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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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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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Pečar Fonović U, Perišić Nanut M, Zidar N, Lenarčič B, Kos J. The Carboxypeptidase Activity of Cathepsin X is not Controlled by Endogenous Inhibitors. Acta Chim Slov 2019. [DOI: 10.17344/acsi.2018.4427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Pečar Fonović U, Perišić Nanut M, Zidar N, Lenarčič B, Kos J. The Carboxypeptidase Activity of Cathepsin X is not Controlled by Endogenous Inhibitors. Acta Chim Slov 2019; 66:58-61. [PMID: 33855476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023] Open
Abstract
Cysteine cathepsins are peptidases with housekeeping functions that play different specific roles in different tissues. Endogenous peptidase inhibitors, such as cystatins and thyropins are the ultimate way of controlling their activity. It appears, however, that cathepsin X, a monocarboxypeptidase, whose overexpression is associated with several pathological processes, is not under the control of endogenous inhibitors. Inhibitors belonging to various groups inhibit other cathepsins tested, but none decrease the carboxypeptidase activity of cathepsin X. This absence of inhibitor control is another feature that distinguishes cathepsin X from other members of the cysteine peptidases.
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Rebernik M, Lenarčič B, Novinec M. The catalytic domain of cathepsin C (dipeptidyl-peptidase I) alone is a fully functional endoprotease. Protein Expr Purif 2019; 157:21-27. [PMID: 30703555 DOI: 10.1016/j.pep.2019.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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: 01/07/2019] [Accepted: 01/25/2019] [Indexed: 02/07/2023]
Abstract
Cathepsin C is a tetrameric lysosomal protease that acts as a dipeptidyl-peptidase due to the presence of the exclusion domain that is unique among papain-like cysteine proteases. Here we describe a recombinant form of cathepsin C lacking its exclusion domain (CatCΔEx) produced in a bacterial expression system (E. coli). CatCΔEx is a monomer with endoprotease activity and affinity for hydrophobic residues such as Phe, Leu or Pro, but not Val, in the P2 position. As opposed to cathepsin C, it does not require chloride ions for its activity. Despite lower turnover rates of hydrolysis of synthetic substrates, CatCΔEx has elastolytic and gelatinolytic activity comparable to other cysteine cathepsins.
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Affiliation(s)
- Mateja Rebernik
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia; Department of Biochemistry and Molecular and Structural Biology, "Jožef Stefan" Institute, Jamova cesta 39, 1000, Ljubljana, Slovenia
| | - Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia.
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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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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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Novinec M, Rebernik M, Lenarčič B. An allosteric site enables fine-tuning of cathepsin K by diverse effectors. FEBS Lett 2016; 590:4507-4518. [DOI: 10.1002/1873-3468.12495] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/14/2016] [Accepted: 11/11/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Marko Novinec
- Department of Chemistry and Biochemistry; Faculty of Chemistry and Chemical Technology; University of Ljubljana; Slovenia
| | - Mateja Rebernik
- Department of Chemistry and Biochemistry; Faculty of Chemistry and Chemical Technology; University of Ljubljana; Slovenia
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry; Faculty of Chemistry and Chemical Technology; University of Ljubljana; Slovenia
- Department of Biochemistry and Molecular and Structural Biology; Jožef Stefan Institute; Ljubljana Slovenia
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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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12
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Korenč M, Lenarčič B, Novinec M. Human cathepsin L, a papain-like collagenase without proline specificity. FEBS J 2015; 282:4328-40. [PMID: 26306868 DOI: 10.1111/febs.13499] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/13/2015] [Accepted: 08/21/2015] [Indexed: 12/01/2022]
Abstract
Several members of the papain-like peptidase family have the ability to degrade collagen molecules by cleaving within the triple helix region of this difficult substrate. A common denominator of these peptidases is their ability to cleave substrates with Pro in the P2 position. In humans, cathepsin K is the best-known papain-like collagenase. Here, we investigate the collagenolytic activity of human cathepsin L, which is closely related to cathepsin K. We show that, despite lacking proline specificity, cathepsin L efficiently cleaves type I collagen within the triple helix region and produces a cleavage pattern similar to that of cathepsin K. We demonstrate that both enzymes have similar affinities for type I collagen and are able to release proteolytic fragments from insoluble collagen. Moreover, cathepsin K is only approximately fourfold more potent than cathepsin L in releasing fragments from reconstituted fibrils of FITC-labeled collagen. Replacing active site residues of cathepsin L with those from cathepsin K introduces cathepsin K-like specificity towards synthetic substrates and increases the collagenolytic activity of cathepsin L. Replacing three residues in the S2 subsite is sufficient to produce a mutant with collagenolytic activity on par with human cathepsin K. These results provide a basis for engineering collagenolytic activity into non-collagenolytic papain-like scaffolds.
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Affiliation(s)
- Matevž Korenč
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia.,Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Slovenia
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13
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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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14
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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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15
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Novinec M, Lenarčič B, Baici A. Probing the activity modification space of the cysteine peptidase cathepsin K with novel allosteric modifiers. PLoS One 2014; 9:e106642. [PMID: 25184245 PMCID: PMC4153677 DOI: 10.1371/journal.pone.0106642] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 05/27/2014] [Accepted: 08/07/2014] [Indexed: 01/08/2023] Open
Abstract
Targeting allosteric sites is gaining increasing recognition as a strategy for modulating the activity of enzymes, especially in drug design. Here we investigate the mechanisms of allosteric regulation of cathepsin K as a representative of cysteine cathepsins and a promising drug target for the treatment of osteoporosis. Eight novel modifiers are identified by computational targeting of predicted allosteric sites on the surface of the enzyme. All act via hyperbolic kinetic mechanisms in presence of low molecular mass substrates, as expected for allosteric effectors. Two compounds have sizable effects on enzyme activity using interstitial collagen as a natural substrate of cathepsin K and four compounds show a significantly stabilizing effect on cathepsin K. The concept of activity modification space is introduced to obtain a global perspective of the effects elicited by the modifiers. Analysis of the activity modification space reveals that the activity of cathepsin K is regulated via multiple, different allosteric mechanisms.
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Affiliation(s)
- Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
- * E-mail: (MN); (AB)
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Antonio Baici
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
- * E-mail: (MN); (AB)
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16
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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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Abstract
Cathepsin K has emerged as a promising target for the treatment of osteoporosis in recent years. Initially identified as a papain-like cysteine peptidase expressed in high levels in osteoclasts, the important role of this enzyme in bone metabolism was highlighted by the finding that mutations in the CTSK gene cause the rare recessive disorder pycnodysostosis, which is characterized by severe bone anomalies. At the molecular level, the physiological role of cathepsin K is reflected by its unique cleavage pattern of type I collagen molecules, which is fundamentally different from that of other endogenous collagenases. Several cathepsin K inhibitors have been developed to reduce the excessive bone matrix degradation associated with osteoporosis, with the frontrunner odanacatib about to successfully conclude Phase 3 clinical trials. Apart from osteoclasts, cathepsin K is expressed in different cell types throughout the body and is involved in processes of adipogenesis, thyroxine liberation and peptide hormone regulation. Elevated activity of cathepsin K has been associated with arthritis, atherosclerosis, obesity, schizophrenia, and tumor metastasis. Accordingly, its activity is tightly regulated via multiple mechanisms, including competitive inhibition by endogenous macromolecular inhibitors and allosteric regulation by glycosaminoglycans. This review provides a state-of-the-art description of the activity of cathepsin K at the molecular level, its biological functions and the mechanisms involved in its regulation.
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Affiliation(s)
- Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
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18
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Novinec M, Lenarčič B. Papain-like peptidases: structure, function, and evolution. Biomol Concepts 2013; 4:287-308. [DOI: 10.1515/bmc-2012-0054] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 02/11/2013] [Indexed: 12/16/2022] Open
Abstract
AbstractPapain-like cysteine peptidases are a diverse family of peptidases found in most known organisms. In eukaryotes, they are divided into multiple evolutionary groups, which can be clearly distinguished on the basis of the structural characteristics of the proenzymes. Most of them are endopeptidases; some, however, evolved into exopeptidases by obtaining additional structural elements that restrict the binding of substrate into the active site. In humans, papain-like peptidases, also called cysteine cathepsins, act both as non-specific hydrolases and as specific processing enzymes. They are involved in numerous physiological processes, such as antigen presentation, extracellular matrix remodeling, and hormone processing. Their activity is tightly regulated and dysregulation of one or more cysteine cathepsins can result in severe pathological conditions, such as cardiovascular diseases and cancer. Other organisms can utilize papain-like peptidases for different purposes and they are often part of host-pathogen interactions. Numerous parasites, such as Plasmodium and flukes, utilize papain-like peptidases for host invasion, whereas plants, in contrast, use these enzymes for host defense. This review presents a state-of-the-art description of the structure and phylogeny of papain-like peptidases as well as an overview of their physiological and pathological functions in humans and in other organisms.
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Affiliation(s)
- Marko Novinec
- 1Faculty of Chemistry and Chemical Technology, Department of Chemistry and Biochemistry, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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19
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Klemenčič M, Novinec M, Maier S, Hartmann U, Lenarčič B. The heparin-binding activity of secreted modular calcium-binding protein 1 (SMOC-1) modulates its cell adhesion properties. PLoS One 2013; 8:e56839. [PMID: 23437253 PMCID: PMC3578922 DOI: 10.1371/journal.pone.0056839] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [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: 10/10/2012] [Accepted: 01/15/2013] [Indexed: 02/04/2023] Open
Abstract
Secreted modular calcium-binding proteins 1 and 2 (SMOC-1 and SMOC-1) are extracellular calcium- binding proteins belonging to the BM-40 family of proteins. In this work we have identified a highly basic region in the extracellular calcium-binding (EC) domain of the SMOC-1 similar to other known glycosaminoglycan-binding motifs. Size-exclusion chromatography shows that full length SMOC-1 as well as its C-terminal EC domain alone bind heparin and heparan sulfate, but not the related chondroitin sulfate or dermatan sulfate glycosaminoglycans. Intrinsic tryptophan fluorescence measurements were used to quantify the binding of heparin to full length SMOC-1 and the EC domain alone. The calculated equilibrium dissociation constants were in the lower micromolar range. The binding site consists of two antiparallel alpha helices and mutagenesis experiments have shown that heparin-binding residues in both helices must be replaced in order to abolish heparin binding. Furthermore, we show that the SMOC-1 EC domain, like the SMOC-2 EC domain, supports the adhesion of epithelial HaCaT cells. Heparin-binding impaired mutants failed to support S1EC-mediated cell adhesion and together with the observation that S1EC in complex with soluble heparin attenuated cell adhesion we conclude that a functional and accessible S1EC heparin-binding site mediates adhesion of epithelial cells to SMOC-1.
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Affiliation(s)
- Marina Klemenčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Silke Maier
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | - Ursula Hartmann
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, Cologne, 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
- * E-mail:
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20
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Torkar A, Bregant S, Devel L, Novinec M, Lenarčič B, Lah T, Dive V. A novel photoaffinity-based probe for selective detection of cathepsin L active form. Chembiochem 2012; 13:2616-21. [PMID: 23125066 DOI: 10.1002/cbic.201200389] [Citation(s) in RCA: 10] [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: 06/11/2012] [Indexed: 01/04/2023]
Abstract
Detecting the active forms of proteases by using activity-based probes in complex proteomes has become an intensively investigated field of research over the past years because many pathogenic conditions involve alterations in protease activities. The detection of lysosomal cysteine proteases, the cathepsins, has mostly relied on the use of probes that incorporate reactive electrophilic moieties to modify a cysteine in the active site covalently. Here we report the first example of an activity-based probe that targets the cathepsins and incorporates a photoactivatable benzophenone group for covalent labelling. When tested on a set of five cathepsins (B, K, L, S and V), this probe selectively labelled the active site of cathepsin L. Furthermore, when tested on crude cell extracts, the probe specifically detected cathepsin L quantities as low as a few picomoles. This study suggests that photoaffinity labelling is a promising approach for developing highly selective and useful cathepsin L probes. In particular, this probe might allow the detection of small amounts of the secreted active cathepsin L form in the cellular microenvironment in vitro and ex vivo.
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Affiliation(s)
- Ana Torkar
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
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21
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Novinec M, Lenarčič B, Baici A. Clusterin is a specific stabilizer and liberator of extracellular cathepsin K. FEBS Lett 2012; 586:1062-6. [PMID: 22569264 DOI: 10.1016/j.febslet.2012.03.004] [Citation(s) in RCA: 9] [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: 02/10/2012] [Revised: 03/02/2012] [Accepted: 03/04/2012] [Indexed: 10/28/2022]
Abstract
The cysteine peptidase cathepsin K is a major player in extracellular proteolysis. Here we describe the identification of the multifunctional extracellular chaperone clusterin as a cathepsin K-binding protein. Clusterin increases the stability of cathepsin K in dilute solution and in the presence of high protein concentration. It does not alter the activity of the enzyme but acts as a liberator by preventing substrate inhibition. Kinetic measurements show that clusterin binds cathepsin K with high affinity (K(d) = 0.5-0.6 nM). Altogether these results provide novel insights into the mechanisms involved in the fine-tuning of cysteine cathepsin activity in the extracellular space.
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Affiliation(s)
- Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia.
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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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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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24
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Anderluh G, Barlič A, Podlesek Z, Menestrina G, Maček P, Gubenšek F, Bavec A, Cigiš B, Zorko M, Čopič A, Vučemilo N, Križaj I, Ivanovski G, Pungerčar J, Jeras M, Tongio MM, Rižner TL, Moeller G, Thole HH, Žakelj-Mavrič M, Adamski J, Malovrh P, Montecucco C, Papini E, De Bernard M, Molinari M, Satin B, Pelicic V, Pogačar M, Rižner TL, Zorko M, Žakelj-Mavrič M, Rogelj B, Ritonja A, Popovič T, Brzin J, Rozman J, Stojan J, Kuhelj R, Turk V, Turk B, Štrukelj B, Gruden K, Lenarčič B, Bosch D, Stiekema WJ, Jongsma MA, Župunski V, Kordiš D. Abstracts. Pflugers Arch 2000. [DOI: 10.1007/s004240000115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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