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Pagadala PC, Dvorak LA, Neet KE. Construction of a mutated pro-nerve growth factor resistant to degradation and suitable for biophysical and cellular utilization. Proc Natl Acad Sci U S A 2006; 103:17939-43. [PMID: 17093052 PMCID: PMC1693851 DOI: 10.1073/pnas.0604139103] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Precursor of nerve growth factor (proNGF) has been found to be proapoptotic in several cell types and mediates its effects by binding to p75 neurotrophin receptor (p75NTR) and sortilin. The proNGF molecule is processed by proteases at three dibasic sites found in the pro domain to form mature NGF (termed herein as sites 1, 2, and 3 from the proNGF N terminus). Of these processing sites, site 3, adjacent to the N terminus of mature NGF, was thought to be the major site responsible for processing of proNGF to mature NGF. We found that mutating this major processing site (site 3) resulted in a form of proNGF that was only partially stable. On introducing additional mutations in the pro domain at the other two dibasic sites, we found the stability of proNGF to increase significantly. Here we describe the construction, expression, and purification of this more stable proNGF molecule. The two consecutive basic residues at each of the three sites were mutated to neutral alanine residues. Expression was performed in stably transfected Sf21 insect cells. Purification involved strong cation-exchange chromatography and N60 immunoaffinity column chromatography. The construct with all three sites mutated (termed proNGF123) gave all proNGF with no mature NGF and was not cleaved by three proconvertases (furin, PACE-4, and PC-2) known to proteolyze proneurotrophins in vivo. This stable proNGF molecule demonstrated proapoptotic activity on rat pheocytochroma PC12 cells, PC12nnr cells, C6 glioblastoma cells, and RN22 schwannoma cells.
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Affiliation(s)
- Promila C. Pagadala
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Laura A. Dvorak
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Kenneth E. Neet
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
- *To whom correspondence should be addressed. E-mail:
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3
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Tzimas GN, Chevet E, Jenna S, Nguyên DT, Khatib AM, Marcus V, Zhang Y, Chrétien M, Seidah N, Metrakos P. Abnormal expression and processing of the proprotein convertases PC1 and PC2 in human colorectal liver metastases. BMC Cancer 2005; 5:149. [PMID: 16293189 PMCID: PMC1310616 DOI: 10.1186/1471-2407-5-149] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Accepted: 11/17/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The family of proprotein convertases has been recently implicated in tumorigenesis and metastasis in animal models. However, these studies have not yet been completely corroborated in human tumors. METHODS Using RT PCR, immunoblot and immunohistochemistry we assessed the presence and the processing patterns of the convertases PC1 and PC2 as well as the PC2 specific chaperone 7B2 in human liver metastases originating from colorectal cancer and compared them to unaffected and normal liver. Furthermore, we assessed the presence and processing profiles of PC1, PC2 and 7B2 in primary colon cancers. RESULTS mRNA, protein expression, and protein cleavage profiles of proprotein convertases 1 and 2 are altered in liver colorectal metastasis, compared to unaffected and normal liver. Active PC1 protein is overexpressed in tumor, correlating with its mRNA profile. Moreover, the enhanced PC2 processing pattern in tumor correlates with the overexpression of its specific binding protein 7B2. These results were corroborated by immunohistochemistry. The specific and uniform convertase pattern observed in the metastases was present only in a fraction of primary colon cancers. CONCLUSION The uniformly altered proprotein convertase profile in liver metastases is observed only in a fraction of primary colon cancers, suggesting possible selection processes involving PCs during metastasis as well as an active role of PCs in liver metastasis. In addition, the exclusive presence of 7B2 in metastatic tumors may represent a new target for early diagnosis, prognosis and/or treatment.
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Affiliation(s)
- George N Tzimas
- Transplant and Hepato-pancreatobiliary Research Group, McGill University Health Center, McGill University, 687 Pine Avenue West, S.10.26, Montreal, Canada H3A1A1
- Department of Surgical Services, Kypselis General Hospital, 24 Drossopoulou Street, Athens 11257, Greece
- Organelle Signaling Laboratory, Department of Surgery, McGill University Health Center, McGill University, 687 Pine Avenue West, S.10.26, Montreal, Canada H3A1A1
| | - Eric Chevet
- Organelle Signaling Laboratory, Department of Surgery, McGill University Health Center, McGill University, 687 Pine Avenue West, S.10.26, Montreal, Canada H3A1A1
| | - Sarah Jenna
- Organelle Signaling Laboratory, Department of Surgery, McGill University Health Center, McGill University, 687 Pine Avenue West, S.10.26, Montreal, Canada H3A1A1
| | - Duc Thang Nguyên
- Organelle Signaling Laboratory, Department of Surgery, McGill University Health Center, McGill University, 687 Pine Avenue West, S.10.26, Montreal, Canada H3A1A1
| | - Abdel M Khatib
- Ottawa Health Research Institute, University of Ottawa, Ottawa, Canada Y1K 4K9
| | - Victoria Marcus
- Department of Pathology, McGill University Health Center, McGill University, 1650 Cedar Avenue, Montreal, Canada H3G 1A4
| | - Yi Zhang
- Department of Pathology, McGill University Health Center, McGill University, 1650 Cedar Avenue, Montreal, Canada H3G 1A4
| | - Michel Chrétien
- Ottawa Health Research Institute, University of Ottawa, Ottawa, Canada Y1K 4K9
| | - Nabil Seidah
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, University of Montreal, Montreal, Canada H2W 1R7, QC
| | - Peter Metrakos
- Transplant and Hepato-pancreatobiliary Research Group, McGill University Health Center, McGill University, 687 Pine Avenue West, S.10.26, Montreal, Canada H3A1A1
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Richer MJ, Keays CA, Waterhouse J, Minhas J, Hashimoto C, Jean F. The Spn4 gene of Drosophila encodes a potent furin-directed secretory pathway serpin. Proc Natl Acad Sci U S A 2004; 101:10560-5. [PMID: 15247425 PMCID: PMC489976 DOI: 10.1073/pnas.0401406101] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Proprotein convertases (PCs) are an important class of host-cell serine endoproteases implicated in many physiological and pathological processes. Owing to their expanding roles in the proteolytic events required for generating infectious microbial pathogens and for tumor growth and invasiveness, there is increasing interest in identifying endogenous PC inhibitors. Here we report the identification of Spn4A, a previously uncharacterized secretory pathway serine protease inhibitor (serpin) from Drosophila melanogaster that contains a consensus furin cleavage site, -Arg(P4)-Arg-Lys-Arg(P1) downsream-, in its reactive site loop (RSL). Our biochemical and kinetics analysis revealed that recombinant Spn4A inhibits human furin (K(i), 13 pM; k(ass), 3.2 x 10(7) M(-1) x s(-1)) and Drosophila PC2 (K(i), 3.5 nM; k(ass), 9.2 x 10(4) M(-1) x s(-1)) by a slow-binding mechanism characteristic of serpin molecules and forms a kinetically trapped SDS-stable complex with each enzyme. For both PCs, the stoichiometry of inhibition by Spn4A is nearly 1, which is characteristic of known physiological serpin-protease interactions. Mass analysis of furin-Spn4A reaction products identified the actual reactive site center of Spn4A to be -Arg(P4)-Arg-Lys-Arg(P1)-downstream-. Moreover, we demonstrate that Spn4A's highly effective PC inhibition properties are critically dependent on the unusual length of its RSL, which is composed of 18 aa instead of the typical 17-residue RSL found in most other inhibitory serpins. The identification of Spn4A, the most potent and effective natural serpin of PCs identified to date, suggests that Spn4A could be a prototype of endogenous serpins involved in the precise regulation of PC-dependent proteolytic cleavage events in the secretory pathway of eukaryotic cells.
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Affiliation(s)
- Martin J Richer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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5
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Booth RE, Misquitta SA, Bateman RC. Human pituitary glutaminyl cyclase: expression in insect cells and dye affinity purification. Protein Expr Purif 2004; 32:141-6. [PMID: 14680951 DOI: 10.1016/s1046-5928(03)00226-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2003] [Revised: 07/15/2003] [Indexed: 11/30/2022]
Abstract
Human pituitary glutaminyl cyclase (hQC) was expressed in Drosophila S2 cells under the control of an inducible metallothionene promoter and fused to the Drosophila immunoglobulin-binding protein signal sequence to enable secretion into the culture media. Expression levels reached 50 microg/mL culture media after 7 days of induction. The enzyme was purified to homogeneity directly from culture media by affinity chromatography on Reactive Blue 4-agarose using a step pH elution. The identity of the expressed protein was confirmed by peptide mass mapping and Western blotting. Glutaminyl cyclase was expressed as a fully active 37 kDa enzyme with kcat/Km values of 14.3, 9.3, and 2.4 mM(-1)s(-1) for the substrates Gln-Gln, Gln-NH(2), and Gln-t-butyl ester, respectively. The two cysteines were disulfide bonded, and the lone predicted glycosylation site, asparagine 49, was shown by both enzymatic deglycosylation of the expressed enzyme and site-directed mutagenesis to be glycosylated.
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Affiliation(s)
- Rachell E Booth
- Department of Chemistry and Biochemistry, University of Southern Mississippi, P.O. Box 5043, Hattiesburg, MS 39406-5043, USA
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Xu B, Michalski B, Racine RJ, Fahnestock M. Continuous infusion of neurotrophin-3 triggers sprouting, decreases the levels of TrkA and TrkC, and inhibits epileptogenesis and activity-dependent axonal growth in adult rats. Neuroscience 2003; 115:1295-308. [PMID: 12453498 DOI: 10.1016/s0306-4522(02)00384-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Neurotrophin-3 (NT-3), a member of the neurotrophin family of neurotrophic factors, is important for cell survival, axonal growth and neuronal plasticity. Epileptiform activation can regulate the expression of neurotrophins, and increases or decreases in neurotrophins can affect both epileptogenesis and seizure-related axonal growth. Interestingly, the expression of nerve growth factor and brain-derived neurotrophic factor is rapidly up-regulated following seizures, while NT-3 mRNA remains unchanged or undergoes a delayed down-regulation, suggesting that NT-3 might have a different function in epileptogenesis. In the present study, we demonstrate that continuous intraventricular infusion of NT-3 in the absence of kindling triggers mossy fiber sprouting in the inner molecular layer of the dentate gyrus and the stratum oriens of the CA3 region. Furthermore, despite this NT-3-related sprouting effect, continuous infusion of NT-3 retards the development of behavioral seizures and inhibits kindling-induced mossy fiber sprouting in the inner molecular layer of the dentate gyrus. We also show that prolonged infusion of NT-3 leads to a decrease in kindling-induced Trk phosphorylation and a down-regulation of the high-affinity Trk receptors, TrkA and TrkC, suggesting an involvement of both cholinergic nerve growth factor receptors and hippocampal NT-3 receptors in these effects. Our results demonstrate an important inhibitory role for NT-3 in seizure development and seizure-related synaptic reorganization.
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MESH Headings
- Animals
- Cell Count
- Cytochrome c Group/pharmacology
- Drug Administration Schedule
- Epilepsy/drug therapy
- Epilepsy/metabolism
- Epilepsy/physiopathology
- Growth Cones/drug effects
- Growth Cones/metabolism
- Kindling, Neurologic/drug effects
- Kindling, Neurologic/metabolism
- Male
- Molecular Weight
- Mossy Fibers, Hippocampal/drug effects
- Mossy Fibers, Hippocampal/growth & development
- Mossy Fibers, Hippocampal/metabolism
- Neuronal Plasticity/drug effects
- Neuronal Plasticity/physiology
- Neuropil/cytology
- Neuropil/drug effects
- Neurotrophin 3/metabolism
- Neurotrophin 3/pharmacology
- Phosphorylation/drug effects
- Rats
- Rats, Long-Evans
- Receptor Protein-Tyrosine Kinases/drug effects
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptor, trkA/drug effects
- Receptor, trkA/metabolism
- Receptor, trkB/drug effects
- Receptor, trkB/metabolism
- Receptor, trkC/drug effects
- Receptor, trkC/metabolism
- Seizures/drug therapy
- Seizures/metabolism
- Seizures/physiopathology
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Affiliation(s)
- B Xu
- Department of Psychology, McMaster University, L8S 4K1, Hamilton, ON, Canada
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Zarreh-Hoshyari-Khah R, Bartsch O, Einspanier A, Pohnke Y, Ivell R. Bioactivity of recombinant prorelaxin from the marmoset monkey. REGULATORY PEPTIDES 2001; 97:139-46. [PMID: 11164949 DOI: 10.1016/s0167-0115(00)00205-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The hormone relaxin (RLX) is generally present in the serum of humans and primates as a heterodimer, though some unprocessed prohormone may also be present. In order to test whether this proRLX is biologically relevant for human or primate physiology, recombinant marmoset monkey proRLX was synthesized in a baculovirus-infected cell system and tested in different bioassays. Marmoset proRLX is >70% identical to human H2 proRLX, especially in the so-called receptor-binding region of the B-peptide. The bioassay systems used were (a) cAMP production by human endometrial stromal cells and (b) cAMP production by the human monocyte cell line THP-1. In both bioassay systems recombinant proRLX showed comparable EC(50) values to pure porcine heterodimeric relaxin (porcine relaxin, 1.5-2.0 nM; marmoset prorelaxin 4.0-5.0 nM). Additionally, recombinant marmoset prorelaxin was shown to stimulate steroidogenesis in primary cultures of marmoset ovarian theca cells, though with a lower apparent activity than porcine relaxin. It thus appears that precursor processing of human or primate relaxin is not an essential prerequisite for the acquisition of bioactivity, as it is for the closely related hormone insulin, and that circulating prorelaxin is physiologically relevant.
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Affiliation(s)
- R Zarreh-Hoshyari-Khah
- Institute for Hormone and Fertility Research, University of Hamburg, Grandweg 64, 22529 Hamburg, Germany
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