1
|
Wang L, Zhu J, Cui L, Wang Q, Huang W, Ji X, Yang Q, Rui C. Overexpression of ATP-binding cassette transporters associated with sulfoxaflor resistance in Aphis gossypii glover. PEST MANAGEMENT SCIENCE 2021; 77:4064-4072. [PMID: 33899308 DOI: 10.1002/ps.6431] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 04/16/2021] [Accepted: 04/26/2021] [Indexed: 05/27/2023]
Abstract
BACKGROUND Sulfoxaflor is a new insecticide for controlling against Aphis gossypii in the field. ATP-binding cassette (ABC) transporters belong to a large superfamily of proteins and play an important role in the detoxification process. However, the potential role of ABC transporters in sulfoxaflor resistance in A. gossypii is unknown. RESULTS In this study, an ABC transporter inhibitor, verapamil, dramatically increased the toxicity of sulfoxaflor in the resistant population with a synergistic ratio of 8.55. However, verapamil did not synergize sulfoxaflor toxicity in the susceptible population. The contents of ABC transporters were significantly increased in the Sul-R population. Based on RT-qPCR analysis, 10 of 23 ABC transcripts, ABCA1, ABCA2, ABCB1, ABCB5, ABCD1, ABCG7, ABCG16, ABCG26, ABCG27, and MRP7, were up-regulated in the Sul-R population compared to the Sus population. Meanwhile, inductive effects of ABCA1, ABCD1, ABCG7 and ABCG26 by sulfoxaflor were found in A. gossypii. Furthermore, knockdown of ABCA1 and ABCD1 using RNAi significantly increased the sulfoxaflor sensitivity in Sul-R aphids. CONCLUSION These results suggested that ABC transporters, especially the ABCA1 and ABCD1 genes, might be related with sulfoxaflor resistance in A. gossypii. This study will promote further work to validate the functional roles of these ABCs in sulfoxaflor resistance and might be helpful for the management of sulfoxaflor-resistant A. gossypii.
Collapse
Affiliation(s)
- Li Wang
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Junshu Zhu
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Li Cui
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Qinqin Wang
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Weiling Huang
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Xuejiao Ji
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Qingjie Yang
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Changhui Rui
- Key Laboratory of Integrated Pest Management in Crops, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing, China
| |
Collapse
|
2
|
Feng Z, Liu D, Wang L, Wang Y, Zang Z, Liu Z, Song B, Gu L, Fan Z, Yang S, Chen J, Cui Y. A Putative Efflux Transporter of the ABC Family, YbhFSR, in Escherichia coli Functions in Tetracycline Efflux and Na +(Li +)/H + Transport. Front Microbiol 2020; 11:556. [PMID: 32390957 PMCID: PMC7190983 DOI: 10.3389/fmicb.2020.00556] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/16/2020] [Indexed: 12/20/2022] Open
Abstract
ATP-binding cassette transporters are ubiquitous in almost all organisms. The Escherichia coli genome is predicted to encode 69 ABC transporters. Eleven of the ABC transporters are presumed to be exporters, of which seven are possible drug export transporters. There has been minimal research on the function of YbhFSR, which is one of the putative drug resistance exporters. In this study, the ybhF gene of this transporter was characterized. Overexpression and knockout strains of ybhF were constructed. The ATPase activity of YbhF was studied using the malachite green assay, and the efflux abilities of knockout strains were demonstrated by using ethidium bromide (EB) as a substrate. The substrates of YbhFSR efflux, examined with the minimum inhibitory concentration (MIC), were determined to be tetracycline, oxytetracycline, chlortetracycline, doxycycline, EB, and Hoechst33342. Furthermore, tetracycline and EB efflux and accumulation experiments confirmed that the substrates of YbhFSR were tetracyclines and EB. The MIC assay and the fluorescence test results showed that tetracyclines are likely to be the major antibiotic substrate of YbhFSR. The existence of the signature NatA motif suggested that YbhFSR may also function as a Na+/H+ transporter. Overexpression of YbhF in E. coli KNabc lacking crucial Na+/H+ transporters conferred tolerance to NaCl, LiCl, and an alkaline pH. Together, the results showed that YbhFSR exhibited dual functions as a drug efflux pump and a Na+ (Li+)/H+ antiporter.
Collapse
Affiliation(s)
- Zhenyue Feng
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Defu Liu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Lizi Wang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yanhong Wang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Zhongjing Zang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Zhenhua Liu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Baifen Song
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Liwei Gu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Zhaowei Fan
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Siyu Yang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Jing Chen
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yudong Cui
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| |
Collapse
|
3
|
Pym A, Singh KS, Nordgren Å, Davies TGE, Zimmer CT, Elias J, Slater R, Bass C. Host plant adaptation in the polyphagous whitefly, Trialeurodes vaporariorum, is associated with transcriptional plasticity and altered sensitivity to insecticides. BMC Genomics 2019; 20:996. [PMID: 31856729 PMCID: PMC6923851 DOI: 10.1186/s12864-019-6397-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/15/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The glasshouse whitefly, Trialeurodes vaporariorum, is a damaging crop pest and an invasive generalist capable of feeding on a broad range of host plants. As such this species has evolved mechanisms to circumvent the wide spectrum of anti-herbivore allelochemicals produced by its host range. T. vaporariorum has also demonstrated a remarkable ability to evolve resistance to many of the synthetic insecticides used for control. RESULTS To gain insight into the molecular mechanisms that underpin the polyphagy of T. vaporariorum and its resistance to natural and synthetic xenobiotics, we sequenced and assembled a reference genome for this species. Curation of genes putatively involved in the detoxification of natural and synthetic xenobiotics revealed a marked reduction in specific gene families between this species and another generalist whitefly, Bemisia tabaci. Transcriptome profiling of T. vaporariorum upon transfer to a range of different host plants revealed profound differences in the transcriptional response to more or less challenging hosts. Large scale changes in gene expression (> 20% of genes) were observed during adaptation to challenging hosts with a range of genes involved in gene regulation, signalling, and detoxification differentially expressed. Remarkably, these changes in gene expression were associated with significant shifts in the tolerance of host-adapted T. vaporariorum lines to natural and synthetic insecticides. CONCLUSIONS Our findings provide further insights into the ability of polyphagous insects to extensively reprogram gene expression during host adaptation and illustrate the potential implications of this on their sensitivity to synthetic insecticides.
Collapse
Affiliation(s)
- Adam Pym
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Penryn Campus, Penryn, Cornwall, UK
| | - Kumar Saurabh Singh
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Penryn Campus, Penryn, Cornwall, UK
| | - Åsa Nordgren
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK
| | - T G Emyr Davies
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, UK
| | - Christoph T Zimmer
- Syngenta Crop Protection, Werk Stein, Schaffhauserstrasse, Stein, Switzerland
| | - Jan Elias
- Syngenta Crop Protection, Werk Stein, Schaffhauserstrasse, Stein, Switzerland
| | - Russell Slater
- Syngenta Crop Protection, Werk Stein, Schaffhauserstrasse, Stein, Switzerland
| | - Chris Bass
- College of Life and Environmental Sciences, Biosciences, University of Exeter, Penryn Campus, Penryn, Cornwall, UK.
| |
Collapse
|
4
|
Yang H, Zhou C, Yang XB, Long GY, Jin DC. Effects of Insecticide Stress on Expression of NlABCG Transporter Gene in the Brown Planthopper, Nilaparvata lugens. INSECTS 2019; 10:insects10100334. [PMID: 31597380 PMCID: PMC6836012 DOI: 10.3390/insects10100334] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022]
Abstract
The brown planthopper (BPH), Nilaparvata lugens, is an important pest of rice that severely affects production. Insecticides are an important means of controlling BPH, but their long-term use has led to resistance. To provide insight into BPH responses to insecticide stress, we determined the expression levels of BPH ABCG transporter genes under treatment with thiamethoxam, abamectin, and cyantraniliprole at LC10, LC25, LC50, and LC90. We cloned 13 BPH ABCG transporters, named NlABCG1 to NlABCG13. Conservative domain analysis showed that all 13 transporters have one nucleotide binding domain and one transmembrane domain, typical of semi-molecular transporters. Real-time quantitative PCR showed that thiamethoxam, abamectin, and cyantraniliprole stress increased the expression of some NlABCG transporters gene in BPH. However, after treatment with thiamethoxam at LC25 and abamectin at LC10, there was no significant upregulation of NlABCG. These results indicate that the expression of NlABCG varies in response to stress from different insecticides. These findings provide baseline information for further understanding of the molecular mechanisms of insecticide resistance in BPH.
Collapse
Affiliation(s)
- Hong Yang
- Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang 550025, China.
- College of Tobacco Science, Guizhou University, Guiyang 550025, China.
| | - Cao Zhou
- Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang 550025, China.
| | - Xi-Bin Yang
- Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang 550025, China.
| | - Gui-Yun Long
- Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang 550025, China.
| | - Dao-Chao Jin
- Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang 550025, China.
| |
Collapse
|
5
|
Qasem-Abdullah H, Perach M, Livnat-Levanon N, Lewinson O. ATP binding and hydrolysis disrupt the high-affinity interaction between the heme ABC transporter HmuUV and its cognate substrate-binding protein. J Biol Chem 2017; 292:14617-14624. [PMID: 28710276 DOI: 10.1074/jbc.m117.779975] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 07/10/2017] [Indexed: 12/17/2022] Open
Abstract
Using the energy of ATP hydrolysis, ABC transporters catalyze the trans-membrane transport of molecules. In bacteria, these transporters partner with a high-affinity substrate-binding protein (SBP) to import essential micronutrients. ATP binding by Type I ABC transporters (importers of amino acids, sugars, peptides, and small ions) stabilizes the interaction between the transporter and the SBP, thus allowing transfer of the substrate from the latter to the former. In Type II ABC transporters (importers of trace elements, e.g. vitamin B12, heme, and iron-siderophores) the role of ATP remains debatable. Here we studied the interaction between the Yersinia pestis ABC heme importer (HmuUV) and its partner substrate-binding protein (HmuT). Using real-time surface plasmon resonance experiments and interaction studies in membrane vesicles, we find that in the absence of ATP the transporter and the SBP tightly bind. Substrate in excess inhibits this interaction, and ATP binding by the transporter completely abolishes it. To release the stable docked SBP from the transporter hydrolysis of ATP is required. Based on these results we propose a mechanism for heme acquisition by HmuUV-T where the substrate-loaded SBP docks to the nucleotide-free outward-facing conformation of the transporter. ATP binding leads to formation of an occluded state with the substrate trapped in the trans-membrane translocation cavity. Subsequent ATP hydrolysis leads to substrate delivery to the cytoplasm, release of the SBP, and resetting of the system. We propose that other Type II ABC transporters likely share the fundamentals of this mechanism.
Collapse
Affiliation(s)
- Hiba Qasem-Abdullah
- From the Department of Biochemistry, The Bruce and Ruth Rappaport Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Michal Perach
- From the Department of Biochemistry, The Bruce and Ruth Rappaport Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa 31096, Israel
| | - Nurit Livnat-Levanon
- From the Department of Biochemistry, The Bruce and Ruth Rappaport Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa 31096, Israel
| | | |
Collapse
|
6
|
Jones PM, George AM. How Intrinsic Dynamics Mediates the Allosteric Mechanism in the ABC Transporter Nucleotide Binding Domain Dimer. J Chem Theory Comput 2017; 13:1712-1722. [PMID: 28240893 DOI: 10.1021/acs.jctc.6b00839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A protein's architecture facilitates specific motions-intrinsic dynamic modes-that are employed to effect function. Here we used molecular dynamics (MD) simulations to investigate the dynamics of the MJ0796 ABC transporter nucleotide-binding domain (NBD). ABC transporter NBDs form a rotationally symmetric dimer whereby two equivalent active sites are formed at their interface; in complex with a dimer of transmembrane domains they hydrolyze ATP to energize translocation of substrates across cellular membranes. Our data suggest the ABC NBD's ensemble of functional states can be understood predominately in terms of conformational changes between its major subdomains, occurring along two orthogonal dynamic modes. The data show that ligands and oligomeric interactions modulate the equilibrium conformation of the NBD with respect to these motions, suggesting that allostery is achieved by affecting the energetic profile along these two modes. The observed dynamics and allostery integrate consonantly and logically within a mechanistic framework for the ABC NBD dimer, which is supported by a large body of experimental and theoretical data, providing a higher resolution view of the enzyme's dynamic cycle. Our study shows how valuable mechanistic inferences can be derived from accessible short-time scale MD simulations of an enzyme's substructures.
Collapse
Affiliation(s)
- Peter M Jones
- School of Life Sciences, University of Technology Sydney , P.O. Box 123, Broadway, New South Wales 2007, Australia
| | - Anthony M George
- School of Life Sciences, University of Technology Sydney , P.O. Box 123, Broadway, New South Wales 2007, Australia
| |
Collapse
|
7
|
Nguyen PT, Li QW, Kadaba NS, Lai JY, Yang JG, Rees DC. The contribution of methionine to the stability of the Escherichia coli MetNIQ ABC transporter-substrate binding protein complex. Biol Chem 2016; 396:1127-34. [PMID: 25803078 DOI: 10.1515/hsz-2015-0131] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/19/2015] [Indexed: 01/23/2023]
Abstract
Despite the ubiquitous role of ATP-binding cassette (ABC) importers in nutrient uptake, only the Escherichia coli maltose and vitamin B12 ABC transporters have been structurally characterized in multiple conformations relevant to the alternating access transport mechanism. To complement our previous structure determination of the E. coli MetNI methionine importer in the inward facing conformation (Kadaba et al. (2008) Science 321, 250-253), we have explored conditions stabilizing the outward facing conformation. Using two variants, the Walker B E166Q mutation with ATP+EDTA to stabilize MetNI in the ATP-bound conformation and the N229A variant of the binding protein MetQ, shown in this work to disrupt methionine binding, a high affinity MetNIQ complex was formed with a dissociation constant measured to be 27 nm. Using wild type MetQ containing a co-purified methionine (for which the crystal structure is reported at 1.6 Å resolution), the dissociation constant for complex formation with MetNI is measured to be ∼40-fold weaker, indicating that complex formation lowers the affinity of MetQ for methionine by this amount. Preparation of a stable MetNIQ complex is an essential step towards the crystallographic analysis of the outward facing conformation, a key intermediate in the uptake of methionine by this transport system.
Collapse
|
8
|
Tracing the structural evolution of eukaryotic ATP binding cassette transporter superfamily. Sci Rep 2015; 5:16724. [PMID: 26577702 PMCID: PMC4649718 DOI: 10.1038/srep16724] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/19/2015] [Indexed: 01/12/2023] Open
Abstract
The ATP binding cassette (ABC) transporters superfamily is one of the largest classes of membrane proteins. The core of the ABC transporter protein is composed of transmembrane domains (TMDs) and nucleotide binding domains (NBD). Eukaryotes ABC transporters are classified into seven main families (ABCA to ABCG) based on sequence similarity and domain organizations. With different domain number and domain organizations, eukaryote ABC transporters show diverse structures: the single structure (NBD or TMD), the ABC2 structure (NBD-NBD), the half structure (TMD-NBD or NBD-TMD) and the full structure (TMD-NBD-TMD-NBD or NBD-TMD-NBD-TMD). However, studies on how various ABC transporter gene structures evolved is still absent. Therefore, in this study, we comprehensively investigated the structural evolution of eukaryotic ABC transporters. The seven eukaryote ABC transporter families (A to G) fell into three groups: A&G group, B,C&D group and E&F group. There were at least four times the number of NBD and TMD fusion events in the origin of the half structure transporter. Two fusion modes were found in the full and ABC2 structure origination. Based on these findings, we present a putative structural evolutionary path of eukaryote ABC transporters that will increase our understanding on their origin, divergence and function.
Collapse
|
9
|
Dong Q, Ernst SE, Ostedgaard LS, Shah VS, Ver Heul AR, Welsh MJ, Randak CO. Mutating the Conserved Q-loop Glutamine 1291 Selectively Disrupts Adenylate Kinase-dependent Channel Gating of the ATP-binding Cassette (ABC) Adenylate Kinase Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Reduces Channel Function in Primary Human Airway Epithelia. J Biol Chem 2015; 290:14140-53. [PMID: 25887396 PMCID: PMC4447984 DOI: 10.1074/jbc.m114.611616] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Indexed: 11/06/2022] Open
Abstract
The ATP-binding cassette (ABC) transporter cystic fibrosis transmembrane conductance regulator (CFTR) and two other non-membrane-bound ABC proteins, Rad50 and a structural maintenance of chromosome (SMC) protein, exhibit adenylate kinase activity in the presence of physiologic concentrations of ATP and AMP or ADP (ATP + AMP ⇆ 2 ADP). The crystal structure of the nucleotide-binding domain of an SMC protein in complex with the adenylate kinase bisubstrate inhibitor P(1),P(5)-di(adenosine-5') pentaphosphate (Ap5A) suggests that AMP binds to the conserved Q-loop glutamine during the adenylate kinase reaction. Therefore, we hypothesized that mutating the corresponding residue in CFTR, Gln-1291, selectively disrupts adenylate kinase-dependent channel gating at physiologic nucleotide concentrations. We found that substituting Gln-1291 with bulky side-chain amino acids abolished the effects of Ap5A, AMP, and adenosine 5'-monophosphoramidate on CFTR channel function. 8-Azidoadenosine 5'-monophosphate photolabeling of the AMP-binding site and adenylate kinase activity were disrupted in Q1291F CFTR. The Gln-1291 mutations did not alter the potency of ATP at stimulating current or ATP-dependent gating when ATP was the only nucleotide present. However, when physiologic concentrations of ADP and AMP were added, adenylate kinase-deficient Q1291F channels opened significantly less than wild type. Consistent with this result, we found that Q1291F CFTR displayed significantly reduced Cl(-) channel function in well differentiated primary human airway epithelia. These results indicate that a highly conserved residue of an ABC transporter plays an important role in adenylate kinase-dependent CFTR gating. Furthermore, the results suggest that adenylate kinase activity is important for normal CFTR channel function in airway epithelia.
Collapse
Affiliation(s)
- Qian Dong
- From the Stead Family Department of Pediatrics
| | - Sarah E Ernst
- the Department of Internal Medicine, the Howard Hughes Medical Institute, Iowa City, Iowa 52242
| | | | - Viral S Shah
- the Department of Molecular Physiology and Biophysics, and the Medical Scientist Training Program, University of Iowa, Iowa City, Iowa 52242 and
| | | | - Michael J Welsh
- the Department of Internal Medicine, the Howard Hughes Medical Institute, Iowa City, Iowa 52242 the Department of Molecular Physiology and Biophysics, and
| | | |
Collapse
|
10
|
Yang X, Yang J, Li L, Sun L, Yi X, Han X, Si W, Yan R, Chen Z, Xie G, Li W, Shang Y, Liang J. PAAT, a novel ATPase and trans-regulator of mitochondrial ABC transporters, is critically involved in the maintenance of mitochondrial homeostasis. FASEB J 2014; 28:4821-34. [PMID: 25063848 DOI: 10.1096/fj.14-254045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ATP-binding cassette (ABC) transporters are implicated in a diverse range of physiological and pathophysiological processes, such as cholesterol and lipid transportation and multidrug resistance. Despite the considerable efforts made in understanding of the cellular function of ABC proteins, the regulation mechanism of this type of protein is still poorly defined. Here we report the identification and functional characterization of a novel ATPase protein, protein associated with ABC transporters (PAAT), in humans. PAAT contains a nucleotide-binding domain (NBD)-like domain and a signal for intramitochondrial sorting. We showed that PAAT is localized in both the cytoplasm and the mitochondria and has an intrinsic ATPase activity. PAAT physically interacts with the 3 known mitochondrial inner membrane ABC proteins, ABCB7, ABCB8, and ABCB10, but not ABCB1, ABCB6, or ABCG2, and functionally regulates the transport of ferric nutrients and heme biosynthesis. Significantly, PAAT deficiency promotes cell death, reduces mitochondrial potential, and sensitizes mitochondria to oxidative stress-induced DNA damages. Our experiments revealed that PAAT is a novel ATPase and a trans-regulator of mitochondrial ABC transporters that plays an important role in the maintenance of mitochondrial homeostasis and cell survival.
Collapse
Affiliation(s)
- Xiaohan Yang
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Jianguo Yang
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Lei Li
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Luyang Sun
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Xia Yi
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Xiao Han
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Wenzhe Si
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and Tianjin Key Laboratory of Medical Epigenetics, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, China
| | - Ruorong Yan
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Zhe Chen
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Guojia Xie
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Wanjin Li
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| | - Yongfeng Shang
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and Tianjin Key Laboratory of Medical Epigenetics, Department of Biochemistry and Molecular Biology, Tianjin Medical University, Tianjin, China
| | - Jing Liang
- Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing, China; and
| |
Collapse
|
11
|
Structural and functional characterization of an orphan ATP-binding cassette ATPase involved in manganese utilization and tolerance in Leptospira spp. J Bacteriol 2013; 195:5583-91. [PMID: 24123817 DOI: 10.1128/jb.00915-13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Pathogenic Leptospira species are the etiological agents of the widespread zoonotic disease leptospirosis. Most organisms, including Leptospira, require divalent cations for proper growth, but because of their high reactivity, these metals are toxic at high concentrations. Therefore, bacteria have acquired strategies to maintain metal homeostasis, such as metal import and efflux. By screening Leptospira biflexa transposon mutants for their ability to use Mn(2+), we have identified a gene encoding a putative orphan ATP-binding cassette (ABC) ATPase of unknown function. Inactivation of this gene in both L. biflexa and L. interrogans strains led to mutants unable to grow in medium in which iron was replaced by Mn(2+), suggesting an involvement of this ABC ATPase in divalent cation uptake. A mutation in this ATPase-coding gene increased susceptibility to Mn(2+) toxicity. Recombinant ABC ATPase of the pathogen L. interrogans exhibited Mg(2+)-dependent ATPase activity involving a P-loop motif. The structure of this ATPase was solved from a crystal containing two monomers in the asymmetric unit. Each monomer adopted a canonical two-subdomain organization of the ABC ATPase fold with an α/β subdomain containing the Walker motifs and an α subdomain containing the ABC signature motif (LSSGE). The two monomers were arranged in a head-to-tail orientation, forming a V-shaped particle with all the conserved ABC motifs at the dimer interface, similar to functional ABC ATPases. These results provide the first structural and functional characterization of a leptospiral ABC ATPase.
Collapse
|
12
|
Randak CO, Dong Q, Ver Heul AR, Elcock AH, Welsh MJ. ATP and AMP mutually influence their interaction with the ATP-binding cassette (ABC) adenylate kinase cystic fibrosis transmembrane conductance regulator (CFTR) at separate binding sites. J Biol Chem 2013; 288:27692-27701. [PMID: 23921386 PMCID: PMC3779764 DOI: 10.1074/jbc.m113.479675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel in the ATP-binding cassette (ABC) transporter protein family. In the presence of ATP and physiologically relevant concentrations of AMP, CFTR exhibits adenylate kinase activity (ATP + AMP ⇆ 2 ADP). Previous studies suggested that the interaction of nucleotide triphosphate with CFTR at ATP-binding site 2 is required for this activity. Two other ABC proteins, Rad50 and a structural maintenance of chromosome protein, also have adenylate kinase activity. All three ABC adenylate kinases bind and hydrolyze ATP in the absence of other nucleotides. However, little is known about how an ABC adenylate kinase interacts with ATP and AMP when both are present. Based on data from non-ABC adenylate kinases, we hypothesized that ATP and AMP mutually influence their interaction with CFTR at separate binding sites. We further hypothesized that only one of the two CFTR ATP-binding sites is involved in the adenylate kinase reaction. We found that 8-azidoadenosine 5′-triphosphate (8-N3-ATP) and 8-azidoadenosine 5′-monophosphate (8-N3-AMP) photolabeled separate sites in CFTR. Labeling of the AMP-binding site with 8-N3-AMP required the presence of ATP. Conversely, AMP enhanced photolabeling with 8-N3-ATP at ATP-binding site 2. The adenylate kinase active center probe P1,P5-di(adenosine-5′) pentaphosphate interacted simultaneously with an AMP-binding site and ATP-binding site 2. These results show that ATP and AMP interact with separate binding sites but mutually influence their interaction with the ABC adenylate kinase CFTR. They further indicate that the active center of the adenylate kinase comprises ATP-binding site 2.
Collapse
Affiliation(s)
| | | | | | | | - Michael J Welsh
- Departments of Internal Medicine; Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242; Howard Hughes Medical Institute, Iowa City, Iowa 52242
| |
Collapse
|
13
|
A single intact ATPase site of the ABC transporter BtuCD drives 5% transport activity yet supports full in vivo vitamin B12 utilization. Proc Natl Acad Sci U S A 2013; 110:5434-9. [PMID: 23513227 DOI: 10.1073/pnas.1209644110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In all kingdoms of life, ATP binding cassette (ABC) transporters are essential to many cellular functions. In this large superfamily of proteins, two catalytic sites hydrolyze ATP to power uphill substrate translocation. A central question in the field concerns the relationship between the two ATPase catalytic sites: Are the sites independent of one another? Are both needed for function? Do they function cooperatively? These issues have been resolved for type I ABC transporters but never for a type II ABC transporter. The many mechanistic differences between type I and type II ABC transporters raise the question whether in respect to ATP hydrolysis the two subtypes are similar or different. We have addressed this question by studying the Escherichia coli vitamin B12 type II ABC transporter BtuCD. We have constructed and purified a series of BtuCD variants where both, one, or none of the ATPase sites were rendered inactive by mutation. We find that, in a membrane environment, the ATPase sites of BtuCD are highly cooperative with a Hill coefficient of 2. We also find that, when one of the ATPase sites is inactive, ATP hydrolysis and vitamin B12 transport by BtuCD is reduced by 95%. These exact features are also shared by the archetypical type I maltose ABC transporter. Remarkably, mutants that have lost 95% of their ATPase and transport capabilities still retain the ability to fully use vitamin B12 in vivo. The results demonstrate that, despite the many differences between type I and type II ABC transporters, the fundamental mechanism of ATP hydrolysis remains conserved.
Collapse
|
14
|
Two molybdate/tungstate ABC transporters that interact very differently with their substrate binding proteins. Proc Natl Acad Sci U S A 2013; 110:5440-5. [PMID: 23513215 DOI: 10.1073/pnas.1213598110] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In all kingdoms of life, ATP Binding Cassette (ABC) transporters participate in many physiological and pathological processes. Despite the diversity of their functions, they have been considered to operate by a largely conserved mechanism. One deviant is the vitamin B12 transporter BtuCD that has been shown to operate by a distinct mechanism. However, it is unknown if this deviation is an exotic example, perhaps arising from the nature of the transported moiety. Here we compared two ABC importers of identical substrate specificity (molybdate/tungstate), and find that their interactions with their substrate binding proteins are utterly different. One system forms a high-affinity, slow-dissociating complex that is destabilized by nucleotide and substrate binding. The other forms a low-affinity, transient complex that is stabilized by ligands. The results highlight significant mechanistic divergence among ABC transporters, even when they share the same substrate specificity. We propose that these differences are correlated with the different folds of the transmembrane domains of ABC transporters.
Collapse
|
15
|
Germann UA, Chambers TC. Molecular analysis of the multidrug transporter, P-glycoprotein. Cytotechnology 2012; 27:31-60. [PMID: 19002782 DOI: 10.1023/a:1008023629269] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Inherent or acquired resistance of tumor cells to cytotoxic drugs represents a major limitation to the successful chemotherapeutic treatment of cancer. During the past three decades dramatic progress has been made in the understanding of the molecular basis of this phenomenon. Analyses of drug-selected tumor cells which exhibit simultaneous resistance to structurally unrelated anti-cancer drugs have led to the discovery of the human MDR1 gene product, P-glycoprotein, as one of the mechanisms responsible for multidrug resistance. Overexpression of this 170 kDa N-glycosylated plasma membrane protein in mammalian cells has been associated with ATP-dependent reduced drug accumulation, suggesting that P-glycoprotein may act as an energy-dependent drug efflux pump. P-glycoprotein consists of two highly homologous halves each of which contains a transmembrane domain and an ATP binding fold. This overall architecture is characteristic for members of the ATP-binding cassette or ABC superfamily of transporters. Cell biological, molecular genetic and biochemical approaches have been used for structure-function studies of P-glycoprotein and analysis of its mechanism of action. This review summarizes the current status of knowledge on the domain organization, topology and higher order structure of P-glycoprotein, the location of drug- and ATP binding sites within P-glycoprotein, its ATPase and drug transport activities, its possible functions as an ion channel, ATP channel and lipid transporter, its potential role in cholesterol biosynthesis, and the effects of phosphorylation on P-glycoprotein activity.
Collapse
Affiliation(s)
- U A Germann
- Vertex Pharmaceuticals Incorporated, 130 Waverly Street, Cambridge, MA, 02139-4242, U.S.A.,
| | | |
Collapse
|
16
|
Abstract
Analysis of multidrug resistant cell lines has led to the identification of the P-glycoprotein multigene family. Two of the three classes of mammalian P-glycoproteins have the ability to confer cellular resistance to a broad range of structurally and functionally diverse cytotoxic agents. P-glycoproteins are integral membrane glycoproteins comprised of two similar halves, each consisting of six membrane spanning domains followed by a cytoplasmic domain which includes a nucleotide binding fold. The P-glycoprotein is a member of a large superfamily of transport proteins which utilize ATP to translocate a wide range of substrates across biological membranes. This superfamily includes transport complexes comprised of multicomponent systems, half P-glycoproteins and P-glycoprotein-like homologs which appear to require approximately 12 alpha-helical transmembrane domains and two nucleotide binding folds for substrate transport. P-glycoprotein homologs have been isolated and characterized from a wide range of species. Amino acid sequences, the similarities between the halves and intron/exon boundaries have been compared to understand the evolutionary origins of the P-glycoprotein.
Collapse
Affiliation(s)
- I Bosch
- Harvard Medical School, The Dana-Faber Cancer Institute, Boston, MA, U.S.A
| | | |
Collapse
|
17
|
Abstract
ATP-binding cassette (ABC) transporters constitute a ubiquitous superfamily of integral membrane proteins that are responsible for the ATP-powered translocation of many substrates across membranes. The highly conserved ABC domains of ABC transporters provide the nucleotide-dependent engine that drives transport. By contrast, the transmembrane domains that create the translocation pathway are more variable. Recent structural advances with prokaryotic ABC transporters have provided a qualitative molecular framework for deciphering the transport cycle. An important goal is to develop quantitative models that detail the kinetic and molecular mechanisms by which ABC transporters couple the binding and hydrolysis of ATP to substrate translocation.
Collapse
|
18
|
Randak CO, Welsh MJ. Role of CFTR's intrinsic adenylate kinase activity in gating of the Cl(-) channel. J Bioenerg Biomembr 2008; 39:473-9. [PMID: 17965924 DOI: 10.1007/s10863-007-9119-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a Cl(-)channel in the ATP-binding cassette (ABC) transporter protein family. CFTR features the modular design characteristic of ABC transporters, which includes two membrane-spanning domains forming the channel pore, and two ABC nucleotide-binding domains that interact with ATP and contain the enzymatic activity coupled to normal gating. Like other ABC transporters CFTR is an ATPase (ATP + H(2)O --> ADP + Pi). Recent work has shown that CFTR also possesses intrinsic adenylate kinase activity (ATP + AMP left arrow over right arrow ADP + ADP). This finding raises important questions: How does AMP influence CFTR gating? Why does ADP inhibit CFTR current? Which enzymatic activity gates CFTR in vivo? Are there implications for other ABC transporters? This minireview attempts to shed light on these questions by summarizing recent advances in our understanding of the role of the CFTR adenylate kinase activity for channel gating.
Collapse
Affiliation(s)
- Christoph O Randak
- Department of Pediatrics, University of Iowa, 500 EMRB, Iowa, IA 52242, USA.
| | | |
Collapse
|
19
|
Anderson DS, Adhikari P, Weaver KD, Crumbliss AL, Mietzner TA. The Haemophilus influenzae hFbpABC Fe3+ transporter: analysis of the membrane permease and development of a gallium-based screen for mutants. J Bacteriol 2007; 189:5130-41. [PMID: 17496104 PMCID: PMC1951847 DOI: 10.1128/jb.00145-07] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The obligate human pathogen Haemophilus influenzae utilizes a siderophore-independent (free) Fe(3+) transport system to obtain this essential element from the host iron-binding protein transferrin. The hFbpABC transporter is a binding protein-dependent ABC transporter that functions to shuttle (free) Fe(3+) through the periplasm and across the inner membrane of H. influenzae. This investigation focuses on the structure and function of the hFbpB membrane permease component of the transporter, a protein that has eluded prior characterization. Based on multiple-sequence alignments between permease orthologs, a series of site-directed mutations targeted at residues within the two conserved permease motifs were generated. The hFbpABC transporter was expressed in a siderophore-deficient Escherichia coli background, and effects of mutations were analyzed using growth rescue and radiolabeled (55)Fe(3+) transport assays. Results demonstrate that mutation of the invariant glycine (G418A) within motif 2 led to attenuated transport activity, while mutation of the invariant glycine (G155A/V/E) within motif 1 had no discernible effect on activity. Individual mutations of well-conserved leucines (L154D and L417D) led to attenuated and null transport activities, respectively. As a complement to site-directed methods, a mutant screen based on resistance to the toxic iron analog gallium, an hFbpABC inhibitor, was devised. The screen led to the identification of several significant hFbpB mutations; V497I, I174F, and S475I led to null transport activities, while S146Y resulted in attenuated activity. Significant residues were mapped to a topological model of the hFbpB permease, and the implications of mutations are discussed in light of structural and functional data from related ABC transporters.
Collapse
Affiliation(s)
- Damon S Anderson
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, E1240 Biomedical Science Tower, Lothrop Street, Pittsburgh, PA 15261, USA
| | | | | | | | | |
Collapse
|
20
|
A phylogenomic analysis of the Actinomycetales mce operons. BMC Genomics 2007; 8:60. [PMID: 17324287 PMCID: PMC1810536 DOI: 10.1186/1471-2164-8-60] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Accepted: 02/26/2007] [Indexed: 01/29/2023] Open
Abstract
Background The genome of Mycobacterium tuberculosis harbors four copies of a cluster of genes termed mce operons. Despite extensive research that has demonstrated the importance of these operons on infection outcome, their physiological function remains obscure. Expanding databases of complete microbial genome sequences facilitate a comparative genomic approach that can provide valuable insight into the role of uncharacterized proteins. Results The M. tuberculosis mce loci each include two yrbE and six mce genes, which have homology to ABC transporter permeases and substrate-binding proteins, respectively. Operons with an identical structure were identified in all Mycobacterium species examined, as well as in five other Actinomycetales genera. Some of the Actinomycetales mce operons include an mkl gene, which encodes an ATPase resembling those of ABC uptake transporters. The phylogenetic profile of Mkl orthologs exactly matched that of the Mce and YrbE proteins. Through topology and motif analyses of YrbE homologs, we identified a region within the penultimate cytoplasmic loop that may serve as the site of interaction with the putative cognate Mkl ATPase. Homologs of the exported proteins encoded adjacent to the M. tuberculosis mce operons were detected in a conserved chromosomal location downstream of the majority of Actinomycetales operons. Operons containing linked mkl, yrbE and mce genes, resembling the classic organization of an ABC importer, were found to be common in Gram-negative bacteria and appear to be associated with changes in properties of the cell surface. Conclusion Evidence presented suggests that the mce operons of Actinomycetales species and related operons in Gram-negative bacteria encode a subfamily of ABC uptake transporters with a possible role in remodeling the cell envelope.
Collapse
|
21
|
Guo X, Chen X, Weber IT, Harrison RW, Tai PC. Molecular basis for differential nucleotide binding of the nucleotide-binding domain of ABC-transporter CvaB. Biochemistry 2007; 45:14473-80. [PMID: 17128986 PMCID: PMC2515628 DOI: 10.1021/bi061506i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The cytoplasmic membrane protein CvaB, involved in colicin V secretion in Escherichia coli, belongs to the ABC-transporter family in which ATP hydrolysis is typically the driving force for substrate transport. However, our previous studies indicated that the nucleotide-binding domain of CvaB could also bind and hydrolyze GTP and, indeed, highly preferred GTP over ATP at low temperatures. In this study, we have examined the molecular basis of this preference. Sequence alignment and homology modeling of the CvaB nucleotide-binding domain predicted that the aromatic stacking region of CvaB (Y501DSQ loop) had a role in the differential binding of nucleotides, and Ser503 and Gln504 provided potential hydrogen bonds to GTP but not to ATP. Site-directed mutagenesis of the Y501DSQ loop, mutations S503A, Q504L, and double mutation S503A/Q504L, was made to test the predicted hydrogen bonds with GTP. The double mutation S503A/Q504L increased the affinity for ATP by 6-fold, whereas the affinity for GTP was reduced slightly: the ATP/GTP-binding ratio increased about 10-fold. The temperature effect assays on nucleotide binding and hydrolysis further indicated that the double mutant protein had largely eliminated the difference for substrates ATP and GTP, and behaved more similarly to the NBD of typical ABC-transporter HlyB. Therefore, we conclude that Ser503 and Gln504 in aromatic stacking region of CvaB block the ATP binding and are important for the GTP-binding preference.
Collapse
Affiliation(s)
- Xiangxue Guo
- Department of Biology, Georgia State University, Atlanta, Georgia 30303
| | - Xianfeng Chen
- Department of Biology, Georgia State University, Atlanta, Georgia 30303
| | - Irene T. Weber
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Robert W. Harrison
- Department of Computer Science, Georgia State University, Atlanta, Georgia 30303
| | - Phang C. Tai
- To whom correspondence should be addressed: Phone, 404-651-3109; fax, 404-651-2509; e-mail,
| |
Collapse
|
22
|
Abstract
ATP-binding cassette (ABC) transporters couple ATP hydrolysis to the uptake and efflux of solutes across the cell membrane in bacteria and eukaryotic cells. In bacteria, these transporters are important virulence factors because they play roles in nutrient uptake and in secretion of toxins and antimicrobial agents. In humans, many diseases, such as cystic fibrosis, hyperinsulinemia, and macular dystrophy, are traced to defects in ABC transporters. Recent advances in structural determination and functional analysis of bacterial ABC transporters, reviewed herein, have greatly increased our understanding of the molecular mechanism of transport in this transport superfamily.
Collapse
Affiliation(s)
- Amy L Davidson
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA.
| | | |
Collapse
|
23
|
Chan KW, Zhang H, Logothetis DE. N-terminal transmembrane domain of the SUR controls trafficking and gating of Kir6 channel subunits. EMBO J 2003; 22:3833-43. [PMID: 12881418 PMCID: PMC169049 DOI: 10.1093/emboj/cdg376] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The sulfonylurea receptor (SUR), an ATP-binding cassette (ABC) protein, assembles with a potassium channel subunit (Kir6) to form the ATP-sensitive potassium channel (K(ATP)) complex. Although SUR is an important regulator of Kir6, the specific SUR domain that associates with Kir6 is still unknown. All functional ABC proteins contain two transmembrane domains but some, including SUR and MRP1 (multidrug resistance protein 1), contain an extra N-terminal transmembrane domain called TMD0. The functions of any TMD0s are largely unclear. Using Xenopus oocytes to coexpress truncated SUR constructs with Kir6, we demonstrated by immunoprecipitation, single-oocyte chemiluminescence and electrophysiological measurements that the TMD0 of SUR1 strongly associated with Kir6.2 and modulated its trafficking and gating. Two TMD0 mutations, A116P and V187D, previously correlated with persistent hyperinsulinemic hypoglycemia of infancy, were found to disrupt the association between TMD0 and Kir6.2. These results underscore the importance of TMD0 in K(ATP) channel function, explaining how specific mutations within this domain result in disease, and suggest how an ABC protein has evolved to regulate a potassium channel.
Collapse
Affiliation(s)
- Kim W Chan
- Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, New York, NY 10029, USA.
| | | | | |
Collapse
|
24
|
Uinuk-ool TS, Mayer WE, Sato A, Takezaki N, Benyon L, Cooper MD, Klein J. Identification and characterization of a TAP-family gene in the lamprey. Immunogenetics 2003; 55:38-48. [PMID: 12679854 DOI: 10.1007/s00251-003-0548-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2002] [Revised: 01/27/2003] [Indexed: 11/30/2022]
Abstract
An expressed sequence tag obtained from a sea lamprey ( Petromyzon marinus) cDNA library was used to obtain a full-length coding sequence showing significant similarity to ABCB transporter proteins. The sequence is closely related to the mammalian ABCB9 protein and the TAP1 and TAP2 proteins that transport peptides for loading onto nascent Mhc class I molecules. The Pema-ABCB9 gene has an exon-intron organization similar to that of the mammalian TAP genes, with the exception of exon 2, which in the lamprey is split into two by a 949-bp long intron. The gene probably occurs in a single copy in the haploid lamprey genome. The ABCB9 genes appear to be evolving four-to-ten times slower than the TAP1 and TAP2 genes. Six putative transmembrane helices and the nucleotide-binding domain of the lamprey ABCB9 protein show high sequence similarity with the TAP1 and TAP2 molecules. The lamprey protein also contains sequence stretches that resemble the putative peptide interacting parts of the TAP1 and TAP2 molecules, but are peppered with ABCB9-specific residues.
Collapse
Affiliation(s)
- Tatiana S Uinuk-ool
- Abteilung Immungenetik, Max-Planck-Institut für Biologie, Corrensstrasse 42, 72076, Tübingen, Germany.
| | | | | | | | | | | | | |
Collapse
|
25
|
Ganoza MC, Kiel MC, Aoki H. Evolutionary conservation of reactions in translation. Microbiol Mol Biol Rev 2002; 66:460-85, table of contents. [PMID: 12209000 PMCID: PMC120792 DOI: 10.1128/mmbr.66.3.460-485.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Current X-ray diffraction and cryoelectron microscopic data of ribosomes of eubacteria have shed considerable light on the molecular mechanisms of translation. Structural studies of the protein factors that activate ribosomes also point to many common features in the primary sequence and tertiary structure of these proteins. The reconstitution of the complex apparatus of translation has also revealed new information important to the mechanisms. Surprisingly, the latter approach has uncovered a number of proteins whose sequence and/or structure and function are conserved in all cells, indicating that the mechanisms are indeed conserved. The possible mechanisms of a new initiation factor and two elongation factors are discussed in this context.
Collapse
Affiliation(s)
- M Clelia Ganoza
- C. H. Best Institute, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6.
| | | | | |
Collapse
|
26
|
Choi JY, Sifri CD, Goumnerov BC, Rahme LG, Ausubel FM, Calderwood SB. Identification of virulence genes in a pathogenic strain of Pseudomonas aeruginosa by representational difference analysis. J Bacteriol 2002; 184:952-61. [PMID: 11807055 PMCID: PMC134824 DOI: 10.1128/jb.184.4.952-961.2002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that may cause severe infections in humans and other vertebrates. In addition, a human clinical isolate of P. aeruginosa, strain PA14, also causes disease in a variety of nonvertebrate hosts, including plants, Caenorhabditis elegans, and the greater wax moth, Galleria mellonella. This has led to the development of a multihost pathogenesis system in which plants, nematodes, and insects have been used as adjuncts to animal models for the identification of P. aeruginosa virulence factors. Another approach to identifying virulence genes in bacteria is to take advantage of the natural differences in pathogenicity between isolates of the same species and to use a subtractive hybridization technique to recover relevant genomic differences. The sequenced strain of P. aeruginosa, strain PAO1, has substantial differences in virulence from strain PA14 in several of the multihost models of pathogenicity, and we have utilized the technique of representational difference analysis (RDA) to directly identify genomic differences between P. aeruginosa strains PA14 and PAO1. We have found that the pilC, pilA, and uvrD genes in strain PA14 differ substantially from their counterparts in strain PAO1. In addition, we have recovered a gene homologous to the ybtQ gene from Yersinia, which is specifically present in strain PA14 but absent in strain PAO1. Mutation of the ybtQ homolog in P. aeruginosa strain PA14 significantly attenuates the virulence of this strain in both G. mellonella and a burned mouse model of sepsis to levels comparable to those seen with PAO1. This suggests that the increased virulence of P. aeruginosa strain PA14 compared to PAO1 may relate to specific genomic differences identifiable by RDA.
Collapse
Affiliation(s)
- Ji Young Choi
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | | | | | | | | | | |
Collapse
|
27
|
Ganoza MC, Kiel MC. A ribosomal ATPase is a target for hygromycin B inhibition on Escherichia coli ribosomes. Antimicrob Agents Chemother 2001; 45:2813-9. [PMID: 11557474 PMCID: PMC90736 DOI: 10.1128/aac.45.10.2813-2819.2001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We demonstrate that the transfer of fully charged aminoacyl-tRNAs into peptides directed by the MS2 RNA template requires both ATP and GTP, initiation factors (IF1, IF2, and IF3), elongation factors (EF-Tu, EF-Ts, and EF-G), and the ribosomal ATPase (RbbA). The nonhydrolyzable analogue AMPPCP inhibits the reactions, suggesting that hydrolysis of ATP is required for synthesis. The RbbA protein occurs bound to ribosomes and stimulates the ATPase activity of Escherichia coli 70S and 30S particles. The gene encoding RbbA harbors four ATP binding domains; the C-terminal half of the protein bears extensive sequence similarity to EF-3, a ribosome-dependent ATPase. Here, we show that the antibiotic hygromycin B selectively inhibits the ATPase activity of RbbA. Other antibiotics with similar effects on miscoding, streptomycin and neomycin, as well as antibiotics that impair peptide bond synthesis and translocation, had little effect on the ATPase activity of RbbA on 70S ribosomes. Immunoblot analysis indicates that at physiological concentrations, hygromycin B selectively releases RbbA from 70S ribosomes. Hygromycin B protects G1494 and A1408 in the decoding region, and RbbA enhances the reactivity of A889 and G890 of the 16S rRNA switch helix region. Cross-linking and X-ray diffraction data have revealed that this helix switch and the decoding region are in close proximity. Mutations in the switch helix (889-890) region affect translational fidelity and translocation. The binding site of hygromycin B and its known dual effect on the fidelity of decoding and translocation suggest a model for the action of this drug on ribosomes.
Collapse
Affiliation(s)
- M C Ganoza
- Banting and Best Department of Medical Research, University of Toronto, 112 College St., Toronto, Ontario M5G 1L6, Canada.
| | | |
Collapse
|
28
|
Sebulsky MT, Heinrichs DE. Identification and characterization of fhuD1 and fhuD2, two genes involved in iron-hydroxamate uptake in Staphylococcus aureus. J Bacteriol 2001; 183:4994-5000. [PMID: 11489851 PMCID: PMC95374 DOI: 10.1128/jb.183.17.4994-5000.2001] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2001] [Accepted: 06/15/2001] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus can utilize several hydroxamate siderophores for growth under iron-restricted conditions. Previous findings have shown that S. aureus possesses a cytoplasmic membrane-associated traffic ATPase that is involved in the specific transport of iron(III)-hydroxamate complexes. In this study, we have identified two additional genes, termed fhuD1 and fhuD2, whose products are involved in this transport process in S. aureus. We have shown that fhuD2 codes for a posttranslationally modified lipoprotein that is anchored in the cytoplasmic membrane, while the deduced amino acid sequence predicts the same for fhuD1. The predicted FhuD1 and FhuD2 proteins share 41.0% identity and 56.4% total similarity with each other, 45.9 and 49.1% total similarity with the FhuD homolog in Bacillus subtilis, and 29.3 and 24.6% total similarity with the periplasmic FhuD protein from Escherichia coli. Insertional inactivation and gene replacement of both genes showed that while FhuD2 is involved in the transport of iron(III) in complex with ferrichrome, ferrioxamine B, aerobactin, and coprogen, FhuD1 shows a more limited substrate range, capable of only iron(III)-ferrichrome and iron(III)-ferrioxamine B transport in S. aureus. Nucleotide sequences present upstream of both fhuD1 and fhuD2 predict the presence of consensus Fur binding sequences. In agreement, transcription of both genes was negatively regulated by exogenous iron levels through the activity of the S. aureus Fur protein.
Collapse
Affiliation(s)
- M T Sebulsky
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | | |
Collapse
|
29
|
Ames GF, Nikaido K, Wang IX, Liu PQ, Liu CE, Hu C. Purification and characterization of the membrane-bound complex of an ABC transporter, the histidine permease. J Bioenerg Biomembr 2001; 33:79-92. [PMID: 11456221 DOI: 10.1023/a:1010797029183] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The bacterial histidine permease, an ABC transporter, from Salmonella typhimurium is composed of a membrane-bound complex, HisQMP2, comprising two hydrophobic subunits (HisQ and HisM), two copies of an ATP-hydrolyzing subunit, HisP, and a soluble receptor, HisJ. We describe the purification and characterization of HisQMP2 using a 6-histidines extension at the carboxy terminus of HisP [HisQMP2(his6)]. The purification is rapid and effective, giving a seven-fold purification with a yield of 85 and 98% purity. Two procedures are described differing in the detergent used (decanoylsucrose and octylglucoside, respectively) and in the presence of phospholipid. HisQMP2(his6) has ATPase and transport activities upon reconstitution into proteoliposomes (PLS). HisQMP2(his6) has a low level ATPase activity (intrinsic activity), which is stimulated to a different extent by the receptor--liganded and unliganded. Its pH optimum is 7.8-8.0, it requires a cation for activity and it displays cooperativity for ATP. The effect of various ATP analogs was analyzed. Determination of the molecular size of HisQMP2(his6) indicates that it is a monomer. The permeability properties of two kinds of reconstituted PLS preparations are described.
Collapse
Affiliation(s)
- G F Ames
- Department of Molecular and Cell Biology, University of California at Berkeley, 94720-3202, USA
| | | | | | | | | | | |
Collapse
|
30
|
Trapping the transition state of an ATP-binding cassette transporter: evidence for a concerted mechanism of maltose transport. Proc Natl Acad Sci U S A 2001. [PMID: 11171984 PMCID: PMC29290 DOI: 10.1073/pnas.041542498] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High-affinity uptake into bacterial cells is mediated by a large class of periplasmic binding protein-dependent transport systems, members of the ATP-binding cassette superfamily. In the maltose transport system of Escherichia coli, the periplasmic maltose-binding protein binds its substrate maltose with high affinity and, in addition, stimulates the ATPase activity of the membrane-associated transporter when maltose is present. Vanadate inhibits maltose transport by trapping ADP in one of the two nucleotide-binding sites of the membrane transporter immediately after ATP hydrolysis, consistent with its ability to mimic the transition state of the gamma-phosphate of ATP during hydrolysis. Here we report that the maltose-binding protein becomes tightly associated with the membrane transporter in the presence of vanadate and simultaneously loses its high affinity for maltose. These results suggest a general model explaining how ATP hydrolysis is coupled to substrate transport in which a binding protein stimulates the ATPase activity of its cognate transporter by stabilizing the transition state.
Collapse
|
31
|
Fousteri MI, Lehmann AR. A novel SMC protein complex in Schizosaccharomyces pombe contains the Rad18 DNA repair protein. EMBO J 2000; 19:1691-702. [PMID: 10747036 PMCID: PMC310237 DOI: 10.1093/emboj/19.7.1691] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In Schizosaccharomyces pombe, rad18 is an essential gene involved in the repair of DNA damage produced by ionizing radiation and in tolerance of UV-induced DNA damage. The Rad18 protein is a member of the SMC (structural maintenance of chromosomes) superfamily, and we show that, like the other SMC proteins in condensin and cohesin, Rad18 is a component of a high-molecular-weight complex. This complex contains at least six other proteins, the largest of which is Spr18, a novel SMC family member closely related to Rad18, and likely to be its heterodimeric partner. SMC proteins have ATP-binding domains at the N- and C-termini, and two extended coiled-coil domains separated by a hinge in the middle. We show that the N-terminal ATP-binding domain of Rad18 is essential for all functions, and overexpression of an N-terminal mutant has a dominant-negative effect. We have identified an important mutation (S1045A) near the C-terminus of Rad18 that separates its repair and essential roles. Potential models for the role of the Rad18-Spr18 complex during DNA repair are discussed.
Collapse
Affiliation(s)
- M I Fousteri
- MRC Cell Mutation Unit, University of Sussex, Falmer, Brighton BN1 9RR, UK
| | | |
Collapse
|
32
|
Van Bibber M, Bradbeer C, Clark N, Roth JR. A new class of cobalamin transport mutants (btuF) provides genetic evidence for a periplasmic binding protein in Salmonella typhimurium. J Bacteriol 1999; 181:5539-41. [PMID: 10464235 PMCID: PMC94070 DOI: 10.1128/jb.181.17.5539-5541.1999] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
No periplasmic binding protein has been demonstrated for the ATP-binding cassette (ABC)-type cobalamin transporter BtuCD. New mutations (btuF) are described that affect inner-membrane transport. The BtuF protein has a signal sequence and resembles the periplasmic binding proteins of several other ABC transporters.
Collapse
Affiliation(s)
- M Van Bibber
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | | | |
Collapse
|
33
|
Leskelä S, Wahlström E, Hyyryläinen HL, Jacobs M, Palva A, Sarvas M, Kontinen VP. Ecs, an ABC transporter of Bacillus subtilis: dual signal transduction functions affecting expression of secreted proteins as well as their secretion. Mol Microbiol 1999; 31:533-43. [PMID: 10027970 DOI: 10.1046/j.1365-2958.1999.01194.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ecs is a three-cistron operon of Bacillus subtilis, encoding proteins with similarity to the ATPase (EcsA) and hydrophobic components (EcsB) of ABC transporters. The ecsA26 point mutation was shown to cause a strong processing defect of a secreted alpha-amylase precursor (preAmyQ) and of three other exoproteins. Northern analysis of the level of amyQ mRNA showed that ecsA26 also decreases amyQ transcription. This effect too was pleiotropic, as judged by a drastic decrease in the expression from an exoprotease promoter of a reporter protein. A knockout mutation of the ecsB cistron caused a processing defect similar to ecsA26 but, unlike ecsA26, did not affect amyQ transcription. These was also no defect in transcription in the ecsA ecsB double mutant. Thus, an intact ecsB product was required for the downregulation of amyQ by the mutant ecsA. These results suggest a dual regulatory function for Ecs, in which Ecs, possibly as part of a signal transduction mechanism, regulates some component(s) of the protein secretion apparatus as well as secretory protein transcription in a co-ordinated fashion.
Collapse
Affiliation(s)
- S Leskelä
- Vaccine Development Laboratory, National Public Health Institute, Helsinki, Finland
| | | | | | | | | | | | | |
Collapse
|
34
|
Schwanstecher M, Sieverding C, Dörschner H, Gross I, Aguilar-Bryan L, Schwanstecher C, Bryan J. Potassium channel openers require ATP to bind to and act through sulfonylurea receptors. EMBO J 1998; 17:5529-35. [PMID: 9755153 PMCID: PMC1170881 DOI: 10.1093/emboj/17.19.5529] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
KATP channels are composed of a small inwardly rectifying K+ channel subunit, either KIR6.1 or KIR6.2, plus a sulfonylurea receptor, SUR1 or SUR2 (A or B), which belong to the ATP-binding cassette superfamily. SUR1/KIR6.2 reconstitute the neuronal/pancreatic beta-cell channel, whereas SUR2A/KIR6.2 and SUR2B/KIR6.1 (or KIR6.2) are proposed to reconstitute the cardiac and the vascular-smooth-muscle-type KATP channels, respectively. We report that potassium channel openers (KCOs) bind to and act through SURs and that binding to SUR1, SUR2A and SUR2B requires ATP. Non-hydrolysable ATP-analogues do not support binding, and Mg2+ or Mn2+ are required. Point mutations in the Walker A motifs or linker regions of both nucleotide-binding folds (NBFs) abolish or weaken [3H]P1075 binding to SUR2B, rendering reconstituted SUR2B/KIR6.2 channels insensitive towards KCOs. The C-terminus of SUR affects KCO affinity with SUR2B approximately SUR1 > SUR2A. KCOs belonging to different structural classes inhibited specific [3H]P1075 binding to SUR2B in a monophasic manner, with the exception of minoxidil sulfate, which induced a biphasic displacement. The affinities of KCO binding to SUR2B were 3.5-8-fold higher than their potencies for activation of SUR2B/KIR6.2 channels. The results establish that SURs are the KCO receptors of KATP channels and suggest that KCO binding requires a conformational change induced by ATP hydrolysis in both NBFs.
Collapse
Affiliation(s)
- M Schwanstecher
- Institut für Pharmakologie und Toxikologie, Universität Braunschweig, Mendelssohnstrasse 1, 38106 Braunschweig, Germany.
| | | | | | | | | | | | | |
Collapse
|
35
|
Liu PQ, Ames GF. In vitro disassembly and reassembly of an ABC transporter, the histidine permease. Proc Natl Acad Sci U S A 1998; 95:3495-500. [PMID: 9520394 PMCID: PMC19864 DOI: 10.1073/pnas.95.7.3495] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/1997] [Accepted: 01/09/1998] [Indexed: 02/06/2023] Open
Abstract
The membrane-bound complex of the Salmonella typhimurium periplasmic histidine permease, a member of the ABC transporters (or traffic ATPases) superfamily, is composed of two integral membrane proteins, HisQ and HisM, and two copies of an ATP-binding subunit, HisP. The complex hydrolyzes ATP upon induction of the activity by the liganded soluble receptor, the periplasmic histidine-binding protein, HisJ. Here we take advantage of the modular organization of this system to show that the nucleotide-binding component can be stripped off the integral membrane components, HisQ and HisM. The complex can be reconstituted by using the HisP-depleted membranes containing HisQ and HisM and pure soluble HisP. We show that HisP has high affinity for the HisP-depleted complex, HisQM, and that two HisP molecules are recruited independently of each other for each HisQM unit. The in vitro reassembled complex has entirely normal properties, responding to HisJ and ATPase inhibitors with the same characteristics as the original complex and in contrast to those of soluble HisP. These results show that HisP is absolutely required for ATP hydrolysis, that HisQM cannot hydrolyze ATP, that HisP depends on HisQM to relay the inducing signal from the soluble receptor, HisJ, and that HisQM regulates the ATPase activity of HisP. We also show that HisP changes conformation upon exposure to phospholipids.
Collapse
Affiliation(s)
- P Q Liu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA
| | | |
Collapse
|
36
|
Goldman BS, Sherman DA, Kranz RG. Comparison of the bacterial HelA protein to the F508 region of the cystic fibrosis transmembrane regulator. J Bacteriol 1997; 179:7869-71. [PMID: 9401049 PMCID: PMC179753 DOI: 10.1128/jb.179.24.7869-7871.1997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The HelA protein of Rhodobacter capsulatus is the ATP-binding-cassette subunit of an exporter complex required for cytochrome c biogenesis. By primary sequence comparisons the F88 residue of HelA is similar to the F508 residue of the cystic fibrosis transmembrane regulator (CFTR) protein. Previous studies have established that CFTR F508delta or F508R proteins are defective but F508C is functional. Our results demonstrate that the HelA F88 mutants functionally mimic the phenotypes of known CFTR F508 mutants. The phenotypes of additional HelA mutants and the in vivo steady-state levels of these proteins are also reported.
Collapse
Affiliation(s)
- B S Goldman
- Department of Biology, Washington University, St. Louis, Missouri 63130-4899, USA
| | | | | |
Collapse
|
37
|
Akabas MH, Cheung M, Guinamard R. Probing the structural and functional domains of the CFTR chloride channel. J Bioenerg Biomembr 1997; 29:453-63. [PMID: 9511930 DOI: 10.1023/a:1022482923122] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) forms an anion-selective channel involved in epithelial chloride transport. Recent studies have provided new insights into the structural determinants of the channel's functional properties, such as anion selectivity, single-channel conductance, and gating. Using the scanning-cysteine-accessibility method we identified 7 residues in the M1 membrane-spanning segment and 11 residues in and flanking the M6 segment that are exposed on the water-accessible surface of the protein; many of these residues may line the ion-conducting pathway. The pattern of the accessible residues suggests that these segments have a largely alpha-helical secondary structure with one face exposed in the channel lumen. Our results suggest that the residues at the cytoplasmic end of the M6 segment loop back into the channel, narrowing the lumen, and thereby forming both the major resistance to ion movement and the charge-selectivity filter.
Collapse
Affiliation(s)
- M H Akabas
- Department of Physiology, Columbia University, New York, NY 10032, USA
| | | | | |
Collapse
|
38
|
Bliss JM, Silver RP. Evidence that KpsT, the ATP-binding component of an ATP-binding cassette transporter, is exposed to the periplasm and associates with polymer during translocation of the polysialic acid capsule of Escherichia coli K1. J Bacteriol 1997; 179:1400-3. [PMID: 9023228 PMCID: PMC178842 DOI: 10.1128/jb.179.4.1400-1403.1997] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
KpsT utilizes ATP to effect translocation of the polysialic acid capsule of Escherichia coli K1. We have previously proposed a mechanistic model for the action of this protein. Here, we provide evidence to support two predictions of the model: that KpsT associates with polymer and that KpsT is accessible from the periplasmic surface of the inner membrane.
Collapse
Affiliation(s)
- J M Bliss
- Department of Microbiology and Immunology, University of Rochester Medical Center, New York 14642, USA
| | | |
Collapse
|
39
|
Croop JM, Tiller GE, Fletcher JA, Lux ML, Raab E, Goldenson D, Son D, Arciniegas S, Wu RL. Isolation and characterization of a mammalian homolog of the Drosophila white gene. Gene 1997; 185:77-85. [PMID: 9034316 DOI: 10.1016/s0378-1119(96)00633-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Drosophila melanogaster white gene is a member of the ABC transporter superfamily of ATPase transmembrane proteins and is involved in the cellular uptake of guanine and tryptophan. We have cloned and sequenced human and mouse homologs of white which share 55-58% amino acid similarity with the Drosophila protein. Northern analysis reveals that the mammalian homolog is highly expressed in several tissues, including brain, spleen, lung and placenta. We have localized the gene to human chromosome 21q22.3 by means of fluorescence in situ hybridization and linkage analysis using a (CA)n polymorphism. The human homolog maps to the interval between D21S212 and D21S171, a region which includes loci for bipolar affective disorder and a recessive form of deafness. Since tryptophan is a precursor for the neurotransmitter serotonin and neurotoxic metabolites of the kynurenine pathway, we propose that the human homolog of white is a suitable candidate gene for these neurological disorders in humans.
Collapse
Affiliation(s)
- J M Croop
- Dana-Farber Cancer Institute, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Chan FY, Torriani A. PstB protein of the phosphate-specific transport system of Escherichia coli is an ATPase. J Bacteriol 1996; 178:3974-7. [PMID: 8682808 PMCID: PMC232664 DOI: 10.1128/jb.178.13.3974-3977.1996] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The PstB protein of the phosphate-specific transport (Pst) system of Escherichia coli bound and hydrolyzed ATP, producing ADP. Urea-treated denatured PstB did not bind ATP. The N-terminal amino acid sequence of the immune serum-precipitable PstB protein was determined, and it corresponded to that deduced from the DNA sequence.
Collapse
Affiliation(s)
- F Y Chan
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | |
Collapse
|
41
|
Cheung M, Akabas MH. Identification of cystic fibrosis transmembrane conductance regulator channel-lining residues in and flanking the M6 membrane-spanning segment. Biophys J 1996; 70:2688-95. [PMID: 8744306 PMCID: PMC1225248 DOI: 10.1016/s0006-3495(96)79838-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) forms a chloride channel that is regulated by phosphorylation and ATP binding. Work by others suggested that some residues in the sixth transmembrane segment (M6) might be exposed in the channel and play a role in ion conduction and selectivity. To identify the residues in M6 that are exposed in the channel and the secondary structure of M6, we used the substituted cysteine accessibility method. We mutated to cysteine, one at a time, 24 consecutive residues in and flanking the M6 segment and expressed these mutants in Xenopus oocytes. We determined the accessibility of the engineered cysteines to charged, lipophobic, sulfhydryl-specific methanethiosulfonate (MTS) reagents applied extracellularly. The cysteines substituted for Ile331, Leu333, Arg334, Lys335, Phe337, Ser341, Ile344, Arg347, Thr351, Arg352, and Gln353 reacted with the MTS reagents, and we infer that they are exposed on the water-accessible surface of the protein. From the pattern of the exposed residues we infer that the secondary structure of the M6 segment includes both alpha-helical and extended regions. The diameter of the channel from the extracellular end to the level of Gln353 must be at least 6 A to allow the MTS reagents to reach these residues.
Collapse
Affiliation(s)
- M Cheung
- Center for Molecular Recognition, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | | |
Collapse
|
42
|
Abstract
▪ Abstract Plant and fungal membrane proteins catalyzing the transmembrane translocation of small molecules without directly using ATP or acting as channels are discussed in this review. Facilitators, ion-cotransporters, and exchange translocators mainly for sugars, amino acids, and ions that have been cloned and characterized from Saccharomyces cerevisiae and from various plant sources have been tabulated. The membrane topology and structure of the most extensively studied carriers (lac permease of Escherichia coli, Glut1 of man, HUP1 of Chlorella) are discussed in detail as well as the kinetic analysis of specific Na+ and H+ cotransporters. Finally, the knowledge concerning regulatory phenomena of carriers—mainly of S. cerevisiae—is summarized.
Collapse
Affiliation(s)
- W. Tanner
- Lehrstuhl fur Zellbiologie und Pflanzenphysiologie, Universitat Regensburg, Regensburg, 93040 Germany
| | | |
Collapse
|
43
|
Browne BL, McClendon V, Bedwell DM. Mutations within the first LSGGQ motif of Ste6p cause defects in a-factor transport and mating in Saccharomyces cerevisiae. J Bacteriol 1996; 178:1712-9. [PMID: 8626301 PMCID: PMC177858 DOI: 10.1128/jb.178.6.1712-1719.1996] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Mating between the two haploid cell types (a and alpha) of the yeast Saccharomyces cerevisiae depends upon the efficient secretion and delivery of the a- and alpha-factor pheromones to their respective target cells. However, a quantitative correlation between the level of transported a-factor and mating efficiency has never been determined. a-Factor is transported by Ste6p, a member of the ATP-binding cassette (ABC) family of transporter proteins. In this study, several missense mutations were introduced in or near the conserved LSGGQ motif within the first nucleotide-binding domain of Ste6p. Quantitation of extracellular a-factor levels indicated that these mutations caused a broad range of a-factor transport defects, and those directly within the LSGGQ motif caused the most severe defects. Overall, we observed a strong correlation between the level of transported a-factor and the mating efficiency of these strains, consistent with the role of Ste6p as the a-factor transporter. The LSGGQ mutations did not cause either a significant alteration in the steady-state level of Ste6p or a detectable change in its subcellular localization. Thus, it appears that these mutations interfere with the ability of Ste6p to transport a-factor out of the MATa cell. The possible involvement of the LSGGQ motif in transporter function is consistent with the strong conservation of this sequence motif throughout the ABC transporter superfamily.
Collapse
Affiliation(s)
- B L Browne
- Department of Microbiology,University of Alabama, Birmingham, Alabama 35294, USA
| | | | | |
Collapse
|
44
|
Swartzman EE, Viswanathan MN, Thorner J. The PAL1 gene product is a peroxisomal ATP-binding cassette transporter in the yeast Saccharomyces cerevisiae. J Biophys Biochem Cytol 1996; 132:549-63. [PMID: 8647887 PMCID: PMC2199874 DOI: 10.1083/jcb.132.4.549] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The PAL1 gene was isolated using PCR and degenerate oligonucleotide primers corresponding to highly conserved amino acid sequence motifs diagnostic of the ATP-binding cassette domain of the superfamily of membrane-bound transport proteins typified by mammalian multidrug resistance transporter 1 and Saccharomyces cerevisiae Ste6. The deduced PAL1 gene product is similar in length to, has the same predicted topology as, and shares the highest degree of amino acid sequence identity with two human proteins, adrenoleukodystrophy protein and peroxisomal membrane protein (70 kD), which are both presumptive ATP-binding cassette transporters thought to be constituents of the peroxisomal membrane. As judged by hybridization of a PAL1 probe to isolated RNA and by expression of a PAL1-lacZ fusion, a PAL1 transcript was only detectable when cells were grown on oleic acid, a carbon source which requires the biogenesis of functional peroxisomes for its metabolism. A pal1delta mutant grew normally on either glucose- or glycerol-containing media; however, unlike PAL1+ cells (or the pal1delta mutant carrying the PAL1 gene on a plasmid), pal1delta cells were unable to grow on either a solid medium or a liquid medium containing oleic acid as the sole carbon source. Antibodies raised against a chimeric protein in which the COOH-terminal domain of Pal1 was fused to glutathione S-transferase specifically recognized a protein in extracts from wild-type cells only when grown on oleic acid; this species represents the PAL1 gene product because it was missing in pal1delta cells and more abundant in pal1delta cells expressing PAL1 from a multicopy plasmid. The Pal1 polypeptide was highly enriched in the organellar pellet fraction prepared from wild-type cells by differential centrifugation and comigrated upon velocity sedimentation in a Nycodenz gradient with a known component of the peroxisomal matrix, e-oxoacyl-CoA thiolase. As judged by both subcellular fractionation and indirect immunofluorescence, localization of 3-oxoacyl-CoA thiolase to peroxisomes was unchanged whether Pal1 was present, absent, or overexpressed. These findings demonstrate that Pal1 is a peroxisome-specific protein, that it is required for peroxisome function, but that it is not necessary for the biogenesis of peroxisomes or for the import of 3-oxoacyl-CoA thiolase (and at least two other peroxisomal matrix proteins).
Collapse
Affiliation(s)
- E E Swartzman
- Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, 94720-3202, USA
| | | | | |
Collapse
|
45
|
Vimr E, Steenbergen S, Cieslewicz M. Biosynthesis of the polysialic acid capsule in Escherichia coli K1. JOURNAL OF INDUSTRIAL MICROBIOLOGY 1995; 15:352-60. [PMID: 8605072 DOI: 10.1007/bf01569991] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The extracellular polysaccharides elaborated by most or all bacterial species function in cell-to-cell and cell-substratum adhesion, cell signaling, and avoidance or inhibition of noxious agents in animal hosts or free-living environments. Recent advances in our understanding of exopolysaccharide synthesis have been facilitated by comparative approaches in both plant and animal pathogens, as well as in microorganisms of industrial importance. One of the best understood of these systems is the kps locus for polysialic acid synthesis in Escherichia coli K1. The genes for sialic acid synthesis, activation, polymerization and translocation have been identified and assigned at least tentative functions in the synthetic and export pathways. Initial studies of kps thermoregulation suggest that genetic control mechanisms will be involved which are distinct from those already described for several other exopolysaccharides. Information about the common as well as unique features of polysialic acid biosynthesis will increase our knowledge of microbial cell surfaces which in turn may suggest novel targets for therapeutic or industrial interventions.
Collapse
Affiliation(s)
- E Vimr
- Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign 61801, USA
| | | | | |
Collapse
|
46
|
Sirko A, Zatyka M, Sadowy E, Hulanicka D. Sulfate and thiosulfate transport in Escherichia coli K-12: evidence for a functional overlapping of sulfate- and thiosulfate-binding proteins. J Bacteriol 1995; 177:4134-6. [PMID: 7608089 PMCID: PMC177147 DOI: 10.1128/jb.177.14.4134-4136.1995] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In Escherichia coli, sulfate and thiosulfate ions are transported by an ABC-type transporter consisting of both the membrane components (the products of cysT, cysW, and cysA genes) and the periplasmic binders (the products of cysP and sbp genes). The single cysP and sbp mutants are able to utilize both sulfate and thiosulfate as a sole sulfur source, while the inactivation of both genes leads to cysteine auxotrophy resulting from the block in the transport of both ions.
Collapse
Affiliation(s)
- A Sirko
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw
| | | | | | | |
Collapse
|
47
|
Wunder DE, Aaronson W, Hayes SF, Bliss JM, Silver RP. Nucleotide sequence and mutational analysis of the gene encoding KpsD, a periplasmic protein involved in transport of polysialic acid in Escherichia coli K1. J Bacteriol 1994; 176:4025-33. [PMID: 8021185 PMCID: PMC205601 DOI: 10.1128/jb.176.13.4025-4033.1994] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The 17-kb kps gene cluster encodes proteins necessary for the synthesis, assembly, and translocation of the polysialic acid capsule of Escherichia coli K1. We previously reported that one of these genes, kpsD, encodes a 60-kDa periplasmic protein that is involved in the translocation of the polymer to the cell surface. The nucleotide sequence of the 2.4-kb BamHI-PstI fragment accommodating the kpsD gene was determined. Sequence analysis showed an open reading frame for a 558-amino-acid protein with a typical N-terminal prokaryotic signal sequence corresponding to the first 20 amino acids. KpsD was overexpressed, partially purified, and used to prepare polyclonal antiserum. A chromosomal insertion mutation was generated in the kpsD gene and results in loss of surface expression of the polysialic acid capsule. Immunodiffusion analysis and electron microscopy indicated that polysaccharide accumulates in the periplasmic space of mutant cells. A wild-type copy of kpsD supplied in trans complemented the chromosomal mutation, restoring extracellular expression of the K1 capsule. However, a kpsD deletion derivative (kpsD delta C11), which results in production of a truncated KpsD protein lacking its 11 C-terminal amino acids, was nonfunctional. Western blot (immunoblot) data from cell fractions expressing KpsD delta C11 suggest that the truncated protein was inefficiently exported into the periplasm and localized primarily to the cytoplasmic membrane.
Collapse
Affiliation(s)
- D E Wunder
- Department of Microbiology and Immunology, University of Rochester Medical Center, New YOrk 14642
| | | | | | | | | |
Collapse
|