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Marafie SK, Al-Mulla F. An Overview of the Role of Furin in Type 2 Diabetes. Cells 2023; 12:2407. [PMID: 37830621 PMCID: PMC10571965 DOI: 10.3390/cells12192407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 09/27/2023] [Indexed: 10/14/2023] Open
Abstract
Post-translational modifications (PTMs) play important roles in regulating several human diseases, like cancer, neurodegenerative disorders, and metabolic disorders. Investigating PTMs' contribution to protein functions is critical for modern biology and medicine. Proprotein convertases (PCs) are irreversible post-translational modifiers that have been extensively studied and are considered as key targets for novel therapeutics. They cleave proteins at specific sites causing conformational changes affecting their functions. Furin is considered as a PC model in regulating growth factors and is involved in regulating many pro-proteins. The mammalian target of the rapamycin (mTOR) signaling pathway is another key player in regulating cellular processes and its dysregulation is linked to several diseases including type 2 diabetes (T2D). The role of furin in the context of diabetes has been rarely explored and is currently lacking. Moreover, furin variants have altered activity that could have implications on overall health. In this review, we aim to highlight the role of furin in T2D in relation to mTOR signaling. We will also address furin genetic variants and their potential effect on T2D and β-cell functions. Understanding the role of furin in prediabetes and dissecting it from other confounding factors like obesity is crucial for future therapeutic interventions in metabolic disorders.
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Affiliation(s)
- Sulaiman K. Marafie
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, P.O. Box 1180, Dasman 15462, Kuwait
| | - Fahd Al-Mulla
- Genetics and Bioinformatics Department, Dasman Diabetes Institute, P.O. Box 1180, Dasman 15462, Kuwait
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2
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Ephrin-A5 potentiates netrin-1 axon guidance by enhancing Neogenin availability. Sci Rep 2019; 9:12009. [PMID: 31427645 PMCID: PMC6700147 DOI: 10.1038/s41598-019-48519-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 08/07/2019] [Indexed: 01/22/2023] Open
Abstract
Axonal growth cones are guided by molecular cues in the extracellular environment. The mechanisms of combinatorial integration of guidance signals at the growth cone cell membrane are still being unravelled. Limb-innervating axons of vertebrate spinal lateral motor column (LMC) neurons are attracted to netrin-1 via its receptor, Neogenin, and are repelled from ephrin-A5 through its receptor EphA4. The presence of both cues elicits synergistic guidance of LMC axons, but the mechanism of this effect remains unknown. Using fluorescence immunohistochemistry, we show that ephrin-A5 increases LMC growth cone Neogenin protein levels and netrin-1 binding. This effect is enhanced by overexpressing EphA4 and is inhibited by blocking ephrin-A5-EphA4 binding. These effects have a functional consequence on LMC growth cone responses since bath addition of ephrin-A5 increases the responsiveness of LMC axons to netrin-1. Surprisingly, the overexpression of EphA4 lacking its cytoplasmic tail, also enhances Neogenin levels at the growth cone and potentiates LMC axon preference for growth on netrin-1. Since netrins and ephrins participate in a wide variety of biological processes, the enhancement of netrin-1 signalling by ephrins may have broad implications.
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López-Jiménez AJ, Basak T, Vanacore RM. Proteolytic processing of lysyl oxidase-like-2 in the extracellular matrix is required for crosslinking of basement membrane collagen IV. J Biol Chem 2017; 292:16970-16982. [PMID: 28864775 DOI: 10.1074/jbc.m117.798603] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/16/2017] [Indexed: 12/13/2022] Open
Abstract
Lysyl oxidase-like-2 (LOXL2) is an enzyme secreted into the extracellular matrix that crosslinks collagens by mediating oxidative deamination of lysine residues. Our previous work demonstrated that this enzyme crosslinks the 7S domain, a structural domain that stabilizes collagen IV scaffolds in the basement membrane. Despite its relevant role in extracellular matrix biosynthesis, little is known about the structural requirements of LOXL2 that enable collagen IV crosslinking. In this study, we demonstrate that LOXL2 is processed extracellularly by serine proteases, generating a 65-kDa form lacking the first two scavenger receptor cysteine-rich domains. Site-specific mutagenesis to prevent proteolytic processing generated a full-length enzyme that is active in vitro toward a soluble substrate, but fails to crosslink insoluble collagen IV within the extracellular matrix. In contrast, the processed form of LOXL2 binds to collagen IV and crosslinks the 7S domain. Together, our data demonstrate that proteolytic processing is an important event that allows LOXL2-mediated crosslinking of basement membrane collagen IV.
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Affiliation(s)
- Alberto J López-Jiménez
- From the Department of Medicine, Division of Nephrology and Hypertension and.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Trayambak Basak
- From the Department of Medicine, Division of Nephrology and Hypertension and.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Roberto M Vanacore
- From the Department of Medicine, Division of Nephrology and Hypertension and .,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
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4
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Li J, Casteels T, Frogne T, Ingvorsen C, Honoré C, Courtney M, Huber KVM, Schmitner N, Kimmel RA, Romanov RA, Sturtzel C, Lardeau CH, Klughammer J, Farlik M, Sdelci S, Vieira A, Avolio F, Briand F, Baburin I, Májek P, Pauler FM, Penz T, Stukalov A, Gridling M, Parapatics K, Barbieux C, Berishvili E, Spittler A, Colinge J, Bennett KL, Hering S, Sulpice T, Bock C, Distel M, Harkany T, Meyer D, Superti-Furga G, Collombat P, Hecksher-Sørensen J, Kubicek S. Artemisinins Target GABA A Receptor Signaling and Impair α Cell Identity. Cell 2016; 168:86-100.e15. [PMID: 27916275 PMCID: PMC5236063 DOI: 10.1016/j.cell.2016.11.010] [Citation(s) in RCA: 273] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 08/04/2016] [Accepted: 11/03/2016] [Indexed: 12/12/2022]
Abstract
Type 1 diabetes is characterized by the destruction of pancreatic β cells, and generating new insulin-producing cells from other cell types is a major aim of regenerative medicine. One promising approach is transdifferentiation of developmentally related pancreatic cell types, including glucagon-producing α cells. In a genetic model, loss of the master regulatory transcription factor Arx is sufficient to induce the conversion of α cells to functional β-like cells. Here, we identify artemisinins as small molecules that functionally repress Arx by causing its translocation to the cytoplasm. We show that the protein gephyrin is the mammalian target of these antimalarial drugs and that the mechanism of action of these molecules depends on the enhancement of GABAA receptor signaling. Our results in zebrafish, rodents, and primary human pancreatic islets identify gephyrin as a druggable target for the regeneration of pancreatic β cell mass from α cells. Artemisinins inhibit ARX function and impair α cell identity Compounds act by stabilizing gephyrin, thus enhancing GABAA receptor signaling Artemisinins increase β cell mass in zebrafish and rodent models Functional and transcriptional data indicate a conserved phenotype in human islets
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Affiliation(s)
- Jin Li
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Tamara Casteels
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Thomas Frogne
- Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Måløv, Denmark
| | | | | | - Monica Courtney
- Université Côte d'Azur, INSERM, CNRS, iBV, 06108 Nice, France
| | - Kilian V M Huber
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Nicole Schmitner
- Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Robin A Kimmel
- Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Caterina Sturtzel
- Children's Cancer Research Institute, Innovative Cancer Models, Zimmermannplatz 10, 1090 Vienna, Austria
| | - Charles-Hugues Lardeau
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria; Christian Doppler Laboratory for Chemical Epigenetics and Antiinfectives, CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | - Johanna Klughammer
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Matthias Farlik
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Sara Sdelci
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Andhira Vieira
- Université Côte d'Azur, INSERM, CNRS, iBV, 06108 Nice, France
| | - Fabio Avolio
- Université Côte d'Azur, INSERM, CNRS, iBV, 06108 Nice, France
| | - François Briand
- Physiogenex S.A.S., Prologue Biotech, 516, rue Pierre et Marie Curie, 31670 Labege, France
| | - Igor Baburin
- Institute of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Peter Májek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Florian M Pauler
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Thomas Penz
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Alexey Stukalov
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Manuela Gridling
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Katja Parapatics
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Charlotte Barbieux
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, 1211 Geneva, Switzerland
| | - Ekaterine Berishvili
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, 1211 Geneva, Switzerland; Institute of Medical Research, Ilia State University, Tbilisi 0162, Georgia
| | - Andreas Spittler
- Core Facility Flow Cytometry and Department of Surgery, Research Laboratories, Medical University of Vienna, 1090 Vienna, Austria
| | - Jacques Colinge
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria
| | - Steffen Hering
- Institute of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Thierry Sulpice
- Physiogenex S.A.S., Prologue Biotech, 516, rue Pierre et Marie Curie, 31670 Labege, France
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria; Department of Laboratory Medicine, Medical University of Vienna, 1090 Vienna, Austria; Max Planck Institute for Informatics, 66123 Saarbrücken, Germany
| | - Martin Distel
- Children's Cancer Research Institute, Innovative Cancer Models, Zimmermannplatz 10, 1090 Vienna, Austria
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Dirk Meyer
- Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria; Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | | | | | - Stefan Kubicek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences. Lazarettgasse 14, 1090 Vienna, Austria; Christian Doppler Laboratory for Chemical Epigenetics and Antiinfectives, CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria.
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5
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Pupovac A, Sluyter R. Roles of extracellular nucleotides and P2 receptors in ectodomain shedding. Cell Mol Life Sci 2016; 73:4159-4173. [PMID: 27180276 PMCID: PMC11108277 DOI: 10.1007/s00018-016-2274-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/10/2016] [Indexed: 02/03/2023]
Abstract
Ectodomain shedding of integral membrane receptors results in the release of soluble molecules and modification of the transmembrane portions to mediate or modulate extracellular and intracellular signalling. Ectodomain shedding is stimulated by a variety of mechanisms, including the activation of P2 receptors by extracellular nucleotides. This review describes in detail the roles of extracellular nucleotides and P2 receptors in the shedding of various cell surface molecules, including amyloid precursor protein, CD23, CD62L, and members of the epidermal growth factor, immunoglobulin and tumour necrosis factor families. This review discusses the mechanisms involved in P2 receptor-mediated shedding, demonstrating central roles for the P2 receptors, P2X7 and P2Y2, and the sheddases, ADAM10 and ADAM17, in this process in a number of cell types.
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Affiliation(s)
- Aleta Pupovac
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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6
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Asano A, Nelson-Harrington JL, Travis AJ. Phospholipase B is activated in response to sterol removal and stimulates acrosome exocytosis in murine sperm. J Biol Chem 2013; 288:28104-15. [PMID: 23943622 DOI: 10.1074/jbc.m113.450981] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite a strict requirement for sterol removal for sperm to undergo acrosome exocytosis (AE), the mechanisms by which changes in membrane sterols are transduced into changes in sperm fertilization competence are poorly understood. We have previously shown in live murine sperm that the plasma membrane overlying the acrosome (APM) contains several types of microdomains known as membrane rafts. When characterizing the membrane raft-associated proteomes, we identified phospholipase B (PLB), a calcium-independent enzyme exhibiting multiple activities. Here, we show that sperm surface PLB is activated in response to sterol removal. Both biochemical activity assays and immunoblots of subcellular fractions of sperm incubated with the sterol acceptor 2-hydroxypropyl-β-cyclodextrin (2-OHCD) confirmed the release of an active PLB fragment. Specific protease inhibitors prevented PLB activation, revealing a mechanistic requirement for proteolytic cleavage. Competitive inhibitors of PLB reduced the ability of sperm both to undergo AE and to fertilize oocytes in vitro, suggesting an important role in fertilization. This was reinforced by our finding that incubation either with protein concentrate released from 2-OHCD-treated sperm or with recombinant PLB peptide corresponding to the catalytic domain was able to induce AE in the absence of other stimuli. Together, these results lead us to propose a novel mechanism by which sterol removal promotes membrane fusogenicity and AE, helping confer fertilization competence. Importantly, this mechanism provides a basis for the newly emerging model of AE in which membrane fusions occur during capacitation/transit through the cumulus, prior to any physical contact between the sperm and the oocyte's zona pellucida.
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Affiliation(s)
- Atsushi Asano
- From the Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853
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7
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Stepwise proteolytic activation of type I procollagen to collagen within the secretory pathway of tendon fibroblasts in situ. Biochem J 2012; 441:707-17. [PMID: 21967573 PMCID: PMC3430002 DOI: 10.1042/bj20111379] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Proteolytic cleavage of procollagen I to collagen I is essential for the formation of collagen fibrils in the extracellular matrix of vertebrate tissues. Procollagen is cleaved by the procollagen N- and C-proteinases, which remove the respective N- and C-propeptides from procollagen. Procollagen processing is initiated within the secretory pathway in tendon fibroblasts, which are adept in assembling an ordered extracellular matrix of collagen fibrils in vivo. It was thought that intracellular processing was restricted to the TGN (trans-Golgi network). In the present study, brefeldin A treatment of tendon explant cultures showed that N-proteinase activity is present in the resulting fused ER (endoplasmic reticulum)–Golgi compartment, but that C-proteinase activity is restricted to the TGN in embryonic chick tendon fibroblasts. In late embryonic and postnatal rat tail and postnatal mouse tail tendon, C-proteinase activity was detected in TGN and pre-TGN compartments. Preventing activation of the procollagen N- and C-proteinases with the furin inhibitor Dec-RVKR-CMK (decanoyl-Arg-Val-Lys-Arg-chloromethylketone) indicated that only a fraction of intracellular procollagen cleavage was mediated by newly activated proteinases. In conclusion, the N-propeptides are removed earlier in the secretory pathway than the C-propeptides. The removal of the C-propeptides in post-Golgi compartments most probably indicates preparation of collagen molecules for fibril formation at the cell–matrix interface.
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8
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Wu M, Hu Y, Ali Z, Khan IA, Verlangeiri AJ, Dasmahapatra AK. Teratogenic effects of blue cohosh (Caulophyllum thalictroides) in Japanese medaka (Oryzias latipes) are probably mediated through GATA2/EDN1 signaling pathway. Chem Res Toxicol 2011; 23:1405-16. [PMID: 20707411 DOI: 10.1021/tx100205a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Blue cohosh (Caulophyllum thalictroides) (BC) has been used widely to induce labor and to treat other uterine conditions. However, the safety and effectiveness of this herbal product has not yet been evaluated by the US Food and Drug Administration (FDA). Several conflicting reports indicated that the root extract of BC is a teratogen and, by some unknown mechanisms, is able to induce cardiovascular malfunctions in new-born babies. To understand the mechanism, we have used Japanese medaka (Oryzias latipes) embryo-larval development as the experimental model and the methanolic extract of BC root as the teratogen. The embryo mortality, hatching efficiency, and morphological abnormalities in craniofacial and cardiovascular systems are considered for the evaluation of BC toxicity. Our results indicate that BC is able to disrupt cardiovascular and craniofacial cartilage development in medaka embryo in a dose and developmental stage-specific manner. Moreover, embryos in precirculation are to some extent more resistant to BC than ones with circulation. By using subtractive hybridization, we have observed that gata2 mRNA was differentially expressed in the circulating embryos after BC treatment. As GATA-binding sequences are required for the expression of the endothelin1 (edn1) gene and edn1 expressed in blood vessels and craniofacial cartilages, we have extended our investigations to edn1 gene expression regulation by BC. We found that edn1, furin1, and endothelin receptor A (ednrA) genes are developmentally regulated; endothelin converting enzyme mRNA (ece1) maintained a steady-state level throughout development. Circulating medaka embryos (3 days post fertilization, dpf) exposed to BC (10 microg/mL) for 48 h have increased levels of gata2, ece1, and preproenodthelin (preproedn1) mRNA contents; however, other mRNAs (furin and ednrA) remained unaltered. Therefore, the enhanced expression of gata2 mRNA followed by ece1 and preproedn1 mRNA by BC might be able to induce vasoconstriction and cardiovascular defects and disrupt craniofacial cartilages in medaka embryos. We conclude that cardiovascular and craniofacial defects in medaka embryogenesis by BC are probably mediated through a GATA2-EDN1 signaling pathway.
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Affiliation(s)
- Minghui Wu
- National Center for Natural Product Research, School of Pharmacy, University of Mississippi, University, MS, USA
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9
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Denton C, Black C. Blocage de l'endothéline dans la sclérodermie systémique : rationnel et bénéfice clinique. Rev Med Interne 2007. [DOI: 10.1016/s0248-8663(07)80019-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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10
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Ghoul A, Serova M, Le Tourneau C, Aïssat N, Hammel P, Raymond E, Faivre S. Role of the endothelins and endothelin receptors in cancer cell signaling and angiogenesis. Target Oncol 2007. [DOI: 10.1007/s11523-007-0056-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The discovery of mammalian subtilases, proprotein convertases (PCs) or subtilisin-like proprotein convertases (SPCs), in 1990 was a result of sustained efforts in searching for enzyme/s responsible for maturation of inactive protein precursors. Since then, seven PCs have so far been discovered that cleave at the carboxy-terminal of a basic amino acid characterized by the consensus sequence Arg/Lys/His-X-X/Lys/Arg-Arg downward arrow, where X denotes any amino acid other than Cys. Two additional PC subtypes--called subtilisin kexin isozyme 1 (SKI-1) or site 1 protease (S1P) and neural apoptosis regulated convertase 1 (NARC-1), also known as PCSK9--that cleave at the carboxy terminus of nonbasic amino acids were discovered later. Numerous studies revealed various important functional roles of PCs in health and diseases such as tumorigenesis, diabetes, viral infections, bacterial pathogenesis, atherosclerosis, and neurodegenarative diseases such as Alzheimer's. Owing to these findings, PCs became a promising frontier for treatment of diverse pathologies. Thus modulation of PC activity with designed inhibitors is an attractive proposition not only for intervention of diseases, but also for biochemical characterization of these enzymes. Various physiological and bioengineered proteins as well as small molecules such as peptide, peptidomimetic, and nonpeptide compounds as inhibitors of PCs have been described in the literature. Among the strategies used for design of PC inhibitors, the most successful is the one based on bioengineered serpin proteins, of which the best example is alpha1-PDX, the double mutant variant of alpha1-antitrypsin (from A(355)IPM(358) to R(355)IPR(358)). Others include small peptide inhibitors with C-terminal carboxyl function modified with a potent neucleophile or those containing pseudo or isosteric peptide bond at the scissile site of a suitable peptide substrate. Among nonpeptide PC inhibitors, the number is very limited. So far, these include 20-carbon atoms containing alicyclic diterpenes of andrographolide family and heterocyclic compounds that are ligands of Zn2+ and Cu2+ ions. Overall, these molecules display only a modest enzyme inhibition; however, they may serve as important lead structures for further development of more potent and specific nonpeptide PC inhibitors as potential therapeutic agents. Many PC inhibitors display their functional properties in proliferation, fertilization, tumorigenesis, obesity, embryogenesis, or diabetes via their inhibitory action on PC activities.
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Benet-Pagès A, Lorenz-Depiereux B, Zischka H, White KE, Econs MJ, Strom TM. FGF23 is processed by proprotein convertases but not by PHEX. Bone 2004; 35:455-62. [PMID: 15268897 DOI: 10.1016/j.bone.2004.04.002] [Citation(s) in RCA: 213] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 03/23/2004] [Accepted: 04/01/2004] [Indexed: 11/26/2022]
Abstract
X-linked hypophosphatemia (XLH) and autosomal dominant hypophosphatemic rickets (ADHR) are characterized by renal phosphate wasting, rickets, and osteomalacia. ADHR is caused by gain of function mutations in the fibroblast growth factor 23 gene (FGF23). During secretion, FGF23 is processed at the C-terminus between amino acids 179 and 180. The cleavage site is mutated in ADHR, preventing processing of FGF23. Here, we show that FGF23 is likely to be cleaved by subtilisin-like proprotein convertases (SPC) as cleavage can be inhibited by a specific SPC inhibitor in HEK293 cells. SPCs, which are widely expressed, were demonstrated to be also present in HEK293 cells as well as in osteoblasts. XLH is caused by loss of function mutations in the putative endopeptidase PHEX. It was tempting to speculate that FGF23 is a substrate of PHEX, but studies have been inconclusive so far. Here, we used a secreted form of PHEX (secPHEX) and tagged and untagged FGF23 constructs for co-incubation experiments. These experiments provided evidence against cleavage of intact FGF23(25-251) as well as of N-terminal (FGF23(25-179)) and C-terminal (FGF23(180-251)) fragments by the endopeptidase PHEX.
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Affiliation(s)
- Anna Benet-Pagès
- Institute of Human Genetics, GSF National Research Center, 85764 München-Neuherberg, Germany
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Nejjari M, Berthet V, Rigot V, Laforest S, Jacquier MF, Seidah NG, Remy L, Bruyneel E, Scoazec JY, Marvaldi J, Luis J. Inhibition of proprotein convertases enhances cell migration and metastases development of human colon carcinoma cells in a rat model. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:1925-33. [PMID: 15161629 PMCID: PMC1615749 DOI: 10.1016/s0002-9440(10)63753-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although proprotein convertases are involved in tumor development, nothing is known about their role in metastatic dissemination. To investigate the involvement of convertase inhibition, we used human colon carcinoma cells overexpressing alpha1-antitrypsin Portland (alpha1-PDX, PDX39P cells), a potent convertase inhibitor. We previously reported that these cells bear uncleaved integrin alpha subunits and display an altered attachment to vitronectin that is correlated with defects in the intracellular signaling pathways activated by alphavbeta5 integrin ligation. In this study, we demonstrate that the inhibition of proprotein convertase activity either by overexpression of alpha1-PDX or with the synthetic inhibitor decanoyl-Arg-Val-Lys-Arg-chloromethylketone (dec-RVKR-cmk) led to a significant increase in cell migration supported by the alphavbeta5 integrin. A collagen gel invasion assay showed that PDX39P cells also displayed an invasive ability, contrary to control cells. Moreover, when injected to immunosuppressed newborn rats, PDX39P cells were highly invasive, as they induce 10 times more metastases than mock-transfected cells. In addition, the aggressiveness of PDX39P cells can be greatly reduced by a function-blocking monoclonal antibody (mAb) against the alphav subunit. It thus seems that inhibition of proprotein convertases enhances the in vivo invasiveness of colon tumor cells likely due to an increase in cell migration mediated by alphav integrins.
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14
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Berthet V, Rigot V, Nejjari M, Marvaldi J, Luis J. The endoproteolytic processing of alphavbeta5 integrin is involved in cytoskeleton remodelling and cell migration. FEBS Lett 2004; 557:159-63. [PMID: 14741360 DOI: 10.1016/s0014-5793(03)01467-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We previously showed that the post-translational cleavage of alphav subunit is essential for integrin-dependent signalling and cell adhesion. Here, we report that blocking alphav subunit cleavage by expression of alpha1-PDX, a convertase inhibitor, modified the capacity of cells to change shape, via a remodelling of the actin cytoskeleton upon cell attachment. These changes are associated with cell scattering and with a dramatic increase in cell migration to vitronectin. The alphav subunit cleavage is thus essential for integrin function and has a considerable impact on integrin-dependent events, especially those leading to cell migration.
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Affiliation(s)
- Virginie Berthet
- CNRS UMR6032, Faculté de Pharmacie, 27 Bd J. Moulin, 13385 Marseille Cedex 5, France
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Cain BM, Vishnuvardhan D, Wang W, Foulon T, Cadel S, Cohen P, Beinfeld MC. Production, purification, and characterization of recombinant prohormone convertase 5 from baculovirus-infected insect cells. Protein Expr Purif 2002; 24:227-33. [PMID: 11858717 DOI: 10.1006/prep.2001.1557] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The discovery of the prohormone convertase (PC) family of enzymes has provided several good candidates (PC1, PC2, and PC5) for the enzymes responsible for the endoproteolytic cleavage of procholecystokinin (pro-CCK). Determination of the role of individual pro-hormone convertases in the processing of pro-CCK is complicated because several of these enzymes are found in endocrine tumor cells expressing CCK mRNA and in identified neurons in the brain. Production of active recombinant PC5 permits the determination of its ability to cleave substrates related to pro-CCK. Active PC5, secreted from baculovirus-infected Sf9 cells, was partially purified by ion-exchange chromatography. Western blot analysis confirmed the presence of the active form of the enzyme in infected cell media and its absence from uninfected cell media. The enzyme is most active at acidic pH 6.5 and is maximally activated by 5 mM calcium. PC5 was able to cleave both monobasic and dibasic substrates without a requirement for a basic residue at P-4 and it displayed a K(m) in the micromolar range. The enzyme was inhibited by EDTA, 1,10-phenanthroline, and p-CMS, as well as by two specific PC inhibitors. This is the first reported preparation of active recombinant PC5. Like the other members of its family, it has the correct catalytic characteristics in vitro to play a role in the processing of neuropeptide precursor proteins into their final bioactive forms.
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Affiliation(s)
- Brian M Cain
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA.
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Stawowy P, Blaschke F, Kilimnik A, Goetze S, Kallisch H, Chrétien M, Marcinkiewicz M, Fleck E, Graf K. Proprotein convertase PC5 regulation by PDGF-BB involves PI3-kinase/p70(s6)-kinase activation in vascular smooth muscle cells. Hypertension 2002; 39:399-404. [PMID: 11882580 DOI: 10.1161/hy0202.103000] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have recently demonstrated that furin, PC5, and PC7, members of the subtilisin/kexin-like mammalian proprotein convertases (PCs), are found in rodent aorta. These PCs have been identified to activate several growth factors, adhesion molecules and extracellular matrix compounds by endoproteolytic cleavage. In the present study, we investigated the regulation of PC5 in vascular smooth muscle cells (VSMCs) in vitro and in vivo. Stimulation of rat aortic VSMCs with platelet-derived growth factor (PDGF)-BB (20 ng/mL), angiotensin II (Ang II, 1 micromol/L), or 10% fetal calf serum (FCS) for 48 hours increased DNA synthesis, as assessed by proliferating cell nuclear antigen (PCNA) immunoblotting. PC5 was strongly upregulated by PDGF-BB and 10% FCS (both 8-fold, P<0.05), whereas Ang II had no effect on PC5 protein levels compared with controls. The PCs furin and PC7, which display a comparable subcellular localization and cleavage activity, were found in VSMCs, but their levels did not increase following PDGF-BB, Ang II, or FCS stimulation. Time-course analysis revealed a rapid increase in PC5 levels after 30 minutes of PDGF-stimulation of VSMCs. PDGF-stimulated PC5 induction was inhibited by the PI3-kinase inhibitor wortmannin, and by rapamycin, an inhibitor of mTOR/p70(s6)-kinase (both P<0.05). In contrast, the mitogen-activated protein kinase (MAPK)-pathway inhibitor PD98059 did not inhibit PDGF-stimulated PC5 induction. Immunocytochemistry and in situ hybridization revealed low PC5 protein and mRNA levels in intact rat aorta in vivo. After balloon injury, PC5 protein and mRNA levels were strongly increased in proliferating PCNA-positive VSMCs. The present data demonstrate that PC5 is upregulated during proliferation of VSMCs in vivo and in vitro. We show that PDGF-induced PC5 expression is PI3-kinase/p70(s6)-kinase dependent. Thus, growth factors regulate the proprotein convertase PC5, which may play an important role during VSMC growth.
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Affiliation(s)
- Philipp Stawowy
- Department of Medicine/Cardiology, Deutsches Herzzentrum Berlin, Germany
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Berthet V, Rigot V, Champion S, Secchi J, Fouchier F, Marvaldi J, Luis J. Role of endoproteolytic processing in the adhesive and signaling functions of alphavbeta5 integrin. J Biol Chem 2000; 275:33308-13. [PMID: 10913146 DOI: 10.1074/jbc.m004834200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Some integrin alpha subunits undergo a post-translational cleavage in their extracellular domain. However, the role of this cleavage in integrin function is unclear. Enzymes involved in this maturation belong to the subtilisin-like endoprotease family (convertases). To understand the role of the alpha subunit cleavage in integrin function, we have designed stable transfectants (PDX39P cells) expressing alpha(1)-PDX, a convertase inhibitor. Immunoprecipitation of cell surface proteins from PDX39P showed that alpha(3), alpha(6) and alpha(v) integrins lack endoproteolytic cleavage. We have compared adhesion between PDX39P cells and mock-transfected cells on different extracellular matrix proteins. No difference in adhesion could be observed on laminin-1 and type I collagen, while attachment of PDX39P cells to vitronectin (ligand of the alpha(v)beta(5) integrin) was dramatically reduced. The reduced adhesion of PDX39P cells was not due to changes in integrin affinity as determined by solid-phase receptor assay in a cell-free environment. Intracellular signaling pathways activated by alpha(v) integrin ligation were also affected in PDX39P cells. It thus seems that the absence of endoproteolytic cleavage of alpha(v) integrins has important consequences on signal transduction pathways leading to alterations in integrin function such as cell adhesion.
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Affiliation(s)
- V Berthet
- Laboratoire de Biochimie Cellulaire, CNRS UPRESA 6032, Faculté de Pharmacie, 27 Bd J. Moulin, 13 385 Marseille Cedex 5, France
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Bolt G, Pedersen LO, Birkeslund HH. Cleavage of the respiratory syncytial virus fusion protein is required for its surface expression: role of furin. Virus Res 2000; 68:25-33. [PMID: 10930660 DOI: 10.1016/s0168-1702(00)00149-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The fusion (F) glycoprotein of respiratory syncytial virus (RSV) is synthesized as a nonfusogenic precursor protein (F(0)), which during its migration to the cell surface is activated by cleavage into the disulfide-linked F(1) and F(2) subunits. In the present study, soluble secreted human furin produced by a recombinant baculovirus cleaved RSV F(0) into proteins the size of F(1) and F(2). Furthermore, cleavage of F(0) was partially inhibited in the furin defective LoVo cell line, in calcium depleted HEp-2 cells, and in HEp-2 cells treated with the furin inhibitor decanoyl-R-V-K-R-chloromethylketon. These findings strongly suggest an important role for furin in activation of the RSV F protein. The F(0) protein could not be detected on the surface of cells, in which F protein activation was inhibited, and RSV particles did not appear to be released from these cells. It thus seems that in contrast to the F proteins of most other paramyxoviruses, the RSV F(0) protein is very inefficient in reaching the cell surface or is unable to reach the cell surface and therefore cannot be incorporated into virus particles.
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Affiliation(s)
- G Bolt
- Department of Medical Microbiology and Immunology, Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark.
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Chapter 9. Endothelin Antagonists. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1996. [DOI: 10.1016/s0065-7743(08)60448-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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