1
|
Jeung HC, Puentes R, Aleshin A, Indarte M, Correa RG, Bankston LA, Layng FIAL, Ahmed Z, Wistuba I, Yao Y, Duenas DG, Zhang S, Meuillet EJ, Marassi F, Liddington RC, Kirkpatrick L, Powis G. PLEKHA7 signaling is necessary for the growth of mutant KRAS driven colorectal cancer. Exp Cell Res 2021; 409:112930. [PMID: 34800542 DOI: 10.1016/j.yexcr.2021.112930] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/26/2021] [Accepted: 11/14/2021] [Indexed: 10/19/2022]
Abstract
Plekha7 (Pleckstrin homology [PH] domain containing, family A member 7) regulates the assembly of proteins of the cytoplasmic apical zonula adherens junction (AJ), thus ensuring cell-cell adhesion and tight-junction barrier integrity. Little is known of Plekha7 function in cancer. In colorectal cancer (CRC) Plekha7 expression is elevated compared to adjacent normal tissue levels, increasing with clinical stage. Plekha7 was present at plasma membrane AJ with wild-type KRas (wt-KRas) but was dispersed in cells expressing mutant KRas (mut-KRas). Fluorescence lifetime imaging microscopy (FLIM) indicated a direct Plekha7 interaction with wt-KRas but scantily with mut-KRas. Inhibiting Plekha7 specifically decreased mut-KRas cell signaling, proliferation, attachment, migration, and retarded mut-KRAS CRC tumor growth. Binding of diC8-phosphoinositides (PI) to the PH domain of Plekha7 was relatively low affinity. This may be because a D175 amino acid residue plays a "sentry" role preventing PI(3,4)P2 and PI(3,4,5)P3 binding. Molecular or pharmacological inhibition of the Plekha7 PH domain prevented the growth of mut-KRas but not wt-KRas cells. Taken together the studies suggest that Plekha7, in addition to maintaining AJ structure plays a role in mut-KRas signaling and phenotype through interaction of its PH domain with membrane mut-KRas, but not wt-KRas, to increase the efficiency of mut-KRas downstream signaling.
Collapse
Affiliation(s)
- Hei-Cheul Jeung
- MD Anderson Cancer Center, Houston, TX, USA; Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Gangnam-Gu, Seoul, South Korea
| | - Roisin Puentes
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | - Alexander Aleshin
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | | | - Ricardo G Correa
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | - Laurie A Bankston
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | - Fabiana I A L Layng
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | | | | | - Yong Yao
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | - Daniela G Duenas
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | | | | | - Francesca Marassi
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | - Robert C Liddington
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA
| | | | - Garth Powis
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, CA, USA; PHusis Therapeutics, La Jolla, CA, USA.
| |
Collapse
|
2
|
Aleshin AE, Yao Y, Iftikhar A, Bobkov AA, Yu J, Cadwell G, Klein MG, Dong C, Bankston LA, Liddington RC, Im W, Powis G, Marassi FM. Structural basis for the association of PLEKHA7 with membrane-embedded phosphatidylinositol lipids. Structure 2021; 29:1029-1039.e3. [PMID: 33878292 DOI: 10.1016/j.str.2021.03.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/15/2021] [Accepted: 03/25/2021] [Indexed: 01/11/2023]
Abstract
PLEKHA7 (pleckstrin homology domain containing family A member 7) plays key roles in intracellular signaling, cytoskeletal organization, and cell adhesion, and is associated with multiple human cancers. The interactions of its pleckstrin homology (PH) domain with membrane phosphatidyl-inositol-phosphate (PIP) lipids are critical for proper cellular localization and function, but little is known about how PLEKHA7 and other PH domains interact with membrane-embedded PIPs. Here we describe the structural basis for recognition of membrane-bound PIPs by PLEHA7. Using X-ray crystallography, nuclear magnetic resonance, molecular dynamics simulations, and isothermal titration calorimetry, we show that the interaction of PLEKHA7 with PIPs is multivalent, distinct from a discrete one-to-one interaction, and induces PIP clustering. Our findings reveal a central role of the membrane assembly in mediating protein-PIP association and provide a roadmap for understanding how the PH domain contributes to the signaling, adhesion, and nanoclustering functions of PLEKHA7.
Collapse
Affiliation(s)
- Alexander E Aleshin
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yong Yao
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Amer Iftikhar
- Departments of Biological Sciences, Chemistry and Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Andrey A Bobkov
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jinghua Yu
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Gregory Cadwell
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Michael G Klein
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Chuqiao Dong
- Departments of Biological Sciences, Chemistry and Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Laurie A Bankston
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Robert C Liddington
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry and Bioengineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Garth Powis
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Francesca M Marassi
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| |
Collapse
|
3
|
Indarte M, Puentes R, Maruggi M, Ihle NT, Grandjean G, Scott M, Ahmed Z, Meuillet EJ, Zhang S, Lemos R, Du-Cuny L, Layng FIAL, Correa RG, Bankston LA, Liddington RC, Kirkpatrick L, Powis G. Correction: An Inhibitor of the Pleckstrin Homology Domain of CNK1 Selectively Blocks the Growth of Mutant KRAS Cells and Tumors. Cancer Res 2019; 79:5457. [PMID: 31615811 DOI: 10.1158/0008-5472.can-19-2586] [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: 11/16/2022]
|
4
|
Indarte M, Puentes R, Maruggi M, Ihle NT, Grandjean G, Scott M, Ahmed Z, Meuillet EJ, Zang S, Lemos R, Du-Cuny L, Layng FIAL, Correa RG, Bankston LA, Liddington RC, Kirkpatrick L, Powis G. An Inhibitor of the Pleckstrin Homology Domain of CNK1 Selectively Blocks the Growth of Mutant KRAS Cells and Tumors. Cancer Res 2019; 79:3100-3111. [PMID: 31040156 DOI: 10.1158/0008-5472.can-18-2372] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 12/03/2018] [Accepted: 04/26/2019] [Indexed: 12/11/2022]
Abstract
Cnk1 (connector enhancer of kinase suppressor of Ras 1) is a pleckstrin homology (PH) domain-containing scaffold protein that increases the efficiency of Ras signaling pathways, imparting efficiency and specificity to the response of cell proliferation, survival, and migration. Mutated KRAS (mut-KRAS) is the most common proto-oncogenic event, occurring in approximately 25% of human cancers and has no effective treatment. In this study, we show that selective inhibition of Cnk1 blocks growth and Raf/Mek/Erk, Rho and RalA/B signaling in mut-KRAS lung and colon cancer cells with little effect on wild-type (wt)-KRAS cells. Cnk1 inhibition decreased anchorage-independent mut-KRas cell growth more so than growth on plastic, without the partial "addiction" to mut-KRAS seen on plastic. The PH domain of Cnk1 bound with greater affinity to PtdIns(4,5)P2 than PtdIns(3,4,5)P3, and Cnk1 localized to areas of the plasma membranes rich in PtdIns, suggesting a role for the PH domain in the biological activity of Cnk1. Through molecular modeling and structural modification, we identified a compound PHT-7.3 that bound selectively to the PH domain of Cnk1, preventing plasma membrane colocalization with mut-KRas. PHT-7.3 inhibited mut-KRas, but not wild-type KRas cancer cell and tumor growth and signaling. Thus, the PH domain of Cnk1 is a druggable target whose inhibition selectively blocks mutant KRas activation, making Cnk1 an attractive therapeutic target in patients with mut-KRAS-driven cancer. SIGNIFICANCE: These findings identify a therapeutic strategy to selectively block oncogenic KRas activity through the PH domain of Cnk1, which reduces its cell membrane binding, decreasing the efficiency of Ras signaling and tumor growth.
Collapse
Affiliation(s)
| | - Roisin Puentes
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | - Marco Maruggi
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | | | - Geoffrey Grandjean
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | | | | | | | | | - Robert Lemos
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | | | - Fabiana I A L Layng
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | - Ricardo G Correa
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | - Laurie A Bankston
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | - Robert C Liddington
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California
| | | | - Garth Powis
- Sanford Burnham Prebys Medical Discovery Institute Cancer Center, La Jolla, California.
| |
Collapse
|
5
|
Stanford SM, Aleshin AE, Zhang V, Ardecky RJ, Hedrick MP, Zou J, Ganji SR, Bliss MR, Yamamoto F, Bobkov AA, Kiselar J, Liu Y, Cadwell GW, Khare S, Yu J, Barquilla A, Chung TDY, Mustelin T, Schenk S, Bankston LA, Liddington RC, Pinkerton AB, Bottini N. Diabetes reversal by inhibition of the low-molecular-weight tyrosine phosphatase. Nat Chem Biol 2017; 13:624-632. [PMID: 28346406 PMCID: PMC5435566 DOI: 10.1038/nchembio.2344] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [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: 05/02/2016] [Accepted: 01/06/2017] [Indexed: 11/09/2022]
Abstract
Obesity-associated insulin resistance plays a central role in type 2 diabetes. As such, tyrosine phosphatases that dephosphorylate the insulin receptor (IR) are potential therapeutic targets. The low-molecular-weight protein tyrosine phosphatase (LMPTP) is a proposed IR phosphatase, yet its role in insulin signaling in vivo has not been defined. Here we show that global and liver-specific LMPTP deletion protects mice from high-fat diet-induced diabetes without affecting body weight. To examine the role of the catalytic activity of LMPTP, we developed a small-molecule inhibitor with a novel uncompetitive mechanism, a unique binding site at the opening of the catalytic pocket, and an exquisite selectivity over other phosphatases. This inhibitor is orally bioavailable, and it increases liver IR phosphorylation in vivo and reverses high-fat diet-induced diabetes. Our findings suggest that LMPTP is a key promoter of insulin resistance and that LMPTP inhibitors would be beneficial for treating type 2 diabetes.
Collapse
Affiliation(s)
- Stephanie M Stanford
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA.,Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Alexander E Aleshin
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Vida Zhang
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA.,Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Robert J Ardecky
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Michael P Hedrick
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Jiwen Zou
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Santhi R Ganji
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Matthew R Bliss
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Fusayo Yamamoto
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Andrey A Bobkov
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Janna Kiselar
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yingge Liu
- Institute for Genetic Medicine, University of Southern California, Los Angeles, California, USA
| | - Gregory W Cadwell
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Shilpi Khare
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Jinghua Yu
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Antonio Barquilla
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Thomas D Y Chung
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Tomas Mustelin
- Department of Respiratory, Inflammation and Autoimmunity, MedImmune LLC, Gaithersburg, Maryland, USA
| | - Simon Schenk
- Department of Orthopaedic Surgery and Department of Pediatrics, University of California, San Diego, La Jolla, California, USA
| | - Laurie A Bankston
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Robert C Liddington
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Anthony B Pinkerton
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Nunzio Bottini
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA.,Department of Medicine, University of California, San Diego, La Jolla, California, USA
| |
Collapse
|
6
|
Grandjean G, de Jong PR, James B, Koh MY, Lemos R, Kingston J, Aleshin A, Bankston LA, Miller CP, Cho EJ, Edupuganti R, Devkota A, Stancu G, Liddington RC, Dalby K, Powis G. Definition of a Novel Feed-Forward Mechanism for Glycolysis-HIF1α Signaling in Hypoxic Tumors Highlights Aldolase A as a Therapeutic Target. Cancer Res 2016; 76:4259-4269. [PMID: 27261507 DOI: 10.1158/0008-5472.can-16-0401] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/06/2016] [Indexed: 11/16/2022]
Abstract
The hypoxia-inducible transcription factor HIF1α drives expression of many glycolytic enzymes. Here, we show that hypoxic glycolysis, in turn, increases HIF1α transcriptional activity and stimulates tumor growth, revealing a novel feed-forward mechanism of glycolysis-HIF1α signaling. Negative regulation of HIF1α by AMPK1 is bypassed in hypoxic cells, due to ATP elevation by increased glycolysis, thereby preventing phosphorylation and inactivation of the HIF1α transcriptional coactivator p300. Notably, of the HIF1α-activated glycolytic enzymes we evaluated by gene silencing, aldolase A (ALDOA) blockade produced the most robust decrease in glycolysis, HIF-1 activity, and cancer cell proliferation. Furthermore, either RNAi-mediated silencing of ALDOA or systemic treatment with a specific small-molecule inhibitor of aldolase A was sufficient to increase overall survival in a xenograft model of metastatic breast cancer. In establishing a novel glycolysis-HIF-1α feed-forward mechanism in hypoxic tumor cells, our results also provide a preclinical rationale to develop aldolase A inhibitors as a generalized strategy to treat intractable hypoxic cancer cells found widely in most solid tumors. Cancer Res; 76(14); 4259-69. ©2016 AACR.
Collapse
Affiliation(s)
- Geoffrey Grandjean
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center. Houston, TX.,Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Petrus R de Jong
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Brian James
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Mei Yee Koh
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Robert Lemos
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - John Kingston
- Department of Experimental Therapeutics, University of Texas MD Anderson Cancer Center. Houston, TX
| | - Alexander Aleshin
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Laurie A Bankston
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Claudia P Miller
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Eun Jeong Cho
- Department of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX
| | - Ramakrishna Edupuganti
- Department of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX
| | - Ashwini Devkota
- Department of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX
| | - Gabriel Stancu
- Department of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX
| | - Robert C Liddington
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Kevin Dalby
- Department of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX
| | - Garth Powis
- Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| |
Collapse
|
7
|
Avnir Y, Tallarico AS, Zhu Q, Bennett AS, Connelly G, Sheehan J, Sui J, Fahmy A, Huang CY, Cadwell G, Bankston LA, McGuire AT, Stamatatos L, Wagner G, Liddington RC, Marasco WA. Molecular signatures of hemagglutinin stem-directed heterosubtypic human neutralizing antibodies against influenza A viruses. PLoS Pathog 2014; 10:e1004103. [PMID: 24788925 PMCID: PMC4006906 DOI: 10.1371/journal.ppat.1004103] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [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: 12/07/2013] [Accepted: 03/15/2014] [Indexed: 12/28/2022] Open
Abstract
Recent studies have shown high usage of the IGHV1-69 germline immunoglobulin gene for influenza hemagglutinin stem-directed broadly-neutralizing antibodies (HV1-69-sBnAbs). Here we show that a major structural solution for these HV1-69-sBnAbs is achieved through a critical triad comprising two CDR-H2 loop anchor residues (a hydrophobic residue at position 53 (Ile or Met) and Phe54), and CDR-H3-Tyr at positions 98±1; together with distinctive V-segment CDR amino acid substitutions that occur in positions sparse in AID/polymerase-η recognition motifs. A semi-synthetic IGHV1-69 phage-display library screen designed to investigate AID/polη restrictions resulted in the isolation of HV1-69-sBnAbs that featured a distinctive Ile52Ser mutation in the CDR-H2 loop, a universal CDR-H3 Tyr at position 98 or 99, and required as little as two additional substitutions for heterosubtypic neutralizing activity. The functional importance of the Ile52Ser mutation was confirmed by mutagenesis and by BCR studies. Structural modeling suggests that substitution of a small amino acid at position 52 (or 52a) facilitates the insertion of CDR-H2 Phe54 and CDR-H3-Tyr into adjacent pockets on the stem. These results support the concept that activation and expansion of a defined subset of IGHV1-69-encoded B cells to produce potent HV1-69-sBnAbs does not necessarily require a heavily diversified V-segment acquired through recycling/reentry into the germinal center; rather, the incorporation of distinctive amino acid substitutions by Phase 2 long-patch error-prone repair of AID-induced mutations or by random non-AID SHM events may be sufficient. We propose that these routes of B cell maturation should be further investigated and exploited as a pathway for HV1-69-sBnAb elicitation by vaccination. The quest for universal influenza vaccine has gained wide interest with the discovery of human neutralizing antibodies that are able to variably cross neutralize and protect against different influenza strains, subtypes, groups and lineages. These antibodies, which bind to a highly conserved epitope in the hemagglutinin stem, are often encoded by rearranged IGHV1-69 germline genes that alone make contact with HA and prevent virus entry and emergence of escape mutants. Our study was undertaken to gain an understanding of what structural requirements enable a rearranged IGHV1-69 Ab to become a potent cross-neutralizing antibody. We found that in addition to a critical amino acid triad consisting of a pair of anchor residues in CDR-H2 and a properly positioned CDR-H3 Tyr, distinctive V-segment substitutions that arise in positions that are distinct from phase I AID somatic hypermutation (SHM) hotspot motifs are often required. As few as two V-segment SHM can fulfill this role which appears to facilitate the optimal binding of CDR-H2 Phe54 and CHR-H3-Tyr into adjacent hydrophobic pockets in the HA stem. These studies provide new information on the SHM requirements for IGHV1-69-encoded B cells to produce HV1-69-sBnAbs and suggest that there may exist alternative routes to their elicitation by vaccination.
Collapse
Affiliation(s)
- Yuval Avnir
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Aimee S Tallarico
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Quan Zhu
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Andrew S Bennett
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gene Connelly
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jared Sheehan
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jianhua Sui
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Amr Fahmy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Chiung-yu Huang
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Greg Cadwell
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Laurie A Bankston
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Andrew T McGuire
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Leonidas Stamatatos
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Robert C Liddington
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Wayne A Marasco
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| |
Collapse
|
8
|
Aleshin AE, Schraufstatter IU, Stec B, Bankston LA, Liddington RC, DiScipio RG. Structure of complement C6 suggests a mechanism for initiation and unidirectional, sequential assembly of membrane attack complex (MAC). J Biol Chem 2012; 287:10210-10222. [PMID: 22267737 DOI: 10.1074/jbc.m111.327809] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The complement membrane attack complex (MAC) is formed by the sequential assembly of C5b with four homologous proteins as follows: one copy each of C6, C7, and C8 and 12-14 copies of C9. Together these form a lytic pore in bacterial membranes. C6 through C9 comprise a MAC-perforin domain flanked by 4-9 "auxiliary" domains. Here, we report the crystal structure of C6, the first and longest of the pore proteins to be recruited by C5b. Comparisons with the structures of the C8αβγ heterodimer and perforin show that the central domain of C6 adopts a "closed" (perforin-like) state that is distinct from the "open" conformations in C8. We further show that C6, C8α, and C8β contain three homologous subdomains ("upper," "lower," and "regulatory") related by rotations about two hinge points. In C6, the regulatory segment includes four auxiliary domains that stabilize the closed conformation, inhibiting release of membrane-inserting elements. In C8β, rotation of the regulatory segment is linked to an opening of the central β-sheet of its clockwise partner, C8α. Based on these observations, we propose a model for initiation and unidirectional propagation of the MAC in which the auxiliary domains play key roles: in the assembly of the C5b-8 initiation complex; in driving and regulating the opening of the β-sheet of the MAC-performin domain of each new recruit as it adds to the growing pore; and in stabilizing the final pore. Our model of the assembled pore resembles those of the cholesterol-dependent cytolysins but is distinct from that recently proposed for perforin.
Collapse
Affiliation(s)
- Alexander E Aleshin
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | | | - Boguslaw Stec
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | - Laurie A Bankston
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | - Robert C Liddington
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and.
| | - Richard G DiScipio
- Torrey Pines Institute for Molecular Studies, San Diego, California 92121
| |
Collapse
|
9
|
Sui J, Sheehan J, Hwang WC, Bankston LA, Burchett SK, Huang CY, Liddington RC, Beigel JH, Marasco WA. Wide prevalence of heterosubtypic broadly neutralizing human anti-influenza A antibodies. Clin Infect Dis 2011; 52:1003-9. [PMID: 21460314 PMCID: PMC3070035 DOI: 10.1093/cid/cir121] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [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: 12/02/2022] Open
Abstract
(See the editorial commentary by Donis and Cox, on pages 1010–1012.) Background. Lack of life-long immunity against influenza viruses represents a major global health care problem with profound medical and economic consequences. A greater understanding of the broad-spectrum “heterosubtypic” neutralizing human antibody (BnAb) response to influenza should bring us closer toward a universal influenza vaccine. Methods. Serum samples obtained from 77 volunteers in an H5N1 vaccine study were analyzed for cross-reactive antibodies (Abs) against both subtype hemagglutinins (HAs) and a highly conserved pocket on the HA stem of Group 1 viruses. Cross-reactive Abs in commercial intravenous immunoglobulin were affinity purified using H5-coupled beads followed by step-wise monoclonal antibody competition or acid elution. Enzyme-linked immunosorbent assays were used to quantify cross-binding, and neutralization activity was determined with HA-pseudotyped viruses. Results. Prevaccination serum samples have detectable levels of heterosubtypic HA binding activity to both Group 1 and 2 influenza A viruses, including subtypes H5 and H7, respectively, to which study subjects had not been vaccinated. Two different populations of Broadly neutralizing Abs (BnAbs) were purified from intravenous immunoglobulin by H5 beads: ∼0.01% of total immunoglobulin G can bind to HAs from both Group 1 and 2 and neutralize H1N1 and H5N1 viruses; ∼0.001% is F10-like Abs directed against the HA stem pocket on Group 1 viruses. Conclusions. These data—to our knowledge, for the first time—quantitatively show the presence, albeit at low levels, of two populations of heterosubtypic BnAbs against influenza A in human serum. These observations warrant further investigation to determine their origin, host polymorphism(s) that may affect their expression levels and how to boost these BnAb responses by vaccination to reach sustainable protective levels.
Collapse
Affiliation(s)
- Jianhua Sui
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Stranzl GR, Santelli E, Bankston LA, La Clair C, Bobkov A, Schwarzenbacher R, Godzik A, Perego M, Grynberg M, Liddington RC. Structural insights into inhibition of Bacillus anthracis sporulation by a novel class of non-heme globin sensor domains. J Biol Chem 2011; 286:8448-8458. [PMID: 21216948 DOI: 10.1074/jbc.m110.207126] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pathogenesis by Bacillus anthracis requires coordination between two distinct activities: plasmid-encoded virulence factor expression (which protects vegetative cells from immune surveillance during outgrowth and replication) and chromosomally encoded sporulation (required only during the final stages of infection). Sporulation is regulated by at least five sensor histidine kinases that are activated in response to various environmental cues. One of these kinases, BA2291, harbors a sensor domain that has ∼35% sequence identity with two plasmid proteins, pXO1-118 and pXO2-61. Because overexpression of pXO2-61 (or pXO1-118) inhibits sporulation of B. anthracis in a BA2291-dependent manner, and pXO2-61 expression is strongly up-regulated by the major virulence gene regulator, AtxA, it was suggested that their function is to titrate out an environmental signal that would otherwise promote untimely sporulation. To explore this hypothesis, we determined crystal structures of both plasmid-encoded proteins. We found that they adopt a dimeric globin fold but, most unusually, do not bind heme. Instead, they house a hydrophobic tunnel and hydrophilic chamber that are occupied by fatty acid, which engages a conserved arginine and chloride ion via its carboxyl head group. In vivo, these domains may therefore recognize changes in fatty acid synthesis, chloride ion concentration, and/or pH. Structure-based comparisons with BA2291 suggest that it binds ligand and dimerizes in an analogous fashion, consistent with the titration hypothesis. Analysis of newly sequenced bacterial genomes points to the existence of a much broader family of non-heme, globin-based sensor domains, with related but distinct functionalities, that may have evolved from an ancestral heme-linked globin.
Collapse
Affiliation(s)
- Gudrun R Stranzl
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Eugenio Santelli
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Laurie A Bankston
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Chandra La Clair
- the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, and
| | - Andrey Bobkov
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Robert Schwarzenbacher
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Adam Godzik
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037
| | - Marta Perego
- the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, and
| | - Marcin Grynberg
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037,; the Institute of Biochemistry and Biophysics PAS, Pawinskiego 5A, 02-106 Warsaw, Poland
| | - Robert C Liddington
- From the Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037,.
| |
Collapse
|
11
|
Premkumar L, Bobkov AA, Patel M, Jaroszewski L, Bankston LA, Stec B, Vuori K, Côté JF, Liddington RC. Structural basis of membrane targeting by the Dock180 family of Rho family guanine exchange factors (Rho-GEFs). J Biol Chem 2010; 285:13211-22. [PMID: 20167601 PMCID: PMC2857062 DOI: 10.1074/jbc.m110.102517] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [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: 01/09/2010] [Revised: 02/15/2010] [Indexed: 02/02/2023] Open
Abstract
The Dock180 family of atypical Rho family guanine nucleotide exchange factors (Rho-GEFs) regulate a variety of processes involving cellular or subcellular polarization, including cell migration and phagocytosis. Each contains a Dock homology region-1 (DHR-1) domain that is required to localize its GEF activity to a specific membrane compartment where levels of phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P(3)) are up-regulated by the local activity of PtdIns 3-kinase. Here we define the structural and energetic bases of phosphoinositide specificity by the DHR-1 domain of Dock1 (a GEF for Rac1), and show that DHR-1 utilizes a C2 domain scaffold and surface loops to create a basic pocket on its upper surface for recognition of the PtdIns(3,4,5)P(3) head group. The pocket has many of the characteristics of those observed in pleckstrin homology domains. We show that point mutations in the pocket that abolish phospholipid binding in vitro ablate the ability of Dock1 to induce cell polarization, and propose a model that brings together recent mechanistic and structural studies to rationalize the central role of DHR-1 in dynamic membrane targeting of the Rho-GEF activity of Dock180.
Collapse
Affiliation(s)
| | - Andrey A. Bobkov
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | - Manishha Patel
- the
Institut de Recherches Cliniques de Montréal, Université de Montréal, Montréal, Québec H2W1R7, Canada
| | - Lukasz Jaroszewski
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | | | - Boguslaw Stec
- From the
Infectious and Inflammatory Disease Center and
| | - Kristiina Vuori
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | - Jean-Francois Côté
- the
Institut de Recherches Cliniques de Montréal, Université de Montréal, Montréal, Québec H2W1R7, Canada
| | | |
Collapse
|
12
|
Sui J, Hwang WC, Perez S, Wei G, Aird D, Chen LM, Santelli E, Stec B, Cadwell G, Ali M, Wan H, Murakami A, Yammanuru A, Han T, Cox NJ, Bankston LA, Donis RO, Liddington RC, Marasco WA. Structural and functional bases for broad-spectrum neutralization of avian and human influenza A viruses. Nat Struct Mol Biol 2009; 16:265-73. [PMID: 19234466 PMCID: PMC2692245 DOI: 10.1038/nsmb.1566] [Citation(s) in RCA: 947] [Impact Index Per Article: 63.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 01/22/2009] [Indexed: 02/03/2023]
Abstract
A group of neutralizing monoclonal antibodies (mAbs) targeting the influenza A hemagglutinin has been selected and characterized. Remarkably, these mAbs were able to neutralize a broad array of group 1 strains and could protect mice from infection when given prophylactically or therapeutically. The crystal structure of one such mAb in complex with hemagglutinin provides insight into its mechanism of neutralization and broad specificity. Influenza virus remains a serious health threat, owing to its ability to evade immune surveillance through rapid genetic drift and reassortment. Here we used a human non-immune antibody phage-display library and the H5 hemagglutinin ectodomain to select ten neutralizing antibodies (nAbs) that were effective against all group 1 influenza viruses tested, including H5N1 'bird flu' and the H1N1 'Spanish flu'. The crystal structure of one such nAb bound to H5 shows that it blocks infection by inserting its heavy chain into a conserved pocket in the stem region, thus preventing membrane fusion. Nine of the nAbs employ the germline gene VH1-69, and all seem to use the same neutralizing mechanism. Our data further suggest that this region is recalcitrant to neutralization escape and that nAb-based immunotherapy is a promising strategy for broad-spectrum protection against seasonal and pandemic influenza viruses.
Collapse
Affiliation(s)
- Jianhua Sui
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street JFB 826, Boston, Massachusetts 02115, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Chen KH, Liu S, Bankston LA, Liddington RC, Leppla SH. Selection of anthrax toxin protective antigen variants that discriminate between the cellular receptors TEM8 and CMG2 and achieve targeting of tumor cells. J Biol Chem 2007; 282:9834-9845. [PMID: 17251181 PMCID: PMC2530824 DOI: 10.1074/jbc.m611142200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [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: 11/06/2022] Open
Abstract
Anthrax toxin, a three-component protein toxin secreted by Bacillus anthracis, assembles into toxic complexes at the surface of receptor-bearing eukaryotic cells. The protective antigen (PA) protein binds to receptors, either tumor endothelial cell marker 8 (TEM8) or CMG2 (capillary morphogenesis protein 2), and orchestrates the delivery of the lethal and edema factors into the cytosol. TEM8 is reported to be overexpressed during tumor angiogenesis, whereas CMG2 is more widely expressed in normal tissues. To extend prior work on targeting of tumor with modified anthrax toxins, we used phage display to select PA variants that preferentially bind to TEM8 as compared with CMG2. Substitutions were randomly introduced into residues 605-729 of PA, within the C-terminal domain 4 of PA, which is the principal region that contacts receptor. Candidates were characterized in cellular cytotoxicity assays with Chinese hamster ovary (CHO) cells expressing either TEM8 or CMG2. A PA mutant having the substitutions R659S and M662R had enhanced specificity toward TEM8-overexpressing CHO cells. This PA variant also displayed broad and potent tumoricidal activity to various human tumor cells, especially to HeLa and A549/ATCC cells. By contrast, the substitution N657Q significantly reduced toxicity to TEM8 but not CMG2-overexpressing CHO cells. Our results indicate that certain amino acid substitutions within PA domain 4 create anthrax toxins that selectively kill human tumor cells. The PA R659S/M662R protein may be useful as a therapeutic agent for cancer treatment.
Collapse
Affiliation(s)
- Kuang-Hua Chen
- Laboratory of Bacterial Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202
| | - Shihui Liu
- Laboratory of Bacterial Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202
| | - Laurie A Bankston
- Infectious and Inflammatory Disease Center, Burnham Institute for Medical Research, La Jolla, California 92037
| | - Robert C Liddington
- Infectious and Inflammatory Disease Center, Burnham Institute for Medical Research, La Jolla, California 92037
| | - Stephen H Leppla
- Laboratory of Bacterial Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202.
| |
Collapse
|
14
|
Maeda S, Hsu LC, Liu H, Bankston LA, Iimura M, Kagnoff MF, Eckmann L, Karin M. Nod2 mutation in Crohn's disease potentiates NF-kappaB activity and IL-1beta processing. Science 2005; 307:734-8. [PMID: 15692052 DOI: 10.1126/science.1103685] [Citation(s) in RCA: 630] [Impact Index Per Article: 33.2] [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: 12/16/2022]
Abstract
Variants of NOD2, an intracellular sensor of bacteria-derived muramyl dipeptide (MDP), increase susceptibility to Crohn's disease (CD). These variants are thought to be defective in activation of nuclear factor kappaB (NF-kappaB) and antibacterial defenses, but CD clinical specimens display elevated NF-kappaB activity. To illuminate the pathophysiological function of NOD2, we introduced such a variant to the mouse Nod2 locus. Mutant mice exhibited elevated NF-kappaB activation in response to MDP and more efficient processing and secretion of the cytokine interleukin-1beta (IL-1beta). These effects are linked to increased susceptibility to bacterial-induced intestinal inflammation and identify NOD2 as a positive regulator of NF-kappaB activation and IL-1beta secretion.
Collapse
Affiliation(s)
- Shin Maeda
- Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0723, USA
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Santelli E, Bankston LA, Leppla SH, Liddington RC. Crystal structure of a complex between anthrax toxin and its host cell receptor. Nature 2004; 430:905-8. [PMID: 15243628 DOI: 10.1038/nature02763] [Citation(s) in RCA: 198] [Impact Index Per Article: 9.9] [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: 05/06/2004] [Accepted: 06/18/2004] [Indexed: 02/07/2023]
Abstract
Anthrax toxin consists of the proteins protective antigen (PA), lethal factor (LF) and oedema factor (EF). The first step of toxin entry into host cells is the recognition by PA of a receptor on the surface of the target cell. Subsequent cleavage of receptor-bound PA enables EF and LF to bind and form a heptameric PA63 pre-pore, which triggers endocytosis. Upon acidification of the endosome, PA63 forms a pore that inserts into the membrane and translocates EF and LF into the cytosol. Two closely related host cell receptors, TEM8 and CMG2, have been identified. Both bind to PA with high affinity and are capable of mediating toxicity. Here, we report the crystal structure of the PA-CMG2 complex at 2.5 A resolution. The structure reveals an extensive receptor-pathogen interaction surface mimicking the non-pathogenic recognition of the extracellular matrix by integrins. The binding surface is closely conserved in the two receptors and across species, but is quite different in the integrin domains, explaining the specificity of the interaction. CMG2 engages two domains of PA, and modelling of the receptor-bound PA63 heptamer suggests that the receptor acts as a pH-sensitive brace to ensure accurate and timely membrane insertion. The structure provides new leads for the discovery of anthrax anti-toxins, and should aid the design of cancer therapeutics.
Collapse
Affiliation(s)
- Eugenio Santelli
- Program on Cell Adhesion, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
| | | | | | | |
Collapse
|
16
|
Bakolitsa C, Cohen DM, Bankston LA, Bobkov AA, Cadwell GW, Jennings L, Critchley DR, Craig SW, Liddington RC. Structural basis for vinculin activation at sites of cell adhesion. Nature 2004; 430:583-6. [PMID: 15195105 DOI: 10.1038/nature02610] [Citation(s) in RCA: 285] [Impact Index Per Article: 14.3] [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: 04/01/2004] [Accepted: 04/29/2004] [Indexed: 01/12/2023]
Abstract
Vinculin is a highly conserved intracellular protein with a crucial role in the maintenance and regulation of cell adhesion and migration. In the cytosol, vinculin adopts a default autoinhibited conformation. On recruitment to cell-cell and cell-matrix adherens-type junctions, vinculin becomes activated and mediates various protein-protein interactions that regulate the links between F-actin and the cadherin and integrin families of cell-adhesion molecules. Here we describe the crystal structure of the full-length vinculin molecule (1,066 amino acids), which shows a five-domain autoinhibited conformation in which the carboxy-terminal tail domain is held pincer-like by the vinculin head, and ligand binding is regulated both sterically and allosterically. We show that conformational changes in the head, tail and proline-rich domains are linked structurally and thermodynamically, and propose a combinatorial pathway to activation that ensures that vinculin is activated only at sites of cell adhesion when two or more of its binding partners are brought into apposition.
Collapse
Affiliation(s)
- Constantina Bakolitsa
- Program on Cell Adhesion, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
Two recent papers provide the first evidence for a common mechanism of targeting and activation of an enzyme that is important in the rapid regulation of both focal adhesion assembly during cell migration and synaptic vesicle recycling at nerve terminals.
Collapse
Affiliation(s)
- Robert C Liddington
- Program on Cell Adhesion, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | | | | |
Collapse
|
18
|
Lipton SA, Choi YB, Takahashi H, Zhang D, Li W, Godzik A, Bankston LA. Cysteine regulation of protein function--as exemplified by NMDA-receptor modulation. Trends Neurosci 2002; 25:474-80. [PMID: 12183209 DOI: 10.1016/s0166-2236(02)02245-2] [Citation(s) in RCA: 298] [Impact Index Per Article: 13.5] [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: 11/17/2022]
Abstract
Until recently cysteine residues, especially those located extracellularly, were thought to be important for metal coordination, catalysis and protein structure by forming disulfide bonds - but they were not thought to regulate protein function. However, this is not the case. Crucial cysteine residues can be involved in modulation of protein activity and signaling events via other reactions of their thiol (sulfhydryl; -SH) groups. These reactions can take several forms, such as redox events (chemical reduction or oxidation), chelation of transition metals (chiefly Zn(2+), Mn(2+) and Cu(2+)) or S-nitrosylation [the catalyzed transfer of a nitric oxide (NO) group to a thiol group]. In several cases, these disparate reactions can compete with one another for the same thiol group on a single cysteine residue, forming a molecular switch composed of a latticework of possible redox, NO or Zn(2+) modifications to control protein function. Thiol-mediated regulation of protein function can also involve reactions of cysteine residues that affect ligand binding allosterically. This article reviews the basis for these molecular cysteine switches, drawing on the NMDA receptor as an exemplary protein, and proposes a molecular model for the action of S-nitrosylation based on recently derived crystal structures.
Collapse
Affiliation(s)
- Stuart A Lipton
- Center for Neuroscience and Aging, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
The A1 domain of von Willebrand factor (vWF) mediates platelet adhesion to sites of vascular injury by binding to the platelet receptor glycoprotein Ib (GpIb), an interaction that is regulated by hydrodynamic shear forces. The GpIb binding surface of A1 is distinct from a regulatory region, suggesting that ligand binding is controlled allosterically. Here we report the crystal structures of the "gain-of-function" mutant A1 domain (I546V) and its complex with the exogenous activator botrocetin. We show that botrocetin switches the mutant A1 back toward the wild-type conformation, suggesting that affinity is enhanced by augmenting the GpIb binding surface rather than through allosteric control. Functional studies of platelet adhesion under flow further suggest that the activation mechanism is distinct from that of the gain-of-function mutation.
Collapse
Affiliation(s)
- Koichi Fukuda
- The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
| | | | | | | | | | | |
Collapse
|
20
|
Affiliation(s)
- R C Liddington
- Program on Cell Adhesion, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, USA.
| | | |
Collapse
|
21
|
Renatus M, Zhou Q, Stennicke HR, Snipas SJ, Turk D, Bankston LA, Liddington RC, Salvesen GS. Crystal structure of the apoptotic suppressor CrmA in its cleaved form. Structure 2000; 8:789-97. [PMID: 10903953 DOI: 10.1016/s0969-2126(00)00165-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [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: 11/20/2022]
Abstract
BACKGROUND Cowpox virus expresses the serpin CrmA (cytokine response modifier A) in order to avoid inflammatory and apoptotic responses of infected host cells. The targets of CrmA are members of the caspase family of proteases that either initiate the extrinsic pathway of apoptosis (caspases 8 and 10) or trigger activation of the pro-inflammatory cytokines interleukin-1beta and interleukin-18 (caspase 1). RESULTS We have determined the structure of a cleaved form of CrmA to 2.26 A resolution. CrmA has the typical fold of a cleaved serpin, even though it lacks the N-terminal half of the A helix, the entire D helix, and a portion of the E helix that are present in all other known serpins. The reactive-site loop of CrmA was mutated to contain the optimal substrate recognition sequence for caspase 3; however, the mutation only marginally increased the ability of CrmA to inhibit caspase 3. Superposition of the reactive-site loop of alpha1-proteinase inhibitor on the cleaved CrmA structure provides a model for virgin CrmA that can be docked to caspase 1, but not to caspase 3. CONCLUSIONS CrmA exemplifies viral economy, selective pressure having resulted in a 'minimal' serpin that lacks the regions not needed for structural integrity or inhibitory activity. The docking model provides an explanation for the selectivity of CrmA. Our demonstration that engineering optimal substrate recognition sequences into the CrmA reactive-site loop fails to generate a good caspase 3 inhibitor is consistent with the docking model.
Collapse
Affiliation(s)
- M Renatus
- Program in Apoptosis and Cell Death Research, The Burnham Institute, La Jolla, CA 92037, USA
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Smith C, Estavillo D, Emsley J, Bankston LA, Liddington RC, Cruz MA. Mapping the collagen-binding site in the I domain of the glycoprotein Ia/IIa (integrin alpha(2)beta(1)). J Biol Chem 2000; 275:4205-9. [PMID: 10660584 DOI: 10.1074/jbc.275.6.4205] [Citation(s) in RCA: 43] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The I domain present within the alpha2 chain of the integrin alpha(2)beta(1) (GPIa/IIa) contains the principal collagen-binding site. Based on the crystal structure of the alpha2-I domain, a hypothetical model was proposed in which collagen binds to a groove on the upper surface of the I domain (Emsley, J., King, S. L., Bergelson, J. M., and Liddington, R. C. (1997) J. Biol. Chem. 272, 28512-28517). We have introduced point mutations into 13 residues on the upper surface of the domain. Recombinant mutant proteins were assayed for binding to monoclonal antibodies 6F1 and 12F1, to collagen under static conditions, and for the ability to retain adhesive activity under flow conditions. The mutations to residues surrounding the metal ion-dependent adhesion site that caused the greatest loss of collagen binding under both static and flow conditions are N154S in the betaA-alpha1 turn, N190D in the betaB-betaC turn, D219R in the alpha3-alpha4 turn, and E256V and H258V in the betaD-alpha5 turn. Mutation in one of the residues that coordinate the metal binding, S155A, completely lost the adhesive activity under flow but bound normally under static conditions, whereas the mutation Y285F had the converse effect. We conclude that the upper surface of the domain, including the metal ion-dependent adhesion site motif, defines the collagen recognition site.
Collapse
Affiliation(s)
- C Smith
- Hematology Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | | | | | | |
Collapse
|
23
|
Petosa C, Masters SC, Bankston LA, Pohl J, Wang B, Fu H, Liddington RC. 14-3-3zeta binds a phosphorylated Raf peptide and an unphosphorylated peptide via its conserved amphipathic groove. J Biol Chem 1998; 273:16305-10. [PMID: 9632691 DOI: 10.1074/jbc.273.26.16305] [Citation(s) in RCA: 263] [Impact Index Per Article: 10.1] [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: 01/19/2023] Open
Abstract
14-3-3 proteins bind a variety of molecules involved in signal transduction, cell cycle regulation and apoptosis. 14-3-3 binds ligands such as Raf-1 kinase and Bad by recognizing the phosphorylated consensus motif, RSXpSXP, but must bind unphosphorylated ligands, such as glycoprotein Ib and Pseudomonas aeruginosa exoenzyme S, via a different motif. Here we report the crystal structures of the zeta isoform of 14-3-3 in complex with two peptide ligands: a Raf-derived phosphopeptide (pS-Raf-259, LSQRQRSTpSTPNVHMV) and an unphosphorylated peptide derived from phage display (R18, PHCVPRDLSWLDLEANMCLP) that inhibits binding of exoenzyme S and Raf-1. The two peptides bind within a conserved amphipathic groove on the surface of 14-3-3 at overlapping but distinct sites. The phosphoserine of pS-Raf-259 engages a cluster of basic residues (Lys49, Arg56, Arg60, and Arg127), whereas R18 binds via the amphipathic sequence, WLDLE, with its two acidic groups coordinating the same basic cluster. 14-3-3 is dimeric, and its two peptide-binding grooves are arranged in an antiparallel fashion, 30 A apart. The ability of each groove to bind different peptide motifs suggests how 14-3-3 can act in signal transduction by inducing either homodimer or heterodimer formation in its target proteins.
Collapse
Affiliation(s)
- C Petosa
- Department of Biochemistry, University of Leicester, Leicester LE1 7RH, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
24
|
Bankston LA, Guidotti G. Characterization of ATP transport into chromaffin granule ghosts. Synergy of ATP and serotonin accumulation in chromaffin granule ghosts. J Biol Chem 1996; 271:17132-8. [PMID: 8663306 DOI: 10.1074/jbc.271.29.17132] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [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: 02/01/2023] Open
Abstract
ATP is an excitatory neurotransmitter that is stored and cosecreted with catecholamines from cells of the adrenal medulla. While the transport of catecholamines into chromaffin granule ghosts has been extensively characterized, there is little information on the mechanism of ATP transport into these structures. Here we show that ATP transport is driven by the electrical component of the electrochemical proton gradient created by the chromaffin granule membrane H+-ATPase, and that the accumulated nucleotide is released from the vesicles by inhibition of the H+-ATPase. GTP and UTP are also substrates for this transporter, distinguishing it from the mitochondrial ADP/ATP exchanger. Accumulation of ADP and ATP (rather than exchange with intravesicular ATP) is demonstrated by high pressure liquid chromatography measurements. The anion transport inhibitor 4,4-diisothiocyanatostilbene-2,2-disulfonic acid (Ki = 27 microM) inhibits ATP transport, while atractyloside, the inhibitor of the mitochondrial ATP/ADP exchanger, is a very poor inhibitor. Finally, we have demonstrated a synergy between the accumulation of ATP and that of serotonin (i.e. more of each solute accumulates when the two are accumulated together), supporting the view that there is an interaction between serotonin and ATP that reduces their effective concentration within the ghosts.
Collapse
Affiliation(s)
- L A Bankston
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | | |
Collapse
|
25
|
Abstract
BACKGROUND Integrins are plasma membrane proteins that mediate adhesion to other cells and to components of the extracellular matrix. Most integrins are constitutively inactive in resting cells, but are rapidly and reversibly activated in response to agonists, leading to highly regulated cell adhesion. This activation is associated with conformational changes in their extracellular portions, but the nature of the structural changes that lead to a change in adhesiveness is not understood. The interactions of several integrins with their extracellular ligands are mediated by an A-type domain (generally called the I-domain in integrins). Binding of the I-domain to protein ligands is dependent on divalent cations. We have described previously the structure of the I-domain from complement receptor 3 with bound Mg2+, in which the glutamate side chain from a second I-domain completes the octahedral coordination sphere of the metal, acting as a ligand mimetic. RESULTS We now describe a new crystal form of the I-domain with bound Mn2+, in which water completes the metal coordination sphere and there is no equivalent of the glutamate ligand. Comparison of the two crystal forms reveals a change in metal coordination which is linked to a large (10 A) shift of the C-terminal helix and the burial of two phenylalanine residues into the hydrophobic core of the Mn2+ form. These structural changes, analogous to those seen in the signal-transducing G-proteins, alter the electrophilicity of the metal, reducing its ability to bind ligand-associated acidic residues, and dramatically alter the surface of the protein implicated in binding ligand. CONCLUSIONS Our observations provide the first atomic resolution view of conformational changes in an integrin domain, and suggest how these changes are linked to a change in integrin adhesiveness. We propose that the Mg2+ form represents the conformation of the domain in the active state and the Mn2+ form the conformation in the inactive state of the integrin.
Collapse
Affiliation(s)
- J O Lee
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | |
Collapse
|