1
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Abdelli F, Jellali K, Anguita E, González-Muñoz M, Villalobo E, Madroñal I, Alcalde J, Ben Ali M, Elloumi-Mseddi J, Jemel I, Tebar F, Enrich C, Aifa S, Villalobo A. The role of the calmodulin-binding and calmodulin-like domains of the epidermal growth factor receptor in tyrosine kinase activation. J Cell Physiol 2020; 236:4997-5011. [PMID: 33305427 DOI: 10.1002/jcp.30205] [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: 08/05/2020] [Revised: 11/20/2020] [Accepted: 11/26/2020] [Indexed: 11/11/2022]
Abstract
The epidermal growth factor receptor (EGFR) harbors a calmodulin (CaM)-binding domain (CaM-BD) and a CaM-like domain (CaM-LD) upstream and downstream, respectively, of the tyrosine kinase (TK) domain. We demonstrate in this paper that deletion of the positively charged CaM-BD (EGFR/CaM-BD∆) inactivated the TK activity of the receptor. Moreover, deletion of the negatively charged CaM-LD (EGFR/CaM-LD∆), leaving a single negative residue (glutamate), reduced the activity of the receptor. In contrast, substituting the CaM-LD with a histidine/valine-rich peptide (EGFR/InvCaM-LD) caused full inactivation. We also demonstrated using confocal microscopy and flow cytometry that the chimera EGFR-green fluorescent protein (GFP)/CaM-BD∆, the EGFR/CaM-LD∆, and EGFR/InvCaM-LD mutants all bind tetramethylrhodamine-labelled EGF. These EGFR mutants were localized at the plasma membrane as the wild-type receptor does. However, only the EGFR/CaM-LD∆ and EGFR/InvCaM-LD mutants appear to undergo ligand-dependent internalization, while the EGFR-GFP/CaM-BD∆ mutant seems to be deficient in this regard. The obtained results and in silico modelling studies of the asymmetric structure of the EGFR kinase dimer support a role of a CaM-BD/CaM-LD electrostatic interaction in the allosteric activation of the EGFR TK.
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Affiliation(s)
- Faten Abdelli
- Centre of Biotechnology of Sfax, Sfax, Tunisia.,Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Karim Jellali
- Centre of Biotechnology of Sfax, Sfax, Tunisia.,Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Estefanía Anguita
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain.,Molecular Biology and Biochemistry Research Center, CIBBIM-Nanomedicine, Vall d'Hebron Hospital Research Institute, Barcelona, Spain
| | - María González-Muñoz
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Eduardo Villalobo
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Ivan Madroñal
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Alcalde
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Jihene Elloumi-Mseddi
- Centre of Biotechnology of Sfax, Sfax, Tunisia.,Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Ikram Jemel
- Centre of Biotechnology of Sfax, Sfax, Tunisia.,Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
| | - Francesc Tebar
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Carlos Enrich
- Unitat de Biologia Cel·lular, Departament de Biomedicina, Facultat de Medicina i Ciències de la Salut, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Sami Aifa
- Centre of Biotechnology of Sfax, Sfax, Tunisia
| | - Antonio Villalobo
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain.,Cancer and Human Molecular Genetics Area-Oto-Neurosurgery Research Group, University Hospital La Paz Research Institute (IdiPAZ), Madrid, Spain
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2
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Sinclair JKL, Walker AS, Doerner AE, Schepartz A. Mechanism of Allosteric Coupling into and through the Plasma Membrane by EGFR. Cell Chem Biol 2018; 25:857-870.e7. [PMID: 29731426 DOI: 10.1016/j.chembiol.2018.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/05/2018] [Accepted: 04/04/2018] [Indexed: 12/12/2022]
Abstract
Epidermal growth factor receptor (EGFR) interacts through its extracellular domain with seven different growth factors. These factors induce different structures within the cytoplasmic juxtamembrane (JM) segment of the dimeric receptor and propagate different growth factor-dependent signals to the cell interior. How this process occurs is unknown. Here we apply diverse experimental and computational tools to show that growth factor identity is encoded by the EGFR transmembrane (TM) helix into discrete helix dimer populations that differ in both cross-location and cross-angle. Helix dimers with smaller cross-angles at multiple cross locations are decoded to induce an EGF-type coiled coil in the adjacent JM, whereas helix dimers with larger cross-angles at fewer cross locations induce the TGF-α-type coiled coil. We propose an updated model for how conformational coupling across multiple EGFR domains results in growth factor-specific information transfer, and demonstrate that this model applies to both EGFR and the related receptor ErbB2.
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Affiliation(s)
| | - Allison S Walker
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
| | - Amy E Doerner
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
| | - Alanna Schepartz
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA.
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3
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Doerner A, Scheck R, Schepartz A. Growth Factor Identity Is Encoded by Discrete Coiled-Coil Rotamers in the EGFR Juxtamembrane Region. ACTA ACUST UNITED AC 2016; 22:776-84. [PMID: 26091170 DOI: 10.1016/j.chembiol.2015.05.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/04/2015] [Accepted: 05/13/2015] [Indexed: 12/24/2022]
Abstract
Binding of transforming growth factor α (TGF-α) to the epidermal growth factor receptor (EGFR) extracellular domain is encoded through the formation of a unique antiparallel coiled coil within the juxtamembrane segment. This new coiled coil is an "inside-out" version of the coiled coil formed in the presence of epidermal growth factor (EGF). A third, intermediary coiled-coil interface is formed in the juxtamembrane region when EGFR is stimulated with betacellulin. The seven growth factors that activate EGFR in mammalian systems (EGF, TGF-α, epigen, epiregulin, betacellulin, heparin-binding EGF, and amphiregulin) fall into distinct categories in which the structure of the coiled coil induced within the juxtamembrane region correlates with cell state. The observation that coiled-coil state tracks with the downstream signaling profiles for each ligand provides evidence for growth factor functional selectivity by EGFR. Encoding growth factor identity in alternative coiled-coil rotamers provides a simple and elegant method for communicating chemical information across the plasma membrane.
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Affiliation(s)
- Amy Doerner
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520-8107, USA
| | - Rebecca Scheck
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520-8107, USA
| | - Alanna Schepartz
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520-8107, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA.
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4
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Li H, Panina S, Kaur A, Ruano MJ, Sánchez-González P, la Cour JM, Stephan A, Olesen UH, Berchtold MW, Villalobo A. Regulation of the ligand-dependent activation of the epidermal growth factor receptor by calmodulin. J Biol Chem 2011; 287:3273-81. [PMID: 22157759 DOI: 10.1074/jbc.m111.317529] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) is the major component of calcium signaling pathways mediating the action of various effectors. Transient increases in the intracellular calcium level triggered by a variety of stimuli lead to the formation of Ca(2+)/CaM complexes, which interact with and activate target proteins. In the present study the role of Ca(2+)/CaM in the regulation of the ligand-dependent activation of the epidermal growth factor receptor (EGFR) has been examined in living cells. We show that addition of different cell permeable CaM antagonists to cultured cells or loading cells with a Ca(2+) chelator inhibited ligand-dependent EGFR auto(trans)phosphorylation. This occurred also in the presence of inhibitors of protein kinase C, CaM-dependent protein kinase II and calcineurin, which are known Ca(2+)- and/or Ca(2+)/CaM-dependent EGFR regulators, pointing to a direct effect of Ca(2+)/CaM on the receptor. Furthermore, we demonstrate that down-regulation of CaM in conditional CaM knock out cells stably transfected with the human EGFR decreased its ligand-dependent phosphorylation. Substitution of six basic amino acid residues within the CaM-binding domain (CaM-BD) of the EGFR by alanine resulted in a decreased phosphorylation of the receptor and of its downstream substrate phospholipase Cγ1. These results support the hypothesis that Ca(2+)/CaM regulates the EGFR activity by directly interacting with the CaM-BD of the receptor located at its cytosolic juxtamembrane region.
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Affiliation(s)
- Hongbing Li
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Arturo Duperier 4, E-28029 Madrid, Spain
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5
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White CD, Li Z, Sacks DB. Calmodulin binds HER2 and modulates HER2 signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1074-82. [PMID: 21185879 DOI: 10.1016/j.bbamcr.2010.12.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 12/11/2010] [Accepted: 12/15/2010] [Indexed: 11/17/2022]
Abstract
Human epidermal growth factor receptor 2 (HER2), a member of the ErbB family of receptor tyrosine kinases, has defined roles in neoplastic transformation and tumor progression. Overexpression of HER2 is an adverse prognostic factor in several human neoplasms and, particularly in breast cancer, correlates strongly with a decrease in overall patient survival. HER2 stimulates breast tumorigenesis by forming protein-protein interactions with a diverse array of intracellular signaling molecules, and evidence suggests that manipulation of these associations holds therapeutic potential. To modulate specific HER2 interactions, the region(s) of HER2 to which each target binds must be accurately identified. Calmodulin (CaM), a ubiquitously expressed Ca(2+) binding protein, interacts with multiple intracellular targets. Interestingly, CaM binds the juxtamembrane region of the epidermal growth factor receptor, a HER2 homolog. Here, we show that CaM interacts, in a Ca(2+)-regulated manner, with two distinct sites on the N-terminal portion of the HER2 intracellular domain. Deletion of residues 676-689 and 714-732 from HER2 prevented CaM-HER2 binding. Inhibition of CaM function or deletion of the CaM binding sites from HER2 significantly decreased both HER2 phosphorylation and HER2-stimulated cell growth. Collectively, these data suggest that inhibition of CaM-HER2 interaction may represent a rational therapeutic strategy for the treatment of patients with breast cancer. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Colin D White
- Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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6
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Sánchez-González P, Jellali K, Villalobo A. Calmodulin-mediated regulation of the epidermal growth factor receptor. FEBS J 2009; 277:327-42. [PMID: 19951361 DOI: 10.1111/j.1742-4658.2009.07469.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this review, we first describe the mechanisms by which the epidermal growth factor receptor generates a Ca(2+) signal and, subsequently, we compile the available experimental evidence regarding the role that the Ca(2+)/calmodulin complex, formed after the rise in cytosolic free Ca(2+) concentration, exerts on the receptor. We focus not only on the indirect action that Ca(2+)/calmodulin exerts on the epidermal growth factor receptor, as a result of the activation of distinct calmodulin-dependent kinases, but also, and more extensively, on the direct interaction of Ca(2+)/calmodulin with the receptor. We also describe several mechanistic models that could account for the Ca(2+)/calmodulin-mediated regulation of epidermal growth factor receptor activity. The control exerted by calmodulin on distinct epidermal growth factor receptor-mediated cellular functions is also discussed. Finally, the phosphorylation of this Ca(2+) sensor by the epidermal growth factor receptor is highlighted.
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Affiliation(s)
- Pablo Sánchez-González
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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7
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Alenghat FJ, Tytell JD, Thodeti CK, Derrien A, Ingber DE. Mechanical control of cAMP signaling through integrins is mediated by the heterotrimeric Galphas protein. J Cell Biochem 2009; 106:529-38. [PMID: 19170051 DOI: 10.1002/jcb.22001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Mechanical stresses that are preferentially transmitted across the cell surface via transmembrane integrin receptors activate gene transcription by triggering production of intracellular chemical second messengers, such as cAMP. Here we show that the sensitivity of the cAMP signaling pathway to mechanical stresses transferred across beta1 integrins is mediated by force-dependent activation of the heterotrimeric G protein subunit Galphas within focal adhesions at the site of stress application. Galphas is recruited to focal adhesions that form within minutes following clustering of beta1 integrins induced by cell binding to magnetic microbeads coated with activating integrin ligands, and beta1 integrin and Galphas co-precipitate when analyzed biochemically. Stress application to activated beta1 integrins using magnetic twisting cytometry increases Galphas recruitment and activates these large G proteins within focal adhesions, as measured by binding of biotinylated azido-anilido-GTP, whereas application of similar stresses to inactivated integrins or control histocompatibility antigens has little effect. This response is relevant physiologically as application of mechanical strain to cells bound to flexible extracellular matrix-coated substrates induce translocation of phospho-CREB to the nucleus, which can be attenuated by inhibiting Galphas activity, either using the inhibitor melittin or suppressing its expression using siRNA. Although integrins are not typical G protein-coupled receptors, these results show that integrins focus mechanical stresses locally on heterotrimeric G proteins within focal adhesions at the site of force application, and transduce mechanical stimuli into an intracellular cAMP signaling response by activating Galphas at these membrane signaling sites.
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Affiliation(s)
- Francis J Alenghat
- Departments of Pathology and Surgery, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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8
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Hake MJ, Choowongkomon K, Kostenko O, Carlin CR, Sönnichsen FD. Specificity determinants of a novel Nck interaction with the juxtamembrane domain of the epidermal growth factor receptor. Biochemistry 2008; 47:3096-108. [PMID: 18269246 DOI: 10.1021/bi701549a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nck is a ubiquitously expressed adaptor protein containing Src homology 2 (SH2) and Src homology 3 (SH3) domains. It integrates downstream effector proteins with cell membrane receptors, such as the epidermal growth factor receptor (EGFR). EGFR plays a critical role in cellular proliferation and differentiation. The 45-residue juxtamembrane domain of EGFR (JM), located between the transmembrane and kinase domains, regulates receptor activation and trafficking to the basolateral membrane of polarized epithelia through a proline-rich motif that resembles a consensus SH3 domain binding site. We demonstrate here that the JM region can bind to Nck, showing a notable binding preference for the second SH3 domain. To elucidate the structural determinants for this interaction, we have determined the NMR solution structures of both the first and second Nck SH3 domains (Nck1-1 and Nck1-2). These domains adopt a canonical SH3 beta-barrel-like fold, containing five antiparallel strands separated by three loop regions and one 3 10-helical turn. Chemical shift perturbation studies have identified the residues that form the binding cleft of Nck1-2, which are primarily located in the RT and n-Src loops. JM binds to Nck1-2 with an affinity of approximately 80 microM through a positively charged sequence near the N-terminus, as opposed to the polyproline sequence. The two Nck SH3 domains exhibit both steric and electrostatic differences in their RT-Src and n-Src loops, and a model of the Nck1-2 domain complexed with the JM highlights the factors that define the putative binding mode for this ligand.
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Affiliation(s)
- Michael J Hake
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
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9
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Aifa S, Miled N, Frikha F, Aniba MR, Svensson SPS, Rebai A. Electrostatic interactions of peptides flanking the tyrosine kinase domain in the epidermal growth factor receptor provides a model for intracellular dimerization and autophosphorylation. Proteins 2006; 62:1036-43. [PMID: 16380971 DOI: 10.1002/prot.20780] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The mechanism by which ligand-activated EGFR induces autophosphorylation via dimerization is not fully understood. Structural studies have revealed an extracellular loop mediated receptor dimerization. We have previously presented experimental data showing the involvement of a positive 13 amino acid peptide (R645-R657; P13+) from the intracellular juxtamembrane domain (JM) of EGFR important for intracellular dimerization and autophosphorylation. A model was presented that suggest that P13+ interacts with a negative peptide (D979-E991; P13-) positioned distal to the tyrosine kinase domain in the opposite EGFR monomer. The present work shows additional data strengthening this model. In fact, by analyzing protein sequences of 21 annotated ErbB proteins from 9 vertebrate genomes, we reveal the high conservation of peptides P13+ and P13- with regard to their sequence as well as their position relative to the tyrosine kinase (TK) domain. Moreover in silico structure modeling of these ErbB intracellular domains supports a general electrostatic P13+/P13- interaction, implying that the C-terminal of one receptor monomer is facing the TK domain of the other monomer in the receptor dimer and vice versa. This model provides new insights into the molecular mechanism of ErbB receptor activation and suggests a new strategy to pharmacologically interfering with ErbB receptor activity.
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Affiliation(s)
- Sami Aifa
- Centre of Biotechnology of Sfax, Sfax, Tunisia
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10
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Choowongkomon K, Carlin CR, Sönnichsen FD. A structural model for the membrane-bound form of the juxtamembrane domain of the epidermal growth factor receptor. J Biol Chem 2005; 280:24043-52. [PMID: 15840573 DOI: 10.1074/jbc.m502698200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine kinase family involved in the regulation of cellular proliferation and differentiation. Its juxtamembrane domain (JX), the region located between the transmembrane and kinase domains, plays important roles in receptor trafficking. Two sorting signals, a PXXP motif and a 658LL659 motif, are responsible for basolateral sorting in polarized epithelial cells, and a 679LL680 motif targets the ligand-activated receptor for lysosomal degradation. To understand the regulation of these signals, we characterized the structural properties of recombinant JX domain in aqueous solution and in dodecylphosphocholine (DPC) detergent. JX is inherently unstructured in aqueous solution, albeit a nascent helix encompasses the lysosomal sorting signal. In DPC micelles, structures derived from NMR data showed three amphipathic, helical segments. A large, internally inconsistent group of long range nuclear Overhauser effects suggest a close proximity of the helices, and the presence of significant conformational averaging. Models were determined for the average JX conformation using restraints representing the translational restriction due to micelle-surface adsorption, and the helix orientations were determined from residual dipolar couplings. Two equivalent average structural models were obtained that differ only in the relative orientation between first and second helices. In these models, the 658LL659 and 679LL680 motifs are located in the first and second helices and face the micelle surface, whereas the PXXP motif is located in a flexible helix-connecting region. The data suggest that the activity of these signals may be regulated by their membrane association and restricted accessibility in the intact receptor.
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Affiliation(s)
- Kiattawee Choowongkomon
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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11
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Aifa S, Aydin J, Nordvall G, Lundström I, Svensson SPS, Hermanson O. A basic peptide within the juxtamembrane region is required for EGF receptor dimerization. Exp Cell Res 2005; 302:108-14. [PMID: 15541730 DOI: 10.1016/j.yexcr.2004.08.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 08/09/2004] [Indexed: 10/26/2022]
Abstract
The epidermal growth factor receptor (EGFR) is fundamental for normal cell growth and organ development, but has also been implicated in various pathologies, notably tumors of epithelial origin. We have previously shown that the initial 13 amino acids (P13) within the intracellular juxtamembrane region (R645-R657) are involved in the interaction with calmodulin, thus indicating an important role for this region in EGFR function. Here we show that P13 is required for proper dimerization of the receptor. We expressed either the intracellular domain of EGFR (TKJM) or the intracellular domain lacking P13 (DeltaTKJM) in COS-7 cells that express endogenous EGFR. Only TKJM was immunoprecipitated with an antibody directed against the extracellular part of EGFR, and only TKJM was tyrosine phosphorylated by endogenous EGFR. Using SK-N-MC cells, which do not express endogenous EGFR, that were stably transfected with either wild-type EGFR or recombinant full-length EGFR lacking P13 demonstrated that P13 is required for appropriate receptor dimerization. Furthermore, mutant EGFR lacking P13 failed to be autophosphorylated. P13 is rich in basic amino acids and in silico modeling of the EGFR in conjunction with our results suggests a novel role for the juxtamembrane domain (JM) of EGFR in mediating intracellular dimerization and thus receptor kinase activation and function.
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Affiliation(s)
- Sami Aifa
- Department of Pharmacology, Linköping University, SE-58185 Linköping, Sweden
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12
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Deng W, Poppleton H, Yasuda S, Makarova N, Shinozuka Y, Wang DA, Johnson LR, Patel TB, Tigyi G. Optimal lysophosphatidic acid-induced DNA synthesis and cell migration but not survival require intact autophosphorylation sites of the epidermal growth factor receptor. J Biol Chem 2004; 279:47871-80. [PMID: 15364923 DOI: 10.1074/jbc.m405443200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysophosphatidic acid (LPA)-elicited transphosphorylation of receptor tyrosine kinases has been implicated in mediating extracellular signal-regulated kinase (ERK) 1/2 activation, which is necessary for LPA-induced cell proliferation, migration, and survival. B82L cells lack epidermal growth factor receptor (EGFR) but express LPA(1-3), platelet-derived growth factor (PDGF), ErbB2, and insulin-like growth factor receptor transcripts, yet LPA caused no detectable transphosphorylation of these receptor tyrosine kinases. LPA equally protected B82L cells, or transfectants expressing EGFR, the kinase dead EGFR(K721A), EGFR(Y5F) receptor mutant, which lacks five autophosphorylation sites, or EGFR(Y845F), which lacks the Src phosphorylation site from tumor necrosis factor-alpha-induced apoptosis. In contrast, LPA-elicited DNA synthesis and migration were augmented in cells expressing EGFR, EGFR(K721A), or EGFR(Y845F), but not EGFR(Y5F), although the PDGF responses were indistinguishable. LPA-induced transphosphorylation of the EGFR, ErbB2, or PDGF receptor was not required for its antiapoptotic effect. EGFR with or without intrinsic kinase activity or without the Src-phosphorylation site augmented, but was not required for, LPA-elicited cell proliferation or migration. In B82L cells, augmentation of these two LPA responses required intact autophosphorylation sites because among the four EGFR mutants, only cells expressing the EGFR(Y5F) mutant showed no enhancement. In EGFR(Y5F)-expressing cells, LPA failed to elicit tyrosine phosphorylation of Src homologous and collagen protein (SHC) and caused only a modest increase in ERK1/2 phosphorylation similar to that in wild-type B82L cells. The present data pinpoint the lack of importance of the intrinsic kinase activity in contrast to the importance of autophosphorylation sites of the EGFR for SHC phosphorylation in the enhancement of select ERK1/2-dependent LPA responses.
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Affiliation(s)
- Wenlin Deng
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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13
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Patel TB. Single Transmembrane Spanning Heterotrimeric G Protein-Coupled Receptors and Their Signaling Cascades. Pharmacol Rev 2004; 56:371-85. [PMID: 15317909 DOI: 10.1124/pr.56.3.4] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heptahelical of serpentine receptors such as the adrenergic receptors are well known to mediate their actions via heterotrimeric GTP-binding proteins. Likewise, receptors that traverse the cell membrane once have been shown to mediate their biological actions by activating several different mechanisms including stimulation of their intrinsic tyrosine kinase activities or the kinase activities of other proteins. Some of these single transmembrane receptors have an intrinsic guanylyl cyclase activity and can stimulate the cyclic GMP second messenger system; however, over the last few years, several studies have shown the involvement of heterotrimeric GTP-binding proteins in mediating signals that eventually culminate in the biological actions of single transmembrane spanning receptors and proteins. These receptors include the receptor tyrosine kinases that mediate the actions of growth factors such as epidermal growth factor, insulin, insulin-like growth factor as well as receptors for atrial natiuretic hormone or the zona pellucida protein (ZP3) and integrins. In this review, the significance of the coupling of the single transmembrane spanning receptors to G proteins has been highlighted by providing several examples of the concept that signaling via these receptors may involve the activation of multiple signaling cascades.
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Affiliation(s)
- Tarun B Patel
- Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60513, USA.
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14
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Choowongkomon K, Hobert ME, He C, Carlin CR, Sonnichsen FD. Aqueous and Micelle-bound Structural Characterization of the Epidermal Growth Factor Receptor Juxtamembrane Domain Containing Basolateral Sorting Motifs. J Biomol Struct Dyn 2004; 21:813-26. [PMID: 15107003 DOI: 10.1080/07391102.2004.10506971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The EGF receptor is the prototype for four highly related receptors constituting the ErbB family. The EGF receptor is normally targeted to the basolateral membrane in polarized epithelial cells, where it relays information from underlying tissues. Two basolateral sorting signals have been mapped to the cytoplasmic juxtamembrane region of the receptor, a dominant signal comprised of a polyproline core (667-PXXP) and a preceding basic residue (Arg662), and a consensus leucine-based signal (658-LL) responsible for residual sorting when the 667-PXXP signal is absent or defective. The goal of this study was to define the structure of these signals, and gain some insights into how these structures might be regulated by cellular microenvironment. Structural information was acquired for two peptides corresponding to EGF receptor residues Arg645 and Ala674 in aqueous solution or in the presence of membrane-mimicking dodecylphosphocholine micelles, using a variety of NMR and CD spectroscopic methods. Chemical shift data indicate that the 667-PXXP signal does not bind to the micelles and is in random coil state in both aqueous solution and a micellar environment, raising the possibility that 667-PXXP switches to an ordered structure during interaction with the basolateral sorting machinery. In contrast, the adjacent region including 658-LL does bind to micelles mediated by a highly positively charged region located between Arg645 and Arg656. The micelle-bound region also includes Thr654, a known substrate for PKC. This suggests a distinct mode of regulation for this signal involving membrane association and/or phosphorylation.
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Affiliation(s)
- K Choowongkomon
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Aifa S, Johansen K, Nilsson UK, Liedberg B, Lundström I, Svensson SPS. Interactions between the juxtamembrane domain of the EGFR and calmodulin measured by surface plasmon resonance. Cell Signal 2002; 14:1005-13. [PMID: 12359306 DOI: 10.1016/s0898-6568(02)00034-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
One early response to epidermal growth factor receptor (EGFR) activation is an increase in intracellular calcium. We have used surface plasmon resonance (SPR) to study real-time interactions between the intracellular juxtamembrane (JM) region of EGFR and calmodulin. The EGFR-JM (Met(644)-Phe(688)) was expressed as a GST fusion protein and immobilised on a sensor chip surface. Calmodulin specifically interacts with EGFR-JM in a calcium-dependent manner with a high on and high off rate. Chemical modification of EGFR-JM by using arginine-selective phenylglyoxal or deletion of the basic segment Arg(645)-Arg(657) inhibits the interaction. Phosphorylation of EGFR-JM by protein kinase C (PKC) or glutamate substitution of Thr(654) inhibits the interaction, suggesting that PKC phosphorylation electrostatically interferes with calmodulin binding to basic arginine residues. Calmodulin binding was also inhibited by suramin. Our results suggest that EGFR-JM is essential for epidermal growth factor (EGF)-mediated calcium-calmodulin signalling and for signal integration between other signalling pathways.
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Affiliation(s)
- Sami Aifa
- Department of Pharmacology, Linköping University, SE-58185 Linköping, Sweden
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Lorita J, Escalona N, Faraudo S, Soley M, Ramírez I. Effects of epidermal growth factor on epinephrine-stimulated heart function in rodents. Am J Physiol Heart Circ Physiol 2002; 283:H1887-95. [PMID: 12384466 DOI: 10.1152/ajpheart.00217.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epidermal growth factor (EGF) interferes with beta-adrenergic receptor (beta-AR) signaling in adipocytes and hepatocytes, which leads to decreased lipolytic and glycogenolytic responses, respectively. We studied the effect of EGF on the heart. EGF interfered with the cAMP signal generated by beta-AR agonists in cardiac myocytes. In perfused hearts, EGF decreased inotropic and chronotropic responses to epinephrine but not to 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate. Sustained epinephrine infusion induced heart contracture, which resulted in altered heart function as demonstrated by decreased inotropy and increased heart rate variability. EGF prevented all these alterations. In the whole animal (anesthetized mice), EGF administration reduced the rise in heart rate induced by a single epinephrine dose and the occurrence of Bezold-Jarisch reflex episodes induced by repeated doses. Sialoadenectomy enhanced the response to epinephrine, and EGF administration restored normal response. All these results suggest that, by interfering with beta-AR signaling, EGF protects the heart against the harmful effects of epinephrine.
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Affiliation(s)
- Jordi Lorita
- Department of Biochemistry and Molecular Biology, University of Barcelona, Avda. Diagonal 645, 08028 Barcelona, Spain
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