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Landi N, Grundner M, Ragucci S, Pavšič M, Mravinec M, Pedone PV, Sepčić K, Di Maro A. Characterization and cytotoxic activity of ribotoxin-like proteins from the edible mushroom Pleurotus eryngii. Food Chem 2022; 396:133655. [PMID: 35868286 DOI: 10.1016/j.foodchem.2022.133655] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/15/2022] [Accepted: 07/06/2022] [Indexed: 11/04/2022]
Abstract
Ribotoxin-like proteins (RL-Ps) represent a novel specific ribonuclease family found in edible mushrooms and are able to inhibit protein synthesis. Here, we report the characterization and cytotoxic effects of four novel RL-Ps, named eryngitins, isolated from fruiting bodies of the king oyster mushroom (Pleurotus eryngii). These proteins induced formation of α-fragment from rabbit ribosomes, characteristic of their enzymatic action. The two 15 kDa eryngitins (3 and 4) are considerably more thermostable than the 21 kDa ones (1 and 2), however their overall structural features, as determined by far-UV CD spectrometry, are similar. Complete in vitro digestibility by pepsin-trypsin, and lack of cytotoxicity towards human HUVEC cells suggest low toxicity of eryngitins, if ingested. However, eryngitins exhibit cytotoxic action against insect Sf9 cells, suggesting their possible use in biotechnological applications as bioinsecticides. This cytotoxicity was not enhanced in the presence of cytolytic protein complexes based on aegerolysin proteins from Pleurotus mushrooms.
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Affiliation(s)
- Nicola Landi
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania 'Luigi Vanvitelli', Via Vivaldi 43, 81100-Caserta, Italy
| | - Maja Grundner
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Sara Ragucci
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania 'Luigi Vanvitelli', Via Vivaldi 43, 81100-Caserta, Italy
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Martina Mravinec
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Paolo V Pedone
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania 'Luigi Vanvitelli', Via Vivaldi 43, 81100-Caserta, Italy
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Antimo Di Maro
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), University of Campania 'Luigi Vanvitelli', Via Vivaldi 43, 81100-Caserta, Italy.
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Pavšič M. Dataset and analysis of molecular dynamics simulation of EpCAM ectodomain dimer. Data Brief 2021; 38:107403. [PMID: 34611538 PMCID: PMC8477132 DOI: 10.1016/j.dib.2021.107403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 10/28/2022] Open
Abstract
The data provided and described here give insight into the solution dynamics of the dimer of human EpCAM ectodomain (EpEX). As the starting point, crystal structure of EpEX non-covalent dimer was used (PDB ID 4MZV). The coordinates of solvent-embedded dimer were used to generate a topology file, which was in turn used for all-atom molecular dynamics (MD) simulation run of 20 ns length using full-system periodic electrostatics at a constant temperature of 310 K and a constant pressure of 1 atm. The MD trajectory file (part of this dataset) contains 4000 frames corresponding to recording/sampling atom positions every 5 ps. The simulation run was then analyzed in terms of root mean square deviations (RMSD) of protein atoms, and non-covalent inter-subunit interactions. The MD trajectory and analyzed data enable-in contrast to the static crystal structure-detailed analysis of solution-like protein structural dynamics and support design of EpCAM-targetting binders and structure-based analysis of EpCAM interactome.
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Affiliation(s)
- Miha Pavšič
- Faculty of Chemistry and Chemical Technology, Department of Chemistry and Biochemistry, University of Ljubljana, Večna pot 113, Ljubljana SI-1000, Slovenia
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Pavšič M. Trop2 Forms a Stable Dimer with Significant Structural Differences within the Membrane-Distal Region as Compared to EpCAM. Int J Mol Sci 2021; 22:ijms221910640. [PMID: 34638982 PMCID: PMC8508679 DOI: 10.3390/ijms221910640] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 02/05/2023] Open
Abstract
Trop2 is a cell-surface transmembrane glycoprotein involved in the maintenance of epithelial tissue integrity and is an important carcinoma marker. It shares similar claudin-interaction capacity with its paralogue EpCAM, and both are implicated in signaling triggered by proteolytic cleavage within the ectodomain. However, the cell proliferation-regulating interactions with IGF-1, neuregulin-1, and α5β1 integrin appear to be Trop2-specific. To illuminate the structural differences between Trop2 and EpCAM, we report the first crystal structure of a Trop2 ectodomain dimer and compare it to the analogous part of EpCAM. While the overall fold of the two proteins is similar, the dimers differ. In Trop2, the inter-subunit contacts are more extensive than in EpCAM, and there are two major differences in the membrane-distal regions. The immunogenic N-terminal domain is in Trop2 almost colinear with the dimer interface plain and consequently more laterally exposed, and the cleft of yet unknown functionality between the two subunits is almost absent. Furthermore, the site of initial signaling-associated proteolytic cleavage in Trop2 is accessible in the dimeric state, while in EpCAM dimer destabilization is required. The structural differences highlight the divergent evolutionary path of the two proteins and pave the way for their structure-based utilization in therapy.
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Affiliation(s)
- Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna Pot 113, SI-1000 Ljubljana, Slovenia
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Konjar Š, Pavšič M, Veldhoen M. Regulation of Oxygen Homeostasis at the Intestinal Epithelial Barrier Site. Int J Mol Sci 2021; 22:ijms22179170. [PMID: 34502078 PMCID: PMC8431628 DOI: 10.3390/ijms22179170] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/28/2021] [Accepted: 08/19/2021] [Indexed: 12/25/2022] Open
Abstract
The unique biology of the intestinal epithelial barrier is linked to a low baseline oxygen pressure (pO2), characterised by a high rate of metabolites circulating through the intestinal blood and the presence of a steep oxygen gradient across the epithelial surface. These characteristics require tight regulation of oxygen homeostasis, achieved in part by hypoxia-inducible factor (HIF)-dependent signalling. Furthermore, intestinal epithelial cells (IEC) possess metabolic identities that are reflected in changes in mitochondrial function. In recent years, it has become widely accepted that oxygen metabolism is key to homeostasis at the mucosae. In addition, the gut has a vast and diverse microbial population, the microbiota. Microbiome–gut communication represents a dynamic exchange of mediators produced by bacterial and intestinal metabolism. The microbiome contributes to the maintenance of the hypoxic environment, which is critical for nutrient absorption, intestinal barrier function, and innate and/or adaptive immune responses in the gastrointestinal tract. In this review, we focus on oxygen homeostasis at the epithelial barrier site, how it is regulated by hypoxia and the microbiome, and how oxygen homeostasis at the epithelium is regulated in health and disease.
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Affiliation(s)
- Špela Konjar
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
- Instituto de Medicina Molecular, João Lobo Antunes, Faculdade de Medicina de Lisboa, 1649-028 Lisbon, Portugal;
- Correspondence:
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia;
| | - Marc Veldhoen
- Instituto de Medicina Molecular, João Lobo Antunes, Faculdade de Medicina de Lisboa, 1649-028 Lisbon, Portugal;
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Gaber A, Pavšič M. Modeling and Structure Determination of Homo-Oligomeric Proteins: An Overview of Challenges and Current Approaches. Int J Mol Sci 2021; 22:9081. [PMID: 34445785 PMCID: PMC8396596 DOI: 10.3390/ijms22169081] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/20/2021] [Accepted: 08/20/2021] [Indexed: 12/12/2022] Open
Abstract
Protein homo-oligomerization is a very common phenomenon, and approximately half of proteins form homo-oligomeric assemblies composed of identical subunits. The vast majority of such assemblies possess internal symmetry which can be either exploited to help or poses challenges during structure determination. Moreover, aspects of symmetry are critical in the modeling of protein homo-oligomers either by docking or by homology-based approaches. Here, we first provide a brief overview of the nature of protein homo-oligomerization. Next, we describe how the symmetry of homo-oligomers is addressed by crystallographic and non-crystallographic symmetry operations, and how biologically relevant intermolecular interactions can be deciphered from the ordered array of molecules within protein crystals. Additionally, we describe the most important aspects of protein homo-oligomerization in structure determination by NMR. Finally, we give an overview of approaches aimed at modeling homo-oligomers using computational methods that specifically address their internal symmetry and allow the incorporation of other experimental data as spatial restraints to achieve higher model reliability.
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Žagar T, Pavšič M, Gaber A. Destabilization of EpCAM dimer is associated with increased susceptibility towards cleavage by TACE. PeerJ 2021; 9:e11484. [PMID: 34055495 PMCID: PMC8142927 DOI: 10.7717/peerj.11484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022] Open
Abstract
The cell-surface protein EpCAM is a carcinoma marker utilized in diagnostics and prognostics, and a promising therapeutic target. It is involved in nuclear signaling via regulated intramembrane proteolysis (RIP). Many aspects of this process are not fully understood, including the events at the molecular level leading to the exposure of cleavage sites, buried at the dimerization interface. To investigate the effect of dimer stability on cleavage susceptibility we prepared two mutants of human EpCAM ectodomain: a monomeric form, and a disulfide-stabilized dimeric form. We show that the disulfide-stabilized dimer is resistant to tumor necrosis factor-α-converting enzyme (TACE) cleavage, while the monomeric form is more susceptible than the predominantly dimeric wild type. This provides experimental evidence that the oligomeric state of EpCAM is a determinant in RIP and demonstrates the usefulness of the oligomeric state-specific mutants in investigations of EpCAM biological function.
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Affiliation(s)
- Tomaž Žagar
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Aljaž Gaber
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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Kostan J, Pavšič M, Puž V, Schwarz TC, Drepper F, Molt S, Graewert MA, Schreiner C, Sajko S, van der Ven PFM, Onipe A, Svergun DI, Warscheid B, Konrat R, Fürst DO, Lenarčič B, Djinović-Carugo K. Molecular basis of F-actin regulation and sarcomere assembly via myotilin. PLoS Biol 2021; 19:e3001148. [PMID: 33844684 PMCID: PMC8062120 DOI: 10.1371/journal.pbio.3001148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/22/2021] [Accepted: 02/16/2021] [Indexed: 12/25/2022] Open
Abstract
Sarcomeres, the basic contractile units of striated muscle cells, contain arrays of thin (actin) and thick (myosin) filaments that slide past each other during contraction. The Ig-like domain-containing protein myotilin provides structural integrity to Z-discs-the boundaries between adjacent sarcomeres. Myotilin binds to Z-disc components, including F-actin and α-actinin-2, but the molecular mechanism of binding and implications of these interactions on Z-disc integrity are still elusive. To illuminate them, we used a combination of small-angle X-ray scattering, cross-linking mass spectrometry, and biochemical and molecular biophysics approaches. We discovered that myotilin displays conformational ensembles in solution. We generated a structural model of the F-actin:myotilin complex that revealed how myotilin interacts with and stabilizes F-actin via its Ig-like domains and flanking regions. Mutant myotilin designed with impaired F-actin binding showed increased dynamics in cells. Structural analyses and competition assays uncovered that myotilin displaces tropomyosin from F-actin. Our findings suggest a novel role of myotilin as a co-organizer of Z-disc assembly and advance our mechanistic understanding of myotilin's structural role in Z-discs.
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Affiliation(s)
- Julius Kostan
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Vid Puž
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Thomas C. Schwarz
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Friedel Drepper
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Sibylle Molt
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | | | - Claudia Schreiner
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Peter F. M. van der Ven
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Adekunle Onipe
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Unit, c/o DESY, Hamburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Robert Konrat
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Dieter O. Fürst
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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Krajnc A, Gaber A, Lenarčič B, Pavšič M. The Central Region of Testican-2 Forms a Compact Core and Promotes Cell Migration. Int J Mol Sci 2020; 21:ijms21249413. [PMID: 33321927 PMCID: PMC7763218 DOI: 10.3390/ijms21249413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 01/25/2023] Open
Abstract
Testicans are modular proteoglycans of the extracellular matrix of various tissues where they contribute to matrix integrity and exert cellular effects like neurite outgrowth and cell migration. Using testican-2 as a representative member of the family, we tackle the complete lack of general structural information and structure-function relationship. First, we show using isothermal titration calorimetry and modeling that extracellular calcium-binding domain (EC) has only one active calcium-binding site, while the other potential site is inactive, and that testican-2 is within extracellular matrix always in the calcium-loaded form. Next, we demonstrate using various prediction methods that N- and C-terminal regions plus interdomain connections are flexible. We support this by small-angle X-ray-scattering analysis of C-terminally truncated testican-2, which indicates that the triplet follistatin-EC-thyroglobulin domain forms a moderately compact core while the unique N-terminal is disordered. Finally, using cell exclusion zone assay, we show that it is this domain triplet that is responsible for promoting cell migration and not the N- and C-terminal regions.
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Affiliation(s)
- Anja Krajnc
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.K.); (A.G.); (B.L.)
| | - Aljaž Gaber
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.K.); (A.G.); (B.L.)
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.K.); (A.G.); (B.L.)
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.K.); (A.G.); (B.L.)
- Correspondence: ; Tel.: +386-1-479-8550
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9
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Abstract
EpCAM, a carcinoma cell-surface marker protein and a therapeutic target, has been primarily addressed as a cell adhesion molecule. With regard to recent discoveries of its role in signaling with implications in cell proliferation and differentiation, and findings contradicting a direct role in mediating adhesion contacts, we provide a comprehensive and updated overview on the available structural data on EpCAM and interpret it in the light of recent reports on its function. First, we describe the structure of extracellular part of EpCAM, both as a subunit and part of a cis-dimer which, according to several experimental observations, represents a biologically relevant oligomeric state. Next, we provide a thorough evaluation of reports on EpCAM as a homophilic cell adhesion molecule with a structure-based explanation why direct EpCAM participation in cell–cell contacts is highly unlikely. Finally, we review the signaling aspect of EpCAM with focus on accessibility of signaling-associated cleavage sites.
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Affiliation(s)
- Aljaž Gaber
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.G.); (B.L.)
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.G.); (B.L.)
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (A.G.); (B.L.)
- Correspondence: ; Tel.: +386-1-479-8550
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Gaber A, Gunčar G, Pavšič M. Proper evaluation of chemical cross-linking-based spatial restraints improves the precision of modeling homo-oligomeric protein complexes. BMC Bioinformatics 2019; 20:464. [PMID: 31500562 PMCID: PMC6734309 DOI: 10.1186/s12859-019-3032-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/16/2019] [Indexed: 11/22/2022] Open
Abstract
Background The function of oligomeric proteins is inherently linked to their quaternary structure. In the absence of high-resolution data, low-resolution information in the form of spatial restraints can significantly contribute to the precision and accuracy of structural models obtained using computational approaches. To obtain such restraints, chemical cross-linking coupled with mass spectrometry (XL-MS) is commonly used. However, the use of XL-MS in the modeling of protein complexes comprised of identical subunits (homo-oligomers) is often hindered by the inherent ambiguity of intra- and inter-subunit connection assignment. Results We present a comprehensive evaluation of (1) different methods for inter-residue distance calculations, and (2) different approaches for the scoring of spatial restraints. Our results show that using Solvent Accessible Surface distances (SASDs) instead of Euclidean distances (EUCs) greatly reduces the assignation ambiguity and delivers better modeling precision. Furthermore, ambiguous connections should be considered as inter-subunit only when the intra-subunit alternative exceeds the distance threshold. Modeling performance can also be improved if symmetry, characteristic for most homo-oligomers, is explicitly defined in the scoring function. Conclusions Our findings provide guidelines for proper evaluation of chemical cross-linking-based spatial restraints in modeling homo-oligomeric protein complexes, which could facilitate structural characterization of this important group of proteins. Electronic supplementary material The online version of this article (10.1186/s12859-019-3032-x) contains supplementary material, which is available to authorized users.
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Pan M, Schinke H, Luxenburger E, Kranz G, Shakhtour J, Libl D, Huang Y, Gaber A, Pavšič M, Lenarčič B, Kitz J, Jakob M, Schwenk-Zieger S, Canis M, Hess J, Unger K, Baumeister P, Gires O. EpCAM ectodomain EpEX is a ligand of EGFR that counteracts EGF-mediated epithelial-mesenchymal transition through modulation of phospho-ERK1/2 in head and neck cancers. PLoS Biol 2018; 16:e2006624. [PMID: 30261040 PMCID: PMC6177200 DOI: 10.1371/journal.pbio.2006624] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/09/2018] [Accepted: 09/12/2018] [Indexed: 12/18/2022] Open
Abstract
Head and neck squamous cell carcinomas (HNSCCs) are characterized by outstanding molecular heterogeneity that results in severe therapy resistance and poor clinical outcome. Inter- and intratumoral heterogeneity in epithelial-mesenchymal transition (EMT) was recently revealed as a major parameter of poor clinical outcome. Here, we addressed the expression and function of the therapeutic target epidermal growth factor receptor (EGFR) and of the major determinant of epithelial differentiation epithelial cell adhesion molecule (EpCAM) in clinical samples and in vitro models of HNSCCs. We describe improved survival of EGFRlow/EpCAMhigh HNSCC patients (n = 180) and provide a molecular basis for the observed disparities in clinical outcome. EGF/EGFR have concentration-dependent dual capacities as inducers of proliferation and EMT through differential activation of the central molecular switch phosphorylated extracellular signal–regulated kinase 1/2 (pERK1/2) and EMT transcription factors (EMT-TFs) Snail, zinc finger E-box-binding homeobox 1 (Zeb1), and Slug. Furthermore, soluble ectodomain of EpCAM (EpEX) was identified as a ligand of EGFR that activates pERK1/2 and phosphorylated AKT (pAKT) and induces EGFR-dependent proliferation but represses EGF-mediated EMT, Snail, Zeb1, and Slug activation and cell migration. EMT repression by EpEX is realized through competitive modulation of pERK1/2 activation strength and inhibition of EMT-TFs, which is reflected in levels of pERK1/2 and its target Slug in clinical samples. Accordingly, high expression of pERK1/2 and/or Slug predicted poor outcome of HNSCCs. Hence, EpEX is a ligand of EGFR that induces proliferation but counteracts EMT mediated by the EGF/EGFR/pERK1/2 axis. Therefore, the emerging EGFR/EpCAM molecular cross talk represents a promising target to improve patient-tailored adjuvant treatment of HNSCCs. Head and neck squamous cell carcinomas (HNSCCs) display poor survival, with death rates above 55%. Major factors affecting survival are metastases’ formation and therapy resistance. Phenotypic changes during partial epithelial-mesenchymal transition (EMT) provide tumor cells with increased migration, invasion, and therapy resistance. Understanding molecular mechanisms of EMT, as a central process of the metastatic cascade and the development of therapy resistance, is therefore important. In the present work, we identified molecular cross talk between epidermal growth factor receptor (EGFR) and epithelial cell adhesion molecule (EpCAM) as a novel determinant of clinical outcome in HNSCCs. Low levels of EGFR but high levels of EpCAM (EGFRlow/EpCAMhigh) were associated with favorable prognosis, with survival rates above 90%, whereas EGFRhigh/EpCAMlow correlated with poor survival, below 10%. EGFR was shown to have a concentration-dependent capacity to induce proliferation and EMT. Proteolytic cleavage of the extracellular domain of EpCAM (EpEX) produces a ligand of EGFR that induces EGFR-dependent proliferation but counteracts EGF-induced EMT. We delineate an EGFR/extracellular signal–regulated kinase 1/2 (ERK1/2)/EpCAM signaling axis that may be a promising therapeutic target for HNSCCs.
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Affiliation(s)
- Min Pan
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Henrik Schinke
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Elke Luxenburger
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Gisela Kranz
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Julius Shakhtour
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Darko Libl
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Yuanchi Huang
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Aljaž Gaber
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Department of Biochemistry, Molecular and Structural Biology, Institute Jožef Stefan, Ljubljana, Slovenia
| | - Julia Kitz
- Institute of Pathology, University Medical Center, Göttingen, Germany
| | - Mark Jakob
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Sabina Schwenk-Zieger
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Martin Canis
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
| | - Julia Hess
- Clinical Cooperation Group “Personalized Radiotherapy in Head and Neck Cancer“, Helmholtz Zentrum München, Research Center for Environmental Health (GmbH), Neuherberg, Germany
- Research Unit Radiation Cytogenetics, Helmholtz Zentrum München, Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Kristian Unger
- Clinical Cooperation Group “Personalized Radiotherapy in Head and Neck Cancer“, Helmholtz Zentrum München, Research Center for Environmental Health (GmbH), Neuherberg, Germany
- Research Unit Radiation Cytogenetics, Helmholtz Zentrum München, Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Philipp Baumeister
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
- Clinical Cooperation Group “Personalized Radiotherapy in Head and Neck Cancer“, Helmholtz Zentrum München, Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Olivier Gires
- Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, Ludwig-Maximilians-University, Munich, Germany
- Clinical Cooperation Group “Personalized Radiotherapy in Head and Neck Cancer“, Helmholtz Zentrum München, Research Center for Environmental Health (GmbH), Neuherberg, Germany
- * E-mail:
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12
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Gaber A, Kim SJ, Kaake RM, Benčina M, Krogan N, Šali A, Pavšič M, Lenarčič B. EpCAM homo-oligomerization is not the basis for its role in cell-cell adhesion. Sci Rep 2018; 8:13269. [PMID: 30185875 PMCID: PMC6125409 DOI: 10.1038/s41598-018-31482-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/20/2018] [Indexed: 01/01/2023] Open
Abstract
Cell-surface tumor marker EpCAM plays a key role in proliferation, differentiation and adhesion processes in stem and epithelial cells. It is established as a cell-cell adhesion molecule, forming intercellular interactions through homophilic association. However, the mechanism by which such interactions arise has not yet been fully elucidated. Here, we first show that EpCAM monomers do not associate into oligomers that would resemble an inter-cellular homo-oligomer, capable of mediating cell-cell adhesion, by using SAXS, XL-MS and bead aggregation assays. Second, we also show that EpCAM forms stable dimers on the surface of a cell with pre-formed cell-cell contacts using FLIM-FRET; however, no inter-cellular homo-oligomers were detectable. Thus, our study provides clear evidence that EpCAM indeed does not function as a homophilic cell adhesion molecule and therefore calls for a significant revision of its role in both normal and cancerous tissues. In the light of this, we strongly support the previously suggested name Epithelial Cell Activating Molecule instead of the Epithelial Cell Adhesion Molecule.
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Affiliation(s)
- Aljaž Gaber
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, Ljubljana, SI 1000, Slovenia
| | - Seung Joong Kim
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, 1700 4th Street, Suite 503B, San Francisco, CA, 94158, USA
| | - Robyn M Kaake
- J. David Gladstone Institutes, San Francisco, CA, 94158, USA
| | - Mojca Benčina
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI 1000, Slovenia
| | - Nevan Krogan
- J. David Gladstone Institutes, San Francisco, CA, 94158, USA
- Quantitative Biosciences Institute, QBI, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Andrej Šali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, 1700 4th Street, Suite 503B, San Francisco, CA, 94158, USA
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, Ljubljana, SI 1000, Slovenia.
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, Ljubljana, SI 1000, Slovenia.
- Department of Biochemistry, Molecular and Structural Biology, Institute Jožef Stefan, Jamova 39, Ljubljana, SI 1000, Slovenia.
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13
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Drmota Prebil S, Slapšak U, Pavšič M, Ilc G, Puž V, de Almeida Ribeiro E, Anrather D, Hartl M, Backman L, Plavec J, Lenarčič B, Djinović-Carugo K. Structure and calcium-binding studies of calmodulin-like domain of human non-muscle α-actinin-1. Sci Rep 2016; 6:27383. [PMID: 27272015 PMCID: PMC4895382 DOI: 10.1038/srep27383] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/16/2016] [Indexed: 12/11/2022] Open
Abstract
The activity of several cytosolic proteins critically depends on the concentration of calcium ions. One important intracellular calcium-sensing protein is α-actinin-1, the major actin crosslinking protein in focal adhesions and stress fibers. The actin crosslinking activity of α-actinin-1 has been proposed to be negatively regulated by calcium, but the underlying molecular mechanisms are poorly understood. To address this, we determined the first high-resolution NMR structure of its functional calmodulin-like domain (CaMD) in calcium-bound and calcium-free form. These structures reveal that in the absence of calcium, CaMD displays a conformationally flexible ensemble that undergoes a structural change upon calcium binding, leading to limited rotation of the N- and C-terminal lobes around the connecting linker and consequent stabilization of the calcium-loaded structure. Mutagenesis experiments, coupled with mass-spectrometry and isothermal calorimetry data designed to validate the calcium binding stoichiometry and binding site, showed that human non-muscle α-actinin-1 binds a single calcium ion within the N-terminal lobe. Finally, based on our structural data and analogy with other α-actinins, we provide a structural model of regulation of the actin crosslinking activity of α-actinin-1 where calcium induced structural stabilisation causes fastening of the juxtaposed actin binding domain, leading to impaired capacity to crosslink actin.
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Affiliation(s)
- Sara Drmota Prebil
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Urška Slapšak
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Gregor Ilc
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.,EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, SI-1000 Ljubljana, Slovenia
| | - Vid Puž
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Euripedes de Almeida Ribeiro
- Department of Structural and Computational Biology, Max F. Perutz Laboratories (MFPL), University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria
| | - Dorothea Anrather
- Mass Spectrometry Service Facility, Max F. Perutz Laboratories (MFPL), University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
| | - Markus Hartl
- Mass Spectrometry Service Facility, Max F. Perutz Laboratories (MFPL), University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, A-1030 Vienna, Austria
| | - Lars Backman
- Department of Chemistry, Umeå University, Linnaeus väg 10, SE-90187 Umeå, Sweden
| | - Janez Plavec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.,Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.,EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, SI-1000 Ljubljana, Slovenia
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.,Department of Biochemistry, Molecular Biology and Structural Biology, Jožef Stefan Institute, Jamova 39,SI-1000 Ljubljana, Slovenia
| | - Kristina Djinović-Carugo
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.,Department of Structural and Computational Biology, Max F. Perutz Laboratories (MFPL), University of Vienna, Campus Vienna Biocenter 5, A-1030 Vienna, Austria
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Tsaktanis T, Kremling H, Pavšič M, von Stackelberg R, Mack B, Fukumori A, Steiner H, Vielmuth F, Spindler V, Huang Z, Jakubowski J, Stoecklein NH, Luxenburger E, Lauber K, Lenarčič B, Gires O. Cleavage and cell adhesion properties of human epithelial cell adhesion molecule (HEPCAM). J Biol Chem 2016; 291:425. [PMID: 26724312 DOI: 10.1074/jbc.a115.662700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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15
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Tsaktanis T, Kremling H, Pavšič M, von Stackelberg R, Mack B, Fukumori A, Steiner H, Vielmuth F, Spindler V, Huang Z, Jakubowski J, Stoecklein NH, Luxenburger E, Lauber K, Lenarčič B, Gires O. Cleavage and cell adhesion properties of human epithelial cell adhesion molecule (HEPCAM). J Biol Chem 2015; 290:24574-91. [PMID: 26292218 DOI: 10.1074/jbc.m115.662700] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Indexed: 12/14/2022] Open
Abstract
Human epithelial cell adhesion molecule (HEPCAM) is a tumor-associated antigen frequently expressed in carcinomas, which promotes proliferation after regulated intramembrane proteolysis. Here, we describe extracellular shedding of HEPCAM at two α-sites through a disintegrin and metalloprotease (ADAM) and at one β-site through BACE1. Transmembrane cleavage by γ-secretase occurs at three γ-sites to generate extracellular Aβ-like fragments and at two ϵ-sites to release human EPCAM intracellular domain HEPICD, which is efficiently degraded by the proteasome. Mapping of cleavage sites onto three-dimensional structures of HEPEX cis-dimer predicted conditional availability of α- and β-sites. Endocytosis of HEPCAM warrants acidification in cytoplasmic vesicles to dissociate protein cis-dimers required for cleavage by BACE1 at low pH values. Intramembrane cleavage sites are accessible and not part of the structurally important transmembrane helix dimer crossing region. Surprisingly, neither chemical inhibition of cleavage nor cellular knock-out of HEPCAM using CRISPR-Cas9 technology impacted the adhesion of carcinoma cell lines. Hence, a direct function of HEPCAM as an adhesion molecule in carcinoma cells is not supported and appears to be questionable.
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Affiliation(s)
- Thanos Tsaktanis
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center
| | - Heidi Kremling
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center
| | - Miha Pavšič
- the Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna Pot 113, SI-1000 Ljubljana, Slovenia
| | - Ricarda von Stackelberg
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center
| | - Brigitte Mack
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center
| | - Akio Fukumori
- the DZNE-German Center for Neurodegenerative Diseases, Feodor-Lynen-Strasse 17, 81377 Munich, Germany
| | - Harald Steiner
- the DZNE-German Center for Neurodegenerative Diseases, Feodor-Lynen-Strasse 17, 81377 Munich, Germany, Biomedical Center, Biochemistry
| | | | | | - Zhe Huang
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center
| | - Jasmine Jakubowski
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center, the Munich Center for Neurosciences, LMU Biocenter, AMGEN Scholars Programme, Ludwig-Maximilians-Universität Munich, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany, and
| | - Nikolas H Stoecklein
- the Department for General, Visceral, and Pediatric Surgery, University Hospital and Medical Faculty of the Heinrich-Heine University Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany
| | - Elke Luxenburger
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center
| | - Kirsten Lauber
- Clinic for Radiotherapy and Radiation Oncology, and the Clinical Cooperation Group Personalized Radiotherapy of Head and Neck Tumors, Ludwig-Maximilians-University of Munich, Marchioninistrasse 15, 81377 Munich, Germany
| | - Brigita Lenarčič
- the Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna Pot 113, SI-1000 Ljubljana, Slovenia
| | - Olivier Gires
- From the Department of Otorhinolaryngology, Head and Neck Surgery, Grosshadern Medical Center,
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16
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Pavšič M, Ilc G, Vidmar T, Plavec J, Lenarčič B. The cytosolic tail of the tumor marker protein Trop2--a structural switch triggered by phosphorylation. Sci Rep 2015; 5:10324. [PMID: 25981199 PMCID: PMC4434849 DOI: 10.1038/srep10324] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 04/08/2015] [Indexed: 01/23/2023] Open
Abstract
Trop2 is a transmembrane signaling glycoprotein upregulated in stem and carcinoma cells. Proliferation-enhancing signaling involves regulated intramembrane proteolytic release of a short cytoplasmic fragment, which is later engaged in a cytosolic signaling complex. We propose that Trop2 function is modulated by phosphorylation of a specific serine residue within this cytosolic region (Ser303), and by proximity effects exerted on the cytosolic tail by Trop2 dimerization. Structural characterization of both the transmembrane (Trop2TM) and cytosolic regions (Trop2IC) support this hypothesis, and shows that the central region of Trop2IC forms an α-helix. Comparison of NMR structures of non-phosphorylated and phosphorylated forms suggest that phosphorylation of Trop2IC triggers salt bridge reshuffling, resulting in significant conformational changes including ordering of the C-terminal tail. In addition, we demonstrate that the cytosolic regions of two Trop2 subunits can be brought into close proximity via transmembrane part dimerization. Finally, we show that Ser303-phosphorylation significantly affects the structure and accessibility of functionally important regions of the cytosolic tail. These observed structural features of Trop2 at the membrane-cytosol interface could be important for regulation of Trop2 signaling activity.
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Affiliation(s)
- Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Gregor Ilc
- 1] Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia [2] EN-FIST Centre of Excellence, Dunajska 156, SI-1000 Ljubljana, Slovenia
| | - Tilen Vidmar
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Janez Plavec
- 1] Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia [2] Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia [3] EN-FIST Centre of Excellence, Dunajska 156, SI-1000 Ljubljana, Slovenia
| | - Brigita Lenarčič
- 1] Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia [2] J. Stefan Institute, Department of Biochemistry, Molecular and Structural Biology, Jamova 39, SI-1000 Ljubljana, Slovenia
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17
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Pavšič M, Gunčar G, Djinović-Carugo K, Lenarčič B. Crystal structure and its bearing towards an understanding of key biological functions of EpCAM. Nat Commun 2014; 5:4764. [DOI: 10.1038/ncomms5764] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/21/2014] [Indexed: 12/19/2022] Open
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18
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Novinec M, Pavšič M, Lenarčič B. A simple and efficient protocol for the production of recombinant cathepsin V and other cysteine cathepsins in soluble form in Escherichia coli. Protein Expr Purif 2012; 82:1-5. [DOI: 10.1016/j.pep.2011.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 10/24/2011] [Accepted: 11/02/2011] [Indexed: 11/27/2022]
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19
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Pavšič M, Lenarčič B. Expression, crystallization and preliminary X-ray characterization of the human epithelial cell-adhesion molecule ectodomain. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1363-6. [PMID: 22102232 DOI: 10.1107/s1744309111031897] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 08/06/2011] [Indexed: 11/10/2022]
Abstract
The epithelial cell-adhesion molecule (EpCAM; CD326) is a transmembrane glycoprotein involved in epithelial cell-cell adhesion, cell proliferation and differentiation. Its elevated expression level in various carcinomas is exploited by several antitumour therapies that are at various stages of clinical development. The 35 kDa polypeptide chain of EpCAM is divided into a large extracellular part, a transmembrane helix and a short cytoplasmic tail. The modular extracellular part of human EpCAM was cloned and mutated to prevent N-linked glycosylation. After expression in insect cells and purification using standard chromatographic techniques, the extracellular part was crystallized. The crystals belonged to space group C2, with unit-cell parameters a = 86.83, b = 50.16, c = 66.56 Å, β = 127.9°. The crystal diffracted to 1.95 Å resolution and contained one molecule in the asymmetric unit.
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Affiliation(s)
- Miha Pavšič
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana, Slovenia
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20
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Kregar M, Kump P, Pavšič M, Ramšak V, Rupnik P, Vakselj M. Experimental evidence for the validity of discontinuous stopping in DSAM analysis. ACTA ACUST UNITED AC 1975. [DOI: 10.1016/0029-554x(75)90494-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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