1
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Marafie SK, Alshawaf E, Abu-Farha M, Thanaraj TA, Wei DQ, Al-Mulla F, Khan A, Abubaker J, Mohammad A. Exploring the Binding Mechanism of NRG1-ERBB3 Complex and Discovery of Potent Natural Products to Reduce Diabetes-Assisted Breast Cancer Progression. Interdiscip Sci 2023:10.1007/s12539-023-00566-y. [PMID: 37389721 PMCID: PMC10374477 DOI: 10.1007/s12539-023-00566-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 03/25/2023] [Accepted: 03/30/2023] [Indexed: 07/01/2023]
Abstract
Diabetes mellitus significantly contributes to breast cancer progression, where hyperglycemia upregulates specific genes, leading to more aggressive tumor growth. In patients with BC that develop diabetes, neuregulin 1 (NRG1) and epidermal growth factor receptor 3 (ERBB3) overexpression exacerbate tumor growth and progression. Since the interaction between NRG1 and ERBB3 is critical for tumor growth, understanding the molecular mechanisms underlying NRG1-ERBB3 complex formation is essential for elucidating diabetes-assisted breast cancer progression. However, the key residues forming the NRG1-ERBB3 complex remain unknown. Here, we substituted specific residues in NRG1 with alanine and studied its interactions with ERBB3 using computational structural biology tools. We further screened the South African natural compounds database to target the complex's interface residues to discover potential inhibitors. The conformational stability and dynamic features of NRG1-WT, -H2A, -L3A, and -K35A complexed with ERBB3 were subjected to 400 ns molecular dynamics simulations. The free binding energies of all NRG1-ERBB3 complexes were calculated using the molecular mechanics-generalized Born surface area (MM/GBSA). The H2 and L3 alanine substitutions caused a loss of interaction with ERBB3 residue D73, weakening the interaction with ERBB3. Screening 1300 natural compounds identified four (SANC00643, SANC00824, SANC00975, and SANC00335) with the best potential to inhibit ERRB3-NRG1 coupling. The binding free energies for each complex were - 48.55 kcal/mol for SANC00643, - 47.68 kcal/mol for SANC00824, - 46.04 kcal/mol for SANC00975, and - 45.29 kcal/mol for SANC00335, showing their overall stronger binding with ERBB3 than NRG1 and their potential to act as ERBB3-NRG1 complex inhibitors. In conclusion, this complex may represent a residue-specific drug target to inhibit BC progression.
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Affiliation(s)
- Sulaiman K Marafie
- Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Eman Alshawaf
- Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Mohamed Abu-Farha
- Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait
- Special Service Facilities, Dasman Diabetes Institute, Kuwait City, Kuwait
| | | | - Dong-Qing Wei
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Fahd Al-Mulla
- Department of Genetics and Bioinformatics, Dasman Diabetes Institute, Kuwait City, Kuwait
| | - Abbas Khan
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Jehad Abubaker
- Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait.
| | - Anwar Mohammad
- Department of Biochemistry and Molecular Biology, Dasman Diabetes Institute, Kuwait City, Kuwait.
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2
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Chevillard PM, Batailler M, Dubois JP, Estienne A, Pillon D, Vaudin P, Piégu B, Blache MC, Dupont J, Just N, Migaud M. Seasonal remodeling of the progenitor pool and its distribution in the ewe mediobasal hypothalamus. Cell Tissue Res 2023:10.1007/s00441-023-03745-x. [PMID: 36795154 DOI: 10.1007/s00441-023-03745-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 01/23/2023] [Indexed: 02/17/2023]
Abstract
Recent studies have reported the presence of adult neurogenesis in the arcuate nucleus periventricular space (pvARH) and in the median eminence (ME), two structures involved in reproductive function. In sheep, a seasonal mammal, decreasing daylight in autumn induces a higher neurogenic activity in these two structures. However, the different types of neural stem and progenitor cells (NSCs/NPCs) that populate the arcuate nucleus and median eminence, as well as their location, have not been evaluated. Here, using semi-automatic image analyzing processes, we identified and quantified the different populations of NSCs/NPCs, showing that, during short days, higher densities of [SOX2 +] cells are found in pvARH and ME. In the pvARH, higher densities of astrocytic and oligodendrocitic progenitors mainly contribute to these variations. The different populations of NSCs/NPCs were mapped according to their position relative to the third ventricle and their proximity to the vasculature. We showed that [SOX2 +] cells extended deeper into the hypothalamic parenchyma during short days. Similarly, [SOX2 +] cells were found further from the vasculature in the pvARH and the ME, at this time of year, indicating the existence of migratory signals. The expression levels of neuregulin transcripts (NRGs), whose proteins are known to stimulate proliferation and adult neurogenesis and to regulate progenitor migration, as well as the expression levels of ERBB mRNAs, cognate receptors for NRGs, were assessed. We showed that mRNA expression changed seasonally in pvARH and ME, suggesting that the ErbB-NRG system is potentially involved in the photoperiodic regulation of neurogenesis in seasonal adult mammals.
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Affiliation(s)
| | - Martine Batailler
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | | | - Anthony Estienne
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | - Delphine Pillon
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | - Pascal Vaudin
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | - Benoît Piégu
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | | | - Joelle Dupont
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | - Nathalie Just
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France
| | - Martine Migaud
- CNRS, IFCE, INRAE, Université de Tours, PRC, F-37380, Nouzilly, France.
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3
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Wang Y, Wei J, Zhang P, Zhang X, Wang Y, Chen W, Zhao Y, Cui X. Neuregulin-1, a potential therapeutic target for cardiac repair. Front Pharmacol 2022; 13:945206. [PMID: 36120374 PMCID: PMC9471952 DOI: 10.3389/fphar.2022.945206] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
NRG1 (Neuregulin-1) is an effective cardiomyocyte proliferator, secreted and released by endothelial vascular cells, and affects the cardiovascular system. It plays a major role in heart growth, proliferation, differentiation, apoptosis, and other cardiovascular processes. Numerous experiments have shown that NRG1 can repair the heart in the pathophysiology of atherosclerosis, myocardial infarction, ischemia reperfusion, heart failure, cardiomyopathy and other cardiovascular diseases. NRG1 can connect related signaling pathways through the NRG1/ErbB pathway, which form signal cascades to improve the myocardial microenvironment, such as regulating cardiac inflammation, oxidative stress, necrotic apoptosis. Here, we summarize recent research advances on the molecular mechanisms of NRG1, elucidate the contribution of NRG1 to cardiovascular disease, discuss therapeutic approaches targeting NRG1 associated with cardiovascular disease, and highlight areas for future research.
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Affiliation(s)
- Yan Wang
- First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Jianliang Wei
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Peng Zhang
- First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Xin Zhang
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Yifei Wang
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Wenjing Chen
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Yanan Zhao
- First Clinical Medical School, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
- *Correspondence: Yanan Zhao, ; Xiangning Cui,
| | - Xiangning Cui
- Department of Cardiovascular, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Yanan Zhao, ; Xiangning Cui,
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4
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Neuregulins: protective and reparative growth factors in multiple forms of cardiovascular disease. Clin Sci (Lond) 2021; 134:2623-2643. [PMID: 33063822 PMCID: PMC7557502 DOI: 10.1042/cs20200230] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 02/06/2023]
Abstract
Neuregulins (NRGs) are protein ligands that act through ErbB receptor tyrosine kinases to regulate tissue morphogenesis, plasticity, and adaptive responses to physiologic needs in multiple tissues, including the heart and circulatory system. The role of NRG/ErbB signaling in cardiovascular biology, and how it responds to physiologic and pathologic stresses is a rapidly evolving field. While initial concepts focused on the role that NRG may play in regulating cardiac myocyte responses, including cell survival, growth, adaptation to stress, and proliferation, emerging data support a broader role for NRGs in the regulation of metabolism, inflammation, and fibrosis in response to injury. The constellation of effects modulated by NRGs may account for the findings that two distinct forms of recombinant NRG-1 have beneficial effects on cardiac function in humans with systolic heart failure. NRG-4 has recently emerged as an adipokine with similar potential to regulate cardiovascular responses to inflammation and injury. Beyond systolic heart failure, NRGs appear to have beneficial effects in diastolic heart failure, prevention of atherosclerosis, preventing adverse effects on diabetes on the heart and vasculature, including atherosclerosis, as well as the cardiac dysfunction associated with sepsis. Collectively, this literature supports the further examination of how this developmentally critical signaling system functions and how it might be leveraged to treat cardiovascular disease.
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5
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Shan L, Cook KM, Haskins N, Omar B, Jiang Y, Garcia A, Koksal A, Oganesyan V, Rosenthal K, Wu H, Dall'Acqua WF, Damschroder MM. Long-acting antibody ligand mimetics for HER4-selective agonism. Sci Rep 2020; 10:17257. [PMID: 33057063 PMCID: PMC7566517 DOI: 10.1038/s41598-020-74176-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/21/2020] [Indexed: 12/03/2022] Open
Abstract
Neuregulin protein 1 (NRG1) is a large (> 60–amino-acid) natural peptide ligand for the ErbB protein family members HER3 and HER4. We developed an agonistic antibody modality, termed antibody ligand mimetics (ALM), by incorporating complex ligand agonists such as NRG1 into an antibody scaffold. We optimized the linker and ligand length to achieve native ligand activity in HEK293 cells and cardiomyocytes derived from induced pluripotent stem cells (iPSCs) and used a monomeric Fc-ligand fusion platform to steer the ligand specificity toward HER4-dominant agonism. With the help of selectivity engineering, these enhanced ALM molecules can provide an antibody scaffold with increased receptor specificity and the potential to greatly improve the pharmacokinetics, stability, and downstream developability profiles from the natural ligand approach. This ligand mimetic design and optimization approach can be expanded to apply to other cardiovascular disease targets and emerging therapeutic areas, providing differentiated drug molecules with increased specificity and extended half-life.
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Affiliation(s)
- Lu Shan
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA. .,Biotherapeutics, Denali Therapeutics, 161 Oyster Point Blvd, South San Francisco, CA, 94070, USA.
| | - Kimberly M Cook
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA
| | - Nantaporn Haskins
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA
| | - Bilal Omar
- Early Oncology, AstraZeneca, Gaithersburg, USA
| | - Yu Jiang
- Clinical Pharmacology and Safety Science, R&D, AstraZeneca, Gaithersburg, USA
| | - Andrew Garcia
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA
| | - Adem Koksal
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA.,Antibody Discovery and Protein Engineering, NextCure, 9000 Virginia Manor Road, Suite 200, Beltsville, MD, 20705, USA
| | - Vaheh Oganesyan
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA
| | - Kim Rosenthal
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA
| | - Herren Wu
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, USA
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6
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Ledonne A, Mercuri NB. On the Modulatory Roles of Neuregulins/ErbB Signaling on Synaptic Plasticity. Int J Mol Sci 2019; 21:ijms21010275. [PMID: 31906113 PMCID: PMC6981567 DOI: 10.3390/ijms21010275] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/27/2019] [Accepted: 12/29/2019] [Indexed: 12/14/2022] Open
Abstract
Neuregulins (NRGs) are a family of epidermal growth factor-related proteins, acting on tyrosine kinase receptors of the ErbB family. NRGs play an essential role in the development of the nervous system, since they orchestrate vital functions such as cell differentiation, axonal growth, myelination, and synapse formation. They are also crucially involved in the functioning of adult brain, by directly modulating neuronal excitability, neurotransmission, and synaptic plasticity. Here, we provide a review of the literature documenting the roles of NRGs/ErbB signaling in the modulation of synaptic plasticity, focusing on evidence reported in the hippocampus and midbrain dopamine (DA) nuclei. The emerging picture shows multifaceted roles of NRGs/ErbB receptors, which critically modulate different forms of synaptic plasticity (LTP, LTD, and depotentiation) affecting glutamatergic, GABAergic, and DAergic synapses, by various mechanisms. Further, we discuss the relevance of NRGs/ErbB-dependent synaptic plasticity in the control of brain processes, like learning and memory and the known involvement of NRGs/ErbB signaling in the modulation of synaptic plasticity in brain’s pathological conditions. Current evidence points to a central role of NRGs/ErbB receptors in controlling glutamatergic LTP/LTD and GABAergic LTD at hippocampal CA3–CA1 synapses, as well as glutamatergic LTD in midbrain DA neurons, thus supporting that NRGs/ErbB signaling is essential for proper brain functions, cognitive processes, and complex behaviors. This suggests that dysregulated NRGs/ErbB-dependent synaptic plasticity might contribute to mechanisms underlying different neurological and psychiatric disorders.
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Affiliation(s)
- Ada Ledonne
- Department of Experimental Neuroscience, Santa Lucia Foundation, Via del Fosso di Fiorano, no 64, 00143 Rome, Italy;
- Correspondence: ; Tel.: +3906-501703160; Fax: +3906-501703307
| | - Nicola B. Mercuri
- Department of Experimental Neuroscience, Santa Lucia Foundation, Via del Fosso di Fiorano, no 64, 00143 Rome, Italy;
- Department of Systems Medicine, University of Rome “Tor Vergata”, Via Montpellier no 1, 00133 Rome, Italy
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7
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Chowdhury I, Branch A, Mehrabi S, Ford BD, Thompson WE. Gonadotropin-Dependent Neuregulin-1 Signaling Regulates Female Rat Ovarian Granulosa Cell Survival. Endocrinology 2017; 158:3647-3660. [PMID: 28938399 PMCID: PMC5659703 DOI: 10.1210/en.2017-00065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 08/08/2017] [Indexed: 12/30/2022]
Abstract
Mammalian ovarian follicular development and maturation of an oocyte competent to be fertilized and develop into an embryo depends on tightly regulated, spatiotemporally orchestrated crosstalk among cell death, survival, and differentiation signals through extra- and intraovarian signals, as well as on a permissive ovarian follicular microenvironment. Neuregulin-1 (NRG1) is a member of the epidermal growth factor-like factor family that mediates its effects by binding to a member of the erythroblastoma (ErbB) family. Our experimental results suggest gonadotropins promote differential expression of NRG1 and erbB receptors in granulosa cells (GCs), and NRG1 in theca cells during follicular development, and promote NRG1 secretions in the follicular fluid (FF) of rat ovaries. During the estrous cycle of rat, NRG1 and erbB receptors are differentially expressed in GCs and correlate positively with serum gonadotropins and steroid hormones. Moreover, in vitro experimental studies suggest that the protein kinase C inhibitor staurosporine (STS) causes the physical destruction of GCs by the activation of caspase-3. Exogenous NRG1 treatment of GCs delayed onset of STS-induced apoptosis and inhibited cleaved caspase-3 expressions. Moreover, exogenous NRG1 treatment of GCs alters STS-induced death by maintaining the expression of ErbB2, ErbB3, pAkt, Bcl2, and BclxL proteins. Taken together, these studies demonstrate that NRG1 is gonadotropin dependent, differentially regulated in GCs and theca cells, and secreted in ovarian FF as an intracellular survival factor that may govern follicular maturation.
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Affiliation(s)
- Indrajit Chowdhury
- Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, Georgia 30310
- Reproductive Science Research Center, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Alicia Branch
- Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, Georgia 30310
- Reproductive Science Research Center, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Sharifeh Mehrabi
- Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, Georgia 30310
- Reproductive Science Research Center, Morehouse School of Medicine, Atlanta, Georgia 30310
| | - Byron D. Ford
- Division of Biomedical Sciences, University of California-Riverside School of Medicine, Riverside, California 92521
| | - Winston E. Thompson
- Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, Georgia 30310
- Reproductive Science Research Center, Morehouse School of Medicine, Atlanta, Georgia 30310
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia 30310
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8
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Fock V, Plessl K, Draxler P, Otti GR, Fiala C, Knöfler M, Pollheimer J. Neuregulin-1-mediated ErbB2-ErbB3 signalling protects human trophoblasts against apoptosis to preserve differentiation. J Cell Sci 2015; 128:4306-16. [PMID: 26490994 PMCID: PMC4712818 DOI: 10.1242/jcs.176933] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 10/15/2015] [Indexed: 01/11/2023] Open
Abstract
During placentation, foetal trophoblasts invade deeply into maternal tissue to establish a foeto–maternal circulation. We have previously shown that extravillous trophoblast (EVT) lineage cells express ErbB2 and ErbB3, of which the potential as an oncogenic unit is well established. However, a physiological function of this receptor combination in humans remains a puzzling question. Here, we demonstrate neuregulin 1 (NRG1) expression and secretion by human decidual stromal cells. Stimulation of human primary trophoblasts with exogenous NRG1 induced phosphorylation of ErbB2, ErbB3 and related downstream effectors. Co-immunoprecipitation experiments confirmed the formation of ErbB2–ErbB3 dimers upon ligand engagement. Along this line, receptor knockdown and ErbB3 neutralization strongly diminished NRG1-dependent activation of the signalling complex. Functional studies revealed that NRG1 promotes EVT formation in placental explant cultures. Although, in the presence of NRG1, basal and camptothecin-induced trophoblast apoptosis was significantly repressed, this effect was abolished upon ErbB3 inhibition. Notably, camptothecin provoked a strong reduction of trophoblast cell column size, whereas NRG1-treated explants were refractory to the compound. Taken together, our findings newly identify a physiological function of the NRG1–ErbB2–ErbB3 axis in trophoblast survival during human placental development. Highlighted Article: Decidual-stromal-cell-derived neuregulin-1 induces ErbB2–ErbB3 heterodimerization in extravillous trophoblasts and stabilizes trophoblast differentiation through suppression of apoptosis.
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Affiliation(s)
- Valerie Fock
- Department of Obstetrics and Fetal-Maternal Medicine, Reproductive Biology Unit, Medical University of Vienna, Vienna 1090, Austria
| | - Kerstin Plessl
- Department of Obstetrics and Fetal-Maternal Medicine, Reproductive Biology Unit, Medical University of Vienna, Vienna 1090, Austria
| | - Peter Draxler
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna 1090, Austria
| | - Gerlinde Regina Otti
- Department of Obstetrics and Fetal-Maternal Medicine, Reproductive Biology Unit, Medical University of Vienna, Vienna 1090, Austria
| | | | - Martin Knöfler
- Department of Obstetrics and Fetal-Maternal Medicine, Reproductive Biology Unit, Medical University of Vienna, Vienna 1090, Austria
| | - Jürgen Pollheimer
- Department of Obstetrics and Fetal-Maternal Medicine, Reproductive Biology Unit, Medical University of Vienna, Vienna 1090, Austria
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9
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Woldring DR, Holec PV, Zhou H, Hackel BJ. High-Throughput Ligand Discovery Reveals a Sitewise Gradient of Diversity in Broadly Evolved Hydrophilic Fibronectin Domains. PLoS One 2015; 10:e0138956. [PMID: 26383268 PMCID: PMC4575168 DOI: 10.1371/journal.pone.0138956] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/04/2015] [Indexed: 12/25/2022] Open
Abstract
Discovering new binding function via a combinatorial library in small protein scaffolds requires balance between appropriate mutations to introduce favorable intermolecular interactions while maintaining intramolecular integrity. Sitewise constraints exist in a non-spatial gradient from diverse to conserved in evolved antibody repertoires; yet non-antibody scaffolds generally do not implement this strategy in combinatorial libraries. Despite the fact that biased amino acid distributions, typically elevated in tyrosine, serine, and glycine, have gained wider use in synthetic scaffolds, these distributions are still predominantly applied uniformly to diversified sites. While select sites in fibronectin domains and DARPins have shown benefit from sitewise designs, they have not been deeply evaluated. Inspired by this disparity between diversity distributions in natural libraries and synthetic scaffold libraries, we hypothesized that binders resulting from discovery and evolution would exhibit a non-spatial, sitewise gradient of amino acid diversity. To identify sitewise diversities consistent with efficient evolution in the context of a hydrophilic fibronectin domain, >105 binders to six targets were evolved and sequenced. Evolutionarily favorable amino acid distributions at 25 sites reveal Shannon entropies (range: 0.3-3.9; median: 2.1; standard deviation: 1.1) supporting the diversity gradient hypothesis. Sitewise constraints in evolved sequences are consistent with complementarity, stability, and consensus biases. Implementation of sitewise constrained diversity enables direct selection of nanomolar affinity binders validating an efficient strategy to balance inter- and intra-molecular interaction demands at each site.
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Affiliation(s)
- Daniel R. Woldring
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, United States of America
| | - Patrick V. Holec
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, United States of America
| | - Hong Zhou
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, United States of America
| | - Benjamin J. Hackel
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN, United States of America
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10
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Lin MCJ, Rojas KS, Cerione RA, Wilson KF. Identification of mTORC2 as a necessary component of HRG/ErbB2-dependent cellular transformation. Mol Cancer Res 2014; 12:940-52. [PMID: 24615340 DOI: 10.1158/1541-7786.mcr-13-0555] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
UNLABELLED Overexpression of the receptor tyrosine kinase HER2/ErbB2 (ERBB2) has been linked to a poor prognosis for patients with breast cancer; thus, its activity is a central target for cancer therapy. Likewise, overexpression of heregulin (HRG/NRG1), a growth factor responsible for ErbB2 activation, has also been shown to be a driver of breast cancer progression. Although ErbB2 inhibitors offer a major advancement in the treatment of ErbB2-dependent breast cancers, patients are highly susceptible to developing clinical resistance to these drugs. Therefore, a detailed understanding of the molecular mechanism that underlies HRG/ErbB2-induced tumorigenesis is essential for the development of effective therapeutic strategies for this subset of patients with breast cancer. Here, it was demonstrated that HRG promoted anchorage-independent breast cancer cell growth more potently than EGF, and that the HRG-dependent activation of phosphoinositide 3-kinase and mTORC1 are necessary events for cell transformation. Functional evaluation of two distinct mTOR (MTOR) inhibitors, rapamycin and INK-128, on HRG-dependent signaling activities, uncovered a necessary role for mTORC2 in the regulation of the AKT/TSC2/mTORC1 axis by affecting the phosphorylation of AKT at the PDK1(PDPK1)-dependent site (T308) as well as at the mTORC2-dependent site (S473). The elimination of Rictor (RICTOR), a critical component of mTORC2, is detrimental to both the activation of mTORC1 and HRG-mediated cellular transformation. Similar results were obtained in multiple breast cancer model systems, highlighting an important role for mTORC2 in HRG/ErbB2-dependent breast cancer. IMPLICATIONS These findings suggest the potential benefits of targeting mTORC2 in HRG/ErbB2-induced breast cancer.
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Affiliation(s)
- Miao-chong J Lin
- Authors' Affiliation: Department of Molecular Medicine, Cornell University, Ithaca, New York
| | - Katherine S Rojas
- Authors' Affiliation: Department of Molecular Medicine, Cornell University, Ithaca, New York
| | - Richard A Cerione
- Authors' Affiliation: Department of Molecular Medicine, Cornell University, Ithaca, New York
| | - Kristin F Wilson
- Authors' Affiliation: Department of Molecular Medicine, Cornell University, Ithaca, New York
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11
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A potent anti-HB-EGF monoclonal antibody inhibits cancer cell proliferation and multiple angiogenic activities of HB-EGF. PLoS One 2012; 7:e51964. [PMID: 23251664 PMCID: PMC3522611 DOI: 10.1371/journal.pone.0051964] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 11/09/2012] [Indexed: 11/22/2022] Open
Abstract
Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family and has a variety of physiological and pathological functions. Modulation of HB-EGF activity might have a therapeutic potential in the oncology area. We explored the therapeutic possibilities by characterizing the in vitro biological activity of anti-HB-EGF monoclonal antibody Y-142. EGF receptor (EGFR) ligand and species specificities of Y-142 were tested. Neutralizing activities of Y-142 against HB-EGF were evaluated in EGFR and ERBB4 signaling. Biological activities of Y-142 were assessed in cancer cell proliferation and angiogenesis assays and compared with the anti-EGFR antibody cetuximab, the HB-EGF inhibitor CRM197, and the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab. The binding epitope was determined with alanine scanning. Y-142 recognized HB-EGF as well as the EGFR ligand amphiregulin, and bound specifically to human HB-EGF, but not to rodent HB-EGF. In addition, Y-142 neutralized HB-EGF-induced phosphorylation of EGFR and ERBB4, and blocked their downstream ERK1/2 and AKT signaling. We also found that Y-142 inhibited HB-EGF-induced cancer cell proliferation, endothelial cell proliferation, tube formation, and VEGF production more effectively than cetuximab and CRM197 and that Y-142 was superior to bevacizumab in the inhibition of HB-EGF-induced tube formation. Six amino acids in the EGF-like domain were identified as the Y-142 binding epitope. Among the six amino acids, the combination of F115 and Y123 determined the amphiregulin cross-reactivity and that F115 accounted for the species selectivity. Furthermore, it was suggested that the potent neutralizing activity of Y-142 was derived from its recognition of R142 and Y123 and its high affinity to HB-EGF. Y-142 has a potent HB-EGF neutralizing activity that modulates multiple biological activities of HB-EGF including cancer cell proliferation and angiogenic activities. Y-142 may have a potential to be developed into a therapeutic agent for the treatment of HB-EGF-dependent cancers.
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12
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Koziolek EJ, Donoghue JF, Bentley JD, Lovrecz G, Dolezal O, Ward CW, Rothacker J, Nice EC, Burgess AW, Hafner M, Johns TG, Adams TE. A high-affinity ErbB4Fc fusion protein is a potent antagonist of heregulin-mediated receptor activation. Growth Factors 2012; 30:310-9. [PMID: 22856597 DOI: 10.3109/08977194.2012.709516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ligand-mediated activation of ErbB3 and ErbB4 is implicated in the pathogenesis of several human malignancies including cancer of the ovary and melanoma. We have used the broad ErbB ligand specificity of ErbB4 to assemble and express an ErbB4 fusion protein comprising the first 497 amino acids of the mature ErbB4 ectodomain fused to the human IgG Fc constant region. The purified fusion protein, designated sErbB4.497.Fc, binds the ErbB receptor ligands betacellulin and heregulin-β1 (HRG-β1) with high affinity (K(D) = 130 pM), an increase in affinity of 10- to 20-fold, respectively, compared with sErbB4.615.Fc. sErbB4.497.Fc inhibited ligand-stimulated phosphorylation of epidermal growth factor receptor and ErbB2, and blocked HRG-β1 activation of the IKB/MAP/JNK/AKT signalling pathways. sErbB4.497.Fc inhibited HRG-β1-stimulated proliferation in MCF7 cells. In a mouse tumour xenograft model, sErbB4.497.Fc as a monotherapy modestly inhibited the growth of MDA-MB-231 breast cancer cells. sErbB4.497.Fc may be useful in an adjuvant setting in combination with conventional therapeutic agents.
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Affiliation(s)
- Eva J Koziolek
- CSIRO Division of Materials Science and Engineering, 343 Royal Parade, Parkville, VIC 3052, Australia
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13
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White PM, Stone JS, Groves AK, Segil N. EGFR signaling is required for regenerative proliferation in the cochlea: conservation in birds and mammals. Dev Biol 2012; 363:191-200. [PMID: 22230616 DOI: 10.1016/j.ydbio.2011.12.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 12/19/2011] [Accepted: 12/22/2011] [Indexed: 11/27/2022]
Abstract
Proliferation and transdifferentiaton of supporting cells in the damaged auditory organ of birds lead to robust regeneration of sensory hair cells. In contrast, regeneration of lost auditory hair cells does not occur in deafened mammals, resulting in permanent hearing loss. In spite of this failure of regeneration in mammals, we have previously shown that the perinatal mouse supporting cells harbor a latent potential for cell division. Here we show that in a subset of supporting cells marked by p75, EGFR signaling is required for proliferation, and this requirement is conserved between birds and mammals. Purified p75+ mouse supporting cells express receptors and ligands for the EGF signaling pathway, and their proliferation in culture can be blocked with the EGFR inhibitor AG1478. Similarly, in cultured chicken basilar papillae, supporting cell proliferation in response to hair cell ablation requires EGFR signaling. In addition, we show that EGFR signaling in p75+ mouse supporting cells is required for the down-regulation of the cell cycle inhibitor p27(Kip1) (CDKN1b) to enable cell cycle re-entry. Taken together, our data suggest that a conserved mechanism involving EGFR signaling governs proliferation of auditory supporting cells in birds and mammals and may represent a target for future hair cell regeneration strategies.
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Affiliation(s)
- Patricia M White
- Division of Cell Biology and Genetics, House Research Institute, 2100 W 3rd St., Los Angeles, CA 90057, USA
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14
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Danovi D, Cremona CA, Machado-da-Silva G, Basu S, Noon LA, Parrinello S, Lloyd AC. A genetic screen for anchorage-independent proliferation in mammalian cells identifies a membrane-bound neuregulin. PLoS One 2010; 5:e11774. [PMID: 20668675 PMCID: PMC2909903 DOI: 10.1371/journal.pone.0011774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 07/01/2010] [Indexed: 12/16/2022] Open
Abstract
Anchorage-independent proliferation is a hallmark of oncogenic transformation and is thought to be conducive to proliferation of cancer cells away from their site of origin. We have previously reported that primary Schwann cells expressing the SV40 Large T antigen (LT) are not fully transformed in that they maintain a strict requirement for attachment, requiring a further genetic change, such as oncogenic Ras, to gain anchorage-independence. Using the LT-expressing cells, we performed a genetic screen for anchorage-independent proliferation and identified Sensory and Motor Neuron Derived Factor (SMDF), a transmembrane class III isoform of Neuregulin 1. In contrast to oncogenic Ras, SMDF induced enhanced proliferation in normal primary Schwann cells but did not trigger cellular senescence. In cooperation with LT, SMDF drove anchorage-independent proliferation, loss of contact inhibition and tumourigenicity. This transforming ability was shared with membrane-bound class III but not secreted class I isoforms of Neuregulin, indicating a distinct mechanism of action. Importantly, we show that despite being membrane-bound signalling molecules, class III neuregulins transform via a cell intrinsic mechanism, as a result of constitutive, elevated levels of ErbB signalling at high cell density and in anchorage-free conditions. This novel transforming mechanism may provide new targets for cancer therapy.
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Affiliation(s)
- Davide Danovi
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
| | - Catherine A. Cremona
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
| | - Gisela Machado-da-Silva
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
| | - Sreya Basu
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
| | - Luke A. Noon
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
| | - Simona Parrinello
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
| | - Alison C. Lloyd
- MRC Laboratory for Molecular Cell Biology and The UCL Cancer Institute, University College London, London, United Kingdom
- * E-mail:
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15
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Kar G, Gursoy A, Keskin O. Human cancer protein-protein interaction network: a structural perspective. PLoS Comput Biol 2009; 5:e1000601. [PMID: 20011507 PMCID: PMC2785480 DOI: 10.1371/journal.pcbi.1000601] [Citation(s) in RCA: 141] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 11/05/2009] [Indexed: 01/12/2023] Open
Abstract
Protein-protein interaction networks provide a global picture of cellular function and biological processes. Some proteins act as hub proteins, highly connected to others, whereas some others have few interactions. The dysfunction of some interactions causes many diseases, including cancer. Proteins interact through their interfaces. Therefore, studying the interface properties of cancer-related proteins will help explain their role in the interaction networks. Similar or overlapping binding sites should be used repeatedly in single interface hub proteins, making them promiscuous. Alternatively, multi-interface hub proteins make use of several distinct binding sites to bind to different partners. We propose a methodology to integrate protein interfaces into cancer interaction networks (ciSPIN, cancer structural protein interface network). The interactions in the human protein interaction network are replaced by interfaces, coming from either known or predicted complexes. We provide a detailed analysis of cancer related human protein-protein interfaces and the topological properties of the cancer network. The results reveal that cancer-related proteins have smaller, more planar, more charged and less hydrophobic binding sites than non-cancer proteins, which may indicate low affinity and high specificity of the cancer-related interactions. We also classified the genes in ciSPIN according to phenotypes. Within phenotypes, for breast cancer, colorectal cancer and leukemia, interface properties were found to be discriminating from non-cancer interfaces with an accuracy of 71%, 67%, 61%, respectively. In addition, cancer-related proteins tend to interact with their partners through distinct interfaces, corresponding mostly to multi-interface hubs, which comprise 56% of cancer-related proteins, and constituting the nodes with higher essentiality in the network (76%). We illustrate the interface related affinity properties of two cancer-related hub proteins: Erbb3, a multi interface, and Raf1, a single interface hub. The results reveal that affinity of interactions of the multi-interface hub tends to be higher than that of the single-interface hub. These findings might be important in obtaining new targets in cancer as well as finding the details of specific binding regions of putative cancer drug candidates. Protein-protein interaction networks provide a global picture of cellular function and biological processes. The dysfunction of some interactions causes many diseases, including cancer. Proteins interact through their interfaces. Therefore, studying the interface properties of cancer-related proteins will help explain their role in the interaction networks. The structural details of interfaces are immensely useful in efforts to answer some fundamental questions such as: (i) what features of cancer-related protein interfaces make them act as hubs; (ii) how hub protein interfaces can interact with tens of other proteins with varying affinities; and (iii) which interactions can occur simultaneously and which are mutually exclusive. Addressing these questions, we propose a method to characterize interactions in a human protein-protein interaction network using three-dimensional protein structures and interfaces. Protein interface analysis shows that the strength and specificity of the interactions of hub proteins and cancer proteins are different than the interactions of non-hub and non-cancer proteins, respectively. In addition, distinguishing overlapping from non-overlapping interfaces, we illustrate how a fourth dimension, that of the sequence of processes, is integrated into the network with case studies. We believe that such an approach should be useful in structural systems biology.
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Affiliation(s)
- Gozde Kar
- Center for Computational Biology and Bioinformatics and College of Engineering, Koc University, Rumeli Feneri Yolu, Sariyer Istanbul, Turkey
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16
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van der Woning SP, Venselaar H, van Rotterdam W, Jacobs-Oomen S, van Leeuwen JEM, van Zoelen EJJ. Role of the C-terminal linear region of EGF-like growth factors in ErbB specificity. Growth Factors 2009; 27:163-72. [PMID: 19384683 DOI: 10.1080/08977190902891010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The epidermal growth factor (EGF)-like growth factors bind their ErbB receptors in a highly selective manner. Recently, we have shown that the sequence YYDLL in the C-terminal linear region is compatible with binding to all ligand-binding ErbB receptors. In the present study, we show that introduction of the YYDLL sequence into the ErbB1 specific ligands EGF and transforming growth factor-alpha (TGFalpha) broadened their receptor specificity towards ErbB4. Upon introduction of the YYDLL sequence into epiregulin, which by itself binds ErbB1 and ErbB4 but not ErbB3, its binding specificity was broadened to ErbB3, concomitant with enhanced affinity for ErbB4. Introduction of the YYDLL sequence into NRG1beta resulted in a 10-fold increase in affinity for ErbB3, without affecting its receptor specificity. Remarkably, the strongly enhanced affinity for ErbB3 negatively influenced their mitogenic activity towards cells coexpressing ErbB2 and ErbB3. These observations are discussed in terms of the optimised ErbB affinity, selectivity and mitogenic potential that have taken place during evolution.
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17
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Park E, Baron R, Landgraf R. Higher-order association states of cellular ERBB3 probed with photo-cross-linkable aptamers. Biochemistry 2008; 47:11992-2005. [PMID: 18942860 DOI: 10.1021/bi8004208] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nucleic acid aptamers are rapidly gaining prominence as diagnostic tools, targeting reagents, and potential therapeutics. To extend the use of aptamers into the biochemical analysis of protein interactions on the surface of live cells, we converted an enzymatically generated RNA aptamer into a photo-cross-linkable affinity tag through the replacement of all uracils with 4-thiouracil. Specifically, we converted a previously selected, inhibitory aptamer that binds the soluble extracellular domains of the ERBB3 receptor into a targeted and highly specific cross-linking reagent in a live cell setting. Since the photo-cross-linkable aptamer has two functionalities, targeted and highly selective as well as unspecific cross-linking capability, the attachment of this inhibitory aptamer converts ERBB3 into a passive and signaling incompetent probe of its immediate receptor environment. This approach detects receptor clustering of endogenous ERBB3 in the breast cancer cell line MCF7 at levels as low as 25000 receptors per cell and at aptamer concentrations as low as 20 nM. Our analysis also indicates that ERBB3 receptors are apparently segregated from ERBB2 receptors in their resting state, and both ligand-activated ERBB3 and ERBB2 do not share the same microenvironment as inactive ERBB3.
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Affiliation(s)
- Euisun Park
- Department of Biochemistry and Molecular Biology, University of Miami, Miami, Florida 33101-6129, USA
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18
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Nagaoka T, Fukuda T, Hashizume T, Nishiyama T, Tada H, Yamada H, Salomon DS, Yamada S, Kojima I, Seno M. A betacellulin mutant promotes differentiation of pancreatic acinar AR42J cells into insulin-producing cells with low affinity of binding to ErbB1. J Mol Biol 2008; 380:83-94. [PMID: 18508082 DOI: 10.1016/j.jmb.2008.03.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 03/10/2008] [Accepted: 03/25/2008] [Indexed: 01/08/2023]
Abstract
Betacellulin (BTC) is one of the members of the epidermal growth factor (EGF) ligand family of ErbB receptor tyrosine kinases. It is a differentiation factor as well as a potent mitogen. BTC promotes the differentiation of pancreatic acinar-derived AR42J cells into insulin-producing cells. It independently and preferentially binds to two type I tyrosine kinase receptors, the EGF receptor (ErbB1) and ErbB4. However, the physiochemical characteristics of BTC that are responsible for its preferential binding to these two receptors have not been fully defined. In this study, to investigate the essential amino acid residues of BTC for binding to the two receptors, we introduced point mutations into the EGF domain of BTC employing error-prone PCR. The receptor binding abilities of 190 mutants expressed in Escherichia coli were assessed by enzyme immunoassay. Replacement of the glutamic acid residue at position 88 with a lysine residue in BTC was found to produce a significant loss of affinity for binding to ErbB1, while the affinity of binding to ErbB4 was unchanged. In addition, the mutant of BTC-E/88/K showed less growth-promoting activity on BALB/c 3T3 cells compared with that of the wild-type BTC protein. Interestingly, the BTC mutant protein promoted differentiation of pancreatic acinar AR42J cells at a high frequency into insulin-producing cells compared with AR42J cells that were treated with wild-type BTC protein. These results indicate the possibility of designing BTC mutants, which have an activity of inducing differentiation only, without facilitating growth promotion.
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Affiliation(s)
- Tadahiro Nagaoka
- Department of Medical Bioengineering, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530, Japan
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19
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Nethery DE, Ghosh S, Erzurum SC, Kern JA. Inactivation of neuregulin-1 by nitration. Am J Physiol Lung Cell Mol Physiol 2006; 292:L287-93. [PMID: 16980377 DOI: 10.1152/ajplung.00058.2006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Nitration is a posttranslational modification that can compromise protein function. We hypothesized that nitration of growth factors secreted in the lung may alter their interaction with their respective receptors and modulate the normal growth and differentiation program induced by ligand-receptor interaction. We tested this hypothesis in vitro by nitration of neuregulin-1's (NRG-1) EGF-like domain and studying the effect on NRG-1's activity. Nitration of NRG-1's (nNRG-1) EGF-like domain resulted in an inability to activate its receptor, the human epidermal growth factor receptors 2 and 3 (HER2/HER3) heterodimer, as defined by loss of HER2 tyrosine phosphorylation induced by nNRG-1 in MCF-7 cells. Receptor activation was not restored with increasing nNRG-1 concentration or exposure times. nNRG-1 did not compete with NRG-1 for HER2/HER3 binding in competition assays. In addition, nNRG-1 no longer induced proliferation of the MCF-7 cell line, as MCF-7 cells exposed to nNRG-1 and NRG-1 concurrently had the same proliferation rate as that induced by NRG-1 alone. Thus nitration of NRG-1's EGF-like domain caused it to lose its ability to bind and activate its receptor with loss of ligand-induced proliferation. Posttranslational nitration of growth factors in states where reactive nitrogen species are increased may be an important means of regulating growth factor receptor effects in the lung.
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Affiliation(s)
- David E Nethery
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University Hospitals of Cleveland, Wearn 610, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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20
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Luo C, Xu L, Zheng S, Luo X, Shen J, Jiang H, Liu X, Zhou M. Computational analysis of molecular basis of 1:1 interactions of NRG-1beta wild-type and variants with ErbB3 and ErbB4. Proteins 2006; 59:742-56. [PMID: 15822127 DOI: 10.1002/prot.20443] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The neuregulin/ErbB system is a growth factor/receptor cascade that has been proven to be essential in the development of the heart and the sympathetic nervous system. However, the basis of the specificity of ligand-receptor recognition remains to be elucidated. In this study, the structures of NRG-1beta/ErbB3 and NRG-1beta/ErbB4 complexes were modeled based on the available structures of the homologous proteins. The binding free energies of NRG-1beta to ErbB3 and ErbB4 were calculated using the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) computational method. In addition, computational alanine-scanning mutagenesis was performed in the binding site of NRG-1beta and the difference in the binding free energies between NRG-1beta mutants and the receptors was calculated. The results specify the contribution of each residue at the interaction interfaces to the binding affinity of NRG-1beta with ErbB3 and ErbB4, identifying several important interaction residue pairs that are in agreement with previously acquired experimental data. This indicates that the presented structural models of NRG-1beta/ErbB3 and NRG-1beta/ErbB4 complexes are reliable and could be used to guide future studies, such as performing desirable mutations on NRG-1beta to increase the binding affinity and selectivity to the receptor and discovering new therapeutic agents for the treatment of heart failure.
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Affiliation(s)
- Cheng Luo
- Center for Drug Discovery and Design, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, and Graduate School, Chinese Academy of Sciences, Shanghai, P.R. China
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21
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Bouyain S, Longo PA, Li S, Ferguson KM, Leahy DJ. The extracellular region of ErbB4 adopts a tethered conformation in the absence of ligand. Proc Natl Acad Sci U S A 2005; 102:15024-9. [PMID: 16203964 PMCID: PMC1257738 DOI: 10.1073/pnas.0507591102] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The human ErbB family of receptor tyrosine kinases comprises the epidermal growth factor receptor (EGFR/ErbB1/HER1), ErbB2 (HER2/Neu), ErbB3 (HER3), and ErbB4 (HER4). ErbBs play fundamental roles in cell growth and differentiation events in embryonic and adult tissues, and inappropriate ErbB activity has been implicated in several human cancers. We report here the 2.4 A crystal structure of the extracellular region of human ErbB4 in the absence of ligand and show that it adopts a tethered conformation similar to inactive forms of ErbB1 and ErbB3. This structure completes the gallery of unliganded ErbB receptors and demonstrates that all human ligand-binding ErbBs adopt the autoinhibited conformation. We also show that the binding of neuregulin-1beta to ErbB4 and ErbB3 and the binding of betacellulin to both ErbB4 and ErbB1 does not decrease at low pH, unlike the binding of epidermal growth factor and transforming growth factor-alpha to ErbB1. These results indicate an important role for ligand in determining pH-dependent binding and may explain different responses observed when the same ErbB receptor is stimulated by different ligands.
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Affiliation(s)
- Samuel Bouyain
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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22
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Yang XL, Huang YZ, Xiong WC, Mei L. Neuregulin-induced expression of the acetylcholine receptor requires endocytosis of ErbB receptors. Mol Cell Neurosci 2005; 28:335-46. [PMID: 15691714 DOI: 10.1016/j.mcn.2004.10.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 09/27/2004] [Accepted: 10/02/2004] [Indexed: 11/24/2022] Open
Abstract
Neuregulin-induced expression of the acetylcholine receptor (AChR) contributes to high concentration of the receptor at the neuromuscular junction (NMJ). Neuregulin-1 activates ErbB tyrosine kinases and subsequently intracellular kinases including Erk that is required for induced AChR expression. Recent studies demonstrate that ligand-induced internalization may regulate signaling of various receptor tyrosine kinases. However, the role of induced ErbB endocytosis in regulating AChR expression was unclear. Here we provide evidence that ErbB tyrosine kinases became rapidly internalized in response to neuregulin. The internalization required the kinase activity of ErbB proteins and involved a clathrin-dependent endocytic pathway. Moreover, neuregulin-induced Erk activation and AChR expression were attenuated when ErbB endocytosis was blocked. These results indicate that ErbB proteins undergo endocytosis in response to neuregulin, and this process is required for neuregulin signaling and induced AChR expression.
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Affiliation(s)
- Xiao-Li Yang
- Department of Neurobiology, University of Alabama at Birmingham, Civitan International Research Center, Birmingham, AL 35294, USA
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23
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Rajpal A, Beyaz N, Haber L, Cappuccilli G, Yee H, Bhatt RR, Takeuchi T, Lerner RA, Crea R. A general method for greatly improving the affinity of antibodies by using combinatorial libraries. Proc Natl Acad Sci U S A 2005; 102:8466-71. [PMID: 15939870 PMCID: PMC1143585 DOI: 10.1073/pnas.0503543102] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Look-through mutagenesis (LTM) is a multidimensional mutagenesis method that simultaneously assesses and optimizes combinatorial mutations of selected amino acids. The process focuses on a precise distribution within one or more complementarity determining region (CDR) domains and explores the synergistic contribution of amino acid side-chain chemistry. LTM was applied to an anti-TNF-alpha antibody, D2E7, which is a challenging test case, because D2E7 was highly optimized (K(d) = 1 nM) by others. We selected and incorporated nine amino acids, representative of the major chemical functionalities, individually at every position in each CDR and across all six CDRs (57 aa). Synthetic oligonucleotides, each introducing one amino acid mutation throughout the six CDRs, were pooled to generate segregated libraries containing single mutations in one, two, and/or three CDRs for each V(H) and V(L) domain. Corresponding antibody libraries were displayed on the cell surface of yeast. After positive binding selection, 38 substitutions in 21 CDR positions were identified that resulted in higher affinity binding to TNF-alpha. These beneficial mutations in both V(H) and V(L) were represented in two combinatorial beneficial mutagenesis libraries and selected by FACS to produce a convergence of variants that exhibit between 500- and 870-fold higher affinities. Importantly, these enhanced affinities translate to a 15- to 30-fold improvement in in vitro TNF-alpha neutralization in an L929 bioassay. Thus, this LTM/combinatorial beneficial mutagenesis strategy generates a comprehensive energetic map of the antibody-binding site in a facile and rapid manner and should be broadly applicable to the affinity maturation of antibodies and other proteins.
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Affiliation(s)
- Arvind Rajpal
- Bioren Inc., 100 Glenn Way, Suite 1, San Carlos, CA 94070, USA
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24
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Hobbs SS, Cameron EM, Hammer RP, Le ATD, Gallo RM, Blommel EN, Coffing SL, Chang H, Riese DJ. Five carboxyl-terminal residues of neuregulin2 are critical for stimulation of signaling by the ErbB4 receptor tyrosine kinase. Oncogene 2004; 23:883-93. [PMID: 14661053 DOI: 10.1038/sj.onc.1207250] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The neuregulins (NRGs) are members of the epidermal growth factor (EGF) family of peptide growth factors. These hormones are agonists for the ErbB family of receptor tyrosine kinases, a family that includes the epidermal growth factor receptor (EGFR/ErbB1), ErbB2/Neu/HER2, ErbB3/HER3, and ErbB4/HER4. We recently observed that the EGF family hormone NRG2beta is a potent agonist for ErbB4. In contrast, NRG2alpha, a splicing isoform of the same gene that encodes NRG2beta, is a poor ErbB4 agonist. We hypothesized that carboxyl-terminal residues of NRG2beta are critical for stimulation of ErbB4 tyrosine phosphorylation and coupling to downstream signaling events. Here, we demonstrate that the substitution of a lysine residue for Phe45 in NRG2beta results in reduced ligand potency. We also demonstrate that substitution of a phenylalanine for Lys45 in NRG2alpha results in increased ligand potency. Finally, analyses of the gain-of-function NRG2alpha Chg5 mutant demonstrate that Gln43, Met47, Asn49, and Phe50 regulate ligand efficacy. Thus, these data indicate that carboxyl-terminal residues of NRG2beta are critical for activation of ErbB4 signaling. Moreover, these NRG2alpha and NRG2beta mutants reveal new insights into models for ligand-induced ErbB family receptor tyrosine phosphorylation and coupling to downstream signaling events.
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Affiliation(s)
- Stuart S Hobbs
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University School of Pharmacy, West Lafayette, IN 47907-2064, USA
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Wingens M, Walma T, van Ingen H, Stortelers C, van Leeuwen JEM, van Zoelen EJJ, Vuister GW. Structural analysis of an epidermal growth factor/transforming growth factor-alpha chimera with unique ErbB binding specificity. J Biol Chem 2003; 278:39114-23. [PMID: 12869572 DOI: 10.1074/jbc.m305603200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Various chimeras of the ErbB1-specific ligands epidermal growth factor (EGF) and transforming growth factor-alpha (TGFalpha) display an enlarged repertoire as activators of ErbB2.ErbB3 heterodimers. Mutational analysis indicated that particularly residues in the N terminus and B-loop region of these ligands are involved in the broadened receptor specificity. In order to understand the receptor specificity of T1E, a chimeric ligand constructed by the introduction of the linear N-terminal region of TGFalpha into EGF, we determined in this study the solution structure and dynamics of T1E by multidimensional NMR analysis. Subsequently, we studied the structural characteristics of T1E binding to both ErbB1 and ErbB3 by superposition modeling of its structure on the known crystal structures of ErbB3 and liganded ErbB1 complexes. The results show that the overall structure of T1E in solution is very similar to that of native EGF and TGFalpha but that its N terminus shows an extended structure that is appropriately positioned to form a triple beta-sheet with the large antiparallel beta-sheet in the B-loop region. This conformational effect of the N terminus together with the large overall flexibility of T1E, as determined by 15N NMR relaxation analysis, may be a facilitative property for its broad receptor specificity. The structural superposition models indicate that hydrophobic and electrostatic interactions of the N terminus and B-loop of T1E are particularly important for its binding to ErbB3.
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Affiliation(s)
- Miriam Wingens
- Department of Cell Biology, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
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26
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Chen CHB, Chernis GA, Hoang VQ, Landgraf R. Inhibition of heregulin signaling by an aptamer that preferentially binds to the oligomeric form of human epidermal growth factor receptor-3. Proc Natl Acad Sci U S A 2003; 100:9226-31. [PMID: 12874383 PMCID: PMC170900 DOI: 10.1073/pnas.1332660100] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Human epidermal growth factor receptor-3 (HER3) is a member of the type I receptor tyrosine kinase family. Several members of this family are overexpressed in various carcinomas. Specifically, HER2 is found to be overexpressed in 20-30% of breast cancers. In contrast to epidermal growth factor receptor or HER2, the kinasedeficient HER3 self-associates readily at low nanomolar concentrations and in the absence of its ligands, various isoforms of heregulin (hrg). Binding of hrg disrupts HER3 oligomerization and leads to the formation of signaling-competent heterodimers, preferentially with HER2. Elevated levels of HER3 contribute to increased drug resistance observed in HER2-overexpressing cells. We have used the SELEX (systematic evolution of ligands by exponential enrichment) methodology to select RNA aptamers against the oligomeric state of the extracellular domains of HER3 (HER3ECD, monomeric molecular mass 82,000 Da). One of the aptamers, A30, binds with high affinity to a limited number of binding sites in the oligomeric state of HER3ECD. Binding of A30 and hrg are not competitive. Instead, the disruption of HER3 oligomers by hrg results in an approximately 10-fold increase in total binding sites, but the newly created binding sites are of lower affinity. High-affinity binding of A30 inhibits hrg-dependent tyrosine phosphorylation of HER2 and the hrg-induced growth response of MCF7 cells. As an example of an aptamer against a large macromolecular protein complex, A30 can serve as a tool for the analysis of receptor interactions and may serve as a lead compound for the development of inhibitors against overexpressed receptor tyrosine kinases in carcinomas.
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Affiliation(s)
- Chi-Hong B Chen
- Department of Medicine, Division of Hematology-Oncology, University of California, Los Angeles CA 90095-1678, USA
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27
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Abstract
Neuregulin (NRG) regulates synapse formation and synaptic plasticity, but little is known about the regulation of NRG signaling at synapses. Here we show that the NRG receptor ErbB4 was localized in anatomically defined postsynaptic densities in the brain. In cultured cortical neurons, ErbB4 was recruited to the neuronal lipid raft fraction after stimulation by NRG. Along with ErbB4, adaptor proteins Grb2 and Shc were translocated to lipid rafts by NRG stimulation. In transfected human embryonic kidney 293 cells, the partitioning of ErbB4 into a detergent-insoluble fraction that includes lipid rafts was increased by PSD-95 (postsynaptic density-95), through interaction of the ErbB4 C terminus with the PDZ [PSD-95/Discs large/zona occludens-1] domains of PSD-95. Disruption of lipid rafts inhibited NRG-induced activation of Erk and prevented NRG-induced blockade of induction of long-term potentiation at hippocampal CA1 synapses. Thus, our results indicate that NRG stimulation causes translocation of ErbB4 into lipid rafts and that lipid rafts are necessary for signaling by ErbB4.
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28
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Stortelers C, van der Woning SP, Jacobs-Oomen S, Wingens M, van Zoelen EJJ. Selective formation of ErbB-2/ErbB-3 heterodimers depends on the ErbB-3 affinity of epidermal growth factor-like ligands. J Biol Chem 2003; 278:12055-63. [PMID: 12556529 DOI: 10.1074/jbc.m211948200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
EGF-like growth factors activate their ErbB receptors by promoting receptor-mediated homodimerization or, alternatively, by the formation of heterodimers with the orphan ErbB-2 through an as yet unknown mechanism. To investigate the selectivity in dimer formation by ligands, we have applied the phage display approach to obtain ligands with modified C-terminal residues that discriminate between ErbB-2 and ErbB-3 as dimerization partners. We used the epidermal growth factor/transforming growth factor alpha chimera T1E as the template molecule because it binds to ErbB-3 homodimers with low affinity and to ErbB-2/ErbB-3 heterodimers with high affinity. Many phage variants were selected with enhanced binding affinity for ErbB-3 homodimers, indicating that C-terminal residues contribute to the interaction with ErbB-3. These variants were also potent ligands for ErbB-2/ErbB-3 heterodimers despite negative selection for such heterodimers. In contrast, phage variants positively selected for binding to ErbB-2/ErbB-3 heterodimers but negatively selected for binding to ErbB-3 homodimers can be considered as "second best" ErbB-3 binders, which require ErbB-2 heterodimerization for stable complex formation. Our findings imply that epidermal growth factor-like ligands bind ErbB-3 through a multi-domain interaction involving at least both linear endings of the ligand. Apparently the ErbB-3 affinity of a ligand determines whether it can form only ErbB-2/ErbB-3 complexes or also ErbB-3 homodimers. Because no separate binding domain for ErbB-2 could be identified, our data support a model in which ErbB heterodimerization occurs through a receptor-mediated mechanism and not through bivalent ligands.
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Affiliation(s)
- Catelijne Stortelers
- University of Nijmegen, Department of Cell Biology, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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29
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Hobbs SS, Coffing SL, Le ATD, Cameron EM, Williams EE, Andrew M, Blommel EN, Hammer RP, Chang H, Riese DJ. Neuregulin isoforms exhibit distinct patterns of ErbB family receptor activation. Oncogene 2002; 21:8442-52. [PMID: 12466964 DOI: 10.1038/sj.onc.1205960] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2002] [Revised: 08/05/2002] [Accepted: 08/12/2002] [Indexed: 12/12/2022]
Abstract
During the last decade, several novel members of the Epidermal Growth Factor family of peptide growth factors have been identified. Most prominent among these are the Neuregulins or Heregulins. To date, four different Neuregulin genes have been identified (Neuregulin1-4) and several different splicing isoforms have been identified for at least two of these genes (Neuregulin1 and Neuregulin2). While Neuregulin1 isoforms have been extensively studied, comparatively little is known about Neuregulin3, Neuregulin4, or the Neuregulin2 isoforms. Indeed, there has been no systematic comparison of the activities of these molecules. Here we demonstrate that Neuregulin2alpha and Neuregulin2beta stimulate ErbB3 tyrosine phosphorylation and coupling to biological responses. In contrast, Neuregulin3 and Neuregulin4 fail to activate ErbB3 signaling. Furthermore, Neuregulin2beta, but not Neuregulin2alpha, stimulates ErbB4 tyrosine phosphorylation and coupling to biological responses. Finally, both Neuregulin3 and Neuregulin4 stimulate modest amounts of ErbB4 tyrosine phosphorylation. However, whereas Neuregulin3 stimulates a modest amount of ErbB4 coupling to biological responses, Neuregulin4 fails to stimulate ErbB4 coupling to biological responses. This suggests that there are qualitative as well as quantitative differences in ErbB family receptor activation by Neuregulin isoforms.
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Affiliation(s)
- Stuart S Hobbs
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University School of Pharmacy, West Lafayette, Indiana, IN 7907-1333, USA
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30
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Agus DB, Akita RW, Fox WD, Lewis GD, Higgins B, Pisacane PI, Lofgren JA, Tindell C, Evans DP, Maiese K, Scher HI, Sliwkowski MX. Targeting ligand-activated ErbB2 signaling inhibits breast and prostate tumor growth. Cancer Cell 2002; 2:127-37. [PMID: 12204533 DOI: 10.1016/s1535-6108(02)00097-1] [Citation(s) in RCA: 656] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
ErbB2 is a ligand-less member of the ErbB receptor family that functions as a coreceptor with EGFR, ErbB3, and ErbB4. Here, we describe an approach to target ErbB2's role as a coreceptor using a monoclonal antibody, 2C4, which sterically hinders ErbB2's recruitment into ErbB ligand complexes. Inhibition of ligand-dependent ErbB2 signaling by 2C4 occurs in both low- and high-ErbB2-expressing systems. Since the ErbB3 receptor contains an inactive tyrosine kinase domain, 2C4 is very effective in blocking heregulin-mediated ErbB3-ErbB2 signaling. We demonstrate that the in vitro and in vivo growth of several breast and prostate tumor models is inhibited by 2C4 treatment.
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MESH Headings
- Androgens/metabolism
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/therapeutic use
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Breast Neoplasms/drug therapy
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cell Division/drug effects
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Ligands
- Male
- Mice
- Neoplasm Transplantation
- Neuregulin-1/pharmacology
- Prostatic Neoplasms/drug therapy
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- Protein Binding/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, ErbB-2/antagonists & inhibitors
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/immunology
- Receptor, ErbB-2/metabolism
- Receptor, ErbB-3/metabolism
- Signal Transduction/drug effects
- Time Factors
- Transplantation, Heterologous
- Tumor Cells, Cultured
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Affiliation(s)
- David B Agus
- Cedars-Sinai Prostate Cancer Center, Los Angeles, California 90048, USA
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31
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Miura K, Doura H, Aizawa T, Tada H, Seno M, Yamada H, Kawano K. Solution structure of betacellulin, a new member of EGF-family ligands. Biochem Biophys Res Commun 2002; 294:1040-6. [PMID: 12074582 DOI: 10.1016/s0006-291x(02)00585-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The solution structure of the EGF-like domain of betacellulin (BTCe), a newly discovered member of the epidermal growth factor (EGF) family, has been determined using two-dimensional nuclear magnetic resonance spectroscopy. This is the first report to identify the solution structure of the EGF-family ligand monomers that interact with both ErbB-1 and ErbB-4. The solution structure of BTCe was calculated using 538 NMR-derived restraints. The overall structure of BTCe was stabilized by three disulfide bonds, a hydrophobic core, and 23 hydrogen bonds. It appears that BTCe is comprised of five beta-strands and one short 3(10) helical turn. The secondary structural elements of BTCe are basically similar to those of the other EGF-family proteins, except that several significant variations of the structural properties were found. It is suggested that the structural variations between BTCe and the other EGF-family ligands may affect the specific receptor-recognition properties of EGF-family ligands.
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Affiliation(s)
- Kazunori Miura
- Bio-oriented Technology Research Advancement Institution, 1-40-2 Nisshin, Saitama, Saitama 331-8537, Japan
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32
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Abstract
ErbB-4 is a receptor tyrosine kinase that is activated by the binding of specific growth factors to its ectodomain. In addition to the initiation of signal transduction pathways that direct cell responses, such as proliferation or differentiation, this receptor is subject to ligand-dependent trafficking events. The signal transduction events are controlled by ligand-dependent activation of the receptor tyrosine kinase activity, which results in receptor autophosphorylation and the tyrosine phosphorylation of other cellular proteins. The trafficking events include migration into and out of membrane microdomains, entry into internalization pathways and endocytosis, plus proteolytic fragmentation.
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Affiliation(s)
- W Zhou
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
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33
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Li C, Plugariu CG, Bajgier J, White JR, Liefer KM, Wu SJ, Chaiken I. Coiled coil miniprotein randomization on phage leads to charge pattern mimicry of the receptor recognition determinant of interleukin 5. J Mol Recognit 2002; 15:33-43. [PMID: 11870920 DOI: 10.1002/jmr.558] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Phage display was used to identify sequences that mimic structural determinants in interleukin5 (IL5) for IL5 receptor recognition. A coiled coil stem loop (CCSL) miniprotein scaffold library was constructed with its turn region randomized and panned for binding variants against human IL5 receptor alpha chain (IL5Ralpha). Competition enzyme-linked immunosorbent assays identified CCSL-phage selectants for which binding to IL5Ralpha was competed by IL5. The most frequently selected and IL5-competed CCSL-phage contain charged residues Arg and Glu in their turn sequences, in this regard resembling a beta strand sequence in the 'CD turn' region, of IL5, that has been proposed to present a key determinant for IL5 receptor alpha chain recognition. The most dominant CCSL-phage selectant sequence, PVEGRV, contains a negative/positive charge pattern similar to that seen in the original CD turn. To test the relatedness of CCSL-phage selectant sequences to the IL5 receptor recognition epitope, PVEGRV was grafted into the sequence 87--92 of a monomeric IL5. The resulting IL5 variant, [(87)PVEGRV(92)]GM1, was able to bind to IL5Ralpha in biosensor assays, to elicit TF-1 cell proliferation and to induce STAT5 phosphorylation in TF-1 cells. The results help discern sequence patterns in the IL5 CD turn region which are key in driving receptor recognition and demonstrate the utility of CCSL miniprotein scaffold phage display to identify local IL5 mimetic sequence arrangements that may ultimately lead to IL5 antagonists.
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Affiliation(s)
- Chuanzhao Li
- Department of Medicine, University of Pennsylvania School of Medicine, 909 Stellar Chance Laboratories, 422 Curie Blvd, Philadelphia PA 19104, USA
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34
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Esparís-Ogando A, Díaz-Rodríguez E, Montero JC, Yuste L, Crespo P, Pandiella A. Erk5 participates in neuregulin signal transduction and is constitutively active in breast cancer cells overexpressing ErbB2. Mol Cell Biol 2002; 22:270-85. [PMID: 11739740 PMCID: PMC134212 DOI: 10.1128/mcb.22.1.270-285.2002] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The four receptor tyrosine kinases of the ErbB family play essential roles in several physiological processes and have also been implicated in tumor generation and/or progression. Activation of ErbB1/EGFR is mainly triggered by epidermal growth factor (EGF) and other related ligands, while activation of ErbB2, ErbB3, and ErbB4 receptors occurs by binding to another set of EGF-like ligands termed neuregulins (NRGs). Here we show that the Erk5 mitogen-activated protein kinase (MAPK) pathway participates in NRG signal transduction. In MCF7 cells, NRG activated Erk5 in a time- and dose-dependent fashion. The action of NRG on Erk5 was dependent on the kinase activity of ErbB receptors but was independent of Ras. Expression in MCF7 cells of a dominant negative form of Erk5 resulted in a significant decrease in NRG-induced proliferation of MCF7 cells. Analysis of Erk5 in several human tumor cell lines indicated that a constitutively active form of this kinase was present in the BT474 and SKBR3 cell lines, which also expressed activated forms of ErbB2, ErbB3, and ErbB4. Treatments aimed at decreasing the activity of these receptors caused Erk5 inactivation, indicating that the active form of Erk5 present in BT474 and SKBR3 cells was due to a persistent positive stimulus originating at the ErbB receptors. In BT474 cells expression of the dominant negative form of Erk5 resulted in reduced proliferation, indicating that in these cells Erk5 was also involved in the control of proliferation. Taken together, these results suggest that Erk5 may play a role in the regulation of cell proliferation by NRG receptors and indicate that constitutively active NRG receptors may induce proliferative responses in cancer cells through this MAPK pathway.
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Affiliation(s)
- Azucena Esparís-Ogando
- Instituto de Microbiología Bioquímica and Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, Spain
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35
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Li C, Dowd CS, Zhang W, Chaiken IM. Phage randomization in a charybdotoxin scaffold leads to CD4-mimetic recognition motifs that bind HIV-1 envelope through non-aromatic sequences. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 57:507-18. [PMID: 11437954 DOI: 10.1046/j.1397-002x.2001.00876.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Binding of HIV-1 gp120 to T-cell receptor CD4 initiates conformational changes in the viral envelope that trigger viral entry into host cells. Phage epitope randomization of a beta-turn loop of a charybdotoxin-based miniprotein scaffold was used to identify peptides that can bind gp120 and block the gp120-CD4 interaction. We describe here the display of the charybdotoxin scaffold on the filamentous phage fUSE5, its use to construct a beta-turn library, and miniprotein sequences identified through library panning with immobilized Env gp120. Competition enzyme-linked immunosorbent assay (ELISA) identified high-frequency phage selectants for which specific gp120 binding was competed by sCD4. Several of these selectants contain hydrophobic residues in place of the Phe that occurs in the gp120-binding beta-turns of both CD4 and previously identified scorpion toxin CD4 mimetics. One of these selectants, denoted TXM[24GQTL27], contains GQTL in place of the CD4 beta-turn sequence 40QGSF43. TXM[24GQTL27] peptide was prepared using solid-phase chemical synthesis, its binding to gp120 demonstrated by optical biosensor kinetics analysis and its affinity for the CD4 binding site of gp120 confirmed by competition ELISA. The results demonstrate that aromatic-less loop-containing CD4 recognition mimetics can be formed with detectable envelope protein binding within a beta-turn of the charybdotoxin miniprotein scaffold. The results of this work establish a methodology for phage display of a charybdotoxin miniprotein scaffold and point to the potential value of phage-based epitope randomization of this miniprotein for identifying novel CD4 mimetics. The latter are potentially useful in deconvoluting structural determinants of CD4-HIV envelope recognition and possibly in designing antagonists of viral entry.
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Affiliation(s)
- C Li
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA
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36
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The Regulation of Enzymatic Activity and Metabolism. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50014-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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37
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Vaisman N, Nissim A, Klapper LN, Tirosh B, Yarden Y, Sela M. Specific inhibition of the reaction between a tumor-inhibitory antibody and the ErbB-2 receptor by a mimotope derived from a phage display library. Immunol Lett 2000; 75:61-7. [PMID: 11163868 DOI: 10.1016/s0165-2478(00)00278-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Overexpression of ErbB-2, a coreceptor for stroma-derived growth factors, is involved in malignancies of epithelial tissues, and a humanized antibody to ErbB-2 was shown to be therapeutic in a clinical setting. In an effort to understand and enhance immunotherapy, the laboratory has raised several tumor inhibitory monoclonal antibodies (mAb), including mAb L26 that blocks inter-receptor interactions. Here the application of the phage display methodology for the isolation of a phage clone that specifically recognizes mAb L26 is described. The isolated mimetic peptide (mimotope) specifically inhibited the binding of mAb L26 to ErbB-2 overexpressing cells. No sequence homology was found between the mimotope and ErbB-2. implying that it mimics a conformational structure of the receptor. Preliminary studies showed that the lead peptide can be truncated by removal of two to three amino acids from either the N- or C-terminal end without drastically affecting the inhibitory properties of the mimotope. A tryptophan'glycine residue at the C-terminus and a lysine at the N-terminus of the peptide seemed to play a role in its ability to compete with L26 antibody for binding to ErbB-2 overexpressing cells. These results highlight the potential of active immunization with conformation mimicking peptides in ErbB-2 overexpressing tumors.
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Affiliation(s)
- N Vaisman
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
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38
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Blaskovich MA, Lin Q, Delarue FL, Sun J, Park HS, Coppola D, Hamilton AD, Sebti SM. Design of GFB-111, a platelet-derived growth factor binding molecule with antiangiogenic and anticancer activity against human tumors in mice. Nat Biotechnol 2000; 18:1065-70. [PMID: 11017044 DOI: 10.1038/80257] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have designed a molecule, GFB-111, that binds to platelet-derived growth factor (PDGF), prevents it from binding to its receptor tyrosine kinase, and blocks PDGF-induced receptor autophosphorylation, activation of Erk1 and Erk2 kinases, and DNA synthesis. GFB-111 is highly potent (IC50 = 250 nM) and selective for PDGF over EGF, IGF-1, aFGF, bFGF, and HRGbeta (IC50 values > 100 microM), but inhibits VEGF-induced Flk-1 tyrosine phosphorylation and Erk1/Erk2 activation with an IC50 of 10 microM. GFB-111 treatment of nude mice bearing human tumors resulted in significant inhibition of tumor growth and angiogenesis. The results demonstrate the feasibility of designing novel growth factor-binding molecules with potent anticancer and antiangiogenic activity.
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MESH Headings
- Angiogenesis Inhibitors/chemistry
- Angiogenesis Inhibitors/metabolism
- Angiogenesis Inhibitors/pharmacology
- Angiogenesis Inhibitors/therapeutic use
- Animals
- Antineoplastic Agents/chemistry
- Antineoplastic Agents/metabolism
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Cell Division/drug effects
- Cell Line
- DNA/biosynthesis
- Drug Design
- Endothelial Growth Factors/antagonists & inhibitors
- Endothelial Growth Factors/pharmacology
- Enzyme Activation/drug effects
- Glioblastoma/blood supply
- Glioblastoma/drug therapy
- Glioblastoma/pathology
- Humans
- Inhibitory Concentration 50
- Lymphokines/antagonists & inhibitors
- Lymphokines/pharmacology
- Mice
- Mice, Nude
- Mitogen-Activated Protein Kinases/metabolism
- Neoplasm Transplantation
- Neovascularization, Pathologic/drug therapy
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/metabolism
- Peptides, Cyclic/pharmacology
- Peptides, Cyclic/therapeutic use
- Phosphorylation/drug effects
- Platelet-Derived Growth Factor/antagonists & inhibitors
- Platelet-Derived Growth Factor/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptors, Growth Factor/metabolism
- Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors
- Receptors, Platelet-Derived Growth Factor/metabolism
- Receptors, Vascular Endothelial Growth Factor
- Substrate Specificity
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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Affiliation(s)
- M A Blaskovich
- Drug Discovery Program, H. Lee Moffitt Cancer Center and Research Institute, Department of Biochemistry and Molecular Biology and of Pathology, University of South Florida, Tampa, FL 33612, USA
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39
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Huang YZ, Won S, Ali DW, Wang Q, Tanowitz M, Du QS, Pelkey KA, Yang DJ, Xiong WC, Salter MW, Mei L. Regulation of neuregulin signaling by PSD-95 interacting with ErbB4 at CNS synapses. Neuron 2000; 26:443-55. [PMID: 10839362 DOI: 10.1016/s0896-6273(00)81176-9] [Citation(s) in RCA: 295] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Neuregulins (NRGs) and their receptors, the ErbB protein tyrosine kinases, are essential for neuronal development, but their functions in the adult CNS are unknown. We report that ErbB4 is enriched in the postsynaptic density (PSD) and associates with PSD-95. Heterologous expression of PSD-95 enhanced NRG activation of ErbB4 and MAP kinase. Conversely, inhibiting expression of PSD-95 in neurons attenuated NRG-mediated activation of MAP kinase. PSD-95 formed a ternary complex with two molecules of ErbB4, suggesting that PSD-95 facilitates ErbB4 dimerization. Finally, NRG suppressed induction of long-term potentiation in the hippocampal CA1 region without affecting basal synaptic transmission. Thus, NRG signaling may be synaptic and regulated by PSD-95. A role of NRG signaling in the adult CNS may be modulation of synaptic plasticity.
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Affiliation(s)
- Y Z Huang
- Department of Neurobiology, Pathology, and Physical Medicine and Rehabilitation, University of Alabama at Birmingham, 35294, USA
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40
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Van Zoelen EJ, Stortelers C, Lenferink AE, Van de Poll ML. The EGF domain: requirements for binding to receptors of the ErbB family. VITAMINS AND HORMONES 2000; 59:99-131. [PMID: 10714238 DOI: 10.1016/s0083-6729(00)59005-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Epidermal growth factor (EGF) has been the prototype growth-stimulating peptide for many years. It has a characteristic structure with three disulfide bridges, which is essential for its activity. However, many other proteins, including both growth factors and proteins with unrelated functions, have similar EGF-like domains. This indicates that besides a characteristic conformation provided by the EGF-like domain, specific amino acids are required to provide specificity in protein functioning. Currently, more than 10 different growth factors with an EGF-like domain have been characterized which all exert their action by binding to the four members of the erbB family of receptors. In this review, studies are described on the structure-function relationship of these EGF-like growth factor molecules in an attempt to analyze the individual amino acids that determine their binding specificity to the individual members of the erbB family.
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Affiliation(s)
- E J Van Zoelen
- Department of Cell Biology, University of Nijmegen, The Netherlands
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41
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Wu SJ, Tambyraja R, Zhang W, Zahn S, Godillot AP, Chaiken I. Epitope randomization redefines the functional role of glutamic acid 110 in interleukin-5 receptor activation. J Biol Chem 2000; 275:7351-8. [PMID: 10702307 DOI: 10.1074/jbc.275.10.7351] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sequence randomization through functional phage display of single chain human interleukin (IL)-5 was used to investigate the limits of replaceability of the Glu(110) residues that form a part of the receptor-binding epitope. Mutational analysis revealed unexpected affinity for IL-5 receptor alpha chain with variants containing E110W or E110Y. Escherichia coli-expressed Glu(110) variants containing E110W in the otherwise sequence-intact N-terminal half, including a variant with an E110A replacement in the sequence-disabled C-terminal half, were shown by their CD spectra to be folded into secondary structures similar to that of single chain human IL-5 (scIL-5). Biosensor kinetics analysis revealed that (E110W/A5)scIL-5 and (E110W/A6)scIL-5 had receptor alpha chain binding affinities similar to that of (wt/A5)scIL-5. However, (E110W/A6)scIL-5 had a significantly reduced bioactivity in TF-1 cell proliferation compared with both (wt/A5)scIL-5 and (E110W/A5)scIL-5, and this activity reduction was disproportionately greater than the much smaller effect of Glu(110) mutation on receptor binding affinity. The marked and disproportionate decrease in TF-1 proliferation observed with (E110W/A6)scIL-5 suggests a role for Glu(110) in the biological activity mediated by the signal transducing receptor betac subunit of the IL-5 receptor. This is also consistent with the lack of stimulation of JAK2 phosphorylation by the (E110W/A6)scIL-5 mutant in recombinant 293T cells, as compared with the concentration-dependent stimulation seen for scIL-5. The results reveal the dispensability of charge in the Glu(110) locus of IL-5 for receptor alpha chain binding and, in contrast, its heretofore underappreciated importance for receptor activation.
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Affiliation(s)
- S J Wu
- Department of Medicine, University of Pennsylvania School of Medicine, 909 Stellar Chance Laboratories, Philadelphia, Pennsylvania 19104, USA
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42
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Landgraf R, Fischer D, Eisenberg D. Analysis of heregulin symmetry by weighted evolutionary tracing. PROTEIN ENGINEERING 1999; 12:943-51. [PMID: 10585499 DOI: 10.1093/protein/12.11.943] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Heregulins are members of the protein family of EGF-like growth and differentiation factors. The primary cell-surface targets of heregulins are heterodimers of the EGF-receptor homolog HER2 with either HER3 or HER4. We used a weighted evolutionary trace analysis to identify structural features that distinguish the EGF-like domain (hrg) of heregulins from other members of the EGF family. In this analysis, each amino acid sequence is weighted according to its uniqueness and the variability in each position is assigned by an amino acid substitution matrix. Conserved residues in heregulin that are variable in other EGF-like domains are considered possible specificity-conferring residues. This analysis identifies two clusters of residues at the foot of the boot-shaped hrg domain. The residues in one cluster are recruited from the N-terminus; those in the other are from the ohm-loop region and show a weak sequence similarity to the N-terminal residues at the opposite side of the boot. The remaining residues with high conservation scores distribute themselves into these two distinct surfaces on hrg. This pseudo-twofold symmetry and the presence of two distinct interfaces may reflect the preference of hrg for heterodimeric versus homodimeric HER complexes.
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Affiliation(s)
- R Landgraf
- University of California, UCLA-DOE Laboratory of Structural Biology and Molecular Medicine and Molecular Biology Institute, 405 Hilgard Avenue, Box 951570, Los Angeles, CA 90095-1570, USA
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43
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Abstract
For almost a decade, in vitro selection experiments have been used to isolate novel nucleic acids, peptides and proteins according to their function. Selection experiments have altered our perception of molecular mimicry and catalysis, and they appear to be more facile than rational design at generating biopolymers with desired properties. New methods that have been developed improve the power of functional strategies in ways that nature has already discovered - by expanding library size and facilitating the recombination of positive mutations. Recent structural information on a number of selected and evolved molecules highlights future challenges for design via rational approaches.
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Affiliation(s)
- R W Roberts
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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44
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Wu SJ, Li J, Tsui P, Cook R, Zhang W, Hu Y, Canziani G, Chaiken I. Randomization of the receptor alpha chain recruitment epitope reveals a functional interleukin-5 with charge depletion in the CD loop. J Biol Chem 1999; 274:20479-88. [PMID: 10400676 DOI: 10.1074/jbc.274.29.20479] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report the functional phage display of single chain human interleukin-5 (scIL-5) and its use for receptor-binding epitope randomization. Enzyme-linked immunosorbent assays and optical biosensor analyses verified expression of scIL-5 on the phage surface and binding of scIL-5 phage to interleukin-5 receptor alpha chain. Furthermore, an asymmetrically disabled but functional scIL-5 mutant, (wt/A5)scIL-5, was displayed on phage. (wt/A5)scIL-5 was constructed from an N-terminal half containing the original five charged residues (88EERRR92) in the CD loop, including the Glu89 and Arg91 believed key in the alpha chain recognition site, combined with a C-terminal half containing a disabled CD loop sequence (88AAAAA92) missing the key recognition residues. This asymmetric variant was used as a starting point to generate an scIL-5 library in which the intact 88-92 N-terminal CD loop was randomized. From this epitope library, a receptor-binding variant of IL-5 was detected, (SLRGG/A5)scIL-5, in which the only charged residue in the CD loop is an Arg at position 90. Characterization of this variant expressed as a soluble protein in E. coli shows that the IL-5 pharmacophore for receptor alpha chain binding can function with a single positive charge in the CD loop. Charge-depleted CD loop mimetics of IL-5 suggest the importance of charge distribution in functional IL-5 receptor recruitment.
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Affiliation(s)
- S J Wu
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Harari D, Tzahar E, Romano J, Shelly M, Pierce JH, Andrews GC, Yarden Y. Neuregulin-4: a novel growth factor that acts through the ErbB-4 receptor tyrosine kinase. Oncogene 1999; 18:2681-9. [PMID: 10348342 DOI: 10.1038/sj.onc.1202631] [Citation(s) in RCA: 192] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ErbB/HER family of receptor tyrosine kinases consists of four receptors that bind a large number of growth factor ligands sharing an epidermal growth factor- (EGF)-like motif. Whereas ErbB-1 binds seven different ligands whose prototype is EGF, the three families of neuregulins (NRGs) activate ErbB-3 and/or ErbB-4. Here we characterize a fourth neuregulin, NRG-4, that acts through ErbB-4. The predicted pro-NRG-4 is a transmembrane protein carrying a unique EGF-like motif and a short cytoplasmic domain. A synthetic peptide encompassing the full-length EGF-like domain can induce growth of interleukin-dependent cells ectopically expressing ErbB-4, but not cells expressing the other three ErbB proteins or their combinations. Consistent with specificity to ErbB-4, NRG-4 can displace an ErbB-4-bound NRG-1 and can activate signaling downstream of this receptor. Expression of NRG-4 mRNA was detected in the adult pancreas and weakly in muscle; other tissues displayed no detectable NRG-4 mRNA. The primary structure and the pattern of expression of NRG-4, together with the strict specificity of this growth factor to ErbB-4, suggest a physiological role distinct from that of the known ErbB ligands.
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Affiliation(s)
- D Harari
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot, Israel
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Jones JT, Akita RW, Sliwkowski MX. Binding specificities and affinities of egf domains for ErbB receptors. FEBS Lett 1999; 447:227-31. [PMID: 10214951 DOI: 10.1016/s0014-5793(99)00283-5] [Citation(s) in RCA: 278] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ErbB receptor activation is a complex process and is dependent upon the type and number of receptors expressed on a given cell. Previous studies with defined combinations of ErbB receptors expressed in mammalian cells have helped elucidate specific biological responses for many of the recognized gene products that serve as ligands for these receptors. However, no study has examined the binding of these ligands in a defined experimental system. To address this issue, the relative binding affinities of the egf domains of eleven ErbB ligands were measured on six ErbB receptor combinations using a soluble receptor-ligand binding format. The ErbB2/4 heterodimer was shown to bind all ligands tested with moderate to very high affinity. In contrast, ErbB3 showed much more restrictive ligand binding specificity and measurable binding was observed only with heregulin, neuregulin2beta, epiregulin and the synthetic heregulin/egf chimera, biregulin. These studies also revealed that ErbB2 preferentially enhances ligand binding to ErbB3 or ErbB4 and to a lesser degree to ErbB1.
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Affiliation(s)
- J T Jones
- Genentech, Inc., Department of Molecular Oncology, South San Francisco, CA 94080, USA
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Fairbrother WJ, Liu J, Pisacane PI, Sliwkowski MX, Palmer AG. Backbone dynamics of the EGF-like domain of heregulin-alpha. J Mol Biol 1998; 279:1149-61. [PMID: 9642091 DOI: 10.1006/jmbi.1998.1837] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The backbone dynamics of the 63 residue epidermal growth factor (EGF)-like domain of heregulin-alpha (HRG-alpha) have been characterized by measurement of longitudinal relaxation rate constants (R1), transverse relaxation rate constants (R2), and steady-state ¿1H¿-15N nuclear Overhauser effects for the 15N nuclear spins using proton-detected heteronuclear NMR spectroscopy. Analysis of the R2/R1 ratios in conjunction with the known structure of the HRG-alpha EGF-like domain yields a rotational correlation time of approximately 8.4 ns, suggesting that the protein aggregates under the solution conditions used (3.8 mM protein, 50 mM sodium acetate, pH 4.5, 20 degreesC), and that it tumbles with an axially symmetric diffusion tensor (D parallel/D perpendicular=1.4). Sedimentation equilibrium experiments confirm that the EGF-like domain of HRG-alpha undergoes weak self-association under these conditions and are consistent with a simple monomer-dimer equilibrium with a dimer-dissociation constant Kd=1.6(+/-0.4) mM. The relaxation data were analyzed using a reduced spectral density mapping approach to avoid systematic effects of aggregation on the usual model-free formalism. The reduced spectral densities show that residues near the N terminus (residues 3 to 5 and 7 to 12), in the Omega-loop between beta-strands 2 and 3 (residues 24 to 31), and in particular the C-terminal 13 residues (residues 51 to 63), have significant mobility on a picosecond/nanosecond time-scale. In addition, conformational exchange on a microsecond time-scale was identified for residues 44 to 46 on the basis of observed differences in R2 at 11.7 and 14.1 T. The mobility identified near the N terminus and in the vicinity of residues 44 to 46 may be important in allowing the interactions of heregulin with multiple receptors.
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Affiliation(s)
- W J Fairbrother
- Department of Protein Engineering, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
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Ballinger MD, Jones JT, Lofgren JA, Fairbrother WJ, Akita RW, Sliwkowski MX, Wells JA. Selection of heregulin variants having higher affinity for the ErbB3 receptor by monovalent phage display. J Biol Chem 1998; 273:11675-84. [PMID: 9565588 DOI: 10.1074/jbc.273.19.11675] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heregulins (HRGs) are epidermal growth factor (egf) domain containing polypeptide growth factors that bind and activate several members of the ErbB receptor family. Although HRG can bind to ErbB3 and ErbB4 homodimers, the highest affinity and most intracellularly active receptor complexes are hetero-oligomers containing ErbB2. The HRGbeta egf domain was displayed on the surface of M13 phage to facilitate mutagenic analysis and optimize for binding to a homodimeric ErbB3-immunoglobulin (IgG) fusion. Nine libraries were constructed in which virtually the entire sequence was randomized in stretches of four to six amino acids. These were selected separately for binding to immobilized ErbB3-IgG. Analysis of the resulting sequences revealed some areas that diverged radically from the wild-type, whereas others showed strong conservation. The degree of wild-type conservation correlated strongly with the functional importance of the residues as determined by alanine scanning mutagenesis (Jones, J. T., Ballinger, M. D., Pisacane, P. I., Lofgren, J. A., Fitzpatrick, V. D., Fairbrother, W. J., Wells, J. A., and Sliwkowski, M. X. (1998) J. Biol. Chem. 273, 11667-11674). Some variants from several libraries showed significant improvements in binding affinity to the ErbB3-IgG. These optimized segments were combined in various ways in the same molecule to generate variants (containing up to 16 mutations) that had >50-fold higher affinity than wild-type HRGbeta. The optimized variants stimulated ErbB2 phophorylation on MCF7 cells at levels similar to wild-type. This indicates wild-type affinity is optimized for potency and that factors other than affinity for ErbB3 are limiting. These variants showed enhanced affinity toward the ErbB4 homodimer, suggesting these receptors use very similar binding determinants despite them having 65% sequence identity.
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Affiliation(s)
- M D Ballinger
- Department of Protein Engineering, Genentech, Incorporated, South San Francisco, California 94080, USA
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