1
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Hirata E, Sakata KT, Dearden GI, Noor F, Menon I, Chiduza GN, Menon AK. Molecular characterization of Rft1, an ER membrane protein associated with congenital disorder of glycosylation RFT1-CDG. J Biol Chem 2024; 300:107584. [PMID: 39025454 DOI: 10.1016/j.jbc.2024.107584] [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: 04/04/2024] [Revised: 07/10/2024] [Accepted: 07/11/2024] [Indexed: 07/20/2024] Open
Abstract
The oligosaccharide needed for protein N-glycosylation is assembled on a lipid carrier via a multistep pathway. Synthesis is initiated on the cytoplasmic face of the endoplasmic reticulum (ER) and completed on the luminal side after transbilayer translocation of a heptasaccharide lipid intermediate. More than 30 congenital disorders of glycosylation (CDGs) are associated with this pathway, including RFT1-CDG which results from defects in the membrane protein Rft1. Rft1 is essential for the viability of yeast and mammalian cells and was proposed as the transporter needed to flip the heptasaccharide lipid intermediate across the ER membrane. However, other studies indicated that Rft1 is not required for heptasaccharide lipid flipping in microsomes or unilamellar vesicles reconstituted with ER membrane proteins, nor is it required for the viability of at least one eukaryote. It is therefore not known what essential role Rft1 plays in N-glycosylation. Here, we present a molecular characterization of human Rft1, using yeast cells as a reporter system. We show that it is a multispanning membrane protein located in the ER, with its N and C termini facing the cytoplasm. It is not N-glycosylated. The majority of RFT1-CDG mutations map to highly conserved regions of the protein. We identify key residues that are important for Rft1's ability to support N-glycosylation and cell viability. Our results provide a necessary platform for future work on this enigmatic protein.
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Affiliation(s)
- Eri Hirata
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA
| | - Ken-Taro Sakata
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA
| | - Grace I Dearden
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA
| | - Faria Noor
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA
| | - Indu Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA
| | - George N Chiduza
- Structure and Function of Biological Membranes - Chemistry Department, Université Libre de Bruxelles - Campus Plaine, Brussels, Belgium
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA.
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2
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Hirata E, Sakata KT, Dearden GI, Noor F, Menon I, Chiduza GN, Menon AK. Molecular characterization of Rft1, an ER membrane protein associated with congenital disorder of glycosylation RFT1-CDG. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.587922. [PMID: 38617304 PMCID: PMC11014557 DOI: 10.1101/2024.04.03.587922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The oligosaccharide needed for protein N-glycosylation is assembled on a lipid carrier via a multi-step pathway. Synthesis is initiated on the cytoplasmic face of the endoplasmic reticulum (ER) and completed on the luminal side after transbilayer translocation of a heptasaccharide lipid intermediate. More than 30 Congenital Disorders of Glycosylation (CDGs) are associated with this pathway, including RFT1-CDG which results from defects in the membrane protein Rft1. Rft1 is essential for the viability of yeast and mammalian cells and was proposed as the transporter needed to flip the heptasaccharide lipid intermediate across the ER membrane. However, other studies indicated that Rft1 is not required for heptasaccharide lipid flipping in microsomes or unilamellar vesicles reconstituted with ER membrane proteins, nor is it required for the viability of at least one eukaryote. It is therefore not known what essential role Rft1 plays in N-glycosylation. Here, we present a molecular characterization of human Rft1, using yeast cells as a reporter system. We show that it is a multi-spanning membrane protein located in the ER, with its N and C-termini facing the cytoplasm. It is not N-glycosylated. The majority of RFT1-CDG mutations map to highly conserved regions of the protein. We identify key residues that are important for Rft1's ability to support N-glycosylation and cell viability. Our results provide a necessary platform for future work on this enigmatic protein.
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Affiliation(s)
- Eri Hirata
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Ken-taro Sakata
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Grace I. Dearden
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Faria Noor
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Indu Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - George N. Chiduza
- Structure and Function of Biological Membranes - Chemistry Department, Université Libre de Bruxelles - Campus Plaine, 1050 Brussels, Belgium
| | - Anant K. Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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3
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Wang Y, Kinoshita T. The role of lipid scramblases in regulating lipid distributions at cellular membranes. Biochem Soc Trans 2023; 51:1857-1869. [PMID: 37767549 DOI: 10.1042/bst20221455] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/12/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023]
Abstract
Glycerophospholipids, sphingolipids and cholesterol assemble into lipid bilayers that form the scaffold of cellular membranes, in which proteins are embedded. Membrane composition and membrane protein profiles differ between plasma and intracellular membranes and between the two leaflets of a membrane. Lipid distributions between two leaflets are mediated by lipid translocases, including flippases and scramblases. Flippases use ATP to catalyze the inward movement of specific lipids between leaflets. In contrast, bidirectional flip-flop movements of lipids across the membrane are mediated by scramblases in an ATP-independent manner. Scramblases have been implicated in disrupting the lipid asymmetry of the plasma membrane, protein glycosylation, autophagosome biogenesis, lipoprotein secretion, lipid droplet formation and communications between organelles. Although scramblases in plasma membranes were identified over 10 years ago, most progress about scramblases localized in intracellular membranes has been made in the last few years. Herein, we review the role of scramblases in regulating lipid distributions in cellular membranes, focusing primarily on intracellular membrane-localized scramblases.
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Affiliation(s)
- Yicheng Wang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing 100190, China
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
- Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka 565-0871, Japan
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4
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Nguyen MN, Chakraborty D, Rao SR, Onysk A, Radkiewicz M, Surmacz L, Swiezewska E, Soubeyrand E, Akhtar TA, Kraft TW, Sherry DM, Fliesler SJ, Pittler SJ. A Dhdds K42E knock-in RP59 mouse model shows inner retina pathology and defective synaptic transmission. Cell Death Dis 2023; 14:420. [PMID: 37443173 PMCID: PMC10345138 DOI: 10.1038/s41419-023-05936-4] [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: 09/11/2022] [Revised: 06/07/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Retinitis pigmentosa (RP) defines a group of hereditary progressive rod-cone degenerations that exhibit a common phenotype caused by variants in over 70 genes. While most variants in the dehydrodolichyl diphosphate synthase (DHDDS) gene result in syndromic abnormalities, some variants cause non-syndromic RP (RP59). DHDDS encodes one subunit of the enzyme cis-prenyltransferase (CPT), which is required for the synthesis of dolichol (Dol), that is a necessary protein glycosylation cofactor. We previously reported the creation and initial characterization of a knock-in (KI) mouse model harboring the most prevalent RP59-associated DHDDS variant (K42E) to understand how defects in DHDDS lead to retina-specific pathology. This model exhibited no profound retinal degeneration, nor protein N-glycosylation defects. Here, we report that the Dol isoprenylogue species in retina, liver, and brain of the K42E mouse model are statistically shorter than in the corresponding tissues of age-matched controls, as reported in blood and urine of RP59 patients. Retinal transcriptome analysis demonstrated elevation of many genes encoding proteins involved in synaptogenesis and synaptic function. Quantitative retinal cell layer thickness measurements demonstrated a significant reduction in the inner nuclear layer (INL) and total retinal thickness (TRT) beginning at postnatal (PN) ∼2 months, progressively increasing to PN 18-mo. Histological analysis revealed cell loss in the INL, outer plexiform layer (OPL) disruption, and ectopic localization of outer nuclear layer (ONL) nuclei into the OPL of K42E mutant retinas, relative to controls. Electroretinograms (ERGs) of mutant mice exhibited reduced b-wave amplitudes beginning at PN 1-mo, progressively declining through PN 18-mo, without appreciable a-wave attenuation, relative to controls. Our results suggest that the underlying cause of DHDDS K42E variant driven RP59 retinal pathology is defective synaptic transmission from outer to inner retina.
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Affiliation(s)
- Mai N Nguyen
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Dibyendu Chakraborty
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Sriganesh Ramachandra Rao
- Research Service, VA Western New York Healthcare System, Buffalo, NY, 14215, USA
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, NY, 14203, USA
| | - Agnieszka Onysk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Mariusz Radkiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02106, Poland
| | - Eric Soubeyrand
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Tariq A Akhtar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Timothy W Kraft
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - David M Sherry
- Departments of Cell Biology, Neurosurgery, and Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Steven J Fliesler
- Research Service, VA Western New York Healthcare System, Buffalo, NY, 14215, USA
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, NY, 14203, USA
| | - Steven J Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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5
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Liew CY, Luo HS, Yang TY, Hung AT, Magoling BJA, Lai CPK, Ni CK. Identification of the High Mannose N-Glycan Isomers Undescribed by Conventional Multicellular Eukaryotic Biosynthetic Pathways. Anal Chem 2023. [PMID: 37235553 DOI: 10.1021/acs.analchem.2c05599] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
N-linked glycosylation is one of the most important post-translational modifications of proteins. Current knowledge of multicellular eukaryote N-glycan biosynthesis suggests high mannose N-glycans are generated in the endoplasmic reticulum and Golgi apparatus through conserved biosynthetic pathways. According to conventional biosynthetic pathways, four Man7GlcNAc2 isomers, three Man6GlcNAc2 isomers, and one Man5GlcNAc2 isomer are generated during this process. In this study, we applied our latest mass spectrometry method, logically derived sequence tandem mass spectrometry (LODES/MSn), to re-examine high mannose N-glycans extracted from various multicellular eukaryotes which are not glycosylation mutants. LODES/MSn identified many high mannose N-glycan isomers previously unreported in plantae, animalia, cancer cells, and fungi. A database consisting of retention time and CID MSn mass spectra was constructed for all possible MannGlcNAc2 (n = 5, 6, 7) isomers that include the isomers by removing arbitrary numbers and positions of mannose from canonical N-glycan, Man9GlcNAc2. Many N-glycans in this database are not found in current N-glycan mass spectrum libraries. The database is useful for rapid high mannose N-glycan isomeric identification.
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Affiliation(s)
- Chia Yen Liew
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- International Graduate Program of Molecular Science and Technology, National Taiwan University (NTU-MST), Taipei 10617, Taiwan
- Molecular Science and Technology (MST), Taiwan International Graduate Program (TIGP), Academia Sinica, Taipei 10617, Taiwan
| | - Hong-Sheng Luo
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Ting-Yi Yang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - An-Ti Hung
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Bryan John Abel Magoling
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei 10617, Taiwan
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
| | - Charles Pin-Kuang Lai
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - Chi-Kung Ni
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Molecular Science and Technology (MST), Taiwan International Graduate Program (TIGP), Academia Sinica, Taipei 10617, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
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6
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Kale D, Kikul F, Phapale P, Beedgen L, Thiel C, Brügger B. Quantification of Dolichyl Phosphates Using Phosphate Methylation and Reverse-Phase Liquid Chromatography-High Resolution Mass Spectrometry. Anal Chem 2023; 95:3210-3217. [PMID: 36716239 PMCID: PMC9933046 DOI: 10.1021/acs.analchem.2c03623] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Dolichyl monophosphates (DolPs) are essential lipids in glycosylation pathways that are highly conserved across almost all domains of life. The availability of DolP is critical for all glycosylation processes, as these lipids serve as membrane-anchored building blocks used by various types of glycosyltransferases to generate complex post-translational modifications of proteins and lipids. The analysis of DolP species by reverse-phase liquid chromatography-mass spectrometry (RPLC-MS) remains a challenge due to their very low abundance and wide range of lipophilicities. Until now, a method for the simultaneous qualitative and quantitative assessment of DolP species from biological membranes has been lacking. Here, we describe a novel approach based on simple sample preparation, rapid and efficient trimethylsilyl diazomethane-dependent phosphate methylation, and RPLC-MS analysis for quantification of DolP species with different isoprene chain lengths. We used this workflow to selectively quantify DolP species from lipid extracts derived of Saccharomyces cerevisiae, HeLa, and human skin fibroblasts from steroid 5-α-reductase 3- congenital disorders of glycosylation (SRD5A3-CDG) patients and healthy controls. Integration of this workflow with global lipidomics analyses will be a powerful tool to expand our understanding of the role of DolPs in pathophysiological alterations of metabolic pathways downstream of HMG-CoA reductase, associated with CDGs, hypercholesterolemia, neurodegeneration, and cancer.
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Affiliation(s)
- Dipali Kale
- Heidelberg
University Biochemistry Center (BZH), 69120Heidelberg, Germany,Leibniz-Institut
für Analytische Wissenschaften-ISAS-e.V., 44139Dortmund, Germany,
| | - Frauke Kikul
- Heidelberg
University Biochemistry Center (BZH), 69120Heidelberg, Germany
| | - Prasad Phapale
- Leibniz-Institut
für Analytische Wissenschaften-ISAS-e.V., 44139Dortmund, Germany
| | - Lars Beedgen
- Centre
for Child and Adolescent Medicine, University
Hospital Heidelberg, 69120Heidelberg, Germany
| | - Christian Thiel
- Centre
for Child and Adolescent Medicine, University
Hospital Heidelberg, 69120Heidelberg, Germany
| | - Britta Brügger
- Heidelberg
University Biochemistry Center (BZH), 69120Heidelberg, Germany,
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7
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Zaongo SD, Chen Y. Gut microbiota: a potential key player in boosting immune reconstitution of immunological nonresponders. Future Microbiol 2023; 18:83-85. [PMID: 36727529 DOI: 10.2217/fmb-2022-0215] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Silvere D Zaongo
- Department of Infectious Diseases, Chongqing Public Health Medical Center, Chongqing, 400036, China
| | - Yaokai Chen
- Department of Infectious Diseases, Chongqing Public Health Medical Center, Chongqing, 400036, China
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8
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Ramírez AS, de Capitani M, Pesciullesi G, Kowal J, Bloch JS, Irobalieva RN, Reymond JL, Aebi M, Locher KP. Molecular basis for glycan recognition and reaction priming of eukaryotic oligosaccharyltransferase. Nat Commun 2022; 13:7296. [PMID: 36435935 PMCID: PMC9701220 DOI: 10.1038/s41467-022-35067-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/17/2022] [Indexed: 11/28/2022] Open
Abstract
Oligosaccharyltransferase (OST) is the central enzyme of N-linked protein glycosylation. It catalyzes the transfer of a pre-assembled glycan, GlcNAc2Man9Glc3, from a dolichyl-pyrophosphate donor to acceptor sites in secretory proteins in the lumen of the endoplasmic reticulum. Precise recognition of the fully assembled glycan by OST is essential for the subsequent quality control steps of glycoprotein biosynthesis. However, the molecular basis of the OST-donor glycan interaction is unknown. Here we present cryo-EM structures of S. cerevisiae OST in distinct functional states. Our findings reveal that the terminal glucoses (Glc3) of a chemo-enzymatically generated donor glycan analog bind to a pocket formed by the non-catalytic subunits WBP1 and OST2. We further find that binding either donor or acceptor substrate leads to distinct primed states of OST, where subsequent binding of the other substrate triggers conformational changes required for catalysis. This alternate priming allows OST to efficiently process closely spaced N-glycosylation sites.
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Affiliation(s)
- Ana S. Ramírez
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Mario de Capitani
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Giorgio Pesciullesi
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Julia Kowal
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Joël S. Bloch
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Rossitza N. Irobalieva
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Jean-Louis Reymond
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Markus Aebi
- grid.5801.c0000 0001 2156 2780Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Kaspar P. Locher
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
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9
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Dalton HM, Viswanatha R, Brathwaite R, Zuno JS, Berman AR, Rushforth R, Mohr SE, Perrimon N, Chow CY. A genome-wide CRISPR screen identifies DPM1 as a modifier of DPAGT1 deficiency and ER stress. PLoS Genet 2022; 18:e1010430. [PMID: 36166480 PMCID: PMC9543880 DOI: 10.1371/journal.pgen.1010430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/07/2022] [Accepted: 09/14/2022] [Indexed: 11/19/2022] Open
Abstract
Partial loss-of-function mutations in glycosylation pathways underlie a set of rare diseases called Congenital Disorders of Glycosylation (CDGs). In particular, DPAGT1-CDG is caused by mutations in the gene encoding the first step in N-glycosylation, DPAGT1, and this disorder currently lacks effective therapies. To identify potential therapeutic targets for DPAGT1-CDG, we performed CRISPR knockout screens in Drosophila cells for genes associated with better survival and glycoprotein levels under DPAGT1 inhibition. We identified hundreds of candidate genes that may be of therapeutic benefit. Intriguingly, inhibition of the mannosyltransferase Dpm1, or its downstream glycosylation pathways, could rescue two in vivo models of DPAGT1 inhibition and ER stress, even though impairment of these pathways alone usually causes CDGs. While both in vivo models ostensibly cause cellular stress (through DPAGT1 inhibition or a misfolded protein), we found a novel difference in fructose metabolism that may indicate glycolysis as a modulator of DPAGT1-CDG. Our results provide new therapeutic targets for DPAGT1-CDG, include the unique finding of Dpm1-related pathways rescuing DPAGT1 inhibition, and reveal a novel interaction between fructose metabolism and ER stress.
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Affiliation(s)
- Hans M. Dalton
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Raghuvir Viswanatha
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Roderick Brathwaite
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jae Sophia Zuno
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Alexys R. Berman
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Rebekah Rushforth
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Stephanie E. Mohr
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Clement Y. Chow
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
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10
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Li M, Zhu P, Huang Z, Huang Y, Lv X, Zheng Q, Zhu Z, Fan Z, Yang Y, Shi P. Aspirin damages the cell wall of Saccharomyces cerevisiae by inhibiting the expression and activity of dolichol-phosphate mannose synthase 1. FEBS Lett 2022; 596:369-380. [PMID: 35028934 DOI: 10.1002/1873-3468.14283] [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: 08/19/2021] [Revised: 12/04/2021] [Accepted: 12/12/2021] [Indexed: 11/10/2022]
Abstract
Aspirin is a commonly used anti-inflammatory, analgesic and antithrombotic drug. It has attracted attention due to its potential antifungal therapeutic effect; however, the molecular mechanism is poorly understood. Here, the effects of aspirin on the cell wall of Saccharomyces cerevisiae were explored. We observed by scanning electron microscopy that aspirin could damage the cell wall ultrastructure. Meanwhile, a cellular surface hydrophobicity (CSH) assay showed that aspirin increased the hydrophobicity of the yeast cell surface. A drug sensitivity assay indicated that the overexpression of dolichol phosphate mannose synthase 1 (DPM1) reversed the cell wall damage and decreased the CSH induced by aspirin. Importantly, aspirin decreased the expression and enzyme activity of DPM1 in S. cerevisiae. Molecular docking results demonstrated that aspirin could directly bind to the Ser141 site of DPM1. Similarly, we found that aspirin damaged the cell wall and inhibited the expression of DPM1 in Candida albicans. These findings improve the current understanding of the action mode of aspirin and provide new strategies for antifungal drug design.
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Affiliation(s)
- Ming Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
| | - Pan Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
| | - Zhiwei Huang
- Key Lab of Science & Technology of Eco-textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, China
| | - Yunxia Huang
- School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Xiaoguang Lv
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
| | - Qiaoqiao Zheng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
| | - Ziting Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
| | - Zheyu Fan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
| | - Youjun Yang
- School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Ping Shi
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, China
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11
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Abstract
Rapid flip-flop of phospholipids across the two leaflets of biological membranes is crucial for many aspects of cellular life. The transport proteins that facilitate this process are classified as pump-like flippases and floppases and channel-like scramblases. Unexpectedly, Class A G protein-coupled receptors (GPCRs), a large class of signaling proteins exemplified by the visual receptor rhodopsin and its apoprotein opsin, are constitutively active as scramblases in vitro. In liposomes, opsin scrambles lipids at a unitary rate of >100,000 per second. Atomistic molecular dynamics simulations of opsin in a lipid membrane reveal conformational transitions that expose a polar groove between transmembrane helices 6 and 7. This groove enables transbilayer lipid movement, conceptualized as the swiping of a credit card (lipid) through a card reader (GPCR). Conformational changes that facilitate scrambling are distinct from those associated with GPCR signaling. In this review, we discuss the physiological significance of GPCR scramblase activity and the modes of its regulation in cells. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, USA; .,Institute of Computational Biomedicine, Weill Cornell Medical College, New York, New York, USA
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, New York, USA;
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12
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Van Gelder K, Virta LKA, Easlick J, Prudhomme N, McAlister JA, Geddes-McAlister J, Akhtar TA. A central role for polyprenol reductase in plant dolichol biosynthesis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 303:110773. [PMID: 33487357 DOI: 10.1016/j.plantsci.2020.110773] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/03/2020] [Accepted: 11/20/2020] [Indexed: 06/12/2023]
Abstract
Dolichol is an essential polyisoprenoid within the endoplasmic reticulum of all eukaryotes. It serves as a membrane bound anchor onto which N-glycans are assembled prior to being transferred to nascent polypeptides, many of which enter the secretory pathway. Historically, it has been posited that the accumulation of dolichol represents the 'rate-limiting' step in the evolutionary conserved process of N-glycosylation, which ultimately affects the efficacy of approximately one fifth of the entire eukaryotic proteome. Therefore, this study aimed to enhance dolichol accumulation by manipulating the enzymes involved in its biosynthesis using an established Nicotiana benthamiana platform. Co-expression of a Solanum lycopersicum (tomato) cis-prenyltransferase (CPT) and its cognate partner protein, CPT binding protein (CPTBP), that catalyze the antepenultimate step in dolichol biosynthesis led to a 400-fold increase in the levels of long-chain polyprenols but resulted in only modest increases in dolichol accumulation. However, when combined with a newly characterized tomato polyprenol reductase, dolichol biosynthesis was enhanced by approximately 20-fold. We provide further evidence that in the aquatic macrophyte, Lemna gibba, dolichol is derived exclusively from the mevalonic acid (MVA) pathway with little participation from the evolutionary co-adopted non-MVA pathway. Taken together these results indicate that to effectively enhance the in planta accumulation of dolichol, coordinated synthesis and reduction of polyprenol to dolichol, is strictly required.
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Affiliation(s)
- Kristen Van Gelder
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Lilia K A Virta
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Jeremy Easlick
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Nicholas Prudhomme
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Jason A McAlister
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | | | - Tariq A Akhtar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
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13
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Verchère A, Cowton A, Jenni A, Rauch M, Häner R, Graumann J, Bütikofer P, Menon AK. Complexity of the eukaryotic dolichol-linked oligosaccharide scramblase suggested by activity correlation profiling mass spectrometry. Sci Rep 2021; 11:1411. [PMID: 33446867 PMCID: PMC7809446 DOI: 10.1038/s41598-020-80956-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/31/2020] [Indexed: 01/22/2023] Open
Abstract
The oligosaccharide required for asparagine (N)-linked glycosylation of proteins in the endoplasmic reticulum (ER) is donated by the glycolipid Glc3Man9GlcNAc2-PP-dolichol. Remarkably, whereas glycosylation occurs in the ER lumen, the initial steps of Glc3Man9GlcNAc2-PP-dolichol synthesis generate the lipid intermediate Man5GlcNAc2-PP-dolichol (M5-DLO) on the cytoplasmic side of the ER. Glycolipid assembly is completed only after M5-DLO is translocated to the luminal side. The membrane protein (M5-DLO scramblase) that mediates M5-DLO translocation across the ER membrane has not been identified, despite its importance for N-glycosylation. Building on our ability to recapitulate scramblase activity in proteoliposomes reconstituted with a crude mixture of ER membrane proteins, we developed a mass spectrometry-based 'activity correlation profiling' approach to identify scramblase candidates in the yeast Saccharomyces cerevisiae. Data curation prioritized six polytopic ER membrane proteins as scramblase candidates, but reconstitution-based assays and gene disruption in the protist Trypanosoma brucei revealed, unexpectedly, that none of these proteins is necessary for M5-DLO scramblase activity. Our results instead strongly suggest that M5-DLO scramblase activity is due to a protein, or protein complex, whose activity is regulated at the level of quaternary structure.
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Affiliation(s)
- Alice Verchère
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY, 10065, USA
| | - Andrew Cowton
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstr. 28, 3012, Bern, Switzerland
| | - Aurelio Jenni
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstr. 28, 3012, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Mittelstr. 43, 3012, Bern, Switzerland
| | - Monika Rauch
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstr. 28, 3012, Bern, Switzerland
| | - Robert Häner
- Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, 3012, Bern, Switzerland
| | - Johannes Graumann
- Max Planck Institute for Heart and Lung Research, W.G. Kerckhoff Institute, Ludwigstr. 43, 61231, Bad Nauheim, Germany.,German Centre for Cardiovascular Research (DZHK), Rhine-Main site, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstr. 28, 3012, Bern, Switzerland.
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY, 10065, USA.
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14
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Picca G, Probst M, Langenegger SM, Khorev O, Bütikofer P, Menon AK, Häner R. Nonenzymatic synthesis of anomerically pure, mannosyl-based molecular probes for scramblase identification studies. Beilstein J Org Chem 2020; 16:1732-1739. [PMID: 32765793 PMCID: PMC7385334 DOI: 10.3762/bjoc.16.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/09/2020] [Indexed: 11/23/2022] Open
Abstract
The chemical synthesis of molecular probes to identify and study membrane proteins involved in the biological pathway of protein glycosylation is described. Two short-chain glycolipid analogs that mimic the naturally occurring substrate mannosyl phosphoryl dolichol exhibit either photoreactive and clickable properties or allow the use of a fluorescence readout. Both probes consist of a hydrophilic mannose headgroup that is linked to a citronellol derivative via a phosphodiester bridge. Moreover, a novel phosphoramidite chemistry-based method offers a straightforward approach for the non-enzymatic incorporation of the saccharide moiety in an anomerically pure form.
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Affiliation(s)
- Giovanni Picca
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Markus Probst
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Simon M Langenegger
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Oleg Khorev
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, 10065 New York, United States of America
| | - Robert Häner
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
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15
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Zhang R, Tang BS, Guo JF. Research advances on neurite outgrowth inhibitor B receptor. J Cell Mol Med 2020; 24:7697-7705. [PMID: 32542927 PMCID: PMC7348171 DOI: 10.1111/jcmm.15391] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/17/2020] [Accepted: 04/27/2020] [Indexed: 12/24/2022] Open
Abstract
Neurite outgrowth inhibitor‐B (Nogo‐B) is a membrane protein which is extensively expressed in multiple organs, especially in endothelial cells and vascular smooth muscle cells of blood vessels and belongs to the reticulon protein family. Notably, its specific receptor, Nogo‐B receptor (NgBR), encoded by NUS1, has been implicated in many crucial cellular processes, such as cholesterol trafficking, lipid metabolism, dolichol synthesis, protein N‐glycosylation, vascular remodelling, angiogenesis, tumorigenesis and neurodevelopment. In recent years, accumulating studies have demonstrated the statistically significant changes of NgBR expression levels in human diseases, including Niemann‐Pick type C disease, fatty liver, congenital disorders of glycosylation, persistent pulmonary hypertension of the newborn, invasive ductal breast carcinoma, malignant melanoma, non‐small cell lung carcinoma, paediatric epilepsy and Parkinson's disease. Besides, both the in vitro and in vivo studies have shown that NgBR overexpression or knockdown contribute to the alteration of various pathophysiological processes. Thus, there is a broad development potential in therapeutic strategies by modifying the expression levels of NgBR.
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Affiliation(s)
- Rui Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Bei-Sha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.,Parkinson's Disease Center, Beijing Institute for Brain Disorders, Beijing, China
| | - Ji-Feng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
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16
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Ramachandra Rao S, Skelton LA, Wu F, Onysk A, Spolnik G, Danikiewicz W, Butler MC, Stacks DA, Surmacz L, Mu X, Swiezewska E, Pittler SJ, Fliesler SJ. Retinal Degeneration Caused by Rod-Specific Dhdds Ablation Occurs without Concomitant Inhibition of Protein N-Glycosylation. iScience 2020; 23:101198. [PMID: 32526701 PMCID: PMC7287266 DOI: 10.1016/j.isci.2020.101198] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/10/2020] [Accepted: 05/20/2020] [Indexed: 12/16/2022] Open
Abstract
Dehydrodolichyl diphosphate synthase (DHDDS) catalyzes the committed step in dolichol synthesis. Recessive mutations in DHDDS cause retinitis pigmentosa (RP59), resulting in blindness. We hypothesized that rod photoreceptor-specific ablation of Dhdds would cause retinal degeneration due to diminished dolichol-dependent protein N-glycosylation. Dhddsflx/flx mice were crossed with rod-specific Cre recombinase-expressing (Rho-iCre75) mice to generate rod-specific Dhdds knockout mice (Dhddsflx/flx iCre+). In vivo morphological and electrophysiological evaluation of Dhddsflx/flx iCre+ retinas revealed mild retinal dysfunction at postnatal (PN) 4 weeks, compared with age-matched controls; however, rapid photoreceptor degeneration ensued, resulting in almost complete loss of rods and cones by PN 6 weeks. Retina dolichol levels were markedly decreased by PN 4 weeks in Dhddsflx/flx iCre+ mice, relative to controls; despite this, N-glycosylation of retinal proteins, including opsin (the dominant rod-specific glycoprotein), persisted in Dhddsflx/flx iCre+ mice. These findings challenge the conventional mechanistic view of RP59 as a congenital disorder of glycosylation. Deletion of Dhdds in rod cells caused rapid retinal degeneration in mice Retinal dolichol levels markedly decreased before onset of degeneration Protein N-glycosylation was uncompromised despite Dhdds deletion Degeneration also involved gliosis, microglial activation, and phagoptosis
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Affiliation(s)
- Sriganesh Ramachandra Rao
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Lara A Skelton
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Fuguo Wu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA; New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Agnieszka Onysk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Grzegorz Spolnik
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw 02106, Poland
| | - Witold Danikiewicz
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw 02106, Poland
| | - Mark C Butler
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA
| | - Delores A Stacks
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Xiuqian Mu
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA; New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Steven J Pittler
- Department of Optometry and Vision Science, Vision Science Research Center, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Steven J Fliesler
- Department of Ophthalmology/Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14209, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY 142015, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY 14203, USA.
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17
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Alam J, Sharma L. Potential Enzymatic Targets in Alzheimer's: A Comprehensive Review. Curr Drug Targets 2020; 20:316-339. [PMID: 30124150 DOI: 10.2174/1389450119666180820104723] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/23/2018] [Accepted: 08/15/2018] [Indexed: 12/13/2022]
Abstract
Alzheimer's, a degenerative cause of the brain cells, is called as a progressive neurodegenerative disease and appears to have a heterogeneous etiology with main emphasis on amyloid-cascade and hyperphosphorylated tau-cascade hypotheses, that are directly linked with macromolecules called enzymes such as β- & γ-secretases, colinesterases, transglutaminases, and glycogen synthase kinase (GSK-3), cyclin-dependent kinase (cdk-5), microtubule affinity-regulating kinase (MARK). The catalytic activity of the above enzymes is the result of cognitive deficits, memory impairment and synaptic dysfunction and loss, and ultimately neuronal death. However, some other enzymes also lead to these dysfunctional events when reduced to their normal activities and levels in the brain, such as α- secretase, protein kinase C, phosphatases etc; metabolized to neurotransmitters, enzymes like monoamine oxidase (MAO), catechol-O-methyltransferase (COMT) etc. or these abnormalities can occur when enzymes act by other mechanisms such as phosphodiesterase reduces brain nucleotides (cGMP and cAMP) levels, phospholipase A2: PLA2 is associated with reactive oxygen species (ROS) production etc. On therapeutic fronts, several significant clinical trials are underway by targeting different enzymes for development of new therapeutics to treat Alzheimer's, such as inhibitors for β-secretase, GSK-3, MAO, phosphodiesterase, PLA2, cholinesterases etc, modulators of α- & γ-secretase activities and activators for protein kinase C, sirtuins etc. The last decades have perceived an increasing focus on findings and search for new putative and novel enzymatic targets for Alzheimer's. Here, we review the functions, pathological roles, and worth of almost all the Alzheimer's associated enzymes that address to therapeutic strategies and preventive approaches for treatment of Alzheimer's.
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Affiliation(s)
- Jahangir Alam
- School of Pharmaceutical Sciences, Shoolini University, Solan, H.P., Pin 173229, India
| | - Lalit Sharma
- School of Pharmaceutical Sciences, Shoolini University, Solan, H.P., Pin 173229, India
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18
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Vletter EM, Koning MT, Scherer HU, Veelken H, Toes REM. A Comparison of Immunoglobulin Variable Region N-Linked Glycosylation in Healthy Donors, Autoimmune Disease and Lymphoma. Front Immunol 2020; 11:241. [PMID: 32133009 PMCID: PMC7040075 DOI: 10.3389/fimmu.2020.00241] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/29/2020] [Indexed: 12/14/2022] Open
Abstract
N-linked glycans play an important role in immunity. Although the role of N-linked glycans in the Fragment crystallizable (Fc) region of immunoglobulins has been thoroughly described, the function of N-linked glycans present in Ig-variable domains is only just being appreciated. Most of the N-linked glycans harbored by immunoglobulin variable domain are of the complex biantennary type and are found as a result of the presence of N-linked glycosylation that most often have been introduced by somatic hypermutation. Furthermore, these glycans are ubiquitously present on autoantibodies observed in some autoimmune diseases as well as certain B-cell lymphomas. For example, variable domain glycans are abundantly found by anti-citrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA) as well as by the B-cell receptors of follicular lymphoma (FL). In FL, variable domain glycans are postulated to convey a selective advantage through interaction with lectins and/or microbiota, whereas the contribution of variable domain glycans on autoantibodies is not known. To aid the understanding how these seemingly comparable phenomena contribute to a variety of deranged B-responses in such different diseases this study summarizes the characteristics of ACPA and other auto-antibodies with FL and healthy donor immunoglobulins, to identify the commonalities and differences between variable domain glycans in autoimmune and malignant settings. Our finding indicate intriguing differences in variable domain glycan distribution, frequency and glycan composition in different conditions. These findings underline that variable domain glycosylation is a heterogeneous process that may lead to a number of pathogenic outcomes. Based on the current body of knowledge, we postulate three disease groups with distinct variable domain glycosylation patterns, which might correspond with distinct underlying pathogenic processes.
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Affiliation(s)
- Esther M Vletter
- Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands.,Department of Hematology, Leiden University Medical Center, Leiden, Netherlands
| | - Marvyn T Koning
- Department of Hematology, Leiden University Medical Center, Leiden, Netherlands
| | - Hans Ulrich Scherer
- Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands
| | - Hendrik Veelken
- Department of Hematology, Leiden University Medical Center, Leiden, Netherlands
| | - Rene E M Toes
- Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands
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19
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Ziogiene D, Valaviciute M, Norkiene M, Timinskas A, Gedvilaite A. Mutations of Kluyveromyces lactis dolichol kinase enhances secretion of recombinant proteins. FEMS Yeast Res 2019; 19:5379315. [DOI: 10.1093/femsyr/foz024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 03/12/2019] [Indexed: 12/16/2022] Open
Abstract
ABSTRACT
Although there are similarities in the core steps of the secretion pathway from yeast to higher eukaryotes, significant functional differences exist even among diverse yeast species. Here, we used next-generation sequencing to identify two mutations in the Kluyveromyces lactis KlSEC59 gene, encoding dolichol kinase (DK), which are responsible for an enhanced secretion phenotype in a previously isolated mutant, MD2/1-9. Compared with the temperature-sensitive Saccharomyces cerevisiae sec59-1 mutant, which exhibits reduced N-glycosylation and decreased secretory efficacy, the identified K. lactis DK mutations had fewer effects on glycosylation, as well as on survival at high temperature and cell wall integrity. Moreover, despite some glycosylation defects, double DK mutations (G405S and I419S) in the K. lactis mutant strain demonstrated three times the level of recombinant α-amylase secretion as the wild-type strain. Overexpression of potential suppressors KlMNN10, KlSEL1, KlERG20, KlSRT1, KlRER2, KlCAX4, KlLPP1 and KlDPP1 in the DK-mutant strain restored carboxypeptidase Y glycosylation to different extents and, with the exception of KISRT1, reduced α-amylase secretion to levels observed in wild-type cells. Our results suggest that enhanced secretion related to reduced activity of mutant DK in K. lactis results from mild glycosylation changes that affect activity of other proteins in the secretory pathway.
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Affiliation(s)
- Danguole Ziogiene
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Monika Valaviciute
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Milda Norkiene
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Albertas Timinskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
| | - Alma Gedvilaite
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Sauletekio al. 7, LT-10257 Vilnius, Lithuania
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20
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Depaoli MR, Hay JC, Graier WF, Malli R. The enigmatic ATP supply of the endoplasmic reticulum. Biol Rev Camb Philos Soc 2018; 94:610-628. [PMID: 30338910 PMCID: PMC6446729 DOI: 10.1111/brv.12469] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/20/2018] [Accepted: 08/30/2018] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is a functionally and morphologically complex cellular organelle largely responsible for a variety of crucial functions, including protein folding, maturation and degradation. Furthermore, the ER plays an essential role in lipid biosynthesis, dynamic Ca2+ storage, and detoxification. Malfunctions in ER‐related processes are responsible for the genesis and progression of many diseases, such as heart failure, cancer, neurodegeneration and metabolic disorders. To fulfill many of its vital functions, the ER relies on a sufficient energy supply in the form of adenosine‐5′‐triphosphate (ATP), the main cellular energy source. Despite landmark discoveries and clarification of the functional principles of ER‐resident proteins and key ER‐related processes, the mechanism underlying ER ATP transport remains somewhat enigmatic. Here we summarize ER‐related ATP‐consuming processes and outline our knowledge about the nature and function of the ER energy supply.
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Affiliation(s)
- Maria R Depaoli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences and Center for Structural and Functional Neuroscience, The University of Montana, 32 Campus Drive, HS410, Missoula, MT 59812-4824, U.S.A
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
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21
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Detection of variants in dystroglycanopathy-associated genes through the application of targeted whole-exome sequencing analysis to a large cohort of patients with unexplained limb-girdle muscle weakness. Skelet Muscle 2018; 8:23. [PMID: 30060766 PMCID: PMC6066920 DOI: 10.1186/s13395-018-0170-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/13/2018] [Indexed: 12/16/2022] Open
Abstract
Background Dystroglycanopathies are a clinically and genetically heterogeneous group of disorders that are typically characterised by limb-girdle muscle weakness. Mutations in 18 different genes have been associated with dystroglycanopathies, the encoded proteins of which typically modulate the binding of α-dystroglycan to extracellular matrix ligands by altering its glycosylation. This results in a disruption of the structural integrity of the myocyte, ultimately leading to muscle degeneration. Methods Deep phenotypic information was gathered using the PhenoTips online software for 1001 patients with unexplained limb-girdle muscle weakness from 43 different centres across 21 European and Middle Eastern countries. Whole-exome sequencing with at least 250 ng DNA was completed using an Illumina exome capture and a 38 Mb baited target. Genes known to be associated with dystroglycanopathies were analysed for disease-causing variants. Results Suspected pathogenic variants were detected in DPM3, ISPD, POMT1 and FKTN in one patient each, in POMK in two patients, in GMPPB in three patients, in FKRP in eight patients and in POMT2 in ten patients. This indicated a frequency of 2.7% for the disease group within the cohort of 1001 patients with unexplained limb-girdle muscle weakness. The phenotypes of the 27 patients were highly variable, yet with a fundamental presentation of proximal muscle weakness and elevated serum creatine kinase. Conclusions Overall, we have identified 27 patients with suspected pathogenic variants in dystroglycanopathy-associated genes. We present evidence for the genetic and phenotypic diversity of the dystroglycanopathies as a disease group, while also highlighting the advantage of incorporating next-generation sequencing into the diagnostic pathway of rare diseases. Electronic supplementary material The online version of this article (10.1186/s13395-018-0170-1) contains supplementary material, which is available to authorized users.
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22
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Van den Bergh PYK, Sznajer Y, Van Parys V, van Tol W, Wevers RA, Lefeber DJ, Xu L, Lek M, MacArthur DG, Johnson K, Phillips L, Töpf A, Straub V. A homozygous DPM3 mutation in a patient with alpha-dystroglycan-related limb girdle muscular dystrophy. Neuromuscul Disord 2017; 27:1043-1046. [PMID: 28803818 DOI: 10.1016/j.nmd.2017.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/27/2017] [Accepted: 07/12/2017] [Indexed: 10/19/2022]
Abstract
Defects of O-linked glycosylation of alpha-dystroglycan cause a wide spectrum of muscular dystrophies ranging from severe congenital muscular dystrophy associated with abnormal brain and eye development to mild limb girdle muscular dystrophy. We report a female patient who developed isolated pelvic girdle muscle weakness and wasting, which became symptomatic at age 42. Exome sequencing uncovered a homozygous c.131T > G (p.Leu44Pro) substitution in DPM3, encoding dolichol-P-mannose (DPM) synthase subunit 3, leading to a 50% reduction of enzymatic activity. Decreased availability of DPM as an essential donor substrate for protein O-mannosyltransferase (POMT) 1 and 2 explains defective skeletal muscle alpha-dystroglycan O-glycosylation. Our findings show that DPM3 mutations may lead to an isolated and mild limb girdle muscular dystrophy phenotype without cardiomyopathy.
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Affiliation(s)
- P Y K Van den Bergh
- Neuromuscular Reference Centre, University Hospital St-Luc, University of Louvain, Brussels, Belgium.
| | - Y Sznajer
- Neuromuscular Reference Centre, University Hospital St-Luc, University of Louvain, Brussels, Belgium; Centre for Human Genetics, University Hospital St-Luc, University of Louvain, Brussels, Belgium
| | - V Van Parys
- Neuromuscular Reference Centre, University Hospital St-Luc, University of Louvain, Brussels, Belgium
| | - W van Tol
- Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands; Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - R A Wevers
- Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - D J Lefeber
- Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands; Translational Metabolic Laboratory, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - L Xu
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - M Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - D G MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - K Johnson
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon-Tyne, United Kingdom
| | - L Phillips
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon-Tyne, United Kingdom
| | - A Töpf
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon-Tyne, United Kingdom
| | - V Straub
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon-Tyne, United Kingdom
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23
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Eichler J, Guan Z. Lipid sugar carriers at the extremes: The phosphodolichols Archaea use in N-glycosylation. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:589-599. [PMID: 28330764 DOI: 10.1016/j.bbalip.2017.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/15/2017] [Accepted: 03/17/2017] [Indexed: 11/28/2022]
Abstract
N-glycosylation, a post-translational modification whereby glycans are covalently linked to select Asn residues of target proteins, occurs in all three domains of life. Across evolution, the N-linked glycans are initially assembled on phosphorylated cytoplasmically-oriented polyisoprenoids, with polyprenol (mainly C55 undecaprenol) fulfilling this role in Bacteria and dolichol assuming this function in Eukarya and Archaea. The eukaryal and archaeal versions of dolichol can, however, be distinguished on the basis of their length, degree of saturation and by other traits. As is true for many facets of their biology, Archaea, best known in their capacity as extremophiles, present unique approaches for synthesizing phosphodolichols. At the same time, general insight into the assembly and processing of glycan-bearing phosphodolichols has come from studies of the archaeal enzymes responsible. In this review, these and other aspects of archaeal phosphodolichol biology are addressed.
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Affiliation(s)
- Jerry Eichler
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva 84105, Israel.
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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24
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Lombard J. Early evolution of polyisoprenol biosynthesis and the origin of cell walls. PeerJ 2016; 4:e2626. [PMID: 27812422 PMCID: PMC5088576 DOI: 10.7717/peerj.2626] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 09/27/2016] [Indexed: 11/30/2022] Open
Abstract
After being a matter of hot debate for years, the presence of lipid membranes in the last common ancestor of extant organisms (i.e., the cenancestor) now begins to be generally accepted. By contrast, cenancestral cell walls have attracted less attention, probably owing to the large diversity of cell walls that exist in the three domains of life. Many prokaryotic cell walls, however, are synthesized using glycosylation pathways with similar polyisoprenol lipid carriers and topology (i.e., orientation across the cell membranes). Here, we provide the first systematic phylogenomic report on the polyisoprenol biosynthesis pathways in the three domains of life. This study shows that, whereas the last steps of the polyisoprenol biosynthesis are unique to the respective domain of life of which they are characteristic, the enzymes required for basic unsaturated polyisoprenol synthesis can be traced back to the respective last common ancestor of each of the three domains of life. As a result, regardless of the topology of the tree of life that may be considered, the most parsimonious hypothesis is that these enzymes were inherited in modern lineages from the cenancestor. This observation supports the presence of an enzymatic mechanism to synthesize unsaturated polyisoprenols in the cenancestor and, since these molecules are notorious lipid carriers in glycosylation pathways involved in the synthesis of a wide diversity of prokaryotic cell walls, it provides the first indirect evidence of the existence of a hypothetical unknown cell wall synthesis mechanism in the cenancestor.
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Affiliation(s)
- Jonathan Lombard
- Biosciences, University of Exeter, Exeter, United Kingdom; National Evolutionary Synthesis Center, Durham, NC, United States of America
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25
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Pomorski TG, Menon AK. Lipid somersaults: Uncovering the mechanisms of protein-mediated lipid flipping. Prog Lipid Res 2016; 64:69-84. [PMID: 27528189 DOI: 10.1016/j.plipres.2016.08.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 08/10/2016] [Indexed: 12/22/2022]
Abstract
Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support diverse aspects of cellular life. Here we discuss the mechanisms by which rapid flip-flop occurs, and what role lipid flipping plays in membrane homeostasis and cell growth. We focus on conceptual aspects, highlighting mechanistic insights from biochemical and in silico experiments, and the recent, ground-breaking identification of a number of lipid scramblases.
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Affiliation(s)
- Thomas Günther Pomorski
- Faculty of Chemistry and Biochemistry, Molecular Biochemistry, Ruhr University Bochum, Universitätstrasse 150, D-44780 Bochum, Germany; Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark.
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.
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26
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DMP1-CDG (CDG1e) with Significant Gastrointestinal Manifestations; Phenotype and Genotype Expansion. JIMD Rep 2016; 34:27-32. [PMID: 27481510 DOI: 10.1007/8904_2016_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/28/2016] [Accepted: 07/08/2016] [Indexed: 12/28/2022] Open
Abstract
The literature describes eight cases of mutations in the DPM1 gene generating DMP1-CDG, causing similar phenotype of early onset seizures, microcephaly and developmental delay. Investigations of these patients revealed associated abnormal findings on brain imaging, elevated CK, abnormal clotting factors and mildly deranged serum transaminases. We describe the ninth case of DMP1-CDG, whose clinical presentation includes severe gastrointestinal involvement, i.e. food protein induced enterocolitis syndrome (FPIES). Gastrointestinal manifestations (GIT) of the congenital glycosylation disorders have included deranged liver function, hepatomegaly, liver fibrosis, steatosis and protein-losing enteropathy. This is the first report of a congenital glycosylation disorder being associated with FPIES.
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27
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Marchese M, Pappalardo A, Baldacci J, Verri T, Doccini S, Cassandrini D, Bruno C, Fiorillo C, Garcia-Gil M, Bertini E, Pitto L, Santorelli FM. Dolichol-phosphate mannose synthase depletion in zebrafish leads to dystrophic muscle with hypoglycosylated α-dystroglycan. Biochem Biophys Res Commun 2016; 477:137-143. [PMID: 27291147 DOI: 10.1016/j.bbrc.2016.06.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 06/08/2016] [Indexed: 12/24/2022]
Abstract
Defective dolichol-phosphate mannose synthase (DPMS) complex is a rare cause of congenital muscular dystrophy associated with hypoglycosylation of alpha-dystroglycan (α-DG) in skeletal muscle. We used the zebrafish (Danio rerio) to model muscle abnormalities due to defects in the subunits of DPMS. The three zebrafish ortholog subunits (encoded by the dpm1, dpm2 and dpm3 genes, respectively) showed high similarity to the human proteins, and their expression displayed localization in the midbrain/hindbrain area and somites. Antisense morpholino oligonucleotides targeting each subunit were used to transiently deplete the dpm genes. The resulting morphant embryos showed early death, muscle disorganization, low DPMS complex activity, and increased levels of apoptotic nuclei, together with hypoglycosylated α-DG in muscle fibers, thus recapitulating most of the characteristics seen in patients with mutations in DPMS. Our results in zebrafish suggest that DPMS plays a role in stabilizing muscle structures and in apoptotic cell death.
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Affiliation(s)
- Maria Marchese
- Molecular Medicine, IRCCS Stella Maris, Via dei Giacinti 2, 56128, Pisa, Italy
| | - Andrea Pappalardo
- Molecular Medicine, IRCCS Stella Maris, Via dei Giacinti 2, 56128, Pisa, Italy
| | - Jacopo Baldacci
- Molecular Medicine, IRCCS Stella Maris, Via dei Giacinti 2, 56128, Pisa, Italy
| | - Tiziano Verri
- Department of Biological and Environmental Sciences and Technologies, University of Salento, S.P. 6 Lecce-Monteroni, 73100, Lecce, Italy
| | - Stefano Doccini
- Molecular Medicine, IRCCS Stella Maris, Via dei Giacinti 2, 56128, Pisa, Italy
| | - Denise Cassandrini
- Molecular Medicine, IRCCS Stella Maris, Via dei Giacinti 2, 56128, Pisa, Italy
| | - Claudio Bruno
- Center of Myology and Neurodegenerative Disorders, Department of Neuroscience, Istituto G. Gaslini, Largo Gaslini 5, 16147, Genoa, Italy
| | - Chiara Fiorillo
- Molecular Medicine, IRCCS Stella Maris, Via dei Giacinti 2, 56128, Pisa, Italy
| | - Mercedes Garcia-Gil
- Department of Biology, University of Pisa, Via Luca Ghini 13, 56126, Pisa, Italy
| | - Enrico Bertini
- IRCCS Bambino Gesù Hospital, Viale S. Paolo 15, 00146, Rome, Italy
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28
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Massarweh A, Bosco M, Iatmanen-Harbi S, Tessier C, Amana L, Busca P, Chantret I, Gravier-Pelletier C, Moore SEH. Brefeldin A promotes the appearance of oligosaccharyl phosphates derived from Glc3Man9GlcNAc2-PP-dolichol within the endomembrane system of HepG2 cells. J Lipid Res 2016; 57:1477-91. [PMID: 27281477 DOI: 10.1194/jlr.m068551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Indexed: 01/04/2023] Open
Abstract
We reported an oligosaccharide diphosphodolichol (DLO) diphosphatase (DLODP) that generates dolichyl-phosphate and oligosaccharyl phosphates (OSPs) from DLO in vitro. This enzyme could underlie cytoplasmic OSP generation and promote dolichyl-phosphate recycling from truncated endoplasmic reticulum (ER)-generated DLO intermediates. However, during subcellular fractionation, DLODP distribution is closer to that of a Golgi apparatus (GA) marker than those of ER markers. Here, we examined the effect of brefeldin A (BFA), which fuses the GA with the ER on OSP metabolism. In order to increase the steady state level of truncated DLO while allowing formation of mature DLO (Glc3Man9GlcNAc2-PP-dolichol), dolichyl-P-mannose Man7GlcNAc2-PP-dolichol mannosyltransferase was partially downregulated in HepG2 cells. We show that BFA provokes GA endomannosidase trimming of Glc3Man9GlcNAc2-PP-dolichol to yield a Man8GlcNAc2-PP-dolichol structure that does not give rise to cytoplasmic Man8GlcNAc2-P. BFA also strikingly increased OSP derived from mature DLO within the endomembrane system without affecting levels of Man7GlcNAc2-PP-dolichol or cytoplasmic Man7GlcNAc2-P. The BFA-provoked increase in endomembrane-situated OSP is sensitive to nocodazole, and BFA causes partial redistribution of DLODP activity from GA- to ER-containing regions of density gradients. These findings are consistent with BFA-provoked microtubule-dependent GA-to-ER transport of a previously reported DLODP that acts to generate a novel endomembrane-situated OSP population.
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Affiliation(s)
- Ahmad Massarweh
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France Université Pierre et Marie Curie, Paris 6, Paris, France
| | - Michaël Bosco
- Université Paris Descartes, CICB-Paris, CNRS UMR8601, LCBPT, Paris, France
| | | | - Clarice Tessier
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
| | - Laura Amana
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
| | - Patricia Busca
- Université Paris Descartes, CICB-Paris, CNRS UMR8601, LCBPT, Paris, France
| | - Isabelle Chantret
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
| | | | - Stuart E H Moore
- INSERM U1149, Paris, France Université Denis Diderot, Paris 7, Paris, France
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29
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Serrano-Villar S, Rojo D, Martínez-Martínez M, Deusch S, Vázquez-Castellanos JF, Bargiela R, Sainz T, Vera M, Moreno S, Estrada V, Gosalbes MJ, Latorre A, Seifert J, Barbas C, Moya A, Ferrer M. Gut Bacteria Metabolism Impacts Immune Recovery in HIV-infected Individuals. EBioMedicine 2016; 8:203-216. [PMID: 27428431 PMCID: PMC4919658 DOI: 10.1016/j.ebiom.2016.04.033] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/01/2016] [Accepted: 04/25/2016] [Indexed: 02/07/2023] Open
Abstract
While changes in gut microbial populations have been described in human immuno-deficiency virus (HIV)-infected patients undergoing antiretroviral therapy (ART), the mechanisms underlying the contributions of gut bacteria and their molecular agents (metabolites and proteins) to immune recovery remain unexplored. To study this, we examined the active fraction of the gut microbiome, through examining protein synthesis and accumulation of metabolites inside gut bacteria and in the bloodstream, in 8 healthy controls and 29 HIV-infected individuals (6 being longitudinally studied). We found that HIV infection is associated to dramatic changes in the active set of gut bacteria simultaneously altering the metabolic outcomes. Effects were accentuated among immunological ART responders, regardless diet, subject characteristics, clinical variables other than immune recovery, the duration and type of ART and sexual preferences. The effect was found at quantitative levels of several molecular agents and active bacteria which were herein identified and whose abundance correlated with HIV immune pathogenesis markers. Although, we cannot rule out the possibility that some changes are partially a random consequence of the disease status, our data suggest that most likely reduced inflammation and immune recovery is a joint solution orchestrated by both the active fraction of the gut microbiota and the host.
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Affiliation(s)
- Sergio Serrano-Villar
- Department of Infectious Diseases, University Hospital Ramón y Cajal and Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
| | - David Rojo
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad CEU San Pablo, Campus Montepríncipe, Madrid, Spain
| | | | - Simon Deusch
- Institute of Animal Science, Universität Hohenheim, Stuttgart, Germany
| | - Jorge F Vázquez-Castellanos
- Foundation for the Promotion of Health and Biomedical Research in the Valencian Community (FISABIO) - Public Health, Valencia, Spain; Network Research Center for Epidemiology and Public Health (CIBER-ESP), Madrid, Spain
| | - Rafael Bargiela
- Institute of Catalysis, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Talía Sainz
- Department of Pediatric Infectious Diseases, University Hospital La Paz, and La Paz Research Institute (IdiPAZ), Madrid, Spain
| | - Mar Vera
- Centro Sanitario Sandoval, Madrid, Spain
| | - Santiago Moreno
- Department of Infectious Diseases, University Hospital Ramón y Cajal and Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
| | - Vicente Estrada
- HIV Unit, Department of Internal Medicine, University Hospital Clínico San Carlos, Madrid, Spain
| | - María José Gosalbes
- Foundation for the Promotion of Health and Biomedical Research in the Valencian Community (FISABIO) - Public Health, Valencia, Spain; Network Research Center for Epidemiology and Public Health (CIBER-ESP), Madrid, Spain
| | - Amparo Latorre
- Foundation for the Promotion of Health and Biomedical Research in the Valencian Community (FISABIO) - Public Health, Valencia, Spain; Network Research Center for Epidemiology and Public Health (CIBER-ESP), Madrid, Spain; Instituto Cavanilles de Biodiversidad y Biología Evolutiva (Universidad de Valencia), Valencia, Spain
| | - Jana Seifert
- Institute of Animal Science, Universität Hohenheim, Stuttgart, Germany
| | - Coral Barbas
- Centro de Metabolómica y Bioanálisis (CEMBIO), Facultad de Farmacia, Universidad CEU San Pablo, Campus Montepríncipe, Madrid, Spain.
| | - Andrés Moya
- Foundation for the Promotion of Health and Biomedical Research in the Valencian Community (FISABIO) - Public Health, Valencia, Spain; Network Research Center for Epidemiology and Public Health (CIBER-ESP), Madrid, Spain; Instituto Cavanilles de Biodiversidad y Biología Evolutiva (Universidad de Valencia), Valencia, Spain.
| | - Manuel Ferrer
- Institute of Catalysis, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.
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30
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Rush JS. Role of Flippases in Protein Glycosylation in the Endoplasmic Reticulum. Lipid Insights 2016; 8:45-53. [PMID: 26917968 PMCID: PMC4762491 DOI: 10.4137/lpi.s31784] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/12/2016] [Accepted: 01/15/2016] [Indexed: 12/21/2022] Open
Abstract
Glycosylation is essential to the synthesis, folding, and function of glycoproteins in eukaryotes. Proteins are co- and posttranslationally modified by a variety of glycans in the endoplasmic reticulum (ER); modifications include C- and O-mannosylation, N-glycosylation, and the addition of glycosylphosphatidylinositol membrane anchors. Protein glycosylation in the ER of eukaryotes involves enzymatic steps on both the cytosolic and lumenal surfaces of the ER membrane. The glycans are first assembled as precursor glycolipids, on the cytosolic surface of the ER, which are tethered to the membrane by attachment to a long-chain polyisoprenyl phosphate (dolichol) containing a reduced α-isoprene. The lipid-anchored building blocks then migrate transversely (flip) across the ER membrane to the lumenal surface, where final assembly of the glycan is completed. This strategy allows the cell to export high-energy biosynthetic intermediates as lipid-bound glycans, while constraining the glycosyl donors to the site of assembly on the membrane surface. This review focuses on the flippases that participate in protein glycosylation in the ER.
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Affiliation(s)
- Jeffrey S Rush
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY, USA
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31
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Park EJ, Grabińska KA, Guan Z, Sessa WC. NgBR is essential for endothelial cell glycosylation and vascular development. EMBO Rep 2016; 17:167-77. [PMID: 26755743 DOI: 10.15252/embr.201540789] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/27/2015] [Indexed: 01/27/2023] Open
Abstract
NgBR is a transmembrane protein identified as a Nogo-B-interacting protein and recently has been shown to be a subunit required for cis-prenyltransferase (cisPTase) activity. To investigate the integrated role of NgBR in vascular development, we have characterized endothelial-specific NgBR knockout embryos. Here, we show that endothelial-specific NgBR knockout results in embryonic lethality due to vascular development defects in yolk sac and embryo proper. Loss of NgBR in endothelial cells reduces proliferation and promotes apoptosis of the cells largely through defects in the glycosylation of key endothelial proteins including VEGFR2, VE-cadherin, and CD31, and defective glycosylation can be rescued by treatment with the end product of cisPTase activity, dolichol phosphate. Moreover, NgBR functions in endothelial cells during embryogenesis are Nogo-B independent. These data uniquely show the importance of NgBR and protein glycosylation during vascular development.
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Affiliation(s)
- Eon Joo Park
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Kariona A Grabińska
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - William C Sessa
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT, USA
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32
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Killing Me Softly: Connotations to Unfolded Protein Response and Oxidative Stress in Alzheimer's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:1805304. [PMID: 26881014 PMCID: PMC4736771 DOI: 10.1155/2016/1805304] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/28/2015] [Accepted: 12/07/2015] [Indexed: 11/18/2022]
Abstract
This review is focused on the possible causes of mitochondrial dysfunction in AD, underlying molecular mechanisms of this malfunction, possible causes and known consequences of APP, Aβ, and hyperphosphorylated tau presence in mitochondria, and the contribution of altered lipid metabolism (nonsterol isoprenoids) to pathological processes leading to increased formation and accumulation of the aforementioned hallmarks of AD. Abnormal protein folding and unfolded protein response seem to be the outcomes of impaired glycosylation due to metabolic disturbances in geranylgeraniol intermediary metabolism. The origin and consecutive fate of APP, Aβ, and tau are emphasized on intracellular trafficking apparently influenced by inaccurate posttranslational modifications. We hypothesize that incorrect intracellular processing of APP determines protein translocation to mitochondria in AD. Similarly, without obvious reasons, the passage of Aβ and tau to mitochondria is observed. APP targeted to mitochondria blocks the activity of protein translocase complex resulting in poor import of proteins central to oxidative phosphorylation. Besides, APP, Aβ, and neurofibrillary tangles of tau directly or indirectly impair mitochondrial biochemistry and bioenergetics, with concomitant generation of oxidative/nitrosative stress. Limited protective mechanisms are inadequate to prevent the free radical-mediated lesions. Finally, neuronal loss is observed in AD-affected brains typically by pathologic apoptosis.
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33
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Kozlov VV, Danilov LL. Reversed-phase ion-pair high-performance liquid chromatography assay of polyprenyl diphosphate oligomer homologues. J Sep Sci 2015; 39:525-7. [PMID: 26608950 DOI: 10.1002/jssc.201501098] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 11/12/2022]
Abstract
A reversed-phase ion-pair high-performance liquid chromatography procedure was developed for the separation of polyprenyl diphosphate oligomer homologues obtained chemically from plant polyprenols. Tetrabutylammonium phosphate was used as the ion-pair reagent, and the dependence of the separation quality on pH of ion-pair reagent was investigated for the first time. The procedure is applicable for the control of commercial available polyprenyl monophosphates (the active components of veterinary drugs Phosprenyl and Gamapren) for the possible presence of polyprenyl diphosphate byproducts.
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Affiliation(s)
- Vyacheslav V Kozlov
- Laboratory of natural immunity, Department of immunology, N.F. Gamaleya Federal Research Centre of Epidemiology and Microbiology, Moscow, Russian Federation
| | - Leonid L Danilov
- Laboratory of Carbohydrate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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34
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Lehrman MA. Flipping a Lipid-Linked Oligosaccharide? You Must Whip It! Trends Biochem Sci 2015; 40:715-717. [PMID: 26476576 DOI: 10.1016/j.tibs.2015.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 10/02/2015] [Indexed: 12/22/2022]
Abstract
The mechanism for flipping large lipid-linked oligosaccharides across membranes has remained a paradox. Perez et al. now report the structure of the PglK protein of C. jejuni, a flippase for a bacterial lipid-linked oligosaccharide, and reveal an unexpected whip-like mechanism.
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Affiliation(s)
- Mark A Lehrman
- Department Pharmacology, UT-Southwestern Medical Center at Dallas, Dallas, TX, USA.
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35
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Affiliation(s)
- Alice Verchère
- Department of Biochemistry, Weill Cornell Medical College, New York, New York 10065, USA
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, New York 10065, USA
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36
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Villacrés C, Tayi VS, Lattová E, Perreault H, Butler M. Low glucose depletes glycan precursors, reduces site occupancy and galactosylation of a monoclonal antibody in CHO cell culture. Biotechnol J 2015; 10:1051-66. [PMID: 26058832 DOI: 10.1002/biot.201400662] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/14/2015] [Accepted: 06/07/2015] [Indexed: 12/12/2022]
Abstract
Controlled feeding of glucose has been employed previously to enhance the productivity of recombinant glycoproteins but there is a concern that low concentrations of glucose could limit the synthesis of precursors of glycosylation. Here we investigate the effect of glucose depletion on the metabolism, productivity and glycosylation of a chimeric human-llama monoclonal antibody secreted by CHO cells. The cells were inoculated into media containing varying concentrations of glucose. Glucose depletion occurred in cultures with an initial glucose ≤5.5 mM and seeded at low density (2.5 × 10(5) cells/mL) or at high cell inoculum (≥2.5 × 10(6) cells/mL) at higher glucose concentration (up to 25 mM). Glucose-depleted cultures produced non-glycosylated Mabs (up to 51%), lower galactosylation index (GI <0.43) and decreased sialylation (by 85%) as measured by mass spectrometry and HPLC. At low glucose a reduced intracellular pool of nucleotides (0.03-0.23 fmoles/cell) was measured as well as a low adenylate energy charge (<0.57). Low glucose also reduced GDP-sugars (by 77%) and UDP-hexosamines (by 90%). The data indicate that under glucose deprivation, low levels of intracellular nucleotides and nucleotide sugars reduced the availability of the immediate precursors of glycosylation. These results are important when applied to the design of fed-batch cultures.
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Affiliation(s)
- Carina Villacrés
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Venkata S Tayi
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Erika Lattová
- Chemistry Department, University of Manitoba, Winnipeg, MB, Canada
- Masaryk University, CEITEC, Proteomics, Czech Republic
| | - Hélène Perreault
- Chemistry Department, University of Manitoba, Winnipeg, MB, Canada
| | - Michael Butler
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada.
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Brasher MI, Surmacz L, Leong B, Pitcher J, Swiezewska E, Pichersky E, Akhtar TA. A two-component enzyme complex is required for dolichol biosynthesis in tomato. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:903-914. [PMID: 25899081 DOI: 10.1111/tpj.12859] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 05/22/2023]
Abstract
Dolichol plays an indispensable role in the N-glycosylation of eukaryotic proteins. As proteins enter the secretory pathway they are decorated by a 'glycan', which is preassembled onto a membrane-anchored dolichol molecule embedded within the endoplasmic reticulum (ER). Genetic and biochemical evidence in yeast and animals indicate that a cis-prenyltransferase (CPT) is required for dolichol synthesis, but also point to other factor(s) that could be involved. In this study, RNAi-mediated suppression of one member of the tomato CPT family (SlCPT3) resulted in a ~60% decrease in dolichol content. We further show that the involvement of SlCPT3 in dolichol biosynthesis requires the participation of a distantly related partner protein, designated as CPT-binding protein (SlCPTBP), which is a close homolog of the human Nogo-B receptor. Yeast two-hybrid and co-immunoprecipitation assays demonstrate that SlCPT3 and its partner protein interact in vivo and that both SlCPT3 and SlCPTBP are required to complement the growth defects and dolichol deficiency of the yeast dolichol mutant, rer2∆. Co-expression of SlCPT3 and SlCPTBP in yeast and in E. coli confirmed that dolichol synthase activity strictly requires both proteins. Finally, organelle isolation and in vivo localization of fluorescent protein fusions showed that both SlCPT3 and SlCPTBP localize to the ER, the site of dolichol accumulation and synthesis in eukaryotes.
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Affiliation(s)
- Megan I Brasher
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego Street, 02-106, Warsaw, Poland
| | - Bryan Leong
- Department of Molecular and Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jocelyn Pitcher
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego Street, 02-106, Warsaw, Poland
| | - Eran Pichersky
- Department of Molecular and Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Tariq A Akhtar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
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Rush JS, Subramanian T, Subramanian KL, Onono FO, Waechter CJ, Spielmann HP. Novel Citronellyl-Based Photoprobes Designed to Identify ER Proteins Interacting with Dolichyl Phosphate in Yeast and Mammalian Cells. ACTA ACUST UNITED AC 2015; 9:123-141. [PMID: 27099830 DOI: 10.2174/2212796810666160216221610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Dolichyl phosphate-linked mono- and oligosaccharides (DLO) are essential intermediates in protein N-glycosylation, C- and O-mannosylation and GPI anchor biosynthesis. While many membrane proteins in the endoplasmic reticulum (ER) involved in the assembly of DLOs are known, essential proteins believed to be required for the transbilayer movement (flip-flopping) and proteins potentially involved in the regulation of DLO synthesis remain to be identified. METHODS The synthesis of a series of Dol-P derivatives composed of citronellyl-based photoprobes with benzophenone groups equipped with alkyne moieties for Huisgen "click" chemistry is now described to utilize as tools for identifying ER proteins involved in regulating the biosynthesis and transbilayer movement of lipid intermediates. In vitro enzymatic assays were used to establish that the photoprobes contain the critical structural features recognized by pertinent enzymes in the dolichol pathway. ER proteins that photoreacted with the novel probes were identified by MS. RESULTS The potential of the newly designed photoprobes, m-PAL-Cit-P and p-PAL-Cit-P, for identifying previously unidentified Dol-P-interacting proteins is supported by the observation that they are enzymatically mannosylated by Man-P-Dol synthase (MPDS) from Chinese Hamster Ovary (CHO) cells at an enzymatic rate similar to that for Dol-P. MS analyses reveal that DPM1, ALG14 and several other yeast ER proteins involved in DLO biosynthesis and lipid-mediated protein O-mannosylation photoreacted with the novel probes. CONCLUSION The newly-designed photoprobes described in this paper provide promising new tools for the identification of yet to be identified Dol-P interacting ER proteins in yeast and mammalian cells, including the Dol-P flippase required for the "re-cycling" of the glycosyl carrier lipid from the lumenal monolayer of the ER to the cytoplasmic leaflet for new rounds of DLO synthesis.
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Affiliation(s)
- Jeffrey S Rush
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Thangaiah Subramanian
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Karunai Leela Subramanian
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Fredrick O Onono
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
| | - Charles J Waechter
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA
| | - H Peter Spielmann
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA; University of Kentucky College of Medicine, Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40536, USA; Kentucky Center for Structural Biology, University of Kentucky, Lexington, Kentucky 40536, USA; Department of Chemistry, University of Kentucky, Lexington, Kentucky 40536, USA
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Kanehara K, Cho Y, Lin YC, Chen CE, Yu CY, Nakamura Y. Arabidopsis DOK1 encodes a functional dolichol kinase involved in reproduction. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:292-303. [PMID: 25406445 DOI: 10.1111/tpj.12727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 05/08/2023]
Abstract
Dolichol phosphate (Dol-P) serves as a carrier of complex polysaccharides during protein glycosylation. Dol-P is synthesized by the phosphorylation of dolichol or the monodephosphorylation of dolichol pyrophosphate (Dol-PP); however, the enzymes that catalyze these reactions remain unidentified in Arabidopsis thaliana. We performed a genome-wide search for cytidylyltransferase motif-containing proteins in Arabidopsis, and found that At3g45040 encodes a protein homologous with Sec59p, a dolichol kinase (DOK) in Saccharomyces cerevisiae. At3g45040, designated AtDOK1, complemented defects in the growth and N-linked glycosylation of the S. cerevisiae sec59 mutant, suggesting that AtDOK1 encodes a functional DOK. To characterize the physiological roles of AtDOK1 in planta, we isolated two independent lines of T-DNA-tagged AtDOK1 mutants, dok1-1 and dok1-2. The heterozygous plants showed developmental defects in male and female gametophytes, including an aberrant pollen structure, low pollen viability, and short siliques. Additionally, the mutations had incomplete penetrance. These results suggest that AtDOK1 is a functional DOK required for reproductive processes in Arabidopsis.
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Affiliation(s)
- Kazue Kanehara
- Academia Sinica, Institute of Plant and Microbial Biology, No. 128 Sec. 2 Academia Rd., Nankang Taipei, 11529, Taiwan; Molecular and Biological Agricultural Sciences Program, Academia Sinica, Taiwan International Graduate Program, No. 128 Sec. 2 Academia Rd., Nankang, Taipei, 11529, Taiwan; Biotechnology Center, National Chung-Hsing University, 250 Kuo-Kuang Rd., Taichung, 402, Taiwan; Department of Applied Science and Engineering, Muroran Institute of Technology, 27-1 Mizumoto-cho, Muroran, Hokkaido, 050-8585, Japan
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Águila S, Martínez-Martínez I, Dichiara G, Gutiérrez-Gallego R, Navarro-Fernández J, Vicente V, Corral J. Increased N-glycosylation efficiency by generation of an aromatic sequon on N135 of antithrombin. PLoS One 2014; 9:e114454. [PMID: 25485983 PMCID: PMC4259341 DOI: 10.1371/journal.pone.0114454] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 11/07/2014] [Indexed: 11/30/2022] Open
Abstract
The inefficient glycosylation of consensus sequence on N135 in antithrombin explains the two glycoforms of this key anticoagulant serpin found in plasma: α and β, with four and three N-glycans, respectively. The lack of this N-glycan increases the heparin affinity of the β-glycoform. Recent studies have demonstrated that an aromatic sequon (Phe-Y-Asn-X-Thr) in reverse β-turns enhances N-glycosylation efficiency and stability of different proteins. We evaluated the effect of the aromatic sequon in this defective glycosylation site of antithrombin, despite of being located in a loop between the helix D and the strand 2A. We analyzed the biochemical and functional features of variants generated in a recombinant cell system (HEK-EBNA). Cells transfected with wild-type plasmid (K133-Y-N135-X-S137) generated 50% of α and β-antithrombin. The S137T, as previously reported, K133F, and the double mutant (K133F/S137T) had improved glycosylation efficiency, leading to the secretion of α-antithrombin, as shown by electrophoretic and mass analysis. The presence of the aromatic sequon did not significantly affect the stability of this conformationally sensitive serpin, as revealed by thermal denaturation assay. Moreover, the aromatic sequon hindered the activation induced by heparin, in which is involved the helix D. Accordingly, K133F and particularly K133F/S137T mutants had a reduced anticoagulant activity. Our data support that aromatic sequons in a different structural context from reverse turns might also improve the efficiency of N-glycosylation.
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Affiliation(s)
- Sonia Águila
- Centro Regional de Hemodonación, Hospital Morales Meseguer, Universidad de Murcia, IMIB, Murcia, Spain
| | - Irene Martínez-Martínez
- Centro Regional de Hemodonación, Hospital Morales Meseguer, Universidad de Murcia, IMIB, Murcia, Spain
| | - Gilda Dichiara
- Division of Cardiovascular Sciences, Laboratory of Thrombosis and Haemostasis, Centre for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Ricardo Gutiérrez-Gallego
- Bioanalysis Group, IMIM-Hospital del Mar, Department of Experimental and Health Sciences, University Pompeu Fabra (UPF), Barcelona, Spain
- Protein and Peptide Chemistry, Anapharm Biotech, Barcelona, Spain
| | - José Navarro-Fernández
- Centro Regional de Hemodonación, Hospital Morales Meseguer, Universidad de Murcia, IMIB, Murcia, Spain
| | - Vicente Vicente
- Centro Regional de Hemodonación, Hospital Morales Meseguer, Universidad de Murcia, IMIB, Murcia, Spain
| | - Javier Corral
- Centro Regional de Hemodonación, Hospital Morales Meseguer, Universidad de Murcia, IMIB, Murcia, Spain
- * E-mail:
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Jiang P, Mukthavaram R, Chao Y, Nomura N, Bharati IS, Fogal V, Pastorino S, Teng D, Cong X, Pingle SC, Kapoor S, Shetty K, Aggrawal A, Vali S, Abbasi T, Chien S, Kesari S. In vitro and in vivo anticancer effects of mevalonate pathway modulation on human cancer cells. Br J Cancer 2014; 111:1562-71. [PMID: 25093497 PMCID: PMC4200085 DOI: 10.1038/bjc.2014.431] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/07/2014] [Accepted: 07/09/2014] [Indexed: 12/13/2022] Open
Abstract
Background: The increasing usage of statins (the 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) has revealed a number of unexpected beneficial effects, including a reduction in cancer risk. Methods: We investigated the direct anticancer effects of different statins approved for clinical use on human breast and brain cancer cells. We also explored the effects of statins on cancer cells using in silico simulations. Results: In vitro studies showed that cerivastatin, pitavastatin, and fluvastatin were the most potent anti-proliferative, autophagy inducing agents in human cancer cells including stem cell-like primary glioblastoma cell lines. Consistently, pitavastatin was more effective than fluvastatin in inhibiting U87 tumour growth in vivo. Intraperitoneal injection was much better than oral administration in delaying glioblastoma growth. Following statin treatment, tumour cells were rescued by adding mevalonate and geranylgeranyl pyrophosphate. Knockdown of geranylgeranyl pyrophosphate synthetase-1 also induced strong cell autophagy and cell death in vitro and reduced U87 tumour growth in vivo. These data demonstrate that statins main effect is via targeting the mevalonate synthesis pathway in tumour cells. Conclusions: Our study demonstrates the potent anticancer effects of statins. These safe and well-tolerated drugs need to be further investigated as cancer chemotherapeutics in comprehensive clinical studies.
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Affiliation(s)
- P Jiang
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - R Mukthavaram
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - Y Chao
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - N Nomura
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - I S Bharati
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - V Fogal
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - S Pastorino
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - D Teng
- Departments of Bioengineering and Medicine and Institute of Engineering in Medicine, UC San Diego, La Jolla, CA 92093, USA
| | - X Cong
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - S C Pingle
- Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA
| | - S Kapoor
- Cellworks Group, Inc., 2025 Gateway Place, Suite 265, San Jose, CA 95110, USA
| | - K Shetty
- Cellworks Group, Inc., 2025 Gateway Place, Suite 265, San Jose, CA 95110, USA
| | - A Aggrawal
- Cellworks Group, Inc., 2025 Gateway Place, Suite 265, San Jose, CA 95110, USA
| | - S Vali
- Cellworks Group, Inc., 2025 Gateway Place, Suite 265, San Jose, CA 95110, USA
| | - T Abbasi
- Cellworks Group, Inc., 2025 Gateway Place, Suite 265, San Jose, CA 95110, USA
| | - S Chien
- Departments of Bioengineering and Medicine and Institute of Engineering in Medicine, UC San Diego, La Jolla, CA 92093, USA
| | - S Kesari
- 1] Translational Neuro-Oncology Laboratories, Moores Cancer Center, UC San Diego, La Jolla, CA 92093, USA [2] Department of Neurosciences, UC San Diego, La Jolla, CA 92093, USA
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Manat G, Roure S, Auger R, Bouhss A, Barreteau H, Mengin-Lecreulx D, Touzé T. Deciphering the metabolism of undecaprenyl-phosphate: the bacterial cell-wall unit carrier at the membrane frontier. Microb Drug Resist 2014; 20:199-214. [PMID: 24799078 DOI: 10.1089/mdr.2014.0035] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
During the biogenesis of bacterial cell-wall polysaccharides, such as peptidoglycan, cytoplasmic synthesized precursors should be trafficked across the plasma membrane. This essential process requires a dedicated lipid, undecaprenyl-phosphate that is used as a glycan lipid carrier. The sugar is linked to the lipid carrier at the inner face of the membrane and is translocated toward the periplasm, where the glycan moiety is transferred to the growing polymer. Undecaprenyl-phosphate originates from the dephosphorylation of its precursor undecaprenyl-diphosphate, with itself generated by de novo synthesis or by recycling after the final glycan transfer. Undecaprenyl-diphosphate is de novo synthesized by the cytosolic cis-prenyltransferase undecaprenyl-diphosphate synthase, which has been structurally and mechanistically characterized in great detail highlighting the condensation process. In contrast, the next step toward the formation of the lipid carrier, the dephosphorylation step, which has been overlooked for many years, has only started revealing surprising features. In contrast to the previous step, two unrelated families of integral membrane proteins exhibit undecaprenyl-diphosphate phosphatase activity: BacA and members of the phosphatidic acid phosphatase type 2 super-family, raising the question of the significance of this multiplicity. Moreover, these enzymes establish an unexpected link between the synthesis of bacterial cell-wall polymers and other biological processes. In the present review, the current knowledge in the field of the bacterial lipid carrier, its mechanism of action, biogenesis, recycling, regulation, and future perspective works are presented.
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Affiliation(s)
- Guillaume Manat
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, IBBMC, UMR 8619 CNRS, Université Paris Sud , Orsay Cedex, France
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Nishimura Y, Shimono N, Yoshimoto T, Kamiguchi H, Nishikawa Y. Cloning and transcriptional expression of mouse mannosyltransferase IV/V cDNA, which is involved in the synthesis of lipid-linked oligosaccharides. Biosci Biotechnol Biochem 2014; 78:400-9. [PMID: 25036826 DOI: 10.1080/09168451.2014.890026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We cloned the mouse mannosyltransferase IV/V gene (mALG11) from FM3A cells by a bioinformatic approach. The ORF contained 1476 bp encoding 492 amino acids. The cloned mALG11 complemented the growth defect of the Saccharomyces cerevisiae ALG11Δ mutant. In addition, we detected a variant cDNA by alternate splicing that had an additional four-nucleotide ATGC insertion at base 276 of the ORF. Consequently the variant cDNA encoded a truncated protein with 92 amino acids, lacking the glycosyltransferase group-1 domain. The variant cDNA occurs in many mouse strains according to EST database searches. Moreover, we detected it in FM3A cDNA, but we did not detect any such variants in the human EST database or in HeLa cDNA, although human ALG11 (hALG11) genomic DNA has the same sequence around the intron-exon boundaries as those of mALG11 genomic DNA. Hence, we concluded that there is different transcriptional control mechanism between mALG11 and hALG11.
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Affiliation(s)
- Yuuki Nishimura
- a Department of Applied Biochemistry , School of Engineering, Tokai University , Hiratsuka , Japan
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Neuhaus O, Hartung HP. Evaluation of atorvastatin and simvastatin for treatment of multiple sclerosis. Expert Rev Neurother 2014; 7:547-56. [PMID: 17492904 DOI: 10.1586/14737175.7.5.547] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Atorvastatin and simvastatin (members of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor family) are widely prescribed as cholesterol-lowering agents. As they have been shown to exhibit potent immunomodulatory effects, they may become a future treatment option for autoimmune disease in general and multiple sclerosis (MS) in particular. Several recent reports have demonstrated that statins prevent and reverse chronic and relapsing experimental autoimmune encephalomyelitis, an animal model of MS. An open-label clinical trial assessing simvastatin in MS revealed a significant decrease in the number and volume of new MRI lesions and a favorable safety profile. The results of a large multicenter, placebo-controlled clinical trial assessing atorvastatin in patients with clinically isolated syndrome (a disease that predisposes to development MS) are expected soon. However, prospective placebo-controlled trials of atorvastatin or simvastatin in definite MS are difficult to perform due to ethical and financial objections. In this review, we discuss the backgrounds, mechanisms of action and future perspectives of atorvastatin and simvastatin as putative future treatment options in MS.
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Affiliation(s)
- Oliver Neuhaus
- Heinrich Heine University, Department of Neurology, Düsseldorf, Germany.
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Wen R, Dallman JE, Li Y, Züchner SL, Vance JM, Peričak-Vance MA, Lam BL. Knock-down DHDDS expression induces photoreceptor degeneration in zebrafish. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:543-50. [PMID: 24664742 DOI: 10.1007/978-1-4614-3209-8_69] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A mutation in the dehydrodolichol diphosphate synthase (DHDDS) was recently identified as the cause of a subtype of recessive retinitis pigmentosa (RP). Molecular modeling indicates that this mutation could result in low enzymatic efficiency of DHDDS. To investigate the possible link between insufficient DHDDS activity and photoreceptor degeneration, the expression of DHDDS was knocked down by morpholino oligonucleotides (MO) injected into zebrafish one cell embryos. The general appearance and behavior of 4-day-old MO-injected fish were normal, but they failed to respond to light-off, suggesting loss of visual function. Morphological analysis showed that photoreceptor outer segments in retinas of MO-injected fish are very short and in many cases completely missing. Peanut agglutinin (PNA) staining confirmed the absence of cone outer segments. These results demonstrate that suppression of DHDDS expression in zebrafish leads to the loss of photoreceptor outer segments and visual function. These results support the hypothesis that insufficient DHDDS function leads to retinal degeneration.
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Affiliation(s)
- Rong Wen
- Bascom Palmer Eye Institute, University of Miami, 506 McKnight Building, 1638 NW 10th Ave, 33136, Miami, FL, USA,
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Lam BL, Züchner SL, Dallman J, Wen R, Alfonso EC, Vance JM, Peričak-Vance MA. Mutation K42E in Dehydrodolichol Diphosphate Synthase (DHDDS) Causes Recessive Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:165-70. [DOI: 10.1007/978-1-4614-3209-8_21] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Yang AC, Ng BG, Moore SA, Rush J, Waechter CJ, Raymond KM, Willer T, Campbell KP, Freeze HH, Mehta L. Congenital disorder of glycosylation due to DPM1 mutations presenting with dystroglycanopathy-type congenital muscular dystrophy. Mol Genet Metab 2013; 110:345-351. [PMID: 23856421 PMCID: PMC3800268 DOI: 10.1016/j.ymgme.2013.06.016] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 06/20/2013] [Accepted: 06/20/2013] [Indexed: 11/18/2022]
Abstract
Congenital disorders of glycosylation (CDG) are rare genetic defects mainly in the post-translational modification of proteins via attachment of carbohydrate chains. We describe an infant with the phenotype of a congenital muscular dystrophy, with borderline microcephaly, hypotonia, camptodactyly, severe motor delay, and elevated creatine kinase. Muscle biopsy showed muscular dystrophy and reduced α-dystroglycan immunostaining with glycoepitope-specific antibodies in a pattern diagnostic of dystroglycanopathy. Carbohydrate deficient transferrin testing showed a pattern pointing to a CDG type I. Sanger sequencing of DPM1 (dolichol-P-mannose synthase subunit 1) revealed a novel Gly > Val change c.455G > T missense mutation resulting in p.Gly152Val) of unknown pathogenicity and deletion/duplication analysis revealed an intragenic deletion from exons 3 to 7 on the other allele. DPM1 activity in fibroblasts was reduced by 80%, while affinity for the substrate was not depressed, suggesting a decrease in the amount of active enzyme. Transfected cells expressing tagged versions of wild type and the p.Gly152Val mutant displayed reduced binding to DPM3, an essential, non-catalytic subunit of the DPM complex, suggesting a mechanism for pathogenicity. The present case is the first individual described with DPM1-CDG (CDG-Ie) to also have clinical and muscle biopsy findings consistent with dystroglycanopathy.
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Affiliation(s)
- Amy C. Yang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
- Correspondence to: Amy C. Yang, MD Icahn School of Medicine at Mount Sinai One Gustave L. Levy Place, Box 1497 New York, NY 10029
| | - Bobby G. Ng
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA
| | - Steven A. Moore
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA
| | - Jeffrey Rush
- Department of Molecular and Cellular Biochemistry, Chandler Medical Center, College of Medicine, University of Kentucky, Lexington, KY
| | - Charles J. Waechter
- Department of Molecular and Cellular Biochemistry, Chandler Medical Center, College of Medicine, University of Kentucky, Lexington, KY
| | - Kimiyo M. Raymond
- Department of Laboratory Medicine and Pathology, Mayo Clinic School of Medicine, Rochester, MN
| | - Tobias Willer
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA
| | - Kevin P. Campbell
- Howard Hughes Medical Institute, Department of Molecular Physiology and Biophysics, Department of Neurology, Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA
| | - Hudson H. Freeze
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA
| | - Lakshmi Mehta
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
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48
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In vitro and in vivo study of dolichyl phosphate on the efflux activity of P-glycoprotein at the blood-brain barrier. Int J Dev Neurosci 2013; 31:828-35. [PMID: 24161469 DOI: 10.1016/j.ijdevneu.2013.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 09/23/2013] [Accepted: 10/14/2013] [Indexed: 11/22/2022] Open
Abstract
It has been commonly recognized that accumulated amyloid-β (Aβ) in the brain plays a crucial role in the pathogenesis of Alzheimer's disease (AD). Since the deficiency of the P-glycoprotein (P-gp) at the blood-brain barrier (BBB) in AD may aggravate Aβ deposition and the P-gp reversal agents display lower selectivity of the action, to selectively restore activity of the efflux pump is eagerly required. This study was designed to investigate the influence of dolichyl-phosphate (dolichyl-P) on the P-gp at the BBB. The results revealed that treatment with dolichyl-P increased transendothelial transfer of Rhodamine123 (Rh123) and Aβ42 from the apical compartment to the basolateral compartment but reduced that from the basolateral compartment to the apical compartment in the co-culture of rat brain microvessel endothelial cells (rBMECs) and astrocytes, down regulated P-gp expression in rBMECs and significantly elevated content of Rh123 in rat cortex and hippocampus tissues. The present results implied that accumulated dolichyl-P in the brain may exert an important role in the depression of the P-gp at the BBB, which may suggest valuable clues to promote function of the pump at the BBB in AD.
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49
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Wen R, Lam BL, Guan Z. Aberrant dolichol chain lengths as biomarkers for retinitis pigmentosa caused by impaired dolichol biosynthesis. J Lipid Res 2013; 54:3516-22. [PMID: 24078709 DOI: 10.1194/jlr.m043232] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We observed a characteristic shortening of plasma and urinary dolichols in retinitis pigmentosa (RP) patients carrying K42E and T206A mutations in the dehydrodolichol diphosphate synthase (DHDDS) gene, using liquid chromatography-mass spectrometry. Dolichol-18 (D18) became the dominant dolichol species in patients instead of dolichol-19 (D19) in normal individuals. The D18/D19 ratio was calculated and used as an index of dolichol length distribution. K42E/K42E and K42E/T206A patients have significantly higher plasma and urinary D18/D19 ratios than K42E and T206A carriers. The ratios of carriers are significantly higher than normal individuals. Receiver operating characteristic (ROC) analysis shows that plasma and urinary D18/D19 ratios can unambiguously discriminate patients from carriers, and carriers from normal individuals. Dolichol analysis also provides evidence that the T206A mutation is RP-causative. The methodologies and procedures used for dolichol profiling are reliable, high throughput, and cost effective. Dolichol profiling, complementary to genotyping, can be readily adapted as a test in the clinic not only for the diagnosis of patients but also for identification of carriers with DHDDS or other genetic mutations that may impair dolichol biosynthesis.
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Affiliation(s)
- Rong Wen
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136
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50
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Pronin AV, Danilov LL, Narovlyansky AN, Sanin AV. Plant polyisoprenoids and control of cholesterol level. Arch Immunol Ther Exp (Warsz) 2013; 62:31-9. [PMID: 23995915 PMCID: PMC3898360 DOI: 10.1007/s00005-013-0253-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 08/21/2013] [Indexed: 12/24/2022]
Abstract
The ability of plant polyisoprenoids (polyprenols and polyprenyl phosphates) to diminish the levels of serum cholesterol affecting its biosynthetic pathway are highlighted here. Possible mechanism of such process is discussed. It is also noted that polyisoprenoids can prevent toxic injuries of the liver and restore disturbed hepatic functions. The possibility of polyprenyl phosphates to reveal at the same time anti-inflammatory action suppressing lipoxygenase activity and lowering the levels of proinflammatory cytokines will be illustrated. Attention will be focused on the potential usefulness of plant polyisoprenoids in the course of prevention and treatment of hypercholesterolemia. High efficiency for combined use of polyprenyl phosphate and β-sitosterol, which leads to substantial enhancement of the ability to overcome hypercholesterolemia versus the individual constituents will be demonstrated.
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Affiliation(s)
- Alexander V Pronin
- N. F. Gamaleya Research Institute of Epidemiology and Microbiology, Moscow, Russia,
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