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Abstract
PURPOSE OF REVIEW Preeclampsia is a common complication of pregnancy and contributes significantly to maternal and fetal morbidity and mortality. A protective hypercoagulable state is often developed during late pregnancy and can evolve into a prothrombotic state in patients with preeclampsia. The underlying mechanism of this prothrombotic transition remains poorly understood. We discuss recent progress in understanding the pathophysiology of preeclampsia and associated prothrombotic state. RECENT FINDINGS The hypercoagulable state developed during pregnancy is initiated by placental factors and progresses into the prothrombotic state in preeclampsia when the placenta is subjected ischemic and oxidative injuries. The cause of the preeclampsia-induced prothrombotic state is multifactorial, involving not only placental factors but also maternal conditions, which include genetic predisposition, preexisting medical conditions, and conditions acquired during pregnancy. Endotheliopathy is the primary pathology of preeclampsia and contributes to the prothrombotic state by inducing the dysregulation of coagulation, platelets, and adhesive ligands. SUMMARY Patients with preeclampsia often develop a severe prothrombotic state that predisposes them to life-threatening thrombosis and thromboembolism during and after pregnancy. Early recognition and treatment of this prothrombotic state can improve maternal and infant outcomes of preeclampsia patients.
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Affiliation(s)
- Chan Han
- Department of Obstetrics and Gynecology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuan-Yuan Chen
- Department of Obstetrics and Gynecology, Tianjin Medical University General Hospital, Tianjin, China
| | - Jing-fei Dong
- Bloodworks Research Institute, Seattle, WA, USA
- Division of Hematology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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Tekin A, Uzuner U, Sezen K. Homology modeling and heterologous expression of highly alkaline subtilisin-like serine protease from Bacillus halodurans C-125. Biotechnol Lett 2020; 43:479-494. [PMID: 33047274 DOI: 10.1007/s10529-020-03025-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/06/2020] [Indexed: 01/22/2023]
Abstract
Here we report heterologous expression, enzymatic characterization and structure homology modeling of a subtilisin-like alkaline serine protease (ASP) from Bacillus halodurans C-125. Encoding gene was successfully obtained by PCR and cloned into pMA0911 shuttle vector under the control of strong HpaII promoter and expressed extracellularly. ASP enzyme was successfully expressed in B. subtilis WB800 cell line lacking eight extracellular proteases and produced extracellularly in the culture medium. Km, Vmax and specific activity parameters of the recombinantly produced ASP were identified as 0.2899 mg/ml, 76.12 U/ml and 9500 U/mg, respectively. The purified enzyme revealed remarkable proteolytic activity at highly alkaline conditions with a pH optimum 12.0 and notable thermostability with temperature optimum at 60 °C. Furthermore, substrate-free enzyme revealed remarkable pH stability at pH 12.0 and maintained 93% of its initial activity when incubated at 37 °C for 24 h and 60% of its initial activity upon incubation at 60 °C for 1 h. Theoretically calculated molecular mass of ASP protein was confirmed through SDS-PAGE and western blot analysis (Mw: 28.3 kDa). The secondary and tertiary structures of ASP protein were also identified through homology modeling and further examined in detail. ASP harbors a typical S8/S53 peptidase domain comprising 17 β-sheets and 9 α-helixes within its secondary structure. The structure dynamics analysis of modeled 3D structure further revealed that transient inactivating propeptide chain is the most dynamic region of ASP enzyme with 8.52 Å2 β-Factor value. Additional residue-dependent fluctuation plot analysis also confirmed the elevated structure dynamics patterning of ASP N-terminus which could be the potential prerequisite for the autonomous propeptide removal of alkaline serine peptidases. Yet the functional domain of ASP becomes quite stable after autonomous exclusion of its propeptide. Although the sequence homology between ASP and commercial detergent additive B. lentus protease (PDB ID:1GCI) was moderate (65.4% sequence similarity), their overlaid 3D structures revealed much higher similarity (98.14%) within 0.80 Å RMSD. In conclusions, with remarkable pH stability, notable thermostability and particularly high specific activity at extreme alkaline conditions, the unveiled ASP protein stands out as a novel protease candidate for various industrial sectors such as textile, detergent, leather, feed, waste, pharmaceutical and others.
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Affiliation(s)
- Aşkın Tekin
- Department of Medical Services and Techniques, Şebinkarahisar Social Sciences Vocational School, 28400, Şebinkarahisar, Giresun, Turkey
| | - Ugur Uzuner
- Department of Molecular Biology and Genetics, Faculty of Science, Karadeniz Technical University, 61080, Trabzon, Turkey.
| | - Kazım Sezen
- Department of Biology, Faculty of Science, Karadeniz Technical University, 61080, Trabzon, Turkey
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3
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Wang N, Chang LL. Maspin suppresses cell invasion and migration in gastric cancer through inhibiting EMT and angiogenesis via ITGB1/FAK pathway. Hum Cell 2020; 33:663-675. [PMID: 32409959 DOI: 10.1007/s13577-020-00345-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/04/2020] [Indexed: 02/07/2023]
Abstract
This study aims to investigate how Maspin affects the EMT and angiogenesis of gastric cancer (GC) cells via ITGB1/FAK pathway. Immunohistochemistry was used to evaluate the expressions of Maspin, ITGB1, FAK, E-cadherin, Vimentin, D2-40, and CD34 in GC and adjacent normal tissues from 160 patients. Then, the human GC cells with different degree of differentiation were transfected with Maspin CRISPR activation plasmid, ITGB1 siRNA and/or Maspin siRNA, followed by the following experiments, including qRT-PCR, western blotting, tube formation assay, Transwell assay and wound healing. GC tumor tissues manifested decreased Maspin with the activated ITGB1/FAK pathway. In tumor tissues, Maspin was negatively correlated with the expressions of ITGB1 and FAK, as well as Lauren's classification, differentiation degree, and TNM stage. Besides, Maspin was negatively related with lymphatic vessel density (LVD) and microvessel density (MVD), Vimentin and VEGF, but was positive correlated with E-cadherin. Maspin expression decreased, but ITGB1 and p-FAK expressions increased gradually in MKN-28 (well differentiated), SGC-7901 (moderate differentiated), and MKN-45 (poorly differentiated). Maspin CRISPR and ITGB1 siRNA increased E-cadherin with the decreased Vimentin, VEGF and bFGF, and the reductions of tube length. In comparison with the ITGB1 siRNA group, cells in the Maspin siRNA + ITGB1 siRNA group presented the more evident EMT and angiogenesis. Furthermore, ITGB1 siRNA reduced the malignancies of GC cells, which could be restored by Maspin siRNA. Maspin was downregulated in GC tissues, which could inhibit the EMT and angiogenesis by blocking the ITGB1/FAK pathway, thereby decreasing cell invasion and migration of GC.
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Affiliation(s)
- Ning Wang
- Department of Gastroenterology, No. 1 Ward, ShiJiaZhuang No. 1 Hospital, No. 36, Fanxi Road, Chang'an District, Shijiazhuang, 050011, China
| | - Li-Li Chang
- Department of Gastroenterology, No. 1 Ward, ShiJiaZhuang No. 1 Hospital, No. 36, Fanxi Road, Chang'an District, Shijiazhuang, 050011, China.
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Vega MV, Nigro A, Luti S, Capitini C, Fani G, Gonnelli L, Boscaro F, Chiti F. Isolation and characterization of soluble human full‐length TDP‐43 associated with neurodegeneration. FASEB J 2019; 33:10780-10793. [DOI: 10.1096/fj.201900474r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mirella Vivoli Vega
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Alessia Nigro
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Simone Luti
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Claudia Capitini
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Leonardo Gonnelli
- Centro di Ricerca di Risonanze Magnetiche (CERM)University of FlorenceFlorenceItaly
| | | | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
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5
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Kojima C, Narita Y, Nakajima Y, Morimoto N, Yoshikawa T, Takahashi N, Handa A, Waku T, Tanaka N. Modulation of Cell Adhesion and Differentiation on Collagen Gels by the Addition of the Ovalbumin Secretory Signal Peptide. ACS Biomater Sci Eng 2019; 5:5698-5704. [DOI: 10.1021/acsbiomaterials.8b01505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Chie Kojima
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan
| | - Yuri Narita
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Gosyokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Yusuke Nakajima
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan
| | - Naoya Morimoto
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Gosyokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Takashi Yoshikawa
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Gosyokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Nobuyuki Takahashi
- Laboratory of Applied Structural Biology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Akihiro Handa
- R & D Division, Kewpie Corporation, 2-5-7 Sengawa-cho, Chofu, Tokyo, 182-0002, Japan
| | - Tomonori Waku
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Gosyokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Naoki Tanaka
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Gosyokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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6
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A comprehensive review of signal peptides: Structure, roles, and applications. Eur J Cell Biol 2018; 97:422-441. [DOI: 10.1016/j.ejcb.2018.06.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/18/2018] [Accepted: 06/18/2018] [Indexed: 01/06/2023] Open
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7
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Kojima C, Narita Y, Waku T, Morimoto N, Togawa D, Takahashi N, Handa A, Tanaka N. Ovalbumin Secretory Signal Peptide-containing Collagen Gel as a Cell Scaffold. CHEM LETT 2017. [DOI: 10.1246/cl.161039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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8
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The aggregation-prone intracellular serpin SRP-2 fails to transit the ER in Caenorhabditis elegans. Genetics 2015; 200:207-19. [PMID: 25786854 DOI: 10.1534/genetics.115.176180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/17/2015] [Indexed: 11/18/2022] Open
Abstract
Familial encephalopathy with neuroserpin inclusions bodies (FENIB) is a serpinopathy that induces a rare form of presenile dementia. Neuroserpin contains a classical signal peptide and like all extracellular serine proteinase inhibitors (serpins) is secreted via the endoplasmic reticulum (ER)-Golgi pathway. The disease phenotype is due to gain-of-function missense mutations that cause neuroserpin to misfold and aggregate within the ER. In a previous study, nematodes expressing a homologous mutation in the endogenous Caenorhabditis elegans serpin, srp-2, were reported to model the ER proteotoxicity induced by an allele of mutant neuroserpin. Our results suggest that SRP-2 lacks a classical N-terminal signal peptide and is a member of the intracellular serpin family. Using confocal imaging and an ER colocalization marker, we confirmed that GFP-tagged wild-type SRP-2 localized to the cytosol and not the ER. Similarly, the aggregation-prone SRP-2 mutant formed intracellular inclusions that localized to the cytosol. Interestingly, wild-type SRP-2, targeted to the ER by fusion to a cleavable N-terminal signal peptide, failed to be secreted and accumulated within the ER lumen. This ER retention phenotype is typical of other obligate intracellular serpins forced to translocate across the ER membrane. Neuroserpin is a secreted protein that inhibits trypsin-like proteinase. SRP-2 is a cytosolic serpin that inhibits lysosomal cysteine peptidases. We concluded that SRP-2 is neither an ortholog nor a functional homolog of neuroserpin. Furthermore, animals expressing an aggregation-prone mutation in SRP-2 do not model the ER proteotoxicity associated with FENIB.
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9
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Escherichia coli SecG is required for residual export mediated by mutant signal sequences and for SecY-SecE complex stability. J Bacteriol 2014; 197:542-52. [PMID: 25404704 DOI: 10.1128/jb.02136-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein export to the bacterial periplasm is achieved by SecYEG, an inner membrane heterotrimer. SecY and SecE are encoded by essential genes, while SecG is not essential for growth under standard laboratory conditions. Using a quantitative and sensitive export assay, we show that SecG plays a critical role for the residual export mediated by mutant signal sequences; the magnitude of this effect is not proportional to the strength of the export defect. In contrast, export mediated by wild-type signal sequences is only barely retarded in the absence of SecG. When probed with mutant signal sequences, secG loss of function mutations display a phenotype opposite to that of prlA mutations in secY. The analysis of secG and prlA single and double mutant strains shows that the increased export conferred by several prlA alleles is enhanced in the absence of SecG. Several combinations of prlA alleles with a secG deletion cannot be easily constructed. This synthetic phenotype is conditional, indicating that cells can adapt to the presence of both alleles. The biochemical basis of this phenomenon is linked to the stability of the SecYE dimer in solubilized membranes. With prlA alleles that can be normally introduced in a secG deletion strain, SecG has only a limited effect on the stability of the SecYE dimer. With the other prlA alleles, the SecYE dimer can often be detected only in the presence of SecG. A possible role for the maintenance of SecG during evolution is proposed.
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Cloning, heterologous expression and structural characterization of an alkaline serine protease from sea water haloalkaliphilic bacterium. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-014-0869-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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11
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Kawachi Y, Kameyama R, Handa A, Takahashi N, Tanaka N. Role of the N-terminal amphiphilic region of ovalbumin during heat-induced aggregation and gelation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:8668-8675. [PMID: 23909792 DOI: 10.1021/jf402456v] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Ovalbumin (OVA), a major globular protein in egg white, forms semiflexible fibrillar aggregates during heat-induced gelation. The N-terminal amphiphilic region (pN1-22) of OVA is removed after treatment with pepsin at pH 4 to leave a large OVA fragment (pOVA). The conformation and thermal stability of pOVA and OVA are similar, but the rheological strength of the heat-induced gel of pOVA is much lower compared to that of OVA. The aggregation rate of pOVA, which forms spherical aggregates, was lower than that of OVA. These results suggest that the N-terminal amphiphilic region of OVA facilitates the α-to-β conformational transition, which triggers OVA fibril formation. Heat treatment of OVA in the presence of pN1-22 consistently resulted in the formation of straight fibrils. The strength of OVA and collagen gels was increased when prepared in the presence of pN1-22, suggesting that pN1-22 may be used to control the properties of protein gels.
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Affiliation(s)
- Yuki Kawachi
- Department of Bio-molecular Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan
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12
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Goulet B, Chan G, Chambers AF, Lewis JD. An emerging role for the nuclear localization of maspin in the suppression of tumor progression and metastasis. Biochem Cell Biol 2011; 90:22-38. [PMID: 22047058 DOI: 10.1139/o11-053] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Maspin, a member of the serpin family of serine protease inhibitors, was originally identified as a tumor suppressor that is expressed in normal mammary epithelial cells but is reduced or absent in breast carcinomas. Early enthusiasm for maspin as a biomarker for disease progression has been tempered by clinical data that associates maspin with favourable outcomes in some studies and poor prognosis in others. Here, we review all of the published clinical studies for maspin in breast and ovarian cancers and propose that the apparent discordance between clinical reports is a consequence of differential cellular distribution of maspin. Indeed, it was thought that an extracellular pool of maspin possessed tumor suppressor activity, acting by inhibiting migration and increasing cell adhesion. Recent evidence from our group and others indicates, however, that the nuclear localization of maspin in cancer cells is necessary for its tumor suppressor activity. We provide additional data here to demonstrate that nuclear-localized maspin binds to chromatin and is required to effectively prevent cells from metastasizing. Our knowledge of other serpins that localize to the nucleus should help to inform future studies of nuclear maspin. Elucidation of the molecular mechanisms regulating the localization and activities of maspin should pave the way for the development of improved diagnostics and therapies for cancer.
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Affiliation(s)
- Brigitte Goulet
- London Regional Cancer Program, Translational Prostate Cancer Research Group, London, ON N6A 4L6, Canada
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13
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Teoh SSY, Whisstock JC, Bird PI. Maspin (SERPINB5) is an obligate intracellular serpin. J Biol Chem 2010; 285:10862-9. [PMID: 20123984 DOI: 10.1074/jbc.m109.073171] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Maspin (SERPINB5) is a tumor suppressor lost in breast and prostate cancer whose molecular function is unknown. It is a non-inhibitory member of the clade B serpins suggested to play a role in a plethora of intracellular and extracellular settings, yet its normal cellular distribution has never been clarified. Here we investigate the distribution of maspin in non-transformed human epithelial cells. By indirect immunofluorescence, maspin has a nucleocytoplasmic distribution in breast (MCF10A) and prostate (RWPE-1) cells and, by immunoblotting and pulse-chase analyses, is neither glycosylated nor secreted. Cell surface biotinylation studies also show that maspin is not present at the cell surface. Differentiation of MCF10A cells into three-dimensional acini results in the redistribution of maspin from the nucleus to the cytoplasm but does not result in secretion. Addition of an efficient conventional signal peptide to maspin directs it into the secretory pathway and results in glycosylation but not secretion. We further show that maspin in the cytoplasm of MCF10A cells is a soluble monomeric protein that is not detectably associated with the cytoskeleton or other extractable components. Taken together, these results suggest that maspin is restricted to an intracellular, possibly nuclear, role in which it influences cell-matrix interactions indirectly. It is probably released only as a consequence of cell damage or necrosis.
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Affiliation(s)
- Sonia S Y Teoh
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Victoria 3800, Australia
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14
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Abstract
General protein export requires the cooperation of two elements, the Sec translocase and a signal sequence. The interactions of both wild type and mutant components can be studied in vivo using a number of genetic systems. Signal sequence mutations that prevent export have been characterized ("down mutations"). Suppressors of these signal sequence mutations, known as prl mutations, have been isolated in most sec genes. More recently, inactive N-terminal regions of cytoplasmic proteins were converted into active signal sequences ("up mutations").Alkaline phosphatase (PhoA), an enzyme only active after export to the periplasm, provides the best and most versatile quantitative reporter for protein translocation studies. Cleavable signal sequences can be used to monitor protein export in a time frame of 15-120 s. Chimeric proteins expressed from an inducible promoter can be used to measure kinetics of enzyme accumulation in a time frame of 10-100 min. Finally, the export activity of PhoA-chimeras can be visualized in a semi-quantitative way by staining colonies growing on Petri dishes with a chromogenic substrate, in the time frame of 10-40 h.
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Affiliation(s)
- Dominique Belin
- Department of Pathology and Immunology, University Medical Center, University of Geneva, Geneva, Switzerland
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15
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Stephenson K. Sec-dependent protein translocation across biological membranes: evolutionary conservation of an essential protein transport pathway (Review). Mol Membr Biol 2009; 22:17-28. [PMID: 16092521 DOI: 10.1080/09687860500063308] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
All living organisms, no matter how simple or complex, possess the ability to translocate proteins across biological membranes and into different cellular compartments. Although a range of membrane transport processes exist, the major pathway used to translocate proteins across the bacterial cytoplasmic membrane or the eukaryotic endoplasmic reticulum membrane is conserved and is known as the Sec or Sec61 pathway, respectively. Over the past two decades the Sec and Sec61 pathways have been studied extensively and are well characterised at the genetic and biochemical levels. However, it is only now with the recent structural determination of a number of the key elements of the pathways that the translocation complex is beginning to give up its secrets in exquisite molecular detail. This article will focus on the routes of Sec- and Sec61-dependent membrane targeting and the nature of the translocation channel in bacteria and eukaryotes.
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Affiliation(s)
- Keith Stephenson
- School of Biochemistry and Microbiology, Leeds University, Leeds, UK.
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16
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Rajalahti T, Huang F, Klement MR, Pisareva T, Edman M, Sjöström M, Wieslander A, Norling B. Proteins in different Synechocystis compartments have distinguishing N-terminal features: a combined proteomics and multivariate sequence analysis. J Proteome Res 2007; 6:2420-34. [PMID: 17508731 DOI: 10.1021/pr0605973] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyanobacteria have a cell envelope consisting of a plasma membrane, a periplasmic space with a peptidoglycan layer, and an outer membrane. A third, separate membrane system, the intracellular thylakoid membranes, is the site for both photosynthesis and respiration. All membranes and luminal spaces have unique protein compositions, which impose an intriguing mechanism for protein sorting of extracytoplasmic proteins due to single sets of translocation protein genes. It is shown here by multivariate sequence analyses of many experimentally identified proteins in Synechocystis, that proteins routed for the different extracytosolic compartments have correspondingly different physicochemical properties in their signal peptide and mature N-terminal segments. The full-length mature sequences contain less significant information. From these multivariate, N-terminal property-profile models for proteins with single experimental localization, proteins with ambiguous localization could, to a large extent, be predicted to a defined compartment. The sequence properties involve amino acids varying especially in volume and polarizability and at certain positions in the sequence segments, in a manner typical for the various compartment classes. Potential means of the cell to recognize the property features are discussed, involving the translocation channels and two Type I signal peptidases with different cellular localization, and charge features at their membrane interfaces.
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Affiliation(s)
- Tarja Rajalahti
- Department of Chemistry, University of Bergen, Bergen, Norway
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Bieler S, Silva F, Soto C, Belin D. Bactericidal activity of both secreted and nonsecreted microcin E492 requires the mannose permease. J Bacteriol 2006; 188:7049-61. [PMID: 17015644 PMCID: PMC1636244 DOI: 10.1128/jb.00688-06] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microcin E492 (MccE492) is a bactericidal protein secreted by Klebsiella pneumoniae that is active against various species of Enterobacteriaceae. Interaction of MccE492 with target cells leads to the depolarization and permeabilization of their inner membranes. Several MccE492-specific proteins are required for the maturation and secretion of active MccE492. Surprisingly, the expression of only MceA, the polypeptide backbone of MccE492, is shown here to be toxic by itself. We refer to this phenomenon as endogenous MceA bactericidal activity to differentiate it from the action of extracellularly secreted MccE492. The toxicity of endogenous MceA is enhanced by an efficient targeting to the inner membrane. However, a periplasmic intermediate state is not required for MceA toxicity. Indeed, endogenous MceA remains fully active when it is fused to thioredoxin-1, a fast-folding protein that promotes retention of the C terminus of MceA in the cytoplasm. The C-terminal domain of MccE492 is required only for delivery from the extracellular environment to the periplasm, and it is not required for inner membrane damage. A common component is absolutely essential for the bactericidal activity of both endogenous MceA and extracellular MccE492. Indeed, toxicity is strictly dependent on the presence of ManYZ, an inner membrane protein complex involved in mannose uptake. Based on these findings, we propose a new model for cell entry, inner membrane insertion, and toxic activity of MccE492.
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Affiliation(s)
- Sylvain Bieler
- Department of Pathology and Immunology, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland
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18
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Buggiotti L, Primmer CR. Molecular evolution of the avian growth hormone gene and comparison with its mammalian counterpart. J Evol Biol 2006; 19:844-54. [PMID: 16674581 DOI: 10.1111/j.1420-9101.2005.01042.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The molecular evolution of all available avian growth hormone (GH) gene sequences was investigated using both maximum-likelihood and parsimony methods, and the patterns compared to those found in mammals. In contrast to the rapid bursts of evolution observed for mammalian GH, the evolutionary rate of the avian GH mature peptide appears to have been more constant. However several positively selected sites were identified at functionally important positions in the avian signal peptide by the site-specific likelihood method. This implies that sequence variation in the avian GH signal peptide may be adaptive, although more conservative parsimony methods failed to confirm this. Nevertheless, the differing patterns of avian and mammalian GH signal peptide molecular evolution are consistent with the apparently differing roles of GH in controlling growth in these taxonomic groups and support the hypothesis that signal peptide sequence variation may in fact be the basis for increased functional complexity.
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Affiliation(s)
- L Buggiotti
- Division of Genetics and Physiology, Department of Biology, University of Turku, Turku, Finland
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Pearson MS, McManus DP, Smyth DJ, Lewis FA, Loukas A. In vitro and in silico analysis of signal peptides from the human blood fluke,Schistosoma mansoni. ACTA ACUST UNITED AC 2005; 45:201-11. [PMID: 16051070 DOI: 10.1016/j.femsim.2005.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 03/14/2005] [Accepted: 03/25/2005] [Indexed: 01/28/2023]
Abstract
Proteins secreted by and anchored on the surfaces of parasites are in intimate contact with host tissues. The transcriptome of infective cercariae of the blood fluke, Schistosoma mansoni, was screened using signal sequence trap to isolate cDNAs encoding predicted proteins with an N-terminal signal peptide. Twenty cDNA fragments were identified, most of which contained predicted signal peptides or transmembrane regions, including a novel putative seven-transmembrane receptor and a membrane-associated mitogen-activated protein kinase. The developmental expression pattern within different life-cycle stages ranged from ubiquitous to a transcript that was highly upregulated in the cercaria. A bioinformatics-based comparison of 100 signal peptides from each of schistosomes, humans, a parasitic nematode and Escherichia coli showed that differences in the sequence composition of signal peptides, notably the residues flanking the predicted cleavage site, might account for the negative bias exhibited in the processing of schistosome signal peptides in mammalian cells.
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Affiliation(s)
- Mark S Pearson
- Division of Infectious Diseases and Immunology, Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research and The University of Queensland, 300 Herston Road, Brisbane, QLD 4006, Australia
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Mergulhão FJM, Summers DK, Monteiro GA. Recombinant protein secretion in Escherichia coli. Biotechnol Adv 2005; 23:177-202. [PMID: 15763404 DOI: 10.1016/j.biotechadv.2004.11.003] [Citation(s) in RCA: 334] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/23/2004] [Accepted: 11/30/2004] [Indexed: 10/25/2022]
Abstract
The secretory production of recombinant proteins by the Gram-negative bacterium Escherichia coli has several advantages over intracellular production as inclusion bodies. In most cases, targeting protein to the periplasmic space or to the culture medium facilitates downstream processing, folding, and in vivo stability, enabling the production of soluble and biologically active proteins at a reduced process cost. This review presents several strategies that can be used for recombinant protein secretion in E. coli and discusses their advantages and limitations depending on the characteristics of the target protein to be produced.
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Affiliation(s)
- F J M Mergulhão
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, Lisbon 1049-001, Portugal.
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