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Khan I, Krishnaswamy S, Sabale M, Groth D, Wijaya L, Morici M, Berger I, Schaffitzel C, Fraser PE, Martins RN, Verdile G. Efficient production of a mature and functional gamma secretase protease. Sci Rep 2018; 8:12834. [PMID: 30150752 PMCID: PMC6110731 DOI: 10.1038/s41598-018-30788-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/06/2018] [Indexed: 12/27/2022] Open
Abstract
Baculoviral protein expression in insect cells has been previously used to generate large quantities of a protein of interest for subsequent use in biochemical and structural analyses. The MultiBac baculovirus protein expression system has enabled, the use of a single baculovirus to reconstitute a protein complex of interest, resulting in a larger protein yield. Using this system, we aimed to reconstruct the gamma (γ)-secretase complex, a multiprotein enzyme complex essential for the production of amyloid-β (Aβ) protein. A MultiBac vector containing all components of the γ-secretase complex was generated and expression was observed for all components. The complex was active in processing APP and Notch derived γ-secretase substrates and proteolysis could be inhibited with γ-secretase inhibitors, confirming specificity of the recombinant γ-secretase enzyme. Finally, affinity purification was used to purify an active recombinant γ-secretase complex. In this study we demonstrated that the MultiBac protein expression system can be used to generate an active γ-secretase complex and provides a new tool to study γ-secretase enzyme and its variants.
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Affiliation(s)
- Imran Khan
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia. .,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia. .,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
| | - Sudarsan Krishnaswamy
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Miheer Sabale
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - David Groth
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Linda Wijaya
- Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,School of Psychology and Exercise Sciences, Murdoch University, Murdoch, Western Australia, Australia
| | - Michael Morici
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Imre Berger
- European Molecular Biology Laboratories, Grenoble, France.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Christiane Schaffitzel
- European Molecular Biology Laboratories, Grenoble, France.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Paul E Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Medical Biophysics, Krembil Discovery Tower, University of Toronto, Toronto, Ontario, Canada
| | - Ralph N Martins
- School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Giuseppe Verdile
- School of Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia. .,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, Western Australia, Australia. .,Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.
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Barron AM, Cake M, Verdile G, Martins RN. Ovariectomy and 17beta-estradiol replacement do not alter beta-amyloid levels in sheep brain. Endocrinology 2009; 150:3228-36. [PMID: 19282379 PMCID: PMC2703524 DOI: 10.1210/en.2008-1252] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 03/03/2009] [Indexed: 11/19/2022]
Abstract
The benefits of estrogen replacement as a preventative treatment for Alzheimer's disease (AD) are subject to debate. Because the effects of estrogen depletion and replacement on accumulation of the neurotoxic beta-amyloid (A beta) peptide in transgenic animal models of AD have been variable, we examined A beta levels and oxidative stress in a nontransgenic animal model. Sheep have traditionally been used as a model for human reproduction; however because they share 100% sequence homology with the human form of A beta, they may also have potential as a nontransgenic model for A beta biology. The effect of ovariectomy and estrogen replacement administered for 6 months via slow-release implant was examined in the brain of 4.5-yr-old sheep. A beta levels were measured by ELISA, and protein levels of the amyloid precursor protein (APP), APP C-terminal fragments (C100), and presenilin-1 were examined semiquantitatively by Western blot as markers of APP processing. Markers of oxidative stress were examined semiquantitatively by Western blot [4-hydroxy-2(E)-nonenal] and oxyblot (protein carbonyls). We found no effects of estrogen depletion and supplementation in terms of AD-related biochemical markers, including A beta levels, APP processing, and oxidative stress levels. Evidence of a trend toward increased P450 side-chain cleavage enzyme levels in the hippocampus of ovariectomized and estrogen supplemented sheep suggests that neurosteroidogenesis may compensate for gonadal estrogen depletion; however, these findings cannot explain the lack of effect of estrogen supplementation on APP processing. It is possible that supraphysiological doses of estrogen are necessary to yield antiamyloidogenic and antioxidative benefits in ovariectomized sheep.
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Affiliation(s)
- A M Barron
- School of Psychiatry and Clinical Neurosciences, The University of Western Australia, Nedlands, Australia
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Kato T, Park EY. Specific expression of GFPuv-β1,3-N-acetylglucosaminyltransferase 2 fusion protein in fat body of Bombyx mori silkworm larvae using signal peptide. Biochem Biophys Res Commun 2007; 359:543-8. [PMID: 17544364 DOI: 10.1016/j.bbrc.2007.05.137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Accepted: 05/18/2007] [Indexed: 10/23/2022]
Abstract
Bombyxin (bx) and prophenoloxidase-activating enzyme (ppae) signal peptides from Bombyx mori, their modified signal peptides, and synthetic signal peptides were investigated for the secretion of GFP(uv)-beta1,3-N-acetylglucosaminyltransferase 2 (GGT2) fusion protein in B. mori Bm5 cells and silkworm larvae using cysteine protease deficient B. mori multiple nucleopolyhedrovirus (BmMNPV-CP(-)) and its bacmid. The secretion efficiencies of all signal peptides were 15-30% in Bm5 cells and 24-30% in silkworm larvae, while that of the +16 signal peptide was 0% in Bm5 cells and 1% in silkworm larvae. The fusion protein that contained the +16 signal peptide was expressed specifically in the endoplasmic reticulum (ER) and in the fractions of cell precipitations. Ninety-four percent of total intracellular beta1,3-N-acetylglucosaminyltransferase (beta3GnT) activity was detected in cell precipitations following the 600, 8000, and 114,000g centrifugations. In the case of the +38 signal peptide, 60% of total intracellular activity was detected in the supernatant from the 114,000g spin, and only 1% was found in the precipitate. Our results suggest that the +16 signal peptide might be situated in the transmembrane region and not cleaved by signal peptidase in silkworm or B. mori cells. Therefore, the fusion protein connected to the +16 signal peptide stayed in the fat body of silkworm larvae with biological function, and was not secreted extracellularly.
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Affiliation(s)
- Tatsuya Kato
- Laboratory of Biotechnology, Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan
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