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Jiang H, Milanov M, Jüngert G, Angebauer L, Flender C, Smudde E, Gather F, Vogel T, Jessen HJ, Koch HG. Control of a chemical chaperone by a universally conserved ATPase. iScience 2024; 27:110215. [PMID: 38993675 PMCID: PMC11237923 DOI: 10.1016/j.isci.2024.110215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/16/2024] [Accepted: 06/05/2024] [Indexed: 07/13/2024] Open
Abstract
The universally conserved YchF/Ola1 ATPases regulate stress response pathways in prokaryotes and eukaryotes. Deletion of YchF/Ola1 leads to increased resistance against environmental stressors, such as reactive oxygen species, while their upregulation is associated with tumorigenesis in humans. The current study shows that in E. coli, the absence of YchF stimulates the synthesis of the alternative sigma factor RpoS by a transcription-independent mechanism. Elevated levels of RpoS then enhance the transcription of major stress-responsive genes. In addition, the deletion of ychF increases the levels of polyphosphate kinase, which in turn boosts the production of the evolutionary conserved and ancient chemical chaperone polyphosphate. This potentially provides a unifying concept for the increased stress resistance in bacteria and eukaryotes upon YchF/Ola1 deletion. Intriguingly, the simultaneous deletion of ychF and the polyphosphate-degrading enzyme exopolyphosphatase causes synthetic lethality in E. coli, demonstrating that polyphosphate production needs to be fine-tuned to prevent toxicity.
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Affiliation(s)
- Hong Jiang
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs University Freiburg, 79104 Freiburg, Germany
| | - Martin Milanov
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs University Freiburg, 79104 Freiburg, Germany
| | - Gabriela Jüngert
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Larissa Angebauer
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Clara Flender
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Eva Smudde
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Fabian Gather
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Tanja Vogel
- Institute for Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Henning J. Jessen
- Institute for Organic Chemistry, Faculty of Chemistry and Pharmacy, University Freiburg 79104 Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
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Toth R, Ilic AM, Huettel B, Duduk B, Kube M. Divergence within the Taxon ' Candidatus Phytoplasma asteris' Confirmed by Comparative Genome Analysis of Carrot Strains. Microorganisms 2024; 12:1016. [PMID: 38792845 PMCID: PMC11123874 DOI: 10.3390/microorganisms12051016] [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: 03/19/2024] [Revised: 04/30/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Phytoplasmas are linked to diseases in hundreds of economically important crops, including carrots. In carrots, phytoplasmosis is associated with leaf chlorosis and necrosis, coupled with inhibited root system development, ultimately leading to significant economic losses. During a field study conducted in Baden-Württemberg (Germany), two strains of the provisional taxon 'Candidatus Phytoplasma asteris' were identified within a carrot plot. For further analysis, strains M8 and M33 underwent shotgun sequencing, utilising single-molecule-real-time (SMRT) long-read sequencing and sequencing-by-synthesis (SBS) paired-end short-read sequencing techniques. Hybrid assemblies resulted in complete de novo assemblies of two genomes harboring circular chromosomes and two plasmids. Analyses, including average nucleotide identity and sequence comparisons of established marker genes, confirmed the phylogenetic divergence of 'Ca. P. asteris' and a different assignment of strains to the 16S rRNA subgroup I-A for M33 and I-B for M8. These groups exhibited unique features, encompassing virulence factors and genes, associated with the mobilome. In contrast, pan-genome analysis revealed a highly conserved gene set related to metabolism across these strains. This analysis of the Aster Yellows (AY) group reaffirms the perception of phytoplasmas as bacteria that have undergone extensive genome reduction during their co-evolution with the host and an increase of genome size by mobilome.
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Affiliation(s)
- Rafael Toth
- Department of Integrative Infection Biology Crops-Livestock, University of Hohenheim, 70599 Stuttgart, Germany; (R.T.); (A.-M.I.)
| | - Anna-Marie Ilic
- Department of Integrative Infection Biology Crops-Livestock, University of Hohenheim, 70599 Stuttgart, Germany; (R.T.); (A.-M.I.)
| | | | - Bojan Duduk
- Institute of Pesticides and Environmental Protection, 11080 Belgrade, Serbia;
| | - Michael Kube
- Department of Integrative Infection Biology Crops-Livestock, University of Hohenheim, 70599 Stuttgart, Germany; (R.T.); (A.-M.I.)
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3
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Osawa T, Fujikawa K, Shimamoto K. Structures, functions, and syntheses of glycero-glycophospholipids. Front Chem 2024; 12:1353688. [PMID: 38389730 PMCID: PMC10881803 DOI: 10.3389/fchem.2024.1353688] [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: 12/11/2023] [Accepted: 01/24/2024] [Indexed: 02/24/2024] Open
Abstract
Biological membranes consist of integral and peripheral protein-associated lipid bilayers. Although constituent lipids vary among cells, membrane lipids are mainly classified as phospholipids, glycolipids, and sterols. Phospholipids are further divided into glycerophospholipids and sphingophospholipids, whereas glycolipids are further classified as glyceroglycolipids and sphingoglycolipids. Both glycerophospholipids and glyceroglycolipids contain diacylglycerol as the common backbone, but their head groups differ. Most glycerolipids have polar head groups containing phosphate esters or sugar moieties. However, trace components termed glycero-glycophospholipids, each possessing both a phosphate ester and a sugar moiety, exist in membranes. Recently, the unique biological activities of glycero-glycophospholipids have attracted considerable attention. In this review, we describe the structure, distribution, function, biosynthesis, and chemical synthetic approaches of representative glycero-glycophospholipids-phosphatidylglucoside (PtdGlc) and enterobacterial common antigen (ECA). In addition, we introduce our recent studies on the rare glycero-glyco"pyrophospho"lipid, membrane protein integrase (MPIase), which is involved in protein translocation across biomembranes.
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Affiliation(s)
- Tsukiho Osawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan
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4
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Njenga R, Boele J, Öztürk Y, Koch HG. Coping with stress: How bacteria fine-tune protein synthesis and protein transport. J Biol Chem 2023; 299:105163. [PMID: 37586589 PMCID: PMC10502375 DOI: 10.1016/j.jbc.2023.105163] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Maintaining a functional proteome under different environmental conditions is challenging for every organism, in particular for unicellular organisms, such as bacteria. In order to cope with changing environments and stress conditions, bacteria depend on strictly coordinated proteostasis networks that control protein production, folding, trafficking, and degradation. Regulation of ribosome biogenesis and protein synthesis are cornerstones of this cellular adaptation in all domains of life, which is rationalized by the high energy demand of both processes and the increased resistance of translationally silent cells against internal or external poisons. Reduced protein synthesis ultimately also reduces the substrate load for protein transport systems, which are required for maintaining the periplasmic, inner, and outer membrane subproteomes. Consequences of impaired protein transport have been analyzed in several studies and generally induce a multifaceted response that includes the upregulation of chaperones and proteases and the simultaneous downregulation of protein synthesis. In contrast, generally less is known on how bacteria adjust the protein targeting and transport machineries to reduced protein synthesis, e.g., when cells encounter stress conditions or face nutrient deprivation. In the current review, which is mainly focused on studies using Escherichia coli as a model organism, we summarize basic concepts on how ribosome biogenesis and activity are regulated under stress conditions. In addition, we highlight some recent developments on how stress conditions directly impair protein targeting to the bacterial membrane. Finally, we describe mechanisms that allow bacteria to maintain the transport of stress-responsive proteins under conditions when the canonical protein targeting pathways are impaired.
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Affiliation(s)
- Robert Njenga
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany; Faculty of Biology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Julian Boele
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany.
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Metabolic Sensing of Extracytoplasmic Copper Availability via Translational Control by a Nascent Exported Protein. mBio 2023; 14:e0304022. [PMID: 36598193 PMCID: PMC9973294 DOI: 10.1128/mbio.03040-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Metabolic sensing is a crucial prerequisite for cells to adjust their physiology to rapidly changing environments. In bacteria, the response to intra- and extracellular ligands is primarily controlled by transcriptional regulators, which activate or repress gene expression to ensure metabolic acclimation. Translational control, such as ribosomal stalling, can also contribute to cellular acclimation and has been shown to mediate responses to changing intracellular molecules. In the current study, we demonstrate that the cotranslational export of the Rhodobacter capsulatus protein CutF regulates the translation of the downstream cutO-encoded multicopper oxidase CutO in response to extracellular copper (Cu). Our data show that CutF, acting as a Cu sensor, is cotranslationally exported by the signal recognition particle pathway. The binding of Cu to the periplasmically exposed Cu-binding motif of CutF delays its cotranslational export via its C-terminal ribosome stalling-like motif. This allows for the unfolding of an mRNA stem-loop sequence that shields the ribosome-binding site of cutO, which favors its subsequent translation. Bioinformatic analyses reveal that CutF-like proteins are widely distributed in bacteria and are often located upstream of genes involved in transition metal homeostasis. Our overall findings illustrate a highly conserved control mechanism using the cotranslational export of a protein acting as a sensor to integrate the changing availability of extracellular nutrients into metabolic acclimation. IMPORTANCE Metabolite sensing is a fundamental biological process, and the perception of dynamic changes in the extracellular environment is of paramount importance for the survival of organisms. Bacteria usually adjust their metabolisms to changing environments via transcriptional regulation. Here, using Rhodobacter capsulatus, we describe an alternative translational mechanism that controls the bacterial response to the presence of copper, a toxic micronutrient. This mechanism involves a cotranslationally secreted protein that, in the presence of copper, undergoes a process resembling ribosomal stalling. This allows for the unfolding of a downstream mRNA stem-loop and enables the translation of the adjacent Cu-detoxifying multicopper oxidase. Bioinformatic analyses reveal that such proteins are widespread, suggesting that metabolic sensing using ribosome-arrested nascent secreted proteins acting as sensors may be a common strategy for the integration of environmental signals into metabolic adaptations.
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6
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Sarmah P, Shang W, Origi A, Licheva M, Kraft C, Ulbrich M, Lichtenberg E, Wilde A, Koch HG. mRNA targeting eliminates the need for the signal recognition particle during membrane protein insertion in bacteria. Cell Rep 2023; 42:112140. [PMID: 36842086 PMCID: PMC10066597 DOI: 10.1016/j.celrep.2023.112140] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 01/10/2023] [Accepted: 02/02/2023] [Indexed: 02/26/2023] Open
Abstract
Signal-sequence-dependent protein targeting is essential for the spatiotemporal organization of eukaryotic and prokaryotic cells and is facilitated by dedicated protein targeting factors such as the signal recognition particle (SRP). However, targeting signals are not exclusively contained within proteins but can also be present within mRNAs. By in vivo and in vitro assays, we show that mRNA targeting is controlled by the nucleotide content and by secondary structures within mRNAs. mRNA binding to bacterial membranes occurs independently of soluble targeting factors but is dependent on the SecYEG translocon and YidC. Importantly, membrane insertion of proteins translated from membrane-bound mRNAs occurs independently of the SRP pathway, while the latter is strictly required for proteins translated from cytosolic mRNAs. In summary, our data indicate that mRNA targeting acts in parallel to the canonical SRP-dependent protein targeting and serves as an alternative strategy for safeguarding membrane protein insertion when the SRP pathway is compromised.
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Affiliation(s)
- Pinku Sarmah
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Wenkang Shang
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University Freiburg, 79104 Freiburg, Germany
| | - Maximilian Ulbrich
- Internal Medicine IV, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | | | - Annegret Wilde
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.
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7
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Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp. Nat Commun 2022; 13:1069. [PMID: 35217658 PMCID: PMC8881573 DOI: 10.1038/s41467-022-28675-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 02/07/2022] [Indexed: 11/08/2022] Open
Abstract
The stringent response enables bacteria to respond to nutrient limitation and other stress conditions through production of the nucleotide-based second messengers ppGpp and pppGpp, collectively known as (p)ppGpp. Here, we report that (p)ppGpp inhibits the signal recognition particle (SRP)-dependent protein targeting pathway, which is essential for membrane protein biogenesis and protein secretion. More specifically, (p)ppGpp binds to the SRP GTPases Ffh and FtsY, and inhibits the formation of the SRP receptor-targeting complex, which is central for the coordinated binding of the translating ribosome to the SecYEG translocon. Cryo-EM analysis of SRP bound to translating ribosomes suggests that (p)ppGpp may induce a distinct conformational stabilization of the NG domain of Ffh and FtsY in Bacillus subtilis but not in E. coli. Bacterial responses to nutrient limitation and other stress conditions are often modulated by the nucleotide-based second messenger (p)ppGpp. Here, the authors show that (p)ppGpp inhibits the SRP membrane-protein insertion and secretion pathway by binding to GTPases Ffh and FtsY.
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8
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Fujikawa K, Mori S, Nishiyama KI, Shimamoto K. A bacterial glycolipid essential for membrane protein integration. Adv Carbohydr Chem Biochem 2022; 81:95-129. [DOI: 10.1016/bs.accb.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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9
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Endo Y, Shimizu Y, Nishikawa H, Sawasato K, Nishiyama KI. Interplay between MPIase, YidC, and PMF during Sec-independent insertion of membrane proteins. Life Sci Alliance 2021; 5:5/1/e202101162. [PMID: 34642230 PMCID: PMC8548208 DOI: 10.26508/lsa.202101162] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 11/24/2022] Open
Abstract
Charges in the N-terminal region and the synthesis level of membrane proteins with N-out topology determine YidC and PMF dependencies with the interplay between glycolipid MPIase, YidC, and PMF. Integral membrane proteins with the N-out topology are inserted into membranes usually in YidC- and PMF-dependent manners. The molecular basis of the various dependencies on insertion factors is not fully understood. A model protein, Pf3-Lep, is inserted independently of both YidC and PMF, whereas the V15D mutant requires both YidC and PMF in vivo. We analyzed the mechanisms that determine the insertion factor dependency in vitro. Glycolipid MPIase was required for insertion of both proteins because MPIase depletion caused a significant defect in insertion. On the other hand, YidC depletion and PMF dissipation had no effects on Pf3-Lep insertion, whereas V15D insertion was reduced. We reconstituted (proteo)liposomes containing MPIase, YidC, and/or F0F1-ATPase. MPIase was essential for insertion of both proteins. YidC and PMF stimulated Pf3-Lep insertion as the synthesis level increased. V15D insertion was stimulated by both YidC and PMF irrespective of the synthesis level. These results indicate that charges in the N-terminal region and the synthesis level are the determinants of YidC and PMF dependencies with the interplay between MPIase, YidC, and PMF.
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Affiliation(s)
- Yuta Endo
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan
| | - Yuko Shimizu
- Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Hanako Nishikawa
- Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Katsuhiro Sawasato
- Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Ken-Ichi Nishiyama
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan .,Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan
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10
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Öztürk Y, Blaby-Haas CE, Daum N, Andrei A, Rauch J, Daldal F, Koch HG. Maturation of Rhodobacter capsulatus Multicopper Oxidase CutO Depends on the CopA Copper Efflux Pathway and Requires the cutF Product. Front Microbiol 2021; 12:720644. [PMID: 34566924 PMCID: PMC8456105 DOI: 10.3389/fmicb.2021.720644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/18/2021] [Indexed: 11/15/2022] Open
Abstract
Copper (Cu) is an essential cofactor required for redox enzymes in all domains of life. Because of its toxicity, tightly controlled mechanisms ensure Cu delivery for cuproenzyme biogenesis and simultaneously protect cells against toxic Cu. Many Gram-negative bacteria contain extracytoplasmic multicopper oxidases (MCOs), which are involved in periplasmic Cu detoxification. MCOs are unique cuproenzymes because their catalytic center contains multiple Cu atoms, which are required for the oxidation of Cu1+ to the less toxic Cu2+. Hence, Cu is both substrate and essential cofactor of MCOs. Here, we investigated the maturation of Rhodobacter capsulatus MCO CutO and its role in periplasmic Cu detoxification. A survey of CutO activity of R. capsulatus mutants with known defects in Cu homeostasis and in the maturation of the cuproprotein cbb 3-type cytochrome oxidase (cbb 3-Cox) was performed. This revealed that CutO activity is largely independent of the Cu-delivery pathway for cbb 3-Cox biogenesis, except for the cupric reductase CcoG, which is required for full CutO activity. The most pronounced decrease of CutO activity was observed with strains lacking the cytoplasmic Cu chaperone CopZ, or the Cu-exporting ATPase CopA, indicating that CutO maturation is linked to the CopZ-CopA mediated Cu-detoxification pathway. Our data demonstrate that CutO is important for cellular Cu resistance under both aerobic and anaerobic growth conditions. CutO is encoded in the cutFOG operon, but only CutF, and not CutG, is essential for CutO activity. No CutO activity is detectable when cutF or its putative Cu-binding motif are mutated, suggesting that the cutF product serves as a Cu-binding component required for active CutO production. Bioinformatic analyses of CutF-like proteins support their widespread roles as putative Cu-binding proteins for several Cu-relay pathways. Our overall findings show that the cytoplasmic CopZ-CopA dependent Cu detoxification pathway contributes to providing Cu to CutO maturation, a process that strictly relies on cutF.
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Affiliation(s)
- Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Crysten E. Blaby-Haas
- Biology Department, Brookhaven National Laboratory, Upton, NY, United States
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Noel Daum
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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Sekiya Y, Sawasato K, Nishiyama KI. Expression of Cds4/5 of Arabidopsis chloroplasts in E. coli reveals the membrane topology of the C-terminal region of CDP-diacylglycerol synthases. Genes Cells 2021; 26:727-738. [PMID: 34166546 DOI: 10.1111/gtc.12880] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022]
Abstract
CDP-diacylglycerol synthases (Cds) are conserved from bacteria to eukaryotes. Bacterial CdsA is involved not only in phospholipid biosynthesis but also in biosynthesis of glycolipid MPIase, an essential glycolipid that catalyzes membrane protein integration. We found that both Cds4 and Cds5 of Arabidopsis chloroplasts complement cdsA knockout by supporting both phospholipid and MPIase biosyntheses. Comparison of the sequences of CdsA and Cds4/5 suggests a difference in membrane topology at the C-termini, since the region assigned as the last transmembrane region of CdsA, which follows the conserved cytoplasmic domain, is missing in Cds4/5. Deletion of the C-terminal region abolished the function, indicating the importance of the region. Both 6 × His tag attachment to CdsA and substitution of the C-terminal 6 residues with 6 × His did not affect the function. These 6 × His tags were sensitive to protease added from the cytosolic side in vitro, indicating that this region is not a transmembrane one but forms a membrane-embedded reentrant loop. Thus, the C-terminal region of Cds homologues forms a reentrant loop, of which structure is important for the Cds function.
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Affiliation(s)
- Yusei Sekiya
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Katsuhiro Sawasato
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Ken-Ichi Nishiyama
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
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12
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Landwehr V, Milanov M, Angebauer L, Hong J, Jüngert G, Hiersemenzel A, Siebler A, Schmit F, Öztürk Y, Dannenmaier S, Drepper F, Warscheid B, Koch HG. The Universally Conserved ATPase YchF Regulates Translation of Leaderless mRNA in Response to Stress Conditions. Front Mol Biosci 2021; 8:643696. [PMID: 34026826 PMCID: PMC8138138 DOI: 10.3389/fmolb.2021.643696] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/13/2021] [Indexed: 12/14/2022] Open
Abstract
The universally conserved P-loop GTPases control diverse cellular processes, like signal transduction, ribosome assembly, cell motility, and intracellular transport and translation. YchF belongs to the Obg-family of P-loop GTPases and is one of the least characterized member of this family. It is unique because it preferentially hydrolyses ATP rather than GTP, but its physiological role is largely unknown. Studies in different organisms including humans suggest a possible role of YchF in regulating the cellular adaptation to stress conditions. In the current study, we explored the role of YchF in the model organism Escherichia coli. By western blot and promoter fusion experiments, we demonstrate that YchF levels decrease during stress conditions or when cells enter stationary phase. The decline in YchF levels trigger increased stress resistance and cells lacking YchF are resistant to multiple stress conditions, like oxidative stress, replication stress, or translational stress. By in vivo site directed cross-linking we demonstrate that YchF interacts with the translation initiation factor 3 (IF3) and with multiple ribosomal proteins at the surface of the small ribosomal subunit. The absence of YchF enhances the anti-association activity of IF3, stimulates the translation of leaderless mRNAs, and increases the resistance against the endoribonuclease MazF, which generates leaderless mRNAs during stress conditions. In summary, our data identify YchF as a stress-responsive regulator of leaderless mRNA translation.
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Affiliation(s)
- Victoria Landwehr
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Martin Milanov
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Larissa Angebauer
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Jiang Hong
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Gabriela Jüngert
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Anna Hiersemenzel
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Ariane Siebler
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fränk Schmit
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Stefan Dannenmaier
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Friedel Drepper
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Signalling Research Centers BIOSS and CIBSS, University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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13
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Oswald J, Njenga R, Natriashvili A, Sarmah P, Koch HG. The Dynamic SecYEG Translocon. Front Mol Biosci 2021; 8:664241. [PMID: 33937339 PMCID: PMC8082313 DOI: 10.3389/fmolb.2021.664241] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
The spatial and temporal coordination of protein transport is an essential cornerstone of the bacterial adaptation to different environmental conditions. By adjusting the protein composition of extra-cytosolic compartments, like the inner and outer membranes or the periplasmic space, protein transport mechanisms help shaping protein homeostasis in response to various metabolic cues. The universally conserved SecYEG translocon acts at the center of bacterial protein transport and mediates the translocation of newly synthesized proteins into and across the cytoplasmic membrane. The ability of the SecYEG translocon to transport an enormous variety of different substrates is in part determined by its ability to interact with multiple targeting factors, chaperones and accessory proteins. These interactions are crucial for the assisted passage of newly synthesized proteins from the cytosol into the different bacterial compartments. In this review, we summarize the current knowledge about SecYEG-mediated protein transport, primarily in the model organism Escherichia coli, and describe the dynamic interaction of the SecYEG translocon with its multiple partner proteins. We furthermore highlight how protein transport is regulated and explore recent developments in using the SecYEG translocon as an antimicrobial target.
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Affiliation(s)
- Julia Oswald
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Robert Njenga
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Ana Natriashvili
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Pinku Sarmah
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
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14
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Steinberg R, Koch HG. The largely unexplored biology of small proteins in pro- and eukaryotes. FEBS J 2021; 288:7002-7024. [PMID: 33780127 DOI: 10.1111/febs.15845] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 12/29/2022]
Abstract
The large abundance of small open reading frames (smORFs) in prokaryotic and eukaryotic genomes and the plethora of smORF-encoded small proteins became only apparent with the constant advancements in bioinformatic, genomic, proteomic, and biochemical tools. Small proteins are typically defined as proteins of < 50 amino acids in prokaryotes and of less than 100 amino acids in eukaryotes, and their importance for cell physiology and cellular adaptation is only beginning to emerge. In contrast to antimicrobial peptides, which are secreted by prokaryotic and eukaryotic cells for combatting pathogens and competitors, small proteins act within the producing cell mainly by stabilizing protein assemblies and by modifying the activity of larger proteins. Production of small proteins is frequently linked to stress conditions or environmental changes, and therefore, cells seem to use small proteins as intracellular modifiers for adjusting cell metabolism to different intra- and extracellular cues. However, the size of small proteins imposes a major challenge for the cellular machinery required for protein folding and intracellular trafficking and recent data indicate that small proteins can engage distinct trafficking pathways. In the current review, we describe the diversity of small proteins in prokaryotes and eukaryotes, highlight distinct and common features, and illustrate how they are handled by the protein trafficking machineries in prokaryotic and eukaryotic cells. Finally, we also discuss future topics of research on this fascinating but largely unexplored group of proteins.
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Affiliation(s)
- Ruth Steinberg
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
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15
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Han R, Fang J, Jiang J, Gaidamakova EK, Tkavc R, Daly MJ, Contreras LM. Signal Recognition Particle RNA Contributes to Oxidative Stress Response in Deinococcus radiodurans by Modulating Catalase Localization. Front Microbiol 2020; 11:613571. [PMID: 33391243 PMCID: PMC7775534 DOI: 10.3389/fmicb.2020.613571] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/27/2020] [Indexed: 12/14/2022] Open
Abstract
The proper functioning of many proteins requires their transport to the correct cellular compartment or their secretion. Signal recognition particle (SRP) is a major protein transport pathway responsible for the co-translational movement of integral membrane proteins as well as periplasmic proteins. Deinococcus radiodurans is a ubiquitous bacterium that expresses a complex phenotype of extreme oxidative stress resistance, which depends on proteins involved in DNA repair, metabolism, gene regulation, and antioxidant defense. These proteins are located extracellularly or subcellularly, but the molecular mechanism of protein localization in D. radiodurans to manage oxidative stress response remains unexplored. In this study, we characterized the SRP complex in D. radiodurans R1 and showed that the knockdown (KD) of the SRP RNA (Qpr6) reduced bacterial survival under hydrogen peroxide and growth under chronic ionizing radiation. Through LC-mass spectrometry (MS/MS) analysis, we detected 162 proteins in the periplasm of wild-type D. radiodurans, of which the transport of 65 of these proteins to the periplasm was significantly reduced in the Qpr6 KD strain. Through Western blotting, we further demonstrated the localization of the catalases in D. radiodurans, DR_1998 (KatE1) and DR_A0259 (KatE2), in both the cytoplasm and periplasm, respectively, and showed that the accumulation of KatE1 and KatE2 in the periplasm was reduced in the SRP-defective strains. Collectively, this study establishes the importance of the SRP pathway in the survival and the transport of antioxidant proteins in D. radiodurans under oxidative stress.
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Affiliation(s)
- Runhua Han
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Jaden Fang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Jessie Jiang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Elena K Gaidamakova
- Uniformed Services University of the Health Sciences, Department of Pathology, Bethesda, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
| | - Rok Tkavc
- Uniformed Services University of the Health Sciences, Department of Pathology, Bethesda, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States.,Uniformed Services University of the Health Sciences, Department of Microbiology and Immunology, Bethesda, MD, United States
| | - Michael J Daly
- Uniformed Services University of the Health Sciences, Department of Pathology, Bethesda, MD, United States
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States.,Institute for Cellular & Molecular Biology, The University of Texas at Austin, Austin, TX, United States
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16
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SecY-mediated quality control prevents the translocation of non-gated porins. Sci Rep 2020; 10:16347. [PMID: 33004891 PMCID: PMC7530735 DOI: 10.1038/s41598-020-73185-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 09/09/2020] [Indexed: 01/24/2023] Open
Abstract
OmpC and OmpF are among the most abundant outer membrane proteins in E. coli and serve as hydrophilic channels to mediate uptake of small molecules including antibiotics. Influx selectivity is controlled by the so-called constriction zone or eyelet of the channel. Mutations in the loop domain forming the eyelet can disrupt transport selectivity and thereby interfere with bacterial viability. In this study we show that a highly conserved motif of five negatively charged amino acids in the eyelet, which is critical to regulate pore selectivity, is also required for SecY-mediated transport of OmpC and OmpF into the periplasm. Variants with a deleted or mutated motif were expressed in the cytosol and translocation was initiated. However, after signal peptide cleavage, import into the periplasm was aborted and the mutated proteins were redirected to the cytosol. Strikingly, reducing the proof-reading capacity of SecY by introducing the PrlA4 substitutions restored transport of OmpC with a mutated channel domain into the periplasm. Our study identified a SecY-mediated quality control pathway to restrict transport of outer membrane porin proteins with a deregulated channel activity into the periplasm.
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17
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Steinberg R, Origi A, Natriashvili A, Sarmah P, Licheva M, Walker PM, Kraft C, High S, Luirink J, Shi WQ, Helmstädter M, Ulbrich MH, Koch HG. Posttranslational insertion of small membrane proteins by the bacterial signal recognition particle. PLoS Biol 2020; 18:e3000874. [PMID: 32997663 PMCID: PMC7549839 DOI: 10.1371/journal.pbio.3000874] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 10/12/2020] [Accepted: 09/02/2020] [Indexed: 01/05/2023] Open
Abstract
Small membrane proteins represent a largely unexplored yet abundant class of proteins in pro- and eukaryotes. They essentially consist of a single transmembrane domain and are associated with stress response mechanisms in bacteria. How these proteins are inserted into the bacterial membrane is unknown. Our study revealed that in Escherichia coli, the 27-amino-acid-long model protein YohP is recognized by the signal recognition particle (SRP), as indicated by in vivo and in vitro site-directed cross-linking. Cross-links to SRP were also observed for a second small membrane protein, the 33-amino-acid-long YkgR. However, in contrast to the canonical cotranslational recognition by SRP, SRP was found to bind to YohP posttranslationally. In vitro protein transport assays in the presence of a SecY inhibitor and proteoliposome studies demonstrated that SRP and its receptor FtsY are essential for the posttranslational membrane insertion of YohP by either the SecYEG translocon or by the YidC insertase. Furthermore, our data showed that the yohP mRNA localized preferentially and translation-independently to the bacterial membrane in vivo. In summary, our data revealed that YohP engages an unique SRP-dependent posttranslational insertion pathway that is likely preceded by an mRNA targeting step. This further highlights the enormous plasticity of bacterial protein transport machineries. Small membrane proteins represent a largely unexplored yet abundant class of proteins, but how they are inserted into the bacterial membrane is unknown. This study identifies a novel posttranslational protein transport pathway that relies on the signal recognition particle and the SecYEG translocon/YidC insertase.
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Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Ana Natriashvili
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Pinku Sarmah
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Mariya Licheva
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Princess M. Walker
- Department of Chemistry, Ball State University, Muncie, Indiana, United States of America
| | - Claudine Kraft
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Stephen High
- School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Joen Luirink
- Molecular Microbiology, AIMMS, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Wei. Q. Shi
- Department of Chemistry, Ball State University, Muncie, Indiana, United States of America
| | - Martin Helmstädter
- Internal Medicine IV, Department of Medicine, Medical Center − University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maximilian H. Ulbrich
- Internal Medicine IV, Department of Medicine, Medical Center − University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- * E-mail:
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18
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Nishikawa H, Sasaki M, Nishiyama KI. In vitro Assay for Bacterial Membrane Protein Integration into Proteoliposomes. Bio Protoc 2020; 10:e3626. [PMID: 33659299 DOI: 10.21769/bioprotoc.3626] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 11/02/2022] Open
Abstract
It is important to experimentally determine how membrane proteins are integrated into biomembranes to unveil the roles of the integration factors, and to understand the functions and structures of membrane proteins. We have developed a reconstitution system for membrane protein integration in E. coli using purified factors, in which the integration reaction in vivo is highly reproducible. This system enabled not only analysis of membrane-embedded factors including glycolipid MPIase, but also elucidation of the detailed mechanisms underlying membrane protein integration. Using the system, the integration of membrane proteins can be evaluated in vitro through a protease-protection assay. We report here how to prepare (proteo)liposomes and to determine the activities of membrane protein integration.
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Affiliation(s)
- Hanako Nishikawa
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan
| | - Masaru Sasaki
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan
| | - Ken-Ichi Nishiyama
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Japan.,Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Japan
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19
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Sasaki M, Nishikawa H, Suzuki S, Moser M, Huber M, Sawasato K, Matsubayashi HT, Kumazaki K, Tsukazaki T, Kuruma Y, Nureki O, Ueda T, Nishiyama KI. The bacterial protein YidC accelerates MPIase-dependent integration of membrane proteins. J Biol Chem 2019; 294:18898-18908. [PMID: 31662434 DOI: 10.1074/jbc.ra119.011248] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/25/2019] [Indexed: 01/06/2023] Open
Abstract
Bacterial membrane proteins are integrated into membranes through the concerted activities of a series of integration factors, including membrane protein integrase (MPIase). However, how MPIase activity is complemented by other integration factors during membrane protein integration is incompletely understood. Here, using inverted inner-membrane vesicle and reconstituted (proteo)liposome preparations from Escherichia coli cells, along with membrane protein integration assays and the PURE system to produce membrane proteins, we found that anti-MPIase IgG inhibits the integration of both the Sec-independent substrate 3L-Pf3 coat and the Sec-dependent substrate MtlA into E. coli membrane vesicles. MPIase-depleted membrane vesicles lacked both 3L-Pf3 coat and MtlA integration, indicating that MPIase is involved in the integration of both proteins. We developed a reconstitution system in which disordered spontaneous integration was precluded, which revealed that SecYEG, YidC, or both, are not sufficient for Sec-dependent and -independent integration. Although YidC had no effect on MPIase-dependent integration of Sec-independent substrates in the conventional assay system, YidC significantly accelerated the integration when the substrate amounts were increased in our PURE system-based assay. Similar acceleration by YidC was observed for MtlA integration. YidC mutants with amino acid substitutions in the hydrophilic cavity inside the membrane were defective in the acceleration of the Sec-independent integration. Of note, MPIase was up-regulated upon YidC depletion. These results indicate that YidC accelerates the MPIase-dependent integration of membrane proteins, suggesting that MPIase and YidC function sequentially and cooperatively during the catalytic cycle of membrane protein integration.
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Affiliation(s)
- Masaru Sasaki
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Hanako Nishikawa
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Sonomi Suzuki
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Michael Moser
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Maria Huber
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Katsuhiro Sawasato
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Hideaki T Matsubayashi
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Kaoru Kumazaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | | | - Yutetsu Kuruma
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Takuya Ueda
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Ken-Ichi Nishiyama
- United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan; Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan; Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan.
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20
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Steinberg R, Knüpffer L, Origi A, Asti R, Koch HG. Co-translational protein targeting in bacteria. FEMS Microbiol Lett 2019; 365:4966980. [PMID: 29790984 DOI: 10.1093/femsle/fny095] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/09/2018] [Indexed: 01/16/2023] Open
Abstract
About 30% of all bacterial proteins execute their function outside of the cytosol and have to be transported into or across the cytoplasmic membrane. Bacteria use multiple protein transport systems in parallel, but the majority of proteins engage two distinct targeting systems. One is the co-translational targeting by two universally conserved GTPases, the signal recognition particle (SRP) and its receptor FtsY, which deliver inner membrane proteins to either the SecYEG translocon or the YidC insertase for membrane insertion. The other targeting system depends on the ATPase SecA, which targets secretory proteins, i.e. periplasmic and outer membrane proteins, to SecYEG for their subsequent ATP-dependent translocation. While SRP selects its substrates already very early during their synthesis, the recognition of secretory proteins by SecA is believed to occur primarily after translation termination, i.e. post-translationally. In this review we highlight recent progress on how SRP recognizes its substrates at the ribosome and how the fidelity of the targeting reaction to SecYEG is maintained. We furthermore discuss similarities and differences in the SRP-dependent targeting to either SecYEG or YidC and summarize recent results that suggest that some membrane proteins are co-translationally targeted by SecA.
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Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Lara Knüpffer
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, Freiburg D-79104, Germany
| | - Rossella Asti
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
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21
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Abstract
Bacterial protein transport via the conserved SecYEG translocon is generally classified as either cotranslational, i.e., when transport is coupled to translation, or posttranslational, when translation and transport are separated. We show here that the ATPase SecA, which is considered to bind its substrates posttranslationally, already scans the ribosomal tunnel for potential substrates. In the presence of a nascent chain, SecA retracts from the tunnel but maintains contact with the ribosomal surface. This is remarkably similar to the ribosome-binding mode of the signal recognition particle, which mediates cotranslational transport. Our data reveal a striking plasticity of protein transport pathways, which likely enable bacteria to efficiently recognize and transport a large number of highly different substrates within their short generation time. Bacteria execute a variety of protein transport systems for maintaining the proper composition of their different cellular compartments. The SecYEG translocon serves as primary transport channel and is engaged in transporting two different substrate types. Inner membrane proteins are cotranslationally inserted into the membrane after their targeting by the signal recognition particle (SRP). In contrast, secretory proteins are posttranslationally translocated by the ATPase SecA. Recent data indicate that SecA can also bind to ribosomes close to the tunnel exit. We have mapped the interaction of SecA with translating and nontranslating ribosomes and demonstrate that the N terminus and the helical linker domain of SecA bind to an acidic patch on the surface of the ribosomal protein uL23. Intriguingly, both also insert deeply into the ribosomal tunnel to contact the intratunnel loop of uL23, which serves as a nascent chain sensor. This binding pattern is remarkably similar to that of SRP and indicates an identical interaction mode of the two targeting factors with ribosomes. In the presence of a nascent chain, SecA retracts from the tunnel but maintains contact with the surface of uL23. Our data further demonstrate that ribosome and membrane binding of SecA are mutually exclusive, as both events depend on the N terminus of SecA. Our study highlights the enormous plasticity of bacterial protein transport systems and reveals that the discrimination between SRP and SecA substrates is already initiated at the ribosome.
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22
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Abstract
Single-molecule studies provide unprecedented details about processes that are difficult to grasp by bulk biochemical assays that yield ensemble-averaged results. One of these processes is the translocation and insertion of proteins across and into the bacterial cytoplasmic membrane. This process is facilitated by the universally conserved secretion (Sec) system, a multi-subunit membrane protein complex that consists of dissociable cytoplasmic targeting components, a molecular motor, a protein-conducting membrane pore, and accessory membrane proteins. Here, we review recent insights into the mechanisms of protein translocation and membrane protein insertion from single-molecule studies.
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Affiliation(s)
- Anne-Bart Seinen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute; and the Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, Netherlands
- Current affiliation: Biophysics Group, AMOLF, 1098 XG Amsterdam, Netherlands
| | - Arnold J.M. Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute; and the Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, Netherlands
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23
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Sawasato K, Sato R, Nishikawa H, Iimura N, Kamemoto Y, Fujikawa K, Yamaguchi T, Kuruma Y, Tamura Y, Endo T, Ueda T, Shimamoto K, Nishiyama KI. CdsA is involved in biosynthesis of glycolipid MPIase essential for membrane protein integration in vivo. Sci Rep 2019; 9:1372. [PMID: 30718729 PMCID: PMC6362211 DOI: 10.1038/s41598-018-37809-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 12/07/2018] [Indexed: 11/17/2022] Open
Abstract
MPIase is a glycolipid that is involved in membrane protein integration. Despite evaluation of its functions in vitro, the lack of information on MPIase biosynthesis hampered verification of its involvement in vivo. In this study, we found that depletion of CdsA, a CDP-diacylglycerol synthase, caused not only a defect in phospholipid biosynthesis but also MPIase depletion with accumulation of the precursors of both membrane protein M13 coat protein and secretory protein OmpA. Yeast Tam41p, a mitochondrial CDP-diacylglycerol synthase, suppressed the defect in phospholipid biosynthesis, but restored neither MPIase biosynthesis, precursor processing, nor cell growth, indicating that MPIase is essential for membrane protein integration and therefore for cell growth. Consistently, we observed a severe defect in protein integration into MPIase-depleted membrane vesicles in vitro. Thus, the function of MPIase as a factor involved in protein integration was proven in vivo as well as in vitro. Moreover, Cds1p, a eukaryotic CdsA homologue, showed a potential for MPIase biosynthesis. From these results, we speculate the presence of a eukaryotic MPIase homologue.
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Affiliation(s)
- Katsuhiro Sawasato
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Ryo Sato
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Hanako Nishikawa
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Naoki Iimura
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Yuki Kamemoto
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan
| | - Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Seika-cho, Kyoto, 619-0284, Japan
| | - Toshiyuki Yamaguchi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Seika-cho, Kyoto, 619-0284, Japan
| | - Yutetsu Kuruma
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan
| | - Yasushi Tamura
- Faculty of Science, Yamagata University, Yamagata, Yamagata, 990-8560, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto, 603-8555, Japan
| | - Takuya Ueda
- Department of Computational Biology and Medical Sciences Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8562, Japan
| | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Seika-cho, Kyoto, 619-0284, Japan
| | - Ken-Ichi Nishiyama
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, 020-8550, Japan. .,Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan. .,Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Iwate, 020-8550, Japan.
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Jeckelmann JM, Erni B. Carbohydrate Transport by Group Translocation: The Bacterial Phosphoenolpyruvate: Sugar Phosphotransferase System. Subcell Biochem 2019; 92:223-274. [PMID: 31214989 DOI: 10.1007/978-3-030-18768-2_8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The Bacterial Phosphoenolpyruvate (PEP) : Sugar Phosphotransferase System (PTS) mediates the uptake and phosphorylation of carbohydrates, and controls the carbon- and nitrogen metabolism in response to the availability of sugars. PTS occur in eubacteria and in a few archaebacteria but not in animals and plants. All PTS comprise two cytoplasmic phosphotransferase proteins (EI and HPr) and a species-dependent, variable number of sugar-specific enzyme II complexes (IIA, IIB, IIC, IID). EI and HPr transfer phosphorylgroups from PEP to the IIA units. Cytoplasmic IIA and IIB units sequentially transfer phosphates to the sugar, which is transported by the IIC and IICIID integral membrane protein complexes. Phosphorylation by IIB and translocation by IIC(IID) are tightly coupled. The IIC(IID) sugar transporters of the PTS are in the focus of this review. There are four structurally different PTS transporter superfamilies (glucose, glucitol, ascorbate, mannose) . Crystal structures are available for transporters of two superfamilies: bcIICmal (MalT, 5IWS, 6BVG) and bcIICchb (ChbC, 3QNQ) of B. subtilis from the glucose family, and IICasc (UlaA, 4RP9, 5ZOV) of E. coli from the ascorbate superfamily . They are homodimers and each protomer has an independent transport pathway which functions by an elevator-type alternating-access mechanism. bcIICmal and bcIICchb have the same fold, IICasc has a completely different fold. Biochemical and biophysical data accumulated in the past with the transporters for mannitol (IICBAmtl) and glucose (IICBglc) are reviewed and discussed in the context of the bcIICmal crystal structures. The transporters of the mannose superfamily are dimers of protomers consisting of a IIC and a IID protein chain. The crystal structure is not known and the topology difficult to predict. Biochemical data indicate that the IICIID complex employs a different transport mechanism . Species specific IICIID serve as a gateway for the penetration of bacteriophage lambda DNA across, and insertion of class IIa bacteriocins into the inner membrane. PTS transporters are inserted into the membrane by SecYEG translocon and have specific lipid requirements. Immunoelectron- and fluorescence microscopy indicate a non-random distribution and supramolecular complexes of PTS proteins.
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Affiliation(s)
- Jean-Marc Jeckelmann
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland.
| | - Bernhard Erni
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland
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25
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Fujikawa K, Suzuki S, Nagase R, Ikeda S, Mori S, Nomura K, Nishiyama KI, Shimamoto K. Syntheses and Activities of the Functional Structures of a Glycolipid Essential for Membrane Protein Integration. ACS Chem Biol 2018; 13:2719-2727. [PMID: 30064209 DOI: 10.1021/acschembio.8b00654] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
MPIase is the first known glycolipid that is essential for membrane protein integration in the inner membrane of E. coli. Since the amount of natural MPIase available for analysis is limited and it contains structural heterogeneity, precisely designed synthetic derivatives are promising tools for further elucidation of its membrane protein integration mechanism. Thus, we synthesized the minimal unit of MPIase, a trisaccharyl pyrophospholipid termed mini-MPIase-3, and its derivatives. Integration assays revealed that the chemically synthesized trisaccharyl pyrophospholipid possesses significant activity, indicating that it includes the essential structure for membrane integration. Structure-activity relationship studies demonstrated that the number of trisaccharide units and the 6- O-acetyl group on N-acetylglucosamine contribute to efficient integration. Furthermore, anchoring in the membrane by a lipid moiety was essential for the integration. However, the addition of phosphorylated glycans devoid of the lipid moiety in the assay solution modulated the integration activity of MPIase embedded in liposomes, suggesting an interaction between phosphorylated glycans and substrate proteins in aqueous solutions. The prevention of protein aggregation required the 6- O-acetyl group on N-acetylglucosamine, a phosphate group at the reducing end of the glycan, and a long glycan chain. Taken together, we verified the mechanism of the initial step of the translocon-independent pathway in which a membrane protein is captured by a glycan of MPIase, which maintains its structure to be competent for integration, and then MPIase integrates it into the membrane by hydrophobic interactions with membrane lipids.
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Affiliation(s)
- Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Sonomi Suzuki
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Ryohei Nagase
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Shiori Ikeda
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Shoko Mori
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Ken-ichi Nishiyama
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
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26
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Lipids modulate the insertion and folding of the nascent chains of alpha helical membrane proteins. Biochem Soc Trans 2018; 46:1355-1366. [PMID: 30190329 DOI: 10.1042/bst20170424] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/18/2018] [Accepted: 07/31/2018] [Indexed: 02/08/2023]
Abstract
Membrane proteins must be inserted into a membrane and folded into their correct structure to function correctly. This insertion occurs during translation and synthesis by the ribosome for most α-helical membrane proteins. Precisely how this co-translational insertion and folding occurs, and the role played by the surrounding lipids, is still not understood. Most of the work on the influence of the lipid environment on folding and insertion has focussed on denatured, fully translated proteins, and thus does not replicate folding during unidirectional elongation of nascent chains that occurs in the cell. This review aims to highlight recent advances in elucidating lipid composition and bilayer properties optimal for insertion and folding of nascent chains in the membrane and in the assembly of oligomeric proteins.
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27
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Gonsberg A, Jung S, Ulbrich S, Origi A, Ziska A, Baier M, Koch HG, Zimmermann R, Winklhofer KF, Tatzelt J. The Sec61/SecY complex is inherently deficient in translocating intrinsically disordered proteins. J Biol Chem 2017; 292:21383-21396. [PMID: 29084847 DOI: 10.1074/jbc.m117.788067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 10/26/2017] [Indexed: 11/06/2022] Open
Abstract
About one-quarter to nearly one-third of the proteins synthesized in the cytosol of eukaryotic cells are integrated into the plasma membrane or are secreted. Translocation of secretory proteins into the lumen of the endoplasmic reticulum or the periplasm of bacteria is mediated by a highly conserved heterotrimeric membrane protein complex denoted Sec61 in eukaryotes and SecYEG in bacteria. To evaluate a possible modulation of the translocation efficiency by secondary structures of the nascent peptide chain, we performed a comparative analysis in bacteria, yeast, and mammalian cells. Strikingly, neither the bacterial SecY nor the eukaryotic Sec61 translocon was able to efficiently transport proteins entirely composed of intrinsically disordered domains (IDDs) or β-strands. However, translocation could be restored by α-helical domains in a position- and organism-dependent manner. In bacteria, we found that the α-helical domains have to precede the IDD or β-strands, whereas in mammalian cells, C-terminally located α-helical domains are sufficient to promote translocation. Our study reveals an evolutionarily conserved deficiency of the Sec61/SecY complex to translocate IDDs and β-strands in the absence of α-helical domains. Moreover, our results may suggest that adaptive pathways co-evolved with the expansion of IDDs in the proteome of eukaryotic cells to increase the transport capacity of the Sec61 translocon.
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Affiliation(s)
- Anika Gonsberg
- From the Departments of Biochemistry of Neurodegenerative Diseases and
| | - Sebastian Jung
- From the Departments of Biochemistry of Neurodegenerative Diseases and
| | - Sarah Ulbrich
- From the Departments of Biochemistry of Neurodegenerative Diseases and
| | - Andrea Origi
- the Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Anke Ziska
- the Department of Medical Biochemistry and Molecular Biology, Saarland University, D-66421 Homburg, Germany, and
| | - Michael Baier
- the Research Group Proteinopathies/Neurodegenerative Diseases, Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, D-13353 Berlin, Germany
| | - Hans-Georg Koch
- the Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs-University Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Richard Zimmermann
- the Department of Medical Biochemistry and Molecular Biology, Saarland University, D-66421 Homburg, Germany, and
| | - Konstanze F Winklhofer
- Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Jörg Tatzelt
- From the Departments of Biochemistry of Neurodegenerative Diseases and
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28
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Nishikawa H, Sasaki M, Nishiyama KI. Membrane insertion of F 0 c subunit of F 0F 1 ATPase depends on glycolipozyme MPIase and is stimulated by YidC. Biochem Biophys Res Commun 2017; 487:477-482. [PMID: 28431927 DOI: 10.1016/j.bbrc.2017.04.095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 04/07/2017] [Indexed: 01/04/2023]
Abstract
The F0 c subunit of F0F1 ATPase (F0-c) possesses two membrane-spanning stretches with N- and C-termini exposed to the periplasmic (extracellular) side of the cytoplasmic membrane of E. coli. Although F0-c insertion has been extensively analyzed in vitro by means of protease protection assaying, it is unclear whether such assays allow elucidation of the insertion process faithfully, since the membrane-protected fragment, an index of membrane insertion, is a full-length polypeptide of F0-c, which is the same as the protease-resistant conformation without membrane insertion. We found that the protease-resistant conformation could be discriminated from membrane-insertion by including octyl glucoside on protease digestion. By means of this system, we found that F0-c insertion depends on MPIase, a glycolipozyme involved in membrane insertion, and is stimulated by YidC. In addition, we found that acidic phospholipids PG and CL transform F0-c into a protease-resistant form, while MPIase prevents the acquisition of such a protease-resistant conformation.
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Affiliation(s)
- Hanako Nishikawa
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Masaru Sasaki
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Ken-Ichi Nishiyama
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka, Japan; Department of Biological Chemistry and Food Science, Faculty of Agriculture, Iwate University, Morioka, Japan.
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29
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Sachelaru I, Winter L, Knyazev DG, Zimmermann M, Vogt A, Kuttner R, Ollinger N, Siligan C, Pohl P, Koch HG. YidC and SecYEG form a heterotetrameric protein translocation channel. Sci Rep 2017; 7:101. [PMID: 28273911 PMCID: PMC5427846 DOI: 10.1038/s41598-017-00109-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/08/2017] [Indexed: 11/26/2022] Open
Abstract
The heterotrimeric SecYEG complex cooperates with YidC to facilitate membrane protein insertion by an unknown mechanism. Here we show that YidC contacts the interior of the SecY channel resulting in a ligand-activated and voltage-dependent complex with distinct ion channel characteristics. The SecYEG pore diameter decreases from 8 Å to only 5 Å for the YidC-SecYEG pore, indicating a reduction in channel cross-section by YidC intercalation. In the presence of a substrate, YidC relocates to the rim of the pore as indicated by increased pore diameter and loss of YidC crosslinks to the channel interior. Changing the surface charge of the pore by incorporating YidC into the channel wall increases the anion selectivity, and the accompanying change in wall hydrophobicity is liable to alter the partition of helices from the pore into the membrane. This could explain how the exit of transmembrane domains from the SecY channel is facilitated by YidC.
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Affiliation(s)
- Ilie Sachelaru
- grid.5963.9Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, Freiburg, 79104 Germany ,grid.5963.9Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, 79104 Freiburg, Germany
| | - Lukas Winter
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Denis G. Knyazev
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Mirjam Zimmermann
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Andreas Vogt
- grid.5963.9Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, Freiburg, 79104 Germany ,grid.5963.9Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, 79104 Freiburg, Germany ,grid.5963.9Spemann-Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Roland Kuttner
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Nicole Ollinger
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Christine Siligan
- 0000 0001 1941 5140grid.9970.7Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020 Linz, Austria
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, A-4020, Linz, Austria.
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Stefan Meier Str. 17, Freiburg, 79104, Germany. .,Spemann-Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany.
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30
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Abstract
The insertion and assembly of proteins into the inner membrane of bacteria are crucial for many cellular processes, including cellular respiration, signal transduction, and ion and pH homeostasis. This process requires efficient membrane targeting and insertion of proteins into the lipid bilayer in their correct orientation and proper conformation. Playing center stage in these events are the targeting components, signal recognition particle (SRP) and the SRP receptor FtsY, as well as the insertion components, the Sec translocon and the YidC insertase. Here, we will discuss new insights provided from the recent high-resolution structures of these proteins. In addition, we will review the mechanism by which a variety of proteins with different topologies are inserted into the inner membrane of Gram-negative bacteria. Finally, we report on the energetics of this process and provide information on how membrane insertion occurs in Gram-positive bacteria and Archaea. It should be noted that most of what we know about membrane protein assembly in bacteria is based on studies conducted in Escherichia coli.
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Affiliation(s)
- Andreas Kuhn
- Institute for Microbiology and Molecular Biology, University of Hohenheim, 70599 Stuttgart, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, 79104, Freiburg, Germany
| | - Ross E Dalbey
- Department of Chemistry, The Ohio State University, Columbus, OH 43210
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31
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Denks K, Sliwinski N, Erichsen V, Borodkina B, Origi A, Koch HG. The signal recognition particle contacts uL23 and scans substrate translation inside the ribosomal tunnel. Nat Microbiol 2017; 2:16265. [PMID: 28134917 DOI: 10.1038/nmicrobiol.2016.265] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 12/09/2016] [Indexed: 01/12/2023]
Abstract
The signal recognition particle (SRP) delivers ∼25% of all bacterial proteins to the membrane for cotranslational insertion. However, a comprehensive model on how the low-abundant SRP scans the vast number of translating ribosomes to identify the correct substrates is lacking. Here, we show that the C-terminal helix of the signal-sequence-binding domain of SRP penetrates into the ribosomal tunnel and contacts the intra-tunnel loop of ribosomal protein uL23. This allows SRP to obtain information about the translational status of the ribosome and possibly the character of the approaching nascent chain. Correct substrates reposition the C-terminal helix of SRP, which facilitates stable binding of the signal sequence by the M-domain of SRP. Thus, SRP already surveys translating ribosomes before the signal sequence is surface exposed. This early interaction probably enables the small number of SRP molecules to scan many ribosomes and to initiate efficient targeting of proper substrates.
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Affiliation(s)
- Kärt Denks
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany.,Faculty of Biology, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany
| | - Nadine Sliwinski
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany
| | - Veronika Erichsen
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany
| | - Bogdana Borodkina
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany
| | - Andrea Origi
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany.,Faculty of Biology, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs Universität Freiburg, Stefan Meier Strasse 17, 79104 Freiburg, Germany
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32
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Ohta N, Kato Y, Watanabe H, Mori H, Matsuura T. In vitro membrane protein synthesis inside Sec translocon-reconstituted cell-sized liposomes. Sci Rep 2016; 6:36466. [PMID: 27808179 PMCID: PMC5093552 DOI: 10.1038/srep36466] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/17/2016] [Indexed: 12/24/2022] Open
Abstract
Protein synthesis using an in vitro transcription-translation system (IVTT) inside cell-sized liposomes has become a valuable tool to study the properties of biological systems under cell-mimicking conditions. However, previous liposome systems lacked the machinery for membrane protein translocation. Here, we reconstituted the translocon consisting of SecYEG from Escherichia coli inside cell-sized liposomes. The cell-sized liposomes also carry the reconstituted IVTT, thereby providing a cell-mimicking environment for membrane protein synthesis. By using EmrE, a multidrug transporter from E. coli, as a model membrane protein, we found that both the amount and activity of EmrE synthesized inside the liposome is increased approximately three-fold by incorporating the Sec translocon. The topological change of EmrE induced by the translocon was also identified. The membrane integration of 6 out of 9 E. coli inner membrane proteins that was tested was increased by incorporation of the translocon. By introducing the Sec translocon, the membrane integration efficiency of the membrane protein of interest was increased, and enabled the integration of membrane proteins that otherwise cannot be inserted. In addition, this work represents an essential step toward the construction of an artificial cell through a bottom-up approach.
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Affiliation(s)
- Naoki Ohta
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
| | - Yasuhiko Kato
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
| | - Hajime Watanabe
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
| | - Hirotada Mori
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-tyou, Ikoma, Nara, Japan
| | - Tomoaki Matsuura
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
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34
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Kuhn P, Draycheva A, Vogt A, Petriman NA, Sturm L, Drepper F, Warscheid B, Wintermeyer W, Koch HG. Ribosome binding induces repositioning of the signal recognition particle receptor on the translocon. J Cell Biol 2016; 211:91-104. [PMID: 26459600 PMCID: PMC4602035 DOI: 10.1083/jcb.201502103] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The cotranslational transfer of nascent membrane proteins to the SecYEG translocon is facilitated by a reorientation of the SecY-bound signal recognition particle (SRP) receptor, FtsY, which accompanies the formation of a quaternary targeting complex consisting of SecYEG, FtsY, SRP, and the ribosome. Cotranslational protein targeting delivers proteins to the bacterial cytoplasmic membrane or to the eukaryotic endoplasmic reticulum membrane. The signal recognition particle (SRP) binds to signal sequences emerging from the ribosomal tunnel and targets the ribosome-nascent-chain complex (RNC) to the SRP receptor, termed FtsY in bacteria. FtsY interacts with the fifth cytosolic loop of SecY in the SecYEG translocon, but the functional role of the interaction is unclear. By using photo-cross-linking and fluorescence resonance energy transfer measurements, we show that FtsY–SecY complex formation is guanosine triphosphate independent but requires a phospholipid environment. Binding of an SRP–RNC complex exposing a hydrophobic transmembrane segment induces a rearrangement of the SecY–FtsY complex, which allows the subsequent contact between SecY and ribosomal protein uL23. These results suggest that direct RNC transfer to the translocon is guided by the interaction between SRP and translocon-bound FtsY in a quaternary targeting complex.
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Affiliation(s)
- Patrick Kuhn
- Institute of Biochemistry and Molecular Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Albena Draycheva
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Andreas Vogt
- Institute of Biochemistry and Molecular Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Narcis-Adrian Petriman
- Institute of Biochemistry and Molecular Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Lukas Sturm
- Institute of Biochemistry and Molecular Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Friedel Drepper
- Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Wolfgang Wintermeyer
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
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Regulation by a chaperone improves substrate selectivity during cotranslational protein targeting. Proc Natl Acad Sci U S A 2015; 112:E3169-78. [PMID: 26056263 DOI: 10.1073/pnas.1422594112] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ribosome exit site is a crowded environment where numerous factors contact nascent polypeptides to influence their folding, localization, and quality control. Timely and accurate selection of nascent polypeptides into the correct pathway is essential for proper protein biogenesis. To understand how this is accomplished, we probe the mechanism by which nascent polypeptides are accurately sorted between the major cotranslational chaperone trigger factor (TF) and the essential cotranslational targeting machinery, signal recognition particle (SRP). We show that TF regulates SRP function at three distinct stages, including binding of the translating ribosome, membrane targeting via recruitment of the SRP receptor, and rejection of ribosome-bound nascent polypeptides beyond a critical length. Together, these mechanisms enhance the specificity of substrate selection into both pathways. Our results reveal a multilayered mechanism of molecular interplay at the ribosome exit site, and provide a conceptual framework to understand how proteins are selected among distinct biogenesis machineries in this crowded environment.
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Song C, van der Voort M, van de Mortel J, Hassan KA, Elbourne LDH, Paulsen IT, Loper JE, Raaijmakers JM. The Rsm regulon of plant growth-promoting Pseudomonas fluorescens SS101: role of small RNAs in regulation of lipopeptide biosynthesis. Microb Biotechnol 2014; 8:296-310. [PMID: 25488342 PMCID: PMC4353343 DOI: 10.1111/1751-7915.12190] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/29/2014] [Accepted: 10/02/2014] [Indexed: 11/28/2022] Open
Abstract
The rhizobacterium Pseudomonas fluorescens SS101 inhibits growth of oomycete and fungal pathogens, and induces resistance in plants against pathogens and insects. To unravel regulatory pathways of secondary metabolite production in SS101, we conducted a genome-wide search for sRNAs and performed transcriptomic analyses to identify genes associated with the Rsm (repressor of secondary metabolites) regulon. In silico analysis led to the identification of 16 putative sRNAs in the SS101 genome. In frame deletion of the sRNAs rsmY and rsmZ showed that the Rsm system regulates the biosynthesis of the lipopeptide massetolide A and involves the two repressor proteins RsmA and RsmE, with the LuxR-type transcriptional regulator MassAR as their most likely target. Transcriptome analyses of the rsmYZ mutant further revealed that genes associated with iron acquisition, motility and chemotaxis were significantly upregulated, whereas genes of the type VI secretion system were downregulated. Comparative transcriptomic analyses showed that most, but not all, of the genes controlled by RsmY/RsmZ are also controlled by the GacS/GacA two-component system. We conclude that the Rsm regulon of P. fluorescens SS101 plays a critical role in the regulation of lipopeptide biosynthesis and controls the expression of other genes involved in motility, competition and survival in the plant rhizosphere.
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Affiliation(s)
- Chunxu Song
- Laboratory of Phytopathology, Wageningen University, 6708 PD, Wageningen, the Netherlands; Department of Microbial Ecology, Netherlands Institute of Ecology, 6708 PB, Wageningen, the Netherlands
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Sachelaru I, Petriman NA, Kudva R, Koch HG. Dynamic interaction of the sec translocon with the chaperone PpiD. J Biol Chem 2014; 289:21706-15. [PMID: 24951590 DOI: 10.1074/jbc.m114.577916] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Sec translocon constitutes a ubiquitous protein transport channel that consists in bacteria of the three core components: SecY, SecE, and SecG. Additional proteins interact with SecYEG during different stages of protein transport. During targeting, SecYEG interacts with SecA, the SRP receptor, or the ribosome. Protein transport into or across the membrane is then facilitated by the interaction of SecYEG with YidC and the SecDFYajC complex. During protein transport, SecYEG is likely to interact also with the protein quality control machinery, but details about this interaction are missing. By in vivo and in vitro site-directed cross-linking, we show here that the periplasmic chaperone PpiD is located in front of the lateral gate of SecY, through which transmembrane domains exit the SecY channel. The strongest contacts were found to helix 2b of SecY. Blue native PAGE analyses verify the presence of a SecYEG-PpiD complex in native Escherichia coli membranes. The PpiD-SecY interaction was not influenced by the addition of SecA and only weakly influenced by binding of nontranslating ribosomes to SecYEG. In contrast, PpiD lost contact to the lateral gate of SecY during membrane protein insertion. These data identify PpiD as an additional and transient subunit of the bacterial SecYEG translocon. The data furthermore demonstrate the highly modular and versatile composition of the Sec translocon, which is probably essential for its ability to transport a wide range of substrates across membranes in bacteria and eukaryotes.
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Affiliation(s)
- Ilie Sachelaru
- From the Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, the Faculty of Biology, and
| | - Narcis-Adrian Petriman
- From the Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, the Faculty of Biology, and
| | - Renuka Kudva
- From the Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, the Faculty of Biology, and the Spemann-Graduate School of Biology and Medicine, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Hans-Georg Koch
- From the Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, the Spemann-Graduate School of Biology and Medicine, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
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Denks K, Vogt A, Sachelaru I, Petriman NA, Kudva R, Koch HG. The Sec translocon mediated protein transport in prokaryotes and eukaryotes. Mol Membr Biol 2014; 31:58-84. [DOI: 10.3109/09687688.2014.907455] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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39
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Zhou Y, Ueda T, Müller M. Signal recognition particle and SecA cooperate during export of secretory proteins with highly hydrophobic signal sequences. PLoS One 2014; 9:e92994. [PMID: 24717922 PMCID: PMC3981701 DOI: 10.1371/journal.pone.0092994] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/28/2014] [Indexed: 12/03/2022] Open
Abstract
The Sec translocon of bacterial plasma membranes mediates the linear translocation of secretory proteins as well as the lateral integration of membrane proteins. Integration of many membrane proteins occurs co-translationally via the signal recognition particle (SRP)-dependent targeting of ribosome-associated nascent chains to the Sec translocon. In contrast, translocation of classical secretory proteins across the Sec translocon is a post-translational event requiring no SRP but the motor protein SecA. Secretory proteins were, however, reported to utilize SRP in addition to SecA, if the hydrophobicity of their signal sequences exceeds a certain threshold value. Here we have analyzed transport of this subgroup of secretory proteins across the Sec translocon employing an entirely defined in vitro system. We thus found SecA to be both necessary and sufficient for translocation of secretory proteins with hydrophobic signal sequences, whereas SRP and its receptor improved translocation efficiency. This SRP-mediated boost of translocation is likely due to the early capture of the hydrophobic signal sequence by SRP as revealed by site-specific photo cross-linking of ribosome nascent chain complexes.
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Affiliation(s)
- Yufan Zhou
- Institute of Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Zellforschung, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Takuya Ueda
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Matthias Müller
- Institute of Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Zellforschung, University of Freiburg, Freiburg, Germany
- * E-mail:
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40
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Aboulwafa M, Saier MH. Lipid dependencies, biogenesis and cytoplasmic micellar forms of integral membrane sugar transport proteins of the bacterial phosphotransferase system. MICROBIOLOGY-SGM 2013; 159:2213-2224. [PMID: 23985145 DOI: 10.1099/mic.0.070953-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Permeases of the prokaryotic phosphoenolpyruvate-sugar phosphotransferase system (PTS) catalyse sugar transport coupled to sugar phosphorylation. The lipid composition of a membrane determines the activities of these enzyme/transporters as well as the degree of coupling of phosphorylation to transport. We have investigated mechanisms of PTS permease biogenesis and identified cytoplasmic (soluble) forms of these integral membrane proteins. We found that the catalytic activities of the soluble forms differ from those of the membrane-embedded forms. Transport via the latter is much more sensitive to lipid composition than to phosphorylation, and some of these enzymes are much more sensitive to the lipid environment than others. While the membrane-embedded PTS permeases are always dimeric, the cytoplasmic forms are micellar, either monomeric or dimeric. Scattered published evidence suggests that other integral membrane proteins also exist in cytoplasmic micellar forms. The possible functions of cytoplasmic PTS permeases in biogenesis, intracellular sugar phosphorylation and permease storage are discussed.
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Affiliation(s)
- Mohammad Aboulwafa
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt.,Department of Molecular Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H Saier
- Department of Molecular Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
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41
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Zhang C, Marcia M, Langer JD, Peng G, Michel H. Role of the N-terminal signal peptide in the membrane insertion ofAquifex aeolicusF1F0ATP synthase c-subunit. FEBS J 2013; 280:3425-35. [DOI: 10.1111/febs.12336] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 05/03/2013] [Accepted: 05/07/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Chunli Zhang
- Max Planck Institute of Biophysics; Department of Molecular Membrane Biology; Frankfurt am Main Germany
| | - Marco Marcia
- Department of Molecular, Cellular and Developmental Biology; Yale University; New Haven CT USA
| | - Julian D. Langer
- Max Planck Institute of Biophysics; Department of Molecular Membrane Biology; Frankfurt am Main Germany
| | - Guohong Peng
- Max Planck Institute of Biophysics; Department of Molecular Membrane Biology; Frankfurt am Main Germany
- Institute of Oceanology; Chinese Academy of Sciences; Qingdao China
| | - Hartmut Michel
- Max Planck Institute of Biophysics; Department of Molecular Membrane Biology; Frankfurt am Main Germany
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42
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Mandon EC, Trueman SF, Gilmore R. Protein translocation across the rough endoplasmic reticulum. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a013342. [PMID: 23251026 DOI: 10.1101/cshperspect.a013342] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The rough endoplasmic reticulum is a major site of protein biosynthesis in all eukaryotic cells, serving as the entry point for the secretory pathway and as the initial integration site for the majority of cellular integral membrane proteins. The core components of the protein translocation machinery have been identified, and high-resolution structures of the targeting components and the transport channel have been obtained. Research in this area is now focused on obtaining a better understanding of the molecular mechanism of protein translocation and membrane protein integration.
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Affiliation(s)
- Elisabet C Mandon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605-2324, USA
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43
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Liechti G, Goldberg JB. Outer membrane biogenesis in Escherichia coli, Neisseria meningitidis, and Helicobacter pylori: paradigm deviations in H. pylori. Front Cell Infect Microbiol 2012; 2:29. [PMID: 22919621 PMCID: PMC3417575 DOI: 10.3389/fcimb.2012.00029] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/28/2012] [Indexed: 12/16/2022] Open
Abstract
The bacterial pathogen Helicobacter pylori is capable of colonizing the gastric mucosa of the human stomach using a variety of factors associated with or secreted from its outer membrane (OM). Lipopolysaccharide (LPS) and numerous OM proteins have been shown to be involved in adhesion and immune stimulation/evasion. Many of these factors are essential for colonization and/or pathogenesis in a variety of animal models. Despite this wide array of potential targets present on the bacterial surface, the ability of H. pylori to vary its OM profile limits the effectiveness of vaccines or therapeutics that target any single one of these components. However, it has become evident that the proteins comprising the complexes that transport the majority of these molecules to the OM are highly conserved and often essential. The field of membrane biogenesis has progressed remarkably in the last few years, and the possibility now exists for targeting the mechanisms by which β-barrel proteins, lipoproteins, and LPS are transported to the OM, resulting in loss of bacterial fitness and significant altering of membrane permeability. In this review, the OM transport machinery for LPS, lipoproteins, and outer membrane proteins (OMPs) are discussed. While the principal investigations of these transport mechanisms have been conducted in Escherichia coli and Neisseria meningitidis, here these systems will be presented in the genetic context of ε proteobacteria. Bioinformatic analysis reveals that minimalist genomes, such as that of Helicobacter pylori, offer insight into the smallest number of components required for these essential pathways to function. Interestingly, in the majority of ε proteobacteria, while the inner and OM associated apparatus of LPS, lipoprotein, and OMP transport pathways appear to all be intact, most of the components associated with the periplasmic compartment are either missing or are almost unrecognizable when compared to their E. coli counterparts. Eventual targeting of these pathways would have the net effect of severely limiting the delivery/transport of components to the OM and preventing the bacterium's ability to infect its human host.
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Affiliation(s)
- George Liechti
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health System, Charlottesville VA, USA
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44
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Liang FC, Bageshwar UK, Musser SM. Position-dependent effects of polylysine on Sec protein transport. J Biol Chem 2012; 287:12703-14. [PMID: 22367204 DOI: 10.1074/jbc.m111.240903] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The bacterial Sec protein translocation system catalyzes the transport of unfolded precursor proteins across the cytoplasmic membrane. Using a recently developed real time fluorescence-based transport assay, the effects of the number and distribution of positive charges on the transport time and transport efficiency of proOmpA were examined. As expected, an increase in the number of lysine residues generally increased transport time and decreased transport efficiency. However, the observed effects were highly dependent on the polylysine position in the mature domain. In addition, a string of consecutive positive charges generally had a more significant effect on transport time and efficiency than separating the charges into two or more charged segments. Thirty positive charges distributed throughout the mature domain resulted in effects similar to 10 consecutive charges near the N terminus of the mature domain. These data support a model in which the local effects of positive charge on the translocation kinetics dominate over total thermodynamic constraints. The rapid translocation kinetics of some highly charged proOmpA mutants suggest that the charge is partially shielded from the electric field gradient during transport, possibly by the co-migration of counter ions. The transport times of precursors with multiple positively charged sequences, or "pause sites," were fairly well predicted by a local effect model. However, the kinetic profile predicted by this local effect model was not observed. Instead, the transport kinetics observed for precursors with multiple polylysine segments support a model in which translocation through the SecYEG pore is not the rate-limiting step of transport.
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Affiliation(s)
- Fu-Cheng Liang
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Science Center, College Station, Texas 77843, USA
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45
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Shen X, Li S, Du Y, Mao X, Li Y. The N-terminal hydrophobic segment of Streptomyces coelicolor FtsY forms a transmembrane structure to stabilize its membrane localization. FEMS Microbiol Lett 2012; 327:164-71. [DOI: 10.1111/j.1574-6968.2011.02478.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 11/26/2011] [Accepted: 12/01/2011] [Indexed: 11/29/2022] Open
Affiliation(s)
- Xueling Shen
- Institute of Biochemistry; College of Life Sciences; Zhejiang University; Hangzhou; China
| | - Shanzhen Li
- Institute of Biochemistry; College of Life Sciences; Zhejiang University; Hangzhou; China
| | - Yiling Du
- Institute of Biochemistry; College of Life Sciences; Zhejiang University; Hangzhou; China
| | - Xuming Mao
- Institute of Biochemistry; College of Life Sciences; Zhejiang University; Hangzhou; China
| | - Yongquan Li
- Institute of Biochemistry; College of Life Sciences; Zhejiang University; Hangzhou; China
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46
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Bonardi F, Nouwen N, Feringa BL, Driessen AJM. Protein conducting channels—mechanisms, structures and applications. MOLECULAR BIOSYSTEMS 2012; 8:709-19. [DOI: 10.1039/c2mb05433g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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47
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Welte T, Kudva R, Kuhn P, Sturm L, Braig D, Müller M, Warscheid B, Drepper F, Koch HG. Promiscuous targeting of polytopic membrane proteins to SecYEG or YidC by the Escherichia coli signal recognition particle. Mol Biol Cell 2011; 23:464-79. [PMID: 22160593 PMCID: PMC3268725 DOI: 10.1091/mbc.e11-07-0590] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The YidC insertase also integrates multispanning membrane proteins that had been considered to be exclusively SecYEG dependent. Only membrane proteins that require SecA can be inserted only via SecYEG. Targeting to YidC is SRP dependent, and the C-terminus of YidC cross-links to SRP, FtsY, and ribosomal subunits. Protein insertion into the bacterial inner membrane is facilitated by SecYEG or YidC. Although SecYEG most likely constitutes the major integration site, small membrane proteins have been shown to integrate via YidC. We show that YidC can also integrate multispanning membrane proteins such as mannitol permease or TatC, which had been considered to be exclusively integrated by SecYEG. Only SecA-dependent multispanning membrane proteins strictly require SecYEG for integration, which suggests that SecA can only interact with the SecYEG translocon, but not with the YidC insertase. Targeting of multispanning membrane proteins to YidC is mediated by signal recognition particle (SRP), and we show by site-directed cross-linking that the C-terminus of YidC is in contact with SRP, the SRP receptor, and ribosomal proteins. These findings indicate that SRP recognizes membrane proteins independent of the downstream integration site and that many membrane proteins can probably use either SecYEG or YidC for integration. Because protein synthesis is much slower than protein transport, the use of YidC as an additional integration site for multispanning membrane proteins may prevent a situation in which the majority of SecYEG complexes are occupied by translating ribosomes during cotranslational insertion, impeding the translocation of secretory proteins.
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Affiliation(s)
- Thomas Welte
- Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
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48
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Kube M, Mitrovic J, Duduk B, Rabus R, Seemüller E. Current view on phytoplasma genomes and encoded metabolism. ScientificWorldJournal 2011; 2012:185942. [PMID: 22550465 PMCID: PMC3322544 DOI: 10.1100/2012/185942] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 11/20/2011] [Indexed: 11/21/2022] Open
Abstract
Phytoplasmas are specialised bacteria that are obligate parasites of plant phloem tissue and insects. These bacteria have resisted all attempts of cell-free cultivation. Genome research is of particular importance to analyse the genetic endowment of such bacteria. Here we review the gene content of the four completely sequenced ‘Candidatus Phytoplasma' genomes that include those of ‘Ca. P. asteris' strains OY-M and AY-WB, ‘Ca. P. australiense,' and ‘Ca. P. mali'. These genomes are characterized by chromosome condensation resulting in sizes below 900 kb and a G + C content of less than 28%. Evolutionary adaption of the phytoplasmas to nutrient-rich environments resulted in losses of genetic modules and increased host dependency highlighted by the transport systems and limited metabolic repertoire. On the other hand, duplication and integration events enlarged the chromosomes and contribute to genome instability. Present differences in the content of membrane and secreted proteins reflect the host adaptation in the phytoplasma strains. General differences are obvious between different phylogenetic subgroups. ‘Ca. P. mali' is separated from the other strains by its deviating chromosome organization, the genetic repertoire for recombination and excision repair of nucleotides or the loss of the complete energy-yielding part of the glycolysis. Apart from these differences, comparative analysis exemplified that all four phytoplasmas are likely to encode an alternative pathway to generate pyruvate and ATP.
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Affiliation(s)
- Michael Kube
- Department of Crop and Animal Sciences, Humboldt-University of Berlin, Lentzeallee 55/57, 14195 Berlin, Germany.
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49
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Zhang D, Sweredoski MJ, Graham RLJ, Hess S, Shan SO. Novel proteomic tools reveal essential roles of SRP and importance of proper membrane protein biogenesis. Mol Cell Proteomics 2011; 11:M111.011585. [PMID: 22030350 DOI: 10.1074/mcp.m111.011585] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The signal recognition particle (SRP), which mediates cotranslational protein targeting to cellular membranes, is universally conserved and essential for bacterial and mammalian cells. However, the current understanding of the role of SRP in cell physiology and pathology is still poor, and the reasons behind its essential role in cell survival remain unclear. Here, we systematically analyzed the consequences of SRP loss in E. coli using time-resolved quantitative proteomic analyses. A series of snapshots of the steady-state and newly synthesized proteome unveiled three stages of cellular responses to SRP depletion, and demonstrated essential roles of SRP in metabolism, membrane potential, and protein and energy homeostasis in both the membrane and cytoplasm. We also identified a group of periplasmic proteins, including key molecular chaperones, whose localization was impaired by the loss of SRP; this and additional results showed that SRP is crucial for protein homeostasis in the bacterial envelope. These results reveal the extensive roles that SRP plays in bacterial physiology, emphasize the importance of proper membrane protein biogenesis, and demonstrate the ability of time-resolved quantitative proteomic analysis to provide new biological insights.
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Affiliation(s)
- Dawei Zhang
- Division of Chemistry and Chemical Engineering, Beckman Institute, California Institute of Technology, Pasadena, California 91125, USA.
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50
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Zalucki YM, Beacham IR, Jennings MP. Coupling between codon usage, translation and protein export in Escherichia coli. Biotechnol J 2011; 6:660-7. [PMID: 21567959 DOI: 10.1002/biot.201000334] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 11/07/2022]
Abstract
Proteins destined for export via the Sec-dependent pathway are synthesized with a short N-terminal signal peptide. A requirement for export is that the proteins are in a translocationally competent state. This is a loosely folded state that allows the protein to pass through the SecYEG apparatus and pass into the periplasm. In order to maintain pre-secretory proteins in an export-competent state, there are many factors that slow the folding of the pre-secretory protein in the cytoplasm. These include cytoplasmic chaperones, such as SecB, and the signal recognition particle, which bind the pre-secretory protein and direct it to the cytoplasmic membrane for export. Recently, evidence has been published that non-optimal codons in the signal sequence are important for a time-critical early event to allow the correct folding of pre-secretory proteins. This review details the recent developments in folding of the signal peptide and the pre-secretory protein.
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Affiliation(s)
- Yaramah M Zalucki
- Department of Microbiology and Immunology, Emory University, Atlanta, GA, USA
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