1
|
Chakrabarti M, Amzel LM, Lau AY. Sodium/Iodide Symporter Metastable Intermediates Provide Insights into Conformational Transition between Principal Thermodynamic States. J Phys Chem B 2023; 127:1540-1551. [PMID: 36758032 DOI: 10.1021/acs.jpcb.2c07604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The Sodium/Iodide Symporter (NIS), a 13-helix transmembrane protein found in the thyroid and other tissues, transports iodide, a required constituent of thyroid hormones T3 and T4. Despite extensive experimental information and clinical data, structural details of the intermediate microstates comprising the conformational transition of NIS between its inwardly and outwardly open states remain unresolved. We present data from a combination of enhanced sampling and transition path molecular dynamics (MD) simulations that elucidate the principal intermediate states comprising the inwardly to outwardly open transition of fully bound and apo NIS under an enforced ionic gradient. Our findings suggest that in both the absence and presence of bound physiological ions, NIS principally occupies a proximally inward to inwardly open state. When fully bound, NIS is also found to occupy a rare "inwardly occluded" state. The results of this work provide novel insight into the populations of NIS intermediates and the free energy landscape comprising the conformational transition, adding to a mechanistic understanding of NIS ion transport. Moreover, the knowledge gained from this approach can serve as a basis for studies of NIS mutants to target therapeutic interventions.
Collapse
Affiliation(s)
- Mayukh Chakrabarti
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., PO Box B, Frederick, Maryland 21702, United States
| | - L Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| | - Albert Y Lau
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, United States
| |
Collapse
|
2
|
Dongre AV, Das S, Bellur A, Kumar S, Chandrashekarmath A, Karmakar T, Balaram P, Balasubramanian S, Balaram H. Structural basis for the hyperthermostability of an archaeal enzyme induced by succinimide formation. Biophys J 2021; 120:3732-3746. [PMID: 34302792 DOI: 10.1016/j.bpj.2021.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/18/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022] Open
Abstract
Stability of proteins from hyperthermophiles (organisms existing under boiling water conditions) enabled by a reduction of conformational flexibility is realized through various mechanisms. A succinimide (SNN) arising from the post-translational cyclization of the side chains of aspartyl/asparaginyl residues with the backbone amide -NH of the succeeding residue would restrain the torsion angle Ψ and can serve as a new route for hyperthermostability. However, such a succinimide is typically prone to hydrolysis, transforming to either an aspartyl or β-isoaspartyl residue. Here, we present the crystal structure of Methanocaldococcus jannaschii glutamine amidotransferase and, using enhanced sampling molecular dynamics simulations, address the mechanism of its increased thermostability, up to 100°C, imparted by an unexpectedly stable succinimidyl residue at position 109. The stability of SNN109 to hydrolysis is seen to arise from its electrostatic shielding by the side-chain carboxylate group of its succeeding residue Asp110, as well as through n → π∗ interactions between SNN109 and its preceding residue Glu108, both of which prevent water access to SNN. The stable succinimidyl residue induces the formation of an α-turn structure involving 13-atom hydrogen bonding, which locks the local conformation, reducing protein flexibility. The destabilization of the protein upon replacement of SNN with a Φ-restricted prolyl residue highlights the specificity of the succinimidyl residue in imparting hyperthermostability to the enzyme. The conservation of the succinimide-forming tripeptide sequence (E(N/D)(E/D)) in several archaeal GATases strongly suggests an adaptation of this otherwise detrimental post-translational modification as a harbinger of thermostability.
Collapse
Affiliation(s)
- Aparna Vilas Dongre
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Sudip Das
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Asutosh Bellur
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Sanjeev Kumar
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India; National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Anusha Chandrashekarmath
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Tarak Karmakar
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India; Department of Chemistry and Applied Biosciences, ETH Zurich, Lugano, Ticino, Switzerland; Facoltà di Informatica, Istituto di Scienze Computationali, Università della Svizzera Italiana, Lugano, Ticino, Switzerland
| | - Padmanabhan Balaram
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India; Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Sundaram Balasubramanian
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India.
| | - Hemalatha Balaram
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India.
| |
Collapse
|
3
|
Feng J, Selvam B, Shukla D. How do antiporters exchange substrates across the cell membrane? An atomic-level description of the complete exchange cycle in NarK. Structure 2021; 29:922-933.e3. [PMID: 33836147 DOI: 10.1016/j.str.2021.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/07/2021] [Accepted: 03/19/2021] [Indexed: 11/19/2022]
Abstract
Major facilitator superfamily (MFS) proteins operate via three different mechanisms: uniport, symport, and antiport. Despite extensive investigations, the molecular understanding of antiporters is less advanced than that of other transporters due to the complex coupling between two substrates and the lack of distinct structures. We employ extensive all-atom molecular dynamics simulations to dissect the complete substrate exchange cycle of the bacterial NO3-/NO2- antiporter, NarK. We show that paired basic residues in the binding site prevent the closure of unbound protein and ensure the exchange of two substrates. Conformational transition occurs only in the presence of substrate, which weakens the electrostatic repulsion and stabilizes the transporter. Furthermore, we propose a state-dependent substrate exchange model, in which the relative spacing between the paired basic residues determines whether NO3- and NO2- bind simultaneously or sequentially. Overall, this work presents a general working model for the antiport mechanism within the MFS.
Collapse
Affiliation(s)
- Jiangyan Feng
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Balaji Selvam
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; NIH Center for Macromolecular Modeling and Bioinformatics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Digital Agriculture, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| |
Collapse
|
4
|
Nandakumar M, Malathi P, Sundar AR, Rajadurai CP, Philip M, Viswanathan R. Role of miRNAs in the host-pathogen interaction between sugarcane and Colletotrichum falcatum, the red rot pathogen. PLANT CELL REPORTS 2021; 40:851-870. [PMID: 33818644 DOI: 10.1007/s00299-021-02682-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/15/2021] [Indexed: 02/08/2023]
Abstract
KEY MESSAGE Sugarcane microRNAs specifically involved during compatible and incompatible interactions with red rot pathogen Colletotrichum falcatum were identified. We have identified how the miRNAs regulate their gene targets and elaborated evidently on the underlying molecular mechanism of sugarcane defense response to C. falcatum for the first time. Resistance against the fungal pathogen Colletotrichum falcatum causing red rot is one of the most desirable traits for sustainable crop cultivation in sugarcane. To gain new insight into the host defense mechanism against C. falcatum, we studied the role of sugarcane microRNAs during compatible and incompatible interactions by adopting the NGS platform. We have sequenced a total of 80 miRNA families that comprised 980 miRNAs, and the putative targets of the miRNAs include transcription factors, membrane-bound proteins, glutamate receptor proteins, lignin biosynthesis proteins, signaling cascade proteins, transporter proteins, mitochondrial proteins, ER proteins, defense-related, stress response proteins, translational regulation proteins, cell proliferation, and ubiquitination proteins. Further, qRT-PCR analyses of 8 differentially regulated miRNAs and 26 gene transcript targets expression indicated that these miRNAs have a regulatory effect on the expression of respective target genes in most of the cases. Also, the results suggest that certain miRNA regulates many target genes that are involved in inciting early responses to the pathogen infection, signaling pathways, endoplasmic reticulum stress, and resistance gene activation through feedback response from various cellular processes during the compatible and incompatible interaction with the red rot pathogen C. falcatum. The present study revealed the role of sugarcane miRNAs and their target genes during sugarcane-C. falcatum interaction and provided new insight into the miRNA-mediated defense mechanism in sugarcane for the first time.
Collapse
Affiliation(s)
- M Nandakumar
- ICAR-Sugarcane Breeding Institute, Coimbatore, Tamil Nadu, 641007, India
| | - P Malathi
- ICAR-Sugarcane Breeding Institute, Coimbatore, Tamil Nadu, 641007, India
| | - A R Sundar
- ICAR-Sugarcane Breeding Institute, Coimbatore, Tamil Nadu, 641007, India
| | - C P Rajadurai
- AgriGenome Labs, Infopark-Smart City Short Rd, Kochi, Kerala, 682030, India
| | - Manuel Philip
- AgriGenome Labs, Infopark-Smart City Short Rd, Kochi, Kerala, 682030, India
| | - R Viswanathan
- ICAR-Sugarcane Breeding Institute, Coimbatore, Tamil Nadu, 641007, India.
| |
Collapse
|
5
|
Tamura K, Sugita Y. Free Energy Analysis of a Conformational Change of Heme ABC Transporter BhuUV-T. J Phys Chem Lett 2020; 11:2824-2829. [PMID: 32202796 PMCID: PMC10961826 DOI: 10.1021/acs.jpclett.0c00547] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The heme ATP-binding cassette (ABC) transporter BhuUV-T of bacterial pathogen Burkholderia cenocepacia is required to transport heme across the inner cell membrane. The current hypothesis is that the binding of two ATPs to the nucleotide-binding domains of the transporter drives the initial steps of the transport cycle in which the empty transport sites are reoriented from the cytosol to the periplasm. Molecular details are missing because the structure of a key occluded intermediate remains hypothetical. Here we perform molecular simulations to analyze the free energy surface (FES) of the first step of the reorientation, namely the transition from an open inward-facing (IF) transport site to an occluded (Occ) conformation. We have modeled the latter structure in silico in a previous study. A simple annealing procedure removes residual bias originating from non-equilibrium targeted molecular dynamics. The calculated FES reveals the role of the ATPs in inducing the IF → Occ conformational change and validates the modeled Occ conformation.
Collapse
Affiliation(s)
- Koichi Tamura
- Computational Biophysics
Research
Team, RIKEN Center for Computational Science, 6-7-1 minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yuji Sugita
- Computational Biophysics
Research
Team, RIKEN Center for Computational Science, 6-7-1 minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Laboratory for Biomolecular Function
Simulation, RIKEN Center for Biosystems
Dynamics Research, 6-7-1
minatojima-Minamimachi,
Chuo-ku, Kobe, Hyogo 650-0047, Japan
| |
Collapse
|
6
|
Parker JL, Corey RA, Stansfeld PJ, Newstead S. Structural basis for substrate specificity and regulation of nucleotide sugar transporters in the lipid bilayer. Nat Commun 2019; 10:4657. [PMID: 31604945 PMCID: PMC6789118 DOI: 10.1038/s41467-019-12673-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/24/2019] [Indexed: 01/21/2023] Open
Abstract
Nucleotide sugars are the activated form of monosaccharides used by glycosyltransferases during glycosylation. In eukaryotes the SLC35 family of solute carriers are responsible for their selective uptake into the Endoplasmic Reticulum or Golgi apparatus. The structure of the yeast GDP-mannose transporter, Vrg4, revealed a requirement for short chain lipids and a marked difference in transport rate between the nucleotide sugar and nucleoside monophosphate, suggesting a complex network of regulatory elements control transport into these organelles. Here we report the crystal structure of the GMP bound complex of Vrg4, revealing the molecular basis for GMP recognition and transport. Molecular dynamics, combined with biochemical analysis, reveal a lipid mediated dimer interface and mechanism for coordinating structural rearrangements during transport. Together these results provide further insight into how SLC35 family transporters function within the secretory pathway and sheds light onto the role that membrane lipids play in regulating transport across the membrane.
Collapse
Affiliation(s)
- Joanne L Parker
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Phillip J Stansfeld
- School of Life Sciences & Department of Chemistry, The University of Warwick, Coventry, CV4 7AL, UK.
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
| |
Collapse
|
7
|
Zhang H, Cheng G, Yang Z, Wang T, Xu J. Identification of Sugarcane Host Factors Interacting with the 6K2 Protein of the Sugarcane Mosaic Virus. Int J Mol Sci 2019; 20:ijms20163867. [PMID: 31398864 PMCID: PMC6719097 DOI: 10.3390/ijms20163867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/03/2019] [Accepted: 08/06/2019] [Indexed: 12/26/2022] Open
Abstract
The 6K2 protein of potyviruses plays a key role in the viral infection in plants. In the present study, the coding sequence of 6K2 was cloned from Sugarcane mosaic virus (SCMV) strain FZ1 into pBT3-STE to generate the plasmid pBT3-STE-6K2, which was used as bait to screen a cDNA library prepared from sugarcane plants infected with SCMV based on the DUALmembrane system. One hundred and fifty-seven positive colonies were screened and sequenced, and the corresponding full-length genes were cloned from sugarcane cultivar ROC22. Then, 24 genes with annotations were obtained, and the deduced proteins were classified into three groups, in which eight proteins were involved in the stress response, 12 proteins were involved in transport, and four proteins were involved in photosynthesis based on their biological functions. Of the 24 proteins, 20 proteins were verified to interact with SCMV-6K2 by yeast two-hybrid assays. The possible roles of these proteins in SCMV infection on sugarcane are analyzed and discussed. This is the first report on the interaction of SCMV-6K2 with host factors from sugarcane, and will improve knowledge on the mechanism of SCMV infection in sugarcane.
Collapse
Affiliation(s)
- Hai Zhang
- National Engineering Research Center for Sugarcane, Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Guangyuan Cheng
- National Engineering Research Center for Sugarcane, Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zongtao Yang
- National Engineering Research Center for Sugarcane, Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Tong Wang
- National Engineering Research Center for Sugarcane, Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jingsheng Xu
- National Engineering Research Center for Sugarcane, Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- State Key Laboratory for Protection and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning 530004, China.
| |
Collapse
|
8
|
Structural basis for the delivery of activated sialic acid into Golgi for sialyation. Nat Struct Mol Biol 2019; 26:415-423. [PMID: 31133698 DOI: 10.1038/s41594-019-0225-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/09/2019] [Indexed: 01/08/2023]
Abstract
The decoration of secretory glycoproteins and glycolipids with sialic acid is critical to many physiological and pathological processes. Sialyation is dependent on a continuous supply of sialic acid into Golgi organelles in the form of CMP-sialic acid. Translocation of CMP-sialic acid into Golgi is carried out by the CMP-sialic acid transporter (CST). Mutations in human CST are linked to glycosylation disorders, and CST is important for glycopathway engineering, as it is critical for sialyation efficiency of therapeutic glycoproteins. The mechanism of how CMP-sialic acid is recognized and translocated across Golgi membranes in exchange for CMP is poorly understood. Here we have determined the crystal structure of a Zea mays CST in complex with CMP. We conclude that the specificity of CST for CMP-sialic acid is established by the recognition of the nucleotide CMP to such an extent that they are mechanistically capable of both passive and coupled antiporter activity.
Collapse
|
9
|
Toscanini MA, Favarolo MB, Gonzalez Flecha FL, Ebert B, Rautengarten C, Bredeston LM. Conserved Glu-47 and Lys-50 residues are critical for UDP- N-acetylglucosamine/UMP antiport activity of the mouse Golgi-associated transporter Slc35a3. J Biol Chem 2019; 294:10042-10054. [PMID: 31118275 DOI: 10.1074/jbc.ra119.008827] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 05/09/2019] [Indexed: 12/17/2022] Open
Abstract
Nucleotide sugar transporters (NSTs) regulate the flux of activated sugars from the cytosol into the lumen of the Golgi apparatus where glycosyltransferases use them for the modification of proteins, lipids, and proteoglycans. It has been well-established that NSTs are antiporters that exchange nucleotide sugars with the respective nucleoside monophosphate. Nevertheless, information about the molecular basis of ligand recognition and transport is scarce. Here, using topology predictors, cysteine-scanning mutagenesis, expression of GFP-tagged protein variants, and phenotypic complementation of the yeast strain Kl3, we identified residues involved in the activity of a mouse UDP-GlcNAc transporter, murine solute carrier family 35 member A3 (mSlc35a3). We specifically focused on the putative transmembrane helix 2 (TMH2) and observed that cells expressing E47C or K50C mSlc35a3 variants had lower levels of GlcNAc-containing glycoconjugates than WT cells, indicating impaired UDP-GlcNAc transport activity of these two variants. A conservative substitution analysis revealed that single or double substitutions of Glu-47 and Lys-50 do not restore GlcNAc glycoconjugates. Analysis of mSlc35a3 and its genetic variants reconstituted into proteoliposomes disclosed the following: (i) all variants act as UDP-GlcNAc/UMP antiporters; (ii) conservative substitutions (E47D, E47Q, K50R, or K50H) impair UDP-GlcNAc uptake; and (iii) substitutions of Glu-47 and Lys-50 dramatically alter kinetic parameters, consistent with a critical role of these two residues in mSlc35a3 function. A bioinformatics analysis revealed that an EXXK motif in TMH2 is highly conserved across SLC35 A subfamily members, and a 3D-homology model predicted that Glu-47 and Lys-50 are facing the central cavity of the protein.
Collapse
Affiliation(s)
- M Agustina Toscanini
- From the Departamento de Química Biológica-IQUIFIB, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Ciudad Autónoma de Buenos Aires, Junín 956 (1113), Argentina and
| | - M Belén Favarolo
- From the Departamento de Química Biológica-IQUIFIB, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Ciudad Autónoma de Buenos Aires, Junín 956 (1113), Argentina and
| | - F Luis Gonzalez Flecha
- From the Departamento de Química Biológica-IQUIFIB, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Ciudad Autónoma de Buenos Aires, Junín 956 (1113), Argentina and
| | - Berit Ebert
- the School of BioSciences, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Carsten Rautengarten
- the School of BioSciences, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Luis M Bredeston
- From the Departamento de Química Biológica-IQUIFIB, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Ciudad Autónoma de Buenos Aires, Junín 956 (1113), Argentina and
| |
Collapse
|
10
|
Parker JL, Newstead S. Gateway to the Golgi: molecular mechanisms of nucleotide sugar transporters. Curr Opin Struct Biol 2019; 57:127-134. [PMID: 30999236 DOI: 10.1016/j.sbi.2019.03.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 03/09/2019] [Accepted: 03/12/2019] [Indexed: 12/16/2022]
Abstract
The Golgi apparatus plays a central role in the secretory pathway as a hub for posttranslational modification, protein sorting and quality control. To date, there is little structural or biochemical information concerning the function of transporters that reside within this organelle. The SLC35 family of nucleotide sugar transporters link the synthesis of activated sugar molecules and sulfate in the cytoplasm, with the luminal transferases that catalyse their attachment to proteins and lipids during glycosylation and sulfation. A recent crystal structure of the GDP-mannose transporter has revealed key sequence motifs that direct ligand recognition and transport. Further biochemical studies unexpectedly found a requirement for short chain lipids in activating the transporter, suggesting a possible route for transport regulation within the Golgi.
Collapse
Affiliation(s)
- Joanne L Parker
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
| |
Collapse
|