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Hikage R, Tadika Y, Asanuma H, Han Y, Nishiyama KI. MucA is a small peptide encoded by an overlapping sequence with cdsA that upregulates the biosynthesis of glycolipid MPIase in the cold. Biochem Biophys Res Commun 2024; 721:150148. [PMID: 38781662 DOI: 10.1016/j.bbrc.2024.150148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 05/19/2024] [Indexed: 05/25/2024]
Abstract
MPIase is a glycolipid involved in protein insertion into and preprotein translocation across the cytoplasmic membranes of E. coli. MPIase is upregulated in the cold conditions to overcome the cold-sensitive protein export. CdsA, a CDP-diacylglycerol synthase, catalyzes the first reaction in MPIase biosynthesis. An open reading frame for a peptide of 50 amino acids is encoded immediately after ispU, a neighboring upstream gene of cdsA, and overlaps cdsA to a large extent. Mutational analysis revealed that the expression of this peptide is essential for upregulation of MPIase in the cold. Consistently, expression of this peptide in trans resulted in cold upregulation of MPIase. We therefore named this peptide MucA after its function (MPIase upregulation in the cold). When the partially purified MucA was added to the reaction of the intermediate in MPIase biosynthesis, a significant increase in the product formation was observed, supporting the function of MucA. The possible role of MucA in MPIase biosynthesis is discussed.
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Affiliation(s)
- Runa Hikage
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, Japan
| | - Yuta Tadika
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Haruka Asanuma
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Youjung Han
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, Japan
| | - Ken-Ichi Nishiyama
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate, Japan; Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan.
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2
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Hikage R, Sekiya Y, Sawasato K, Nishiyama KI. CdsA, a CDP-diacylglycerol synthase involved in phospholipid and glycolipid MPIase biosynthesis, possesses multiple initiation codons. Genes Cells 2024; 29:347-355. [PMID: 38351722 DOI: 10.1111/gtc.13104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 01/25/2024] [Accepted: 02/01/2024] [Indexed: 04/04/2024]
Abstract
CdsA is a CDP-diacylglycerol synthase essential for phospholipid and glycolipid MPIase biosynthesis, and therefore for growth. The initiation codon of CdsA has been assigned as "TTG," while methionine at the 37th codon was reported to be an initiation codon in the original report. Since a vector containing the open reading frame starting with "TTG" under a controllable promoter complemented the cdsA knockout, "TTG" could function as an initiation codon. However, no evidence supporting that this "TTG" is the sole initiation codon has been reported. We determined the initiation codon by examining the ability of mutants around the N-terminal region to complement cdsA mutants. Even if the "TTG" was substituted with a stop codon, the clear complementation was observed. Moreover, the clones with multiple mutations of stop codons complemented the cdsA mutant up to the 37th codon, indicating that cdsA possesses multiple codons that can function as initiation codons. We constructed an experimental system in which the chromosomal expression of cdsA can be analyzed. By means of this system, we found that the cdsA mutant with substitution of "TTG" with a stop codon is fully functional. Thus, we concluded that CdsA contains multiple initiation codons.
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Affiliation(s)
- Runa Hikage
- Department of Applied Biological Chemistry, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Yusei Sekiya
- Department of Applied Biological Chemistry, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Katsuhiro Sawasato
- Department of Applied Biological Chemistry, Faculty of Agriculture, Iwate University, Morioka, Japan
| | - Ken-Ichi Nishiyama
- Department of Applied Biological Chemistry, Faculty of Agriculture, Iwate University, Morioka, Japan
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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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Kamemoto Y, Hikage R, Han Y, Sekiya Y, Sawasato K, Nishiyama KI. Coordinated upregulation of two CDP-diacylglycerol synthases, YnbB and CdsA, is essential for cell growth and membrane protein export in the cold. FEMS Microbiol Lett 2023; 370:fnad131. [PMID: 38070879 DOI: 10.1093/femsle/fnad131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/29/2023] Open
Abstract
YnbB is a paralogue of CdsA, a CDP-diacylglycerol synthase. While the cdsA gene is essential, the ynbB gene is dispensable. So far, no phenotype of ynbB knockout has been observed. We found that a ynbB knockout strain acquired cold-sensitivity on growth under CdsA-limited conditions. We found that MPIase, a glycolipid involved in protein export, is cold-upregulated to facilitate protein export in the cold, by increasing the mRNA levels of not only CdsA but also that of YnbB. Under non-permissive conditions, phospholipid biosynthesis proceeded normally, however, MPIase upregulation was inhibited with accumulation of precursors of membrane and secretory proteins such as M13 procoat and proOmpA, indicating that YnbB is dedicated to MPIase biosynthesis, complementing the CdsA function.
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Affiliation(s)
- Yuki Kamemoto
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Runa Hikage
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Youjung Han
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Yusei Sekiya
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Katsuhiro Sawasato
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
| | - Ken-Ichi Nishiyama
- The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan
- Department of Applied Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
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5
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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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6
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The Role of the Universally Conserved ATPase YchF/Ola1 in Translation Regulation during Cellular Stress. Microorganisms 2021; 10:microorganisms10010014. [PMID: 35056463 PMCID: PMC8779481 DOI: 10.3390/microorganisms10010014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 11/17/2022] Open
Abstract
The ability to respond to metabolic or environmental changes is an essential feature in all cells and involves both transcriptional and translational regulators that adjust the metabolic activity to fluctuating conditions. While transcriptional regulation has been studied in detail, the important role of the ribosome as an additional player in regulating gene expression is only beginning to emerge. Ribosome-interacting proteins are central to this translational regulation and include universally conserved ribosome interacting proteins, such as the ATPase YchF (Ola1 in eukaryotes). In both eukaryotes and bacteria, the cellular concentrations of YchF/Ola1 determine the ability to cope with different stress conditions and are linked to several pathologies in humans. The available data indicate that YchF/Ola1 regulates the stress response via controlling non-canonical translation initiation and via protein degradation. Although the molecular mechanisms appear to be different between bacteria and eukaryotes, increased non-canonical translation initiation is a common consequence of YchF/Ola1 regulated translational control in E. coli and H. sapiens. In this review, we summarize recent insights into the role of the universally conserved ATPase YchF/Ola1 in adapting translation to unfavourable conditions.
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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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8
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Jiang X, Tan WB, Shrivastava R, Seow DCS, Chen SL, Guan XL, Chng SS. Mutations in enterobacterial common antigen biosynthesis restore outer membrane barrier function in Escherichia coli tol-pal mutants. Mol Microbiol 2020; 114:991-1005. [PMID: 32808719 DOI: 10.1111/mmi.14590] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/12/2020] [Indexed: 12/27/2022]
Abstract
The outer membrane (OM) is an essential component of the Gram-negative bacterial envelope that protects the cells against external threats. To maintain a functional OM, cells require distinct mechanisms to ensure balance of proteins and lipids in the membrane. Mutations in OM biogenesis and/or homeostasis pathways often result in permeability defects, but how molecular changes in the OM affect barrier function is unclear. Here, we seek potential mechanism(s) that can alleviate permeability defects in Escherichia coli cells lacking the Tol-Pal complex, which accumulate excess PLs in the OM. We identify mutations in enterobacterial common antigen (ECA) biosynthesis that re-establish OM barrier function against large hydrophilic molecules, yet did not restore lipid homeostasis. Furthermore, we demonstrate that build-up of biosynthetic intermediates, but not loss of ECA itself, contributes to the rescue. This suppression of OM phenotypes is unrelated to known effects that accumulation of ECA intermediates have on the cell wall. Finally, we reveal that an unusual diacylglycerol pyrophosphoryl-linked lipid species also accumulates in ECA mutants, and might play a role in the rescue phenotype. Our work provides insights into how OM barrier function can be restored independent of lipid homeostasis, and highlights previously unappreciated effects of ECA-related species in OM biology.
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Affiliation(s)
- Xiang'Er Jiang
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Wee Boon Tan
- Singapore Center for Environmental Life Sciences Engineering, National University of Singapore (SCELSE-NUS), Singapore, Singapore
| | - Rahul Shrivastava
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Deborah Chwee San Seow
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Swaine Lin Chen
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Xue Li Guan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Singapore Center for Environmental Life Sciences Engineering, National University of Singapore (SCELSE-NUS), Singapore, Singapore
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9
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Kamemoto Y, Funaba N, Kawakami M, Sawasato K, Kanno K, Suzuki S, Nishikawa H, Sato R, Nishiyama KI. Biosynthesis of glycolipid MPIase (membrane protein integrase) is independent of the genes for ECA (enterobacterial common antigen). J GEN APPL MICROBIOL 2020; 66:169-174. [DOI: 10.2323/jgam.2019.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Yuki Kamemoto
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University
| | - Nanaka Funaba
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University
| | - Mayu Kawakami
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University
| | | | - Kotoka Kanno
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University
| | - Sonomi Suzuki
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University
| | - Hanako Nishikawa
- The United Graduate School of Agricultural Sciences, Iwate University
| | - Ryo Sato
- The United Graduate School of Agricultural Sciences, Iwate University
| | - Ken-ichi Nishiyama
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University
- The United Graduate School of Agricultural Sciences, Iwate University
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10
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Fujikawa K, Nomura K, Nishiyama KI, Shimamoto K. Novel Glycolipid Involved in Membrane Protein Integration: Structure and Mode of Action. J SYN ORG CHEM JPN 2019. [DOI: 10.5059/yukigoseikyokaishi.77.1096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences
| | - Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences
| | - Ken-ichi Nishiyama
- Department of Biological Chemistry, Faculty of Agriculture, Iwate University
| | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences
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11
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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: 11] [Impact Index Per Article: 2.2] [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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12
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Sawasato K, Sekiya Y, Nishiyama K. Two‐step induction ofcdsApromoters leads to upregulation of the glycolipidMPIase at cold temperature. FEBS Lett 2019; 593:1711-1723. [DOI: 10.1002/1873-3468.13460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Katsuhiro Sawasato
- The United Graduate School of Agricultural Sciences Iwate University Morioka Japan
| | - Yusei Sekiya
- 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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13
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Nomura K, Yamaguchi T, Mori S, Fujikawa K, Nishiyama KI, Shimanouchi T, Tanimoto Y, Morigaki K, Shimamoto K. Alteration of Membrane Physicochemical Properties by Two Factors for Membrane Protein Integration. Biophys J 2019; 117:99-110. [PMID: 31164197 PMCID: PMC6626835 DOI: 10.1016/j.bpj.2019.05.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/08/2019] [Accepted: 05/14/2019] [Indexed: 12/01/2022] Open
Abstract
After a nascent chain of a membrane protein emerges from the ribosomal tunnel, the protein is integrated into the cell membrane. This process is controlled by a series of proteinaceous molecular devices, such as signal recognition particles and Sec translocons. In addition to these proteins, we discovered two endogenous components regulating membrane protein integration in the inner membrane of Escherichia coli. The integration is blocked by diacylglycerol (DAG), whereas the blocking is relieved by a glycolipid named membrane protein integrase (MPIase). Here, we investigated the influence of these integration-blocking and integration-promoting factors on the physicochemical properties of membrane lipids via solid-state NMR and fluorescence measurements. These factors did not have destructive effects on membrane morphology because the membrane maintained its lamellar structure and did not fuse in the presence of DAG and/or MPIase at their effective concentrations. We next focused on membrane flexibility. DAG did not affect the mobility of the membrane surface, whereas the sugar chain in MPIase was highly mobile and enhanced the flexibility of membrane lipid headgroups. Comparison with a synthetic MPIase analog revealed the effects of the long sugar chain on membrane properties. The acyl chain order inside the membrane was increased by DAG, whereas the increase was cancelled by the addition of MPIase. MPIase also loosened the membrane lipid packing. Focusing on the transbilayer movement, MPIase reduced the rapid flip-flop motion of DAG. On the other hand, MPIase could not compensate for the diminished lateral diffusion by DAG. These results suggest that by manipulating the membrane lipids dynamics, DAG inhibits the protein from contacting the inner membrane, whereas the flexible long sugar chain of MPIase increases the opportunity for interaction between the membrane and the protein, leading to membrane integration of the newly formed protein.
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Affiliation(s)
- Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
| | - Toshiyuki Yamaguchi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Shoko Mori
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Kohki Fujikawa
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Ken-Ichi Nishiyama
- Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | | | - Yasushi Tanimoto
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | | | - Keiko Shimamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan.
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