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Feser CJ, Williams JM, Lammers DT, Bingham JR, Eckert MJ, Tolar J, Osborn MJ. Engineering Human Cells Expressing CRISPR/Cas9-Synergistic Activation Mediators for Recombinant Protein Production. Int J Mol Sci 2023; 24:8468. [PMID: 37239814 PMCID: PMC10218281 DOI: 10.3390/ijms24108468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/26/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
Recombinant engineering for protein production commonly employs plasmid-based gene templates for introduction and expression of genes in a candidate cell system in vitro. Challenges to this approach include identifying cell types that can facilitate proper post-translational modifications and difficulty expressing large multimeric proteins. We hypothesized that integration of the CRISPR/Cas9-synergistic activator mediator (SAM) system into the human genome would be a powerful tool capable of robust gene expression and protein production. SAMs are comprised of a "dead" Cas9 (dCas9) linked to transcriptional activators viral particle 64 (VP64), nuclear factor-kappa-B p65 subunit (p65), and heat shock factor 1 (HSF1) and are programmable to single or multiple gene targets. We integrated the components of the SAM system into human HEK293, HKB11, SK-HEP1, and HEP-g2 cells using coagulation factor X (FX) and fibrinogen (FBN) as proof of concept. We observed upregulation of mRNA in each cell type with concomitant protein expression. Our findings demonstrate the capability of human cells stably expressing SAM for user-defined singleplex and multiplex gene targeting and highlight their broad potential utility for recombinant engineering as well as transcriptional modulation across networks for basic, translational, and clinical modeling and applications.
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Affiliation(s)
- Colby J. Feser
- Department of Pediatrics, Division of Blood and Marrow Transplantation, MMC 366 Mayo, 8366A, 420 Delaware Street SE, Minneapolis, MN 55455, USA; (C.J.F.); (J.T.)
| | - James M. Williams
- Department of General Surgery, Madigan Army Medical Center, 9040 Jackson Ave, Tacoma, WA 98431, USA; (J.M.W.); (D.T.L.); (J.R.B.); (M.J.E.)
| | - Daniel T. Lammers
- Department of General Surgery, Madigan Army Medical Center, 9040 Jackson Ave, Tacoma, WA 98431, USA; (J.M.W.); (D.T.L.); (J.R.B.); (M.J.E.)
| | - Jason R. Bingham
- Department of General Surgery, Madigan Army Medical Center, 9040 Jackson Ave, Tacoma, WA 98431, USA; (J.M.W.); (D.T.L.); (J.R.B.); (M.J.E.)
| | - Matthew J. Eckert
- Department of General Surgery, Madigan Army Medical Center, 9040 Jackson Ave, Tacoma, WA 98431, USA; (J.M.W.); (D.T.L.); (J.R.B.); (M.J.E.)
- Department of Surgery, University of North Carolina, 160 Dental Circle, Chapel Hill, NC 27599, USA
| | - Jakub Tolar
- Department of Pediatrics, Division of Blood and Marrow Transplantation, MMC 366 Mayo, 8366A, 420 Delaware Street SE, Minneapolis, MN 55455, USA; (C.J.F.); (J.T.)
| | - Mark J. Osborn
- Department of Pediatrics, Division of Blood and Marrow Transplantation, MMC 366 Mayo, 8366A, 420 Delaware Street SE, Minneapolis, MN 55455, USA; (C.J.F.); (J.T.)
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Ebert M, Raquet E, Schweisgut S, Schmidt PM, Weimer T. Identification of a modified coagulation factor X with enhanced activation properties as potential hemostatic agent. Blood Cells Mol Dis 2021; 89:102570. [PMID: 33962291 DOI: 10.1016/j.bcmd.2021.102570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 10/21/2022]
Abstract
Hemophilia A and hemophilia B are X-linked inherited bleeding disorders caused by a deficiency of coagulation factor VIII and IX, respectively. Standard of care is prophylactic factor replacement therapy; however, the development of neutralizing antibodies against these factors represents serious complications underlining the need for alternative treatment approaches. Human coagulation factor X has a central role within the blood coagulation system making it an attractive target for the development of alternative treatment strategies for patients with hemophilia. This study focuses on a modified variant of the human coagulation factor X with enhanced hemostatic bypass activity due to insertion of a factor IX derived activation sequence. This molecule design leads to the direct activation of the modified factor X protein by factor XIa allowing it to bypass the need for coagulation factor VIIIa/factor IXa. The modified variant was able to correct in-vitro activated partial prothrombin time of human and murine factor VIII/factor IX deficient plasma. Furthermore, reduced blood loss in factor VIII knock-out mice was observed after intravenous application of the modified factor X variant. In conclusion, these data suggest that the factor X variant described here could potentially serve as a bypassing agent independent of the inhibitor status of hemophilia patients. However, more research is needed to further investigate the potential of this molecule.
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Affiliation(s)
- Mariana Ebert
- Research and Development, CSL Behring Innovation GmbH, Marburg, Germany.
| | - Elmar Raquet
- Research and Development, CSL Behring Innovation GmbH, Marburg, Germany
| | - Sabine Schweisgut
- Research and Development, CSL Behring Innovation GmbH, Marburg, Germany
| | - Peter M Schmidt
- Research and Development, CSL Behring Innovation GmbH, Marburg, Germany
| | - Thomas Weimer
- Research and Development, CSL Behring Innovation GmbH, Marburg, Germany
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3
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Böttcher-Friebertshäuser E, Garten W, Klenk HD. Characterization of Proprotein Convertases and Their Involvement in Virus Propagation. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7122180 DOI: 10.1007/978-3-319-75474-1_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Wolfgang Garten
- Institut für Virologie, Philipps Universität, Marburg, Germany
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4
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Al Rifai O, Chow J, Lacombe J, Julien C, Faubert D, Susan-Resiga D, Essalmani R, Creemers JW, Seidah NG, Ferron M. Proprotein convertase furin regulates osteocalcin and bone endocrine function. J Clin Invest 2017; 127:4104-4117. [PMID: 28972540 DOI: 10.1172/jci93437] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 08/15/2017] [Indexed: 12/12/2022] Open
Abstract
Osteocalcin (OCN) is an osteoblast-derived hormone that increases energy expenditure, insulin sensitivity, insulin secretion, and glucose tolerance. The cDNA sequence of OCN predicts that, like many other peptide hormones, OCN is first synthesized as a prohormone (pro-OCN). The importance of pro-OCN maturation in regulating OCN and the identity of the endopeptidase responsible for pro-OCN cleavage in osteoblasts are still unknown. Here, we show that the proprotein convertase furin is responsible for pro-OCN maturation in vitro and in vivo. Using pharmacological and genetic experiments, we also determined that furin-mediated pro-OCN cleavage occurred independently of its γ-carboxylation, a posttranslational modification that is known to hamper OCN endocrine action. However, because pro-OCN is not efficiently decarboxylated and activated during bone resorption, inactivation of furin in osteoblasts in mice resulted in decreased circulating levels of undercarboxylated OCN, impaired glucose tolerance, and reduced energy expenditure. Furthermore, we show that Furin deletion in osteoblasts reduced appetite, a function not modulated by OCN, thus suggesting that osteoblasts may secrete additional hormones that regulate different aspects of energy metabolism. Accordingly, the metabolic defects of the mice lacking furin in osteoblasts became more apparent under pair-feeding conditions. These findings identify furin as an important regulator of bone endocrine function.
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Affiliation(s)
- Omar Al Rifai
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Molecular Biology Programs of the Faculty of Medicine, Université de Montréal, Québec, Canada
| | - Jacqueline Chow
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Julie Lacombe
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Catherine Julien
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | | | | | - Rachid Essalmani
- Biochemical Neuroendocrinology Research Unit, IRCM, Québec, Canada
| | | | - Nabil G Seidah
- Biochemical Neuroendocrinology Research Unit, IRCM, Québec, Canada.,Department of Medicine, Université de Montréal, Québec, Canada.,Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
| | - Mathieu Ferron
- Integrative and Molecular Physiology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Molecular Biology Programs of the Faculty of Medicine, Université de Montréal, Québec, Canada.,Department of Medicine, Université de Montréal, Québec, Canada.,Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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Sathyamurthy M, Kim CL, Bang YL, Kim YS, Jang JW, Lee GM. Characterization and expression of proprotein convertases in CHO cells: Efficient proteolytic maturation of human bone morphogenetic protein-7. Biotechnol Bioeng 2014; 112:560-8. [DOI: 10.1002/bit.25458] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/15/2014] [Accepted: 09/01/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Madhavi Sathyamurthy
- Department of Biological Sciences; KAIST; 335 Gwahak-ro, Yuseong-gu Daejeon 305-701 Republic of Korea
| | - Che Lin Kim
- Department of Biological Sciences; KAIST; 335 Gwahak-ro, Yuseong-gu Daejeon 305-701 Republic of Korea
| | - You Lim Bang
- Institute of Biomaterial and Medical Engineering; Cellumed; 402 Gasan-dong, Geumcheon-gu Seoul 153-782 Republic of Korea
| | - Young Sik Kim
- Institute of Biomaterial and Medical Engineering; Cellumed; 402 Gasan-dong, Geumcheon-gu Seoul 153-782 Republic of Korea
| | - Ju Woong Jang
- Institute of Biomaterial and Medical Engineering; Cellumed; 402 Gasan-dong, Geumcheon-gu Seoul 153-782 Republic of Korea
| | - Gyun Min Lee
- Department of Biological Sciences; KAIST; 335 Gwahak-ro, Yuseong-gu Daejeon 305-701 Republic of Korea
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Antigenicity of recombinant maltose binding protein-Mycobacterium avium subsp. paratuberculosis fusion proteins with and without factor Xa cleaving. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1817-26. [PMID: 24132604 DOI: 10.1128/cvi.00596-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mycobacterium avium subsp. paratuberculosis causes Johne's disease (JD) in ruminants. Proteomic studies have shown that M. avium subsp. paratuberculosis expresses certain proteins when exposed to in vitro physiological stress conditions similar to the conditions experienced within a host during natural infection. Such proteins are hypothesized to be expressed in vivo, are recognized by the host immune system, and may be of potential use in the diagnosis of JD. In this study, 50 recombinant maltose binding protein (MBP)-M. avium subsp. paratuberculosis fusion proteins were evaluated using serum samples from sheep infected with M. avium subsp. paratuberculosis, and 29 (58%) were found to be antigenic. Among 50 fusion proteins, 10 were evaluated in MBP fusion and factor Xa-cleaved forms. A total of 31 proteins (62%) were found to be antigenic in either MBP fusion or factor Xa-cleaved forms. Antigenicity after cleavage and removal of the MBP tag was marginally enhanced.
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Pharmacokinetics, distribution, and excretion of 125I-labeled human plasma-derived-FVIIa and -FX with MC710 (FVIIa/FX mixture) in rats. Thromb Res 2012; 129:62-7. [DOI: 10.1016/j.thromres.2011.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 03/16/2011] [Accepted: 04/26/2011] [Indexed: 11/19/2022]
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Gorenflo VM, Pfeifer TA, Lesnicki G, Kwan EM, Grigliatti TA, Kilburn DG, Piret JM. Production of a self-activating CBM-factor X fusion protein in a stable transformed Sf9 insect cell line using high cell density perfusion culture. Cytotechnology 2011; 44:93-102. [PMID: 19003232 DOI: 10.1007/s10616-005-0703-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Accepted: 09/03/2003] [Indexed: 11/25/2022] Open
Abstract
Factor Xa is a serine protease, whose high selectivity can be used to cleave protein tags from recombinant proteins. A fusion protein comprised of a self-activating form of factor X linked to a cellulose-binding module, saCBMFX, was produced in a stable transformed Sf9 insect cell line. The activity of the insect cell produced saCBMFX was higher than the equivalent mammalian cell produced material. A 1.5 l batch fermentation reached a maximum cell concentration of 1.6 x 10(7) cells ml(-1) and a final saCBMFX concentration of 4 mg l(-1). The production of saCBMFX by this cell line was also analyzed in a 1.5 l perfusion system using an ultrasonic filter as a cell-retention device for flow rates up to 3.5 l day(-1). The cell-retention efficiency of an air backflush mode of acoustic filter operation was greater than 95% and eliminated the need to pump the relatively shear sensitive insect cells. In the perfusion system over 4 x 10(7) Sf9 cells ml(-1) were obtained with a viability greater than 80%. With a doubling of viable cell concentration from 1.5 to 3 x 10(7) cells ml(-1) the saCBMFX production rate was doubled to 6 mg l(-1) day(-1). The saCBMFX volumetric productivity of the perfusion system was higher than the batch fermentations (0.6 mg l(-1) day(-1)) by an order of magnitude.
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Affiliation(s)
- Volker M Gorenflo
- Biotechnology Laboratory, University of British Columbia, 6174 University Boulevard, V6T 1Z3, Vancouver, BC, Canada,
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Preininger A, Schlokat U, Mohr G, Himmelspach M, Stichler V, Kyd-Rebenburg A, Plaimauer B, Turecek PL, Schwarz HP, Wernhart W, Fischer BE, Dorner F. Strategies for recombinant Furin employment in a biotechnological process: complete target protein precursor cleavage. Cytotechnology 2011; 30:1-16. [PMID: 19003349 DOI: 10.1023/a:1008030407679] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Coagulation factors, amongst many other proteins, often require posttranslational endoproteolytic processing for maturation. Upon high yield expression of recombinant forms of these proteins, processing frequently becomes severely limiting, resulting in a hampered function of the protein. In this report, the human endoprotease Furin was used to achieve complete propeptide removal from recombinant von Willebrand Factor (rvWF) precursors in CHO cells. At expression beyond 200 ng rvWF/106 cells x day, processing became insufficient. Stable co- and overexpression of full length Furin resulted in complete precursor cleavage in cell clones expressing 2 mug rvWF/106 cells x day. Rather than occuring intracellularly, processing was found to be mediated by a naturally secreted form of rFurin, present in 100 fold higher concentrations than endogenous Furin and accumulating in the cell culture supernatant. Attempts to increase rFurin yield by amplification, in order to ensure complete rvWF precursor processing at expression rates beyond 2 mug rvWF/106 cells x day, failed. Truncation of the trans-membrane domain resulted in immediate secretion of rFurin and approximately 10 fold higher concentrations in the conditioned medium. In cases where these high rFurin concentrations are not sufficient to ensure complete processing, an in vitro downstream processing procedure has to be established. Secreted affinity epitope-tagged rFurin derivatives were constructed, the fate of which, at expression, was dependent on the size of the C-terminal truncation and the type of the heterologous epitope added. A suitable candidate was purified by a one step affinity procedure, and successfully used for in vitro processing. This allows complete proteolytic processing of large amounts of precursor molecules by comparably small quantities of rFurin. Complete precursor cleavage of a target protein at expression rates of up to approximately 200 ng, 2 mug, and 20 mug, as well as beyond 20 mug/106 cells x day can thus be anticipated to be accomplished by endogenous Furin, additional expression of full length rFurin, co-expression of truncated and hence secreted rFurin, and a protein-chemical in vitro procedure, respectively.
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Affiliation(s)
- A Preininger
- IMMUNO Division of BAXTER, Biomedical Research Center, Uferstrasse 15, 2304, Orth/Donau, Austria
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Complex assemblies of factors IX and X regulate the initiation, maintenance, and shutdown of blood coagulation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 99:51-103. [PMID: 21238934 DOI: 10.1016/b978-0-12-385504-6.00002-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Blood hemostasis is accomplished by a complex network of (anti-)coagulatory and fibrinolytic processes. These physiological processes are implemented by the assembly of multiprotein complexes involving both humoral and cellular components. Coagulation factor X, and particularly, factor IX, exemplify the dramatic enhancement that is obtained by the synergistic interaction of cell surface, inorganic and protein cofactors, protease, and substrate. With a focus on structure-function relationship, we review the current knowledge of activity modulation principles in the coagulation proteases factors IX and X and indicate future challenges for hemostasis research. This chapter is organized by describing the principles of hierarchical activation of blood coagulation proteases, including endogenous and exogenous protease activators, cofactor binding, substrate specificities, and protein inhibitors. We conclude by outlining pharmaceutical opportunities for unmet needs in hemophilia and thrombosis.
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Abstract
Hospital pharmacists are often consulted for their knowledge about coagulation and therapeutic interventions for the management of critical bleeding. Many pharmacotherapies are available for this purpose, both systemic and topical, and others are in development. These agents and their mechanisms of action are reviewed, and perspectives are provided regarding their use in various clinical settings. Also provided are associated precautions to promote safe use. Current controversies surrounding pharmacotherapeutic agents used to control serious bleeding (e.g., in various types of surgery, trauma, obstetrics, and intracranial hemorrhage) are also discussed.
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Affiliation(s)
- Stacy Voils
- School of Pharmacy, Virginia Commonwealth University, Medical College of Virginia Hospitals, Richmond, Virginia 23298, USA.
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12
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Filippovich I, Sorokina N, St Pierre L, Flight S, de Jersey J, Perry N, Masci PP, Lavin MF. Cloning and functional expression of venom prothrombin activator protease from Pseudonaja textilis with whole blood procoagulant activity. Br J Haematol 2005; 131:237-46. [PMID: 16197456 DOI: 10.1111/j.1365-2141.2005.05744.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The snake venom group C prothrombin activators contain a number of components that enhance the rate of prothrombin activation. The cloning and expression of full-length cDNA for one of these components, an activated factor X (factor Xa)-like protease from Pseudonaja textilis as well as the generation of functional chimeric constructs with procoagulant activity were described. The complete cDNA codes for a propeptide, light chain, activation peptide (AP) and heavy chain related in sequence to mammalian factor X. Efficient expression of the protease was achieved with constructs where the AP was deleted and the cleavage sites between the heavy and light chains modified, or where the AP was replaced with a peptide involved in insulin receptor processing. In human kidney cells (H293F) transfected with these constructs, up to 80% of the pro-form was processed to heavy and light chains. Binding of the protease to barium citrate and use of specific antibodies demonstrated that gamma-carboxylation of glutamic acid residues had occurred on the light chain in both cases, as observed in human factor Xa and the native P. textilis protease. The recombinant protease caused efficient coagulation of whole citrated blood and citrated plasma that was enhanced by the presence of Ca2+. This study identified the complete cDNA sequence of a factor Xa-like protease from P. textilis and demonstrated for the first time the expression of a recombinant form of P. textilis protease capable of blood coagulation.
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Affiliation(s)
- Igor Filippovich
- The Queensland Institute of Medical Research, PO Royal Brisbane Hospital, Herston, Australia
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Abstract
Many secretory proteins and peptides are synthesized as inactive precursors that in addition to signal peptide cleavage undergo post-translational processing to become biologically active polypeptides. Precursors are usually cleaved at sites composed of single or paired basic amino acid residues by members of the subtilisin/kexin-like proprotein convertase (PC) family. In mammals, seven members have been identified, with furin being the one first discovered and best characterized. Recently, the involvement of furin in diseases ranging from Alzheimer's disease and cancer to anthrax and Ebola fever has created additional focus on proprotein processing. We have developed a method for prediction of cleavage sites for PCs based on artificial neural networks. Two different types of neural networks have been constructed: a furin-specific network based on experimental results derived from the literature, and a general PC-specific network trained on data from the Swiss-Prot protein database. The method predicts cleavage sites in independent sequences with a sensitivity of 95% for the furin neural network and 62% for the general PC network. The ProP method is made publicly available at http://www.cbs.dtu.dk/services/ProP.
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Affiliation(s)
- Peter Duckert
- Center for Biological Sequence Analysis, BioCentrum-DTU, Technical University of Denmark, Building 208, DK-2800 Lyngby, Denmark
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Kwan E, Guarna MM, Boraston AB, Gilkes NR, Haynes CA, Kilburn DG, Warren RAJ. Self-activating factor X derivative fused to the C-terminus of a cellulose-binding module: Production and properties. Biotechnol Bioeng 2002; 79:724-32. [PMID: 12209795 DOI: 10.1002/bit.10312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work, a new derivative of FX was engineered. It comprises a cellulose-binding module (CBM) fused to the N-terminus of the truncated light chain (E2FX) of FX and a hexahistidine tag (H6) fused to the C-terminus of the heavy chain. The sequence LTR at the site of cleavage of the activation peptide from the N-terminus of the heavy chain is changed to IEGR to render the derivative self-activating. However, N-linked glycans on the CBM of the derivative blocked its binding to cellulose and those on the activation peptide slowed its activation. Therefore, the sites of N-linked glycosylation on the CBM and on the activation peptide were eliminated by mutation. The final derivative can be produced in good yield by cultured mammalian cells. It is purified easily with Ni(2+)-agarose, it is self-activating, and it can be immobilized on cellulose. When immobilized on a column of cellulose beads, the activated derivative retains approximately 80% of its initial activity after 30 days of continuous hydrolysis of a fusion protein substrate. Under these conditions of operation, the effective substrate:enzyme ratio is >10(4).
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Affiliation(s)
- Emily Kwan
- Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, Canada
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Pfeifer TA, Guarna MM, Kwan EM, Lesnicki G, Theilmann DA, Grigliatti TA, Kilburn DG. Expression analysis of a modified factor X in stably transformed insect cell lines. Protein Expr Purif 2001; 23:233-41. [PMID: 11676597 DOI: 10.1006/prep.2001.1503] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A modified Factor X protein was combined with a cellulose-binding domain tag and expressed in insect cell lines. The protein, CBDFX, was expressed and secreted into the medium. Stable, transformed Hi5 and Sf9 insect cell lines were generated and tested for production of secreted CBDFX. The highest Sf9 and Hi5 CBDFX-producing cell lines were scaled up to 2-liter fermentors to evaluate production of this recombinant protein. Secreted protein production levels reached 4 mg/liter for the stable, transformed Hi5 cell line and 18 mg/liter for the stable, transformed Sf9 cell line. The protein was properly processed as determined by amino terminal sequencing and bound well to the cellulose substrate Avicel. In addition the activated recombinant CBDFX(a) was capable of recognizing and efficiently processing a Factor X cleavage site.
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Affiliation(s)
- T A Pfeifer
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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Plaimauer B, Mohr G, Wernhart W, Himmelspach M, Dorner F, Schlokat U. 'Shed' furin: mapping of the cleavage determinants and identification of its C-terminus. Biochem J 2001; 354:689-95. [PMID: 11237874 PMCID: PMC1221701 DOI: 10.1042/0264-6021:3540689] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The human endoprotease furin is involved in the proteolytic maturation of the precursor molecules of a wide variety of bioactive proteins. Despite its localization in the membranes of the trans-Golgi system by means of a transmembrane domain, it has repeatedly been reported to form a C-terminally truncated, naturally secreted form referred to as 'shed' furin. In order to identify the cleavage site, internal deletion mutants of increasing size, N-terminal to Leu(708), and subsequently individual amino acid substitutions were introduced, and Arg(683) was identified as the prime determinant for shedding. MS analysis determined Ser(682) as the C-terminus of shed furin, suggesting that monobasic cleavage may occur N-terminal to Arg(683). Alteration of Arg(683) directs the shedding mechanism to alternative cleaving sites previously unused.
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Affiliation(s)
- B Plaimauer
- Biomedical Research Center, Hyland-Immuno Division, Baxter Healthcare, Uferstr. 15, 2304 Orth/Donau, Austria
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