
Transient receptor potential (TRP) vanilloid 1 (TRPV1) is a molecular pain receptor belonging to the TRP superfamily of nonselective cation channels. As a polymodal receptor, TRPV1 responds to heat and a wide range of chemical stimuli. The influx of calcium after channel activation serves as a negative feedback mechanism leading to TRPV1 desensitization. The cellular calcium sensor calmodulin (CaM) likely participates in the desensitization of TRPV1. Two CaM-binding sites are identified in TRPV1: the N-terminal ankyrin repeat domain (ARD) and a short distal C-terminal (CT) segment. Here, we present the crystal structure of calcium-bound CaM (Ca(2+)-CaM) in complex with the TRPV1-CT segment, determined to 1.95-Å resolution. The two lobes of Ca(2+)-CaM wrap around a helical TRPV1-CT segment in an antiparallel orientation, and two hydrophobic anchors, W787 and L796, contact the C-lobe and N-lobe of Ca(2+)-CaM, respectively. This structure is similar to canonical Ca(2+)-CaM-peptide complexes, although TRPV1 contains no classical CaM recognition sequence motif. Using structural and mutational studies, we established the TRPV1 C terminus as a high affinity Ca(2+)-CaM-binding site in both the isolated TRPV1 C terminus and in full-length TRPV1. Although a ternary complex of CaM, TRPV1-ARD, and TRPV1-CT had previously been postulated, we found no biochemical evidence of such a complex. In electrophysiology studies, mutation of the Ca(2+)-CaM-binding site on TRPV1-ARD abolished desensitization in response to repeated application of capsaicin, whereas mutation of the Ca(2+)-CaM-binding site in TRPV1-CT led to a more subtle phenotype of slowed and reduced TRPV1 desensitization. In summary, our results show that the TRPV1-ARD is an important mediator of TRPV1 desensitization, whereas TRPV1-CT has higher affinity for CaM and is likely involved in separate regulatory mechanisms.
Collapse
Affiliation(s)
- Sze-Yi Lau
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | |
Collapse
|
45
|
Inada H, Procko E, Sotomayor M, Gaudet R. Structural and biochemical consequences of disease-causing mutations in the ankyrin repeat domain of the human TRPV4 channel. Biochemistry 2012; 51:6195-206. [PMID: 22702953 PMCID: PMC3413242 DOI: 10.1021/bi300279b] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The TRPV4 calcium-permeable cation channel plays important
physiological
roles in osmosensation, mechanosensation, cell barrier formation,
and bone homeostasis. Recent studies reported that mutations in TRPV4,
including some in its ankyrin repeat domain (ARD), are associated
with human inherited diseases, including neuropathies and skeletal
dysplasias, probably because of the increased constitutive activity
of the channel. TRPV4 activity is regulated by the binding of calmodulin
and small molecules such as ATP to the ARD at its cytoplasmic N-terminus.
We determined structures of ATP-free and -bound forms of human TRPV4-ARD
and compared them with available TRPV-ARD structures. The third inter-repeat
loop region (Finger 3 loop) is flexible and may act as a switch to
regulate channel activity. Comparisons of TRPV-ARD structures also
suggest an evolutionary link between ARD structure and ATP binding
ability. Thermal stability analyses and molecular dynamics simulations
suggest that ATP increases stability in TRPV-ARDs that can bind ATP.
Biochemical analyses of a large panel of TRPV4-ARD mutations associated
with human inherited diseases showed that some impaired thermal stability
while others weakened ATP binding ability, suggesting molecular mechanisms
for the diseases.
Collapse
Affiliation(s)
- Hitoshi Inada
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
46
|
Abstract
Adaptive, cell-mediated immunity involves the presentation of antigenic peptides on class I MHC molecules at the cell surface. This requires an ABC transporter associated with antigen processing (TAP) to transport antigenic peptides generated in the cytosol into the endoplasmic reticulum (ER) for loading onto class I MHC. Recent crystal structures of bacterial ABC transporters suggest how the transmembrane domains of TAP form a peptide-binding cavity that acquires peptides from the cytosol, and following ATP-induced conformational changes, the peptide-binding cavity closes to the cytosol and instead opens to the ER lumen for peptide release. Extensive biochemical studies show how transport is driven by ATP binding and hydrolysis on an asymmetric pair of cytosolic nucleotide-binding domains, which are physically coupled to the peptide-binding site to propagate conformational changes through the protein.
Collapse
Affiliation(s)
- Erik Procko
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | | |
Collapse
|
47
|
Procko E, O'Mara ML, Bennett WFD, Tieleman DP, Gaudet R. The mechanism of ABC transporters: general lessons from structural and functional studies of an antigenic peptide transporter. FASEB J 2009; 23:1287-302. [PMID: 19174475 DOI: 10.1096/fj.08-121855] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The shuttling of substrates across a cellular membrane frequently requires a specialized ATP-binding cassette (ABC) transporter, which couples the energy of ATP binding and hydrolysis to substrate transport. Due to its importance in immunity, the ABC transporter associated with antigen processing (TAP) has been studied extensively and is an excellent model for other ABC transporters. The TAP protein pumps cytosolic peptides into the endoplasmic reticulum for loading onto class I major histocompatibility complex (MHC) for subsequent immune surveillance. Here, we outline a potential mechanism for the TAP protein with supporting evidence from bacterial transporter structures. The similarities and differences between TAP and other transporters support the notion that ABC transporters in general have adapted around a universal transport mechanism.
Collapse
Affiliation(s)
- Erik Procko
- Department of Molecular and Cellular Biology, Harvard University 7 Divinity Ave., Cambridge, MA 02138, USA
| | | | | | | | | |
Collapse
|
48
|
Procko E, Gaudet R. Functionally important interactions between the nucleotide-binding domains of an antigenic peptide transporter. Biochemistry 2008; 47:5699-708. [PMID: 18452308 DOI: 10.1021/bi7024854] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The transporter associated with antigen processing (TAP), an ABC transporter, pumps cytosolic peptides into the endoplasmic reticulum, where the peptides are loaded onto class I MHC molecules for presentation to the immune system. Transport is fueled by the binding of ATP to two cytosolic nucleotide-binding domains (NBDs) and ATP hydrolysis. We demonstrate biochemically that there are two electrostatic interactions across the interface between the two TAP NBDs and that these interactions are important for peptide transport. Notably, disrupting these interactions by mutagenesis does not greatly alter the ATP hydrolysis rate in an isolated NBD model system, suggesting that the interactions function at alternative stages in the transport cycle. The data support the general model for ABC transporters in which the NBDs form a tight, closed conformation during transport. Our results are discussed in relation to other ABC transporters that do or do not conserve potential interacting residues of opposite charges at the homologous positions.
Collapse
Affiliation(s)
- Erik Procko
- Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, Massachusetts 02138, USA
| | | |
Collapse
|
49
|
Procko E, Raghuraman G, Wiley DC, Raghavan M, Gaudet R. Identification of domain boundaries within the N-termini of TAP1 and TAP2 and their importance in tapasin binding and tapasin-mediated increase in peptide loading of MHC class I. Immunol Cell Biol 2008; 83:475-82. [PMID: 16174096 DOI: 10.1111/j.1440-1711.2005.01354.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Before exit from the endoplasmic reticulum (ER), MHC class I molecules transiently associate with the transporter associated with antigen processing (TAP1/TAP2) in an interaction that is bridged by tapasin. TAP1 and TAP2 belong to the ATP-binding cassette (ABC) transporter family, and are necessary and sufficient for peptide translocation across the ER membrane during loading of MHC class I molecules. Most ABC transporters comprise a transmembrane region with six membrane-spanning helices. TAP1 and TAP2, however, contain additional N-terminal sequences whose functions may be linked to interactions with tapasin and MHC class I molecules. Upon expression and purification of human TAP1/TAP2 complexes from insect cells, proteolytic fragments were identified that result from cleavage at residues 131 and 88 of TAP1 and TAP2, respectively. N-Terminally truncated TAP variants lacking these segments retained the ability to bind peptide and nucleotide substrates at a level comparable to that of wild-type TAP. The truncated constructs were also capable of peptide translocation in vitro, although with reduced efficiency. In an insect cell-based assay that reconstituted the class I loading pathway, the truncated TAP variants promoted HLA-B*2705 processing to similar levels as wild-type TAP. However, correlating with the observed reduction in tapasin binding, the tapasin-mediated increase in processing of HLA-B*2705 and HLA-B*4402 was lower for the truncated TAP constructs relative to the wild type. Together, these studies indicate that N-terminal domains of TAP1 and TAP2 are important for tapasin binding and for optimal peptide loading onto MHC class I molecules.
Collapse
Affiliation(s)
- Erik Procko
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | | | | | |
Collapse
|
50
|
Lishko PV, Procko E, Jin X, Phelps CB, Gaudet R. The ankyrin repeats of TRPV1 bind multiple ligands and modulate channel sensitivity. Neuron 2007; 54:905-18. [PMID: 17582331 DOI: 10.1016/j.neuron.2007.05.027] [Citation(s) in RCA: 301] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 05/08/2007] [Accepted: 05/30/2007] [Indexed: 10/23/2022]
Abstract
TRPV1 plays a key role in nociception, as it is activated by heat, low pH, and ligands such as capsaicin, leading to a burning pain sensation. We describe the structure of the cytosolic ankyrin repeat domain (ARD) of TRPV1 and identify a multiligand-binding site important in regulating channel sensitivity within the TRPV1-ARD. The structure reveals a binding site that accommodates triphosphate nucleotides such as ATP, and biochemical studies demonstrate that calmodulin binds the same site. Electrophysiology experiments show that either ATP or PIP2 prevent desensitization to repeated applications of capsaicin, i.e., tachyphylaxis, while calmodulin plays an opposing role and is necessary for tachyphylaxis. Mutations in the TRPV1-ARD binding site eliminate tachyphylaxis. We present a model for the calcium-dependent regulation of TRPV1 via competitive interactions of ATP and calmodulin at the TRPV1-ARD-binding site and discuss its relationship to the C-terminal region previously implicated in interactions with PIP2 and calmodulin.
Collapse
Affiliation(s)
- Polina V Lishko
- Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA
| | | | | | | | | |
Collapse
|