1
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Mensah GAK, Schaefer KG, Roberts AG, King GM, Bartlett MG. Probing the Mechanisms Underlying the Transport of the Vinca Alkaloids by P-glycoprotein. J Pharm Sci 2024; 113:1960-1974. [PMID: 38527618 DOI: 10.1016/j.xphs.2024.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/18/2024] [Accepted: 03/18/2024] [Indexed: 03/27/2024]
Abstract
The efficacy of many cancer drugs is hindered by P-glycoprotein (Pgp), a cellular pump that removes drugs from cells. To improve chemotherapy, drugs capable of evading Pgp must be developed. Despite similarities in structure, vinca alkaloids (VAs) show disparate Pgp-mediated efflux ratios. ATPase activity and binding affinity studies show at least two binding sites for the VAs: high- and low-affinity sites that stimulate and inhibit the ATPase activity rate, respectively. The affinity for ATP from the ATPase kinetics curve for vinblastine (VBL) at the high-affinity site was 2- and 9-fold higher than vinorelbine (VRL) and vincristine (VCR), respectively. Conversely, VBL had the highest Km (ATP) for the low-affinity site. The dissociation constants (KDs) determined by protein fluorescence quenching were in the order VBL < VRL< VCR. The order of the KDs was reversed at higher substrate concentrations. Acrylamide quenching of protein fluorescence indicate that the VAs, either at 10 µM or 150 µM, predominantly maintain Pgp in an open-outward conformation. When 3.2 mM AMPPNP was present, 10 µM of either VBL, VRL, or VCR cause Pgp to shift to an open-outward conformation, while 150 µM of the VAs shifted the conformation of Pgp to an intermediate orientation, between opened inward and open-outward. However, the conformational shift induced by saturating AMPPNP and VCR condition was less than either VBL or VRL in the presence of AMPPNP. At 150 µM, atomic force microscopy (AFM) revealed that the VAs shift Pgp population to a predominantly open-inward conformation. Additionally, STDD NMR studies revealed comparable groups in VBL, VRL, and VCR are in contact with the protein during binding. Our results, when coupled with VAs-microtubule structure-activity relationship studies, could lay the foundation for developing next-generation VAs that are effective as anti-tumor agents. A model that illustrates the intricate process of Pgp-mediated transport of the VAs is presented.
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Affiliation(s)
- Gershon A K Mensah
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA
| | - Katherine G Schaefer
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
| | - Arthur G Roberts
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA.
| | - Gavin M King
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA; Joint with Biochemistry, University of Missouri, Columbia, MO 65211, USA.
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA.
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2
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Dixit S, Middelkoop TC, Choubey S. Governing principles of transcriptional logic out of equilibrium. Biophys J 2024; 123:1015-1029. [PMID: 38486450 PMCID: PMC11052701 DOI: 10.1016/j.bpj.2024.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 03/04/2024] [Accepted: 03/11/2024] [Indexed: 03/24/2024] Open
Abstract
To survive, adapt, and develop, cells respond to external and internal stimuli by tightly regulating transcription. Transcriptional regulation involves the combinatorial binding of a repertoire of transcription factors to DNA, which often results in switch-like binary outputs akin to Boolean logic gates. Recent experimental studies have demonstrated that in eukaryotes, transcription factor binding to DNA often involves energy expenditure, thereby driving the system out of equilibrium. The governing principles of transcriptional logic operations out of equilibrium remain unexplored. Here, we employ a simple two-input, single-locus model of transcription that can accommodate both equilibrium and nonequilibrium mechanisms. Using this model, we find that nonequilibrium regimes can give rise to all the logic operations accessible in equilibrium. Strikingly, energy expenditure alters the regulatory function of the two transcription factors in a mutually exclusive manner. This allows for the emergence of new logic operations that are inaccessible in equilibrium. Overall, our results show that energy expenditure can expand the range of cellular decision-making without the need for more complex promoter architectures.
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Affiliation(s)
- Smruti Dixit
- The Institute of Mathematical Sciences, CIT Campus, Chennai, India.
| | - Teije C Middelkoop
- Laboratory of Developmental Mechanobiology, Division BIOCEV, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Sandeep Choubey
- The Institute of Mathematical Sciences, CIT Campus, Chennai, India; Homi Bhabha National Institute, Training School Complex, Mumbai, India.
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3
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Miwa S, Takikawa H, Takeuchi R, Mizunuma R, Matsuoka K, Ogawa H, Kato H, Takasu K. Structure-ATPase Activity Relationship of Rhodamine Derivatives as Potent Inhibitors of P-Glycoprotein CmABCB1. ACS Med Chem Lett 2024; 15:287-293. [PMID: 38352840 PMCID: PMC10860176 DOI: 10.1021/acsmedchemlett.3c00526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/05/2024] [Accepted: 01/13/2024] [Indexed: 02/16/2024] Open
Abstract
Understanding the transport and inhibition mechanisms of substrates by P-glycoprotein (P-gp) is one of the important approaches in addressing multidrug resistance (MDR). In this study, we evaluated a variety of rhodamine derivatives as potential P-gp inhibitors targeting CmABCB1, a P-gp homologue, with a focus on their ATPase activity. Notably, a Q-rhodamine derivative with an o,o'-dimethoxybenzyl ester moiety (RhQ-DMB) demonstrated superior affinity and inhibitory activity, which was further confirmed by a drug susceptibility assay in yeast strains expressing CmABCB1. Results from a tryptophan fluorescence quenching experiment using a CmABCB1 mutant suggested that RhQ-DMB effectively enters and binds to the inner chamber of CmABCB1. These findings underscore the promising potential of RhQ-DMB as a tool for future studies aimed at elucidating the substrate-bound state of CmABCB1.
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Affiliation(s)
- Sorachi Miwa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroshi Takikawa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Rina Takeuchi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Ryo Mizunuma
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Keita Matsuoka
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Haruo Ogawa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroaki Kato
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
- RIKEN Harima Institute at SPring-8, Hyogo 679-5148 Japan
| | - Kiyosei Takasu
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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4
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Mensah GAK, Schaefer KG, Bartlett MG, Roberts AG, King GM. Drug-Induced Conformational Dynamics of P-Glycoprotein Underlies the Transport of Camptothecin Analogs. Int J Mol Sci 2023; 24:16058. [PMID: 38003248 PMCID: PMC10671697 DOI: 10.3390/ijms242216058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 10/24/2023] [Accepted: 10/28/2023] [Indexed: 11/26/2023] Open
Abstract
P-glycoprotein (Pgp) plays a pivotal role in drug bioavailability and multi-drug resistance development. Understanding the protein's activity and designing effective drugs require insight into the mechanisms underlying Pgp-mediated transport of xenobiotics. In this study, we investigated the drug-induced conformational changes in Pgp and adopted a conformationally-gated model to elucidate the Pgp-mediated transport of camptothecin analogs (CPTs). While Pgp displays a wide range of conformations, we simplified it into three model states: 'open-inward', 'open-outward', and 'intermediate'. Utilizing acrylamide quenching of Pgp fluorescence as a tool to examine the protein's tertiary structure, we observed that topotecan (TPT), SN-38, and irinotecan (IRT) induced distinct conformational shifts in the protein. TPT caused a substantial shift akin to AMPPNP, suggesting ATP-independent 'open-outward' conformation. IRT and SN-38 had relatively moderate effects on the conformation of Pgp. Experimental atomic force microscopy (AFM) imaging supports these findings. Further, the rate of ATPase hydrolysis was correlated with ligand-induced Pgp conformational changes. We hypothesize that the separation between the nucleotide-binding domains (NBDs) creates a conformational barrier for substrate transport. Substrates that reduce the conformational barrier, like TPT, are better transported. The affinity for ATP extracted from Pgp-mediated ATP hydrolysis kinetics curves for TPT was about 2-fold and 3-fold higher than SN-38 and IRT, respectively. On the contrary, the dissociation constants (KD) determined by fluorescence quenching for these drugs were not significantly different. Saturation transfer double difference (STDD) NMR of TPT and IRT with Pgp revealed that similar functional groups of the CPTs are accountable for Pgp-CPTs interactions. Efforts aimed at modifying these functional groups, guided by available structure-activity relationship data for CPTs and DNA-Topoisomerase-I complexes, could pave the way for the development of more potent next-generation CPTs.
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Affiliation(s)
- Gershon A. K. Mensah
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA; (G.A.K.M.)
| | - Katherine G. Schaefer
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA;
| | - Michael G. Bartlett
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA; (G.A.K.M.)
| | - Arthur G. Roberts
- Department of Pharmaceutical and Biomedical Science, University of Georgia, Athens, GA 30602, USA; (G.A.K.M.)
| | - Gavin M. King
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA;
- Joint with Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
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5
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Murakami M, Sajid A, Lusvarghi S, Durell SR, Abel B, Vahedi S, Golin J, Ambudkar SV. Second-site suppressor mutations reveal connection between the drug-binding pocket and nucleotide-binding domain 1 of human P-glycoprotein (ABCB1). Drug Resist Updat 2023; 71:101009. [PMID: 37797431 PMCID: PMC10842643 DOI: 10.1016/j.drup.2023.101009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/07/2023]
Abstract
Human P-glycoprotein (P-gp) or ABCB1 is overexpressed in many cancers and has been implicated in altering the bioavailability of chemotherapeutic drugs due to their efflux, resulting in the development of chemoresistance. To elucidate the mechanistic aspects and structure-function relationships of P-gp, we previously utilized a tyrosine (Y)-enriched P-gp mutant (15Y) and demonstrated that at least 15 conserved residues in the drug-binding pocket of P-gp are responsible for optimal substrate interaction and transport. To further understand the role of these 15 residues, two new mutants were generated, namely 6Y with the substitution of six residues (F72, F303, I306, F314, F336 and L339) with Y in transmembrane domain (TMD) 1 and 9Y with nine substitutions (F732, F759, F770, F938, F942, M949, L975, F983 and F994) in TMD2. Although both the mutants were expressed at normal levels at the cell surface, the 6Y mutant failed to transport all the tested substrates except Bodipy-verapamil, whereas the 9Y mutant effluxed all tested substrates in a manner very similar to that of the wild-type protein. Further mutational analysis revealed that two second-site mutations, one in intracellular helix (ICH) 4 (F916Y) and one in the Q loop of nucleotide-binding domain (NBD) 1 (F480Y) restored the transport function of 6Y. Additional biochemical data and comparative molecular dynamics simulations of the 6Y and 6Y+F916Y mutant indicate that the Q-loop of NBD1 of P-gp communicates with the substrate-binding sites in the transmembrane region through ICH4. This is the first evidence for the existence of second-site suppressors in human P-gp that allow recovery of the loss of transport function caused by primary mutations. Further study of such mutations could facilitate mapping of the communication pathway between the substrate-binding pocket and the NBDs of P-gp and possibly other ABC drug transporters.
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Affiliation(s)
- Megumi Murakami
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Andaleeb Sajid
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sabrina Lusvarghi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Biebele Abel
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Shahrooz Vahedi
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - John Golin
- Department of Biology, Catholic University of America, Washington, DC 20064, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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6
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Panigrahy M, Dua A. Molecular noise-induced activator-inhibitor duality in enzyme inhibition kinetics. J Chem Phys 2023; 159:155101. [PMID: 37843064 DOI: 10.1063/5.0152686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023] Open
Abstract
Classical theories of enzyme inhibition kinetics predict a monotonic decrease in the mean catalytic activity with the increase in inhibitor concentration. The steady-state result, derived from deterministic mass action kinetics, ignores molecular noise in enzyme-inhibition mechanisms. Here, we present a stochastic generalization of enzyme inhibition kinetics to mesoscopic enzyme concentrations by systematically accounting for molecular noise in competitive and uncompetitive mechanisms of enzyme inhibition. Our work reveals an activator-inhibitor duality as a non-classical effect in the transient regime in which inhibitors tend to enhance enzymatic activity. We introduce statistical measures that quantify this counterintuitive response through the stochastic analog of the Lineweaver-Burk plot that shows a merging of the inhibitor-dependent velocity with the Michaelis-Menten velocity. The statistical measures of mean and temporal fluctuations - fractional enzyme activity and waiting time correlations - show a non-monotonic rise with the increase in inhibitors before subsiding to their baseline value. The inhibitor and substrate dependence of the fractional enzyme activity yields kinetic phase diagrams for non-classical activator-inhibitor duality. Our work links this duality to a molecular memory effect in the transient regime, arising from positive correlations between consecutive product turnover times. The vanishing of memory in the steady state recovers all the classical results.
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Affiliation(s)
- Manmath Panigrahy
- Department of Chemistry, Indian Institute of Technology, Madras, Chennai 600036, India
| | - Arti Dua
- Department of Chemistry, Indian Institute of Technology, Madras, Chennai 600036, India
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7
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Badiee SA, Isu UH, Khodadadi E, Moradi M. The Alternating Access Mechanism in Mammalian Multidrug Resistance Transporters and Their Bacterial Homologs. MEMBRANES 2023; 13:568. [PMID: 37367772 DOI: 10.3390/membranes13060568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 05/23/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023]
Abstract
Multidrug resistance (MDR) proteins belonging to the ATP-Binding Cassette (ABC) transporter group play a crucial role in the export of cytotoxic drugs across cell membranes. These proteins are particularly fascinating due to their ability to confer drug resistance, which subsequently leads to the failure of therapeutic interventions and hinders successful treatments. One key mechanism by which multidrug resistance (MDR) proteins carry out their transport function is through alternating access. This mechanism involves intricate conformational changes that enable the binding and transport of substrates across cellular membranes. In this extensive review, we provide an overview of ABC transporters, including their classifications and structural similarities. We focus specifically on well-known mammalian multidrug resistance proteins such as MRP1 and Pgp (MDR1), as well as bacterial counterparts such as Sav1866 and lipid flippase MsbA. By exploring the structural and functional features of these MDR proteins, we shed light on the roles of their nucleotide-binding domains (NBDs) and transmembrane domains (TMDs) in the transport process. Notably, while the structures of NBDs in prokaryotic ABC proteins, such as Sav1866, MsbA, and mammalian Pgp, are identical, MRP1 exhibits distinct characteristics in its NBDs. Our review also emphasizes the importance of two ATP molecules for the formation of an interface between the two binding sites of NBD domains across all these transporters. ATP hydrolysis occurs following substrate transport and is vital for recycling the transporters in subsequent cycles of substrate transportation. Specifically, among the studied transporters, only NBD2 in MRP1 possesses the ability to hydrolyze ATP, while both NBDs of Pgp, Sav1866, and MsbA are capable of carrying out this reaction. Furthermore, we highlight recent advancements in the study of MDR proteins and the alternating access mechanism. We discuss the experimental and computational approaches utilized to investigate the structure and dynamics of MDR proteins, providing valuable insights into their conformational changes and substrate transport. This review not only contributes to an enhanced understanding of multidrug resistance proteins but also holds immense potential for guiding future research and facilitating the development of effective strategies to overcome multidrug resistance, thus improving therapeutic interventions.
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Affiliation(s)
- Shadi A Badiee
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ugochi H Isu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ehsaneh Khodadadi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
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8
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Meier G, Thavarasah S, Ehrenbolger K, Hutter CAJ, Hürlimann LM, Barandun J, Seeger MA. Deep mutational scan of a drug efflux pump reveals its structure-function landscape. Nat Chem Biol 2023; 19:440-450. [PMID: 36443574 PMCID: PMC7615509 DOI: 10.1038/s41589-022-01205-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/10/2022] [Indexed: 11/30/2022]
Abstract
Drug efflux is a common resistance mechanism found in bacteria and cancer cells, but studies providing comprehensive functional insights are scarce. In this study, we performed deep mutational scanning (DMS) on the bacterial ABC transporter EfrCD to determine the drug efflux activity profile of more than 1,430 single variants. These systematic measurements revealed that the introduction of negative charges at different locations within the large substrate binding pocket results in strongly increased efflux activity toward positively charged ethidium, whereas additional aromatic residues did not display the same effect. Data analysis in the context of an inward-facing cryogenic electron microscopy structure of EfrCD uncovered a high-affinity binding site, which releases bound drugs through a peristaltic transport mechanism as the transporter transits to its outward-facing conformation. Finally, we identified substitutions resulting in rapid Hoechst influx without affecting the efflux activity for ethidium and daunorubicin. Hence, single mutations can convert EfrCD into a drug-specific ABC importer.
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Affiliation(s)
- Gianmarco Meier
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Sujani Thavarasah
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Kai Ehrenbolger
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Cedric A J Hutter
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Linkster Therapeutics AG, Zurich, Switzerland
| | - Lea M Hürlimann
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Linkster Therapeutics AG, Zurich, Switzerland
| | - Jonas Barandun
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
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9
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Orelle C, Schmitt L, Jault JM. Waste or die: The price to pay to stay alive. Trends Microbiol 2023; 31:233-241. [PMID: 36192292 DOI: 10.1016/j.tim.2022.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/06/2022] [Accepted: 09/06/2022] [Indexed: 11/19/2022]
Abstract
Microorganisms need to constantly exchange with their habitat to capture nutrients and expel toxic compounds. The ATP-binding cassette (ABC) transporters, a family of membrane proteins especially abundant in microorganisms, are at the core of these processes. Due to their extraordinary ability to expel structurally unrelated compounds, some transporters play a protective role in different organisms. Yet, the downside of these multidrug transporters is their entanglement in the resistance to therapeutic treatments. Intriguingly, some multidrug ABC transporters show a high level of ATPase activity, even in the absence of transported substrates. Although this basal ATPase activity might seem a waste, we surmise that this inherent capacity allows multidrug transporters to promptly translocate any bound drug before it penetrates into the cell.
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Affiliation(s)
- Cédric Orelle
- University of Lyon, CNRS, UMR5086 'Molecular Microbiology and Structural Biochemistry', IBCP, 7 Passage du Vercors, F-69367, Lyon, France.
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
| | - Jean-Michel Jault
- University of Lyon, CNRS, UMR5086 'Molecular Microbiology and Structural Biochemistry', IBCP, 7 Passage du Vercors, F-69367, Lyon, France.
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10
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Interaction of a Homologous Series of Amphiphiles with P-glycoprotein in a Membrane Environment-Contributions of Polar and Non-Polar Interactions. Pharmaceutics 2023; 15:pharmaceutics15010174. [PMID: 36678803 PMCID: PMC9862096 DOI: 10.3390/pharmaceutics15010174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/06/2022] [Accepted: 12/26/2022] [Indexed: 01/05/2023] Open
Abstract
The transport of drugs by efflux transporters in biomembranes limits their bioavailability and is a major determinant of drug resistance development by cancer cells and pathogens. A large number of chemically dissimilar drugs are transported, and despite extensive studies, the molecular determinants of substrate specificity are still not well understood. In this work, we explore the role of polar and non-polar interactions on the interaction of a homologous series of fluorescent amphiphiles with the efflux transporter P-glycoprotein. The interaction of the amphiphiles with P-glycoprotein is evaluated through effects on ATPase activity, efficiency in inhibition of [125I]-IAAP binding, and partition to the whole native membranes containing the transporter. The results were complemented with partition to model membranes with a representative lipid composition, and details on the interactions established were obtained from MD simulations. We show that when the total concentration of amphiphile is considered, the binding parameters obtained are apparent and do not reflect the affinity for P-gp. A new formalism is proposed that includes sequestration of the amphiphiles in the lipid bilayer and the possible binding of several molecules in P-gp's substrate-binding pocket. The intrinsic binding affinity thus obtained is essentially independent of amphiphile hydrophobicity, highlighting the importance of polar interactions. An increase in the lipophilicity and amphiphilicity led to a more efficient association with the lipid bilayer, which maintains the non-polar groups of the amphiphiles in the bilayer, while the polar groups interact with P-gp's binding pocket. The presence of several amphiphiles in this orientation is proposed as a mechanism for inhibition of P-pg function.
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11
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Gyöngy Z, Mocsár G, Hegedűs É, Stockner T, Ritter Z, Homolya L, Schamberger A, Orbán TI, Remenyik J, Szakacs G, Goda K. Nucleotide binding is the critical regulator of ABCG2 conformational transitions. eLife 2023; 12:83976. [PMID: 36763413 PMCID: PMC9917445 DOI: 10.7554/elife.83976] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/27/2023] [Indexed: 02/11/2023] Open
Abstract
ABCG2 is an exporter-type ABC protein that can expel numerous chemically unrelated xeno- and endobiotics from cells. When expressed in tumor cells or tumor stem cells, ABCG2 confers multidrug resistance, contributing to the failure of chemotherapy. Molecular details orchestrating substrate translocation and ATP hydrolysis remain elusive. Here, we present methods to concomitantly investigate substrate and nucleotide binding by ABCG2 in cells. Using the conformation-sensitive antibody 5D3, we show that the switch from the inward-facing (IF) to the outward-facing (OF) conformation of ABCG2 is induced by nucleotide binding. IF-OF transition is facilitated by substrates, and hindered by the inhibitor Ko143. Direct measurements of 5D3 and substrate binding to ABCG2 indicate that the high-to-low affinity switch of the drug binding site coincides with the transition from the IF to the OF conformation. Low substrate binding persists in the post-hydrolysis state, supporting that dissociation of the ATP hydrolysis products is required to reset the high substrate affinity IF conformation of ABCG2.
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Affiliation(s)
- Zsuzsanna Gyöngy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary,Doctoral School of Molecular Cell and Immune Biology, University of DebrecenDebrecenHungary
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary
| | - Éva Hegedűs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of ViennaViennaAustria
| | - Zsuzsanna Ritter
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary,Doctoral School of Molecular Cell and Immune Biology, University of DebrecenDebrecenHungary
| | - László Homolya
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Anita Schamberger
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Tamás I Orbán
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Judit Remenyik
- Institute of Food Technology, Faculty of Agricultural and Food Sciences and Environmental Management, University of DebrecenDebrecenHungary
| | - Gergely Szakacs
- Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary,Institute of Cancer Research, Medical University of ViennaViennaAustria
| | - Katalin Goda
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of DebrecenDebrecenHungary
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12
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The lysosomal transporter TAPL has a dual role as peptide translocator and phosphatidylserine floppase. Nat Commun 2022; 13:5851. [PMID: 36195619 PMCID: PMC9532399 DOI: 10.1038/s41467-022-33593-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 09/23/2022] [Indexed: 11/08/2022] Open
Abstract
TAPL is a lysosomal ATP-binding cassette transporter that translocates a broad spectrum of polypeptides from the cytoplasm into the lysosomal lumen. Here we report that, in addition to its well-known role as a peptide translocator, TAPL exhibits an ATP-dependent phosphatidylserine floppase activity that is the possible cause of its high basal ATPase activity and of the lack of coupling between ATP hydrolysis and peptide efflux. We also present the cryo-EM structures of mouse TAPL complexed with (i) phospholipid, (ii) cholesteryl hemisuccinate (CHS) and 9-mer peptide, and (iii) ADP·BeF3. The inward-facing structure reveals that F449 protrudes into the cylindrical transport pathway and divides it into a large hydrophilic central cavity and a sizable hydrophobic upper cavity. In the structure, the peptide binds to TAPL in horizontally-stretched fashion within the central cavity, while lipid molecules plug vertically into the upper cavity. Together, our results suggest that TAPL uses different mechanisms to function as a peptide translocase and a phosphatidylserine floppase.
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Inoue Y, Yamaguchi T, Otsuka T, Utsunomiya Y, Pan D, Ogawa H, Kato H. Structure-based alteration of tryptophan residues of the multidrug transporter CmABCB1 to assess substrate binding using fluorescence spectroscopy. Protein Sci 2022; 31:e4331. [PMID: 35634783 PMCID: PMC9123602 DOI: 10.1002/pro.4331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/01/2022] [Accepted: 04/06/2022] [Indexed: 09/17/2023]
Abstract
ABCB1, also known as P-glycoprotein, is an essential component of many physiological barriers and extrudes a variety of hydrophobic chemicals out of the cell. Structures of ABCB1 provided insights into the structural changes that occur upon ATP binding and the characteristic architecture of the substrate binding site. Yet, the structure-function relationship between substrate binding and transporting still remains largely obscured because there is no robust method for accurately measuring substrate binding constants. The methods currently used cannot identify whether the bound substrates are located in the inner chamber of the molecule in the transmembrane region or not because of the low spatial resolution. Here, we report a system for measuring the affinity of substrate binding to the Cyanidioschyzon merolae ABCB1 (CmABCB1) using site-specific tryptophan (Trp) fluorescence quenching. We designed a CmABCB1 mutant with an extrinsic Trp residue introduced into the inner chamber. Trp fluorescence was quenched by three substrates and one inhibitor, including rhodamine 6G, in a saturable fashion, allowing for accurate estimation of the dissociation constant (KD ) for each molecule. The KD for rhodamine 6G is similar to that determined using a reciprocal fluorescence quenching assay using rhodamine 6G fluorescence, suggesting that Trp fluorescence of the mutant was quenched by the interaction between the extrinsic Trp and substrates bound in the inner chamber. Structural comparison of the ABCB1 structures suggests that the system presented in this study could be ideal method of choice to determine the substrate binding affinities of compounds bound to the chamber of mammalian ABCB1.
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Affiliation(s)
- Yoshiki Inoue
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Tomohiro Yamaguchi
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Tetsuo Otsuka
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Yuto Utsunomiya
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Dongqing Pan
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Haruo Ogawa
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
| | - Hiroaki Kato
- Department of Structural Biology, Graduate School of Pharmaceutical SciencesKyoto UniversityKyotoJapan
- Advanced Photon Technology DivisionRIKEN Harima Institute at SPring‐8Sayo‐gunHyogoJapan
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14
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Magalhães N, Simões GM, Ramos C, Samelo J, Oliveira AC, Filipe HAL, Ramalho JPP, Moreno MJ, Loura LMS. Interactions between Rhodamine Dyes and Model Membrane Systems—Insights from Molecular Dynamics Simulations. Molecules 2022; 27:molecules27041420. [PMID: 35209208 PMCID: PMC8876248 DOI: 10.3390/molecules27041420] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023] Open
Abstract
Background: rhodamines are dyes widely used as fluorescent tags in cell imaging, probing of mitochondrial membrane potential, and as P-glycoprotein model substrates. In all these applications, detailed understanding of the interaction between rhodamines and biomembranes is fundamental. Methods: we combined atomistic molecular dynamics (MD) simulations and fluorescence spectroscopy to characterize the interaction between rhodamines 123 and B (Rh123 and RhB, respectively) and POPC bilayers. Results: while the xanthene moiety orients roughly parallel to the membrane plane in unrestrained MD simulations, variations on the relative position of the benzoic ring (below the xanthene for Rh123, above it for RhB) were observed, and related to the structure of the two dyes and their interactions with water and lipids. Subtle distinctions were found among different ionization forms of the probes. Experimentally, RhB displayed a lipid/water partition coefficient more than two orders of magnitude higher than Rh123, in agreement with free energy profiles obtained from umbrella sampling MD. Conclusions: this work provided detailed insights on the similarities and differences in the behavior of bilayer-inserted Rh123 and RhB, related to the structure of the probes. The much higher affinity of RhB for the membranes increases the local concentration and explains its higher apparent affinity for P-glycoprotein reconstituted in model membranes.
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Affiliation(s)
- Nisa Magalhães
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Guilherme M. Simões
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Cristiana Ramos
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Jaime Samelo
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Alexandre C. Oliveira
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Hugo A. L. Filipe
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- CPIRN-IPG—Center of Potential and Innovation of Natural Resources, Polytechnic Institute of Guarda, 6300-559 Guarda, Portugal
| | - João P. Prates Ramalho
- Hercules Laboratory, LAQV, REQUIMTE, Department of Chemistry, School of Science and Technology, University of Évora, 7000-671 Evora, Portugal;
| | - Maria João Moreno
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
- CNC—Center for Neuroscience and Cell Biology, 3004-504 Coimbra, Portugal
| | - Luís M. S. Loura
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (N.M.); (G.M.S.); (C.R.); (J.S.); (A.C.O.); (H.A.L.F.); (M.J.M.)
- CNC—Center for Neuroscience and Cell Biology, 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
- Correspondence:
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Rahmanian-Devin P, Baradaran Rahimi V, Jaafari MR, Golmohammadzadeh S, Sanei-far Z, Askari VR. Noscapine, an Emerging Medication for Different Diseases: A Mechanistic Review. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2021; 2021:8402517. [PMID: 34880922 PMCID: PMC8648453 DOI: 10.1155/2021/8402517] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/08/2021] [Accepted: 11/15/2021] [Indexed: 12/11/2022]
Abstract
Noscapine is a benzylisoquinoline alkaloid isolated from poppy extract, used as an antitussive since the 1950s, and has no addictive or euphoric effects. Various studies have shown that noscapine has excellent anti-inflammatory effects and potentiates the antioxidant defences by inhibiting nitric oxide (NO) metabolites and reactive oxygen species (ROS) levels and increasing total glutathione (GSH). Furthermore, noscapine has indicated antiangiogenic and antimetastatic effects. Noscapine induces apoptosis in many cancerous cell types and provides favourable antitumour activities and inhibitory cell proliferation in solid tumours, even drug-resistant strains, via mitochondrial pathways. Moreover, this compound attenuates the dynamic properties of microtubules and arrests the cell cycle in the G2/M phase. Noscapine can reduce endothelial cell migration in the brain by inhibiting endothelial cell activator interleukin 8 (IL-8). In fact, this study aimed to elaborate on the possible mechanisms of noscapine against different disorders.
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Affiliation(s)
- Pouria Rahmanian-Devin
- Department of Pharmaceutics, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Cardiovascular Diseases, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Vafa Baradaran Rahimi
- Department of Cardiovascular Diseases, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Reza Jaafari
- Nanotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmaceutical Nanotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Shiva Golmohammadzadeh
- Nanotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmaceutical Nanotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra Sanei-far
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Vahid Reza Askari
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Pharmaceutical Sciences in Persian Medicine, School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Persian Medicine, School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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16
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Inhibitor Resistant Mutants Give Important Insights into Candida albicans ABC Transporter Cdr1 Substrate Specificity and Help Elucidate Efflux Pump Inhibition. Antimicrob Agents Chemother 2021; 66:e0174821. [PMID: 34780272 PMCID: PMC8765293 DOI: 10.1128/aac.01748-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Overexpression of ATP-binding cassette (ABC) transporters is a major cause of drug resistance in fungal pathogens. Milbemycins, enniatin B, beauvericin and FK506 are promising leads for broad-spectrum fungal multidrug efflux pump inhibitors. The characterization of naturally generated inhibitor resistant mutants is a powerful tool to elucidate structure-activity relationships in ABC transporters. We isolated twenty Saccharomyces cerevisiae mutants overexpressing Candida albicans ABC pump Cdr1 variants resistant to fluconazole efflux inhibition by milbemycin α25 (eight mutants), enniatin B (eight) or beauvericin (four). The twenty mutations were in just nine residues at the centres of transmembrane segment 1 (TMS1) (six mutations), TMS4 (four), TMS5 (four), TMS8 (one) and TMS11 (two) and in A713P (three), a previously reported FK506-resistant 'hotspot 1' mutation in extracellular loop 3. Six Cdr1-G521S/C/V/R (TMS1) variants were resistant to all four inhibitors, four Cdr1-M639I (TMS4) isolates were resistant to milbemycin α25 and enniatin B, and two Cdr1-V668I/D (TMS5) variants were resistant to enniatin B and beauvericin. The eight milbemycin α25 resistant mutants were altered in four amino acids: G521R, M639I, A713P and T1355N. These four Cdr1 variants responded differently to various types of inhibitors, and each exhibited altered substrate specificity and kinetic properties. The data infer an entry gate function for Cdr1-G521 and a role for Cdr1-A713 in the constitutively high Cdr1 ATPase activity. Cdr1-M639I and -T1355N (TMS11) possibly cause inhibitor-resistance by altering TMS-contacts near the substrate/inhibitor-binding pocket. Models for the interactions of substrates and different types of inhibitors with Cdr1 at various stages of the transport cycle are presented.
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17
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Pearson SA, Wachnowsky C, Cowan JA. Defining the mechanism of the mitochondrial Atm1p [2Fe-2S] cluster exporter. Metallomics 2021; 12:902-915. [PMID: 32337520 DOI: 10.1039/c9mt00286c] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Iron-sulfur cluster proteins play key roles in a multitude of physiological processes; including gene expression, nitrogen and oxygen sensing, electron transfer, and DNA repair. Biosynthesis of iron-sulfur clusters occurs in mitochondria on iron-sulfur cluster scaffold proteins in the form of [2Fe-2S] cores that are then transferred to apo targets within metabolic or respiratory pathways. The mechanism by which cytosolic Fe-S cluster proteins mature to their holo forms remains controversial. The mitochondrial inner membrane protein Atm1p can transport glutathione-coordinated iron-sulfur clusters, which may connect the mitochondrial and cytosolic iron-sulfur cluster assembly systems. Herein we describe experiments on the yeast Atm1p/ABCB7 exporter that provide additional support for a glutathione-complexed cluster as the natural physiological substrate and a reflection of the endosymbiotic model of mitochondrial evolution. These studies provide insight on the mechanism of cluster transport and the molecular basis of human disease conditions related to ABCB7. Recruitment of MgATP following cluster binding promotes a structural transition from closed to open conformations that is mediated by coupling helices, with MgATP hydrolysis facilitating the return to the closed state.
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Affiliation(s)
- Stephen A Pearson
- The Ohio State University Biophysics Program, The Ohio State University, 484 West 12th Avenue, Columbus, Ohio, USA43210.
| | - Christine Wachnowsky
- The Ohio State University Biochemistry Program, The Ohio State University, 484 West 12th Avenue, Columbus, Ohio, USA43210
| | - J A Cowan
- The Ohio State University Biophysics Program, The Ohio State University, 484 West 12th Avenue, Columbus, Ohio, USA43210. and The Ohio State University Biochemistry Program, The Ohio State University, 484 West 12th Avenue, Columbus, Ohio, USA43210 and Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio, USA43210
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18
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Prescher M, Bonus M, Stindt J, Keitel-Anselmino V, Smits SHJ, Gohlke H, Schmitt L. Evidence for a credit-card-swipe mechanism in the human PC floppase ABCB4. Structure 2021; 29:1144-1155.e5. [PMID: 34107287 DOI: 10.1016/j.str.2021.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/27/2021] [Accepted: 05/17/2021] [Indexed: 10/21/2022]
Abstract
ABCB4 is described as an ATP-binding cassette (ABC) transporter that primarily transports lipids of the phosphatidylcholine (PC) family but is also capable of translocating a subset of typical multidrug-resistance-associated drugs. The high degree of amino acid identity of 76% for ABCB4 and ABCB1, which is a prototype multidrug-resistance-mediating protein, results in ABCB4's second subset of substrates, which overlap with ABCB1's substrates. This often leads to incomplete annotations of ABCB4, in which it was described as exclusively PC-lipid specific. When the hydrophilic amino acids from ABCB4 are changed to the analogous but hydrophobic ones from ABCB1, the stimulation of ATPase activity by 1,2-dioleoyl-sn-glycero-3-phosphocholine, as a prime example of PC lipids, is strongly diminished, whereas the modulation capability of ABCB1 substrates remains unchanged. This indicates two distinct and autonomous substrate binding sites in ABCB4.
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Affiliation(s)
- Martin Prescher
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Michele Bonus
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jan Stindt
- Clinic for Gastroenterology, Hepatology and Infectious Diseases University Hospital Düsseldorf, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Verena Keitel-Anselmino
- Clinic for Gastroenterology, Hepatology and Infectious Diseases University Hospital Düsseldorf, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; Center for Structural Studies, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute of Biological Information Processing (IBI-7: Structural Biochemistry) and Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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Kapoor K, Pant S, Tajkhorshid E. Active participation of membrane lipids in inhibition of multidrug transporter P-glycoprotein. Chem Sci 2021; 12:6293-6306. [PMID: 34084427 PMCID: PMC8115088 DOI: 10.1039/d0sc06288j] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 03/31/2021] [Indexed: 01/04/2023] Open
Abstract
P-glycoprotein (Pgp) is a major efflux pump in humans, overexpressed in a variety of cancers and associated with the development of multi-drug resistance. Allosteric modulation by various ligands (e.g., transport substrates, inhibitors, and ATP) has been biochemically shown to directly influence structural dynamics, and thereby, the function of Pgp. However, the molecular details of such effects, particularly with respect to the role and involvement of the surrounding lipids, are not well established. Here, we employ all-atom molecular dynamics (MD) simulations to study the conformational landscape of Pgp in the presence of a high-affinity, third-generation inhibitor, tariquidar, in comparison to the nucleotide-free (APO) and the ATP-bound states, in order to characterize the mechanical effects of the inhibitor that might be of relevance to its blocking mechanism of Pgp. Simulations in a multi-component lipid bilayer show a dynamic equilibrium between open(er) and more closed inward-facing (IF) conformations in the APO state, with binding of ATP shifting the equilibrium towards conformations more prone to ATP hydrolysis and subsequent events in the transport cycle. In the presence of the inhibitor bound to the drug-binding pocket within the transmembrane domain (TMD), Pgp samples more open IF conformations, and the nucleotide binding domains (NBDs) become highly dynamic. Interestingly, and reproduced in multiple independent simulations, the inhibitor is observed to facilitate recruitment of lipid molecules into the Pgp lumen through the two proposed drug-entry portals, where the lipid head groups from the cytoplasmic leaflet penetrate into and, in some cases, translocate inside the TMD, while the lipid tails remain extended into the bulk lipid environment. These "wedge" lipids likely enhance the inhibitor-induced conformational restriction of the TMD leading to the differential modulation of coupling pathways observed with the NBDs downstream. We suggest a novel inhibitory mechanism for tariquidar, and potentially for related third-generation Pgp inhibitors, where lipids are seen to enhance the inhibitory role in the catalytic cycle of membrane transporters.
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Affiliation(s)
- Karan Kapoor
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
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20
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Gräfe K, Schmitt L. The ABC transporter G subfamily in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:92-106. [PMID: 32459300 DOI: 10.1093/jxb/eraa260] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 05/21/2020] [Indexed: 05/02/2023]
Abstract
ABC transporters are ubiquitously present in all kingdoms and mediate the transport of a large spectrum of structurally different compounds. Plants possess high numbers of ABC transporters in relation to other eukaryotes; the ABCG subfamily in particular is extensive. Earlier studies demonstrated that ABCG transporters are involved in important processes influencing plant fitness. This review summarizes the functions of ABCG transporters present in the model plant Arabidopsis thaliana. These transporters take part in diverse processes such as pathogen response, diffusion barrier formation, or phytohormone transport. Studies involving knockout mutations reported pleiotropic phenotypes of the mutants. In some cases, different physiological roles were assigned to the same protein. The actual transported substrate(s), however, still remain to be determined for the majority of ABCG transporters. Additionally, the proposed substrate spectrum of different ABCG proteins is not always reflected by sequence identities between ABCG members. Applying only reverse genetics is thereby insufficient to clearly identify the substrate(s). We therefore stress the importance of in vitro studies in addition to in vivo studies in order to (i) clarify the substrate identity; (ii) determine the transport characteristics including directionality; and (iii) identify dimerization partners of the half-size proteins, which might in turn affect substrate specificity.
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Affiliation(s)
- Katharina Gräfe
- Institute of Biochemistry and Cluster of Excellence on Plant Sciences CEPLAS, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry and Cluster of Excellence on Plant Sciences CEPLAS, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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21
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Dehghani-Ghahnaviyeh S, Kapoor K, Tajkhorshid E. Conformational changes in the nucleotide-binding domains of P-glycoprotein induced by ATP hydrolysis. FEBS Lett 2020; 595:735-749. [PMID: 33159693 DOI: 10.1002/1873-3468.13992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/19/2020] [Accepted: 10/30/2020] [Indexed: 12/16/2022]
Abstract
P-glycoprotein (Pgp) is a member of the ABC transporter superfamily with high physiological importance. Pgp nucleotide-binding domains (NBDs) drive the transport cycle through ATP binding and hydrolysis. We use molecular dynamics simulations to investigate the ATP hydrolysis-induced conformational changes in NBDs. Five systems, including all possible ATP/ADP combinations in the NBDs and the APO system, are simulated. ATP/ADP exchange induces conformational changes mostly within the conserved signature motif of the NBDs, resulting in relative orientational changes in the NBDs. Nucleotide removal leads to additional orientational changes in the NBDs, allowing their dissociation. Furthermore, we capture putative hydrolysis-competent configurations in which the conserved glutamate in the Walker-B motif acts as a catalytic base capturing a water molecule likely initiating ATP hydrolysis.
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Affiliation(s)
- Sepehr Dehghani-Ghahnaviyeh
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL, USA
| | - Karan Kapoor
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL, USA
| | - Emad Tajkhorshid
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, IL, USA
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22
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Nicklisch SC, Hamdoun A. Disruption of small molecule transporter systems by Transporter-Interfering Chemicals (TICs). FEBS Lett 2020; 594:4158-4185. [PMID: 33222203 PMCID: PMC8112642 DOI: 10.1002/1873-3468.14005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/17/2020] [Accepted: 11/17/2020] [Indexed: 12/25/2022]
Abstract
Small molecule transporters (SMTs) in the ABC and SLC families are important players in disposition of diverse endo- and xenobiotics. Interactions of environmental chemicals with these transporters were first postulated in the 1990s, and since validated in numerous in vitro and in vivo scenarios. Recent results on the co-crystal structure of ABCB1 with the flame-retardant BDE-100 demonstrate that a diverse range of man-made and natural toxic molecules, hereafter termed transporter-interfering chemicals (TICs), can directly bind to SMTs and interfere with their function. TIC-binding modes mimic those of substrates, inhibitors, modulators, inducers, and possibly stimulants through direct and allosteric mechanisms. Similarly, the effects could directly or indirectly agonize, antagonize or perhaps even prime the SMT system to alter transport function. Importantly, TICs are distinguished from drugs and pharmaceuticals that interact with transporters in that exposure is unintended and inherently variant. Here, we review the molecular mechanisms of environmental chemical interaction with SMTs, the methodological considerations for their evaluation, and the future directions for TIC discovery.
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Affiliation(s)
- Sascha C.T. Nicklisch
- Department of Environmental Toxicology, University of California, Davis, Davis, CA 95616
| | - Amro Hamdoun
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202
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23
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Carey Hulyer AR, Briggs DA, O'Mara ML, Kerr ID, Harmer JR, Callaghan R. Cross-linking, DEER-spectroscopy and molecular dynamics confirm the inward facing state of P-glycoprotein in a lipid membrane. J Struct Biol 2020; 211:107513. [PMID: 32339763 DOI: 10.1016/j.jsb.2020.107513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/09/2020] [Accepted: 04/23/2020] [Indexed: 02/07/2023]
Abstract
The drug efflux pump P-glycoprotein (P-gp) displays a complex transport mechanism involving multiple drug binding sites and two centres for nucleotide hydrolysis. Elucidating the molecular mechanism of transport remains elusive and the availability of P-gp structures in distinct natural and ligand trapped conformations will accelerate our understanding. The present investigation sought to provide biochemical data to validate specific features of these structures; with particular focus on the transmembrane domain that provides the transport conduit. Hence our focus was on transmembrane helices six and twelve (TM6/TM12), which are believed to participate in drug binding, as they line the central transport conduit and provide a direct link to the catalytic centres. A series of P-gp mutants were generated with a single cysteine in both TM6 and TM12 to facilitate measurement of inter-helical distances using cross-linking and DEER strategies. Experimental results were compared to published structures per se and those refined by MD simulations. This analysis revealed that the refined inward-facing murine structure (4M1M) of P-gp provides a good representation of the proximity, topography and relative motions of TM6 and TM12 in reconstituted human P-gp.
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Affiliation(s)
- Alex R Carey Hulyer
- Research School of Biology, and the Medical School, Australian National University, Canberra, ACT 2601, Australia
| | - Deborah A Briggs
- Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Megan L O'Mara
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Ian D Kerr
- Centre for Biochemistry and Cell Biology, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Jeffrey R Harmer
- The Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Richard Callaghan
- Research School of Biology, and the Medical School, Australian National University, Canberra, ACT 2601, Australia.
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24
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Nasim F, Schmid D, Szakács G, Sohail A, Sitte HH, Chiba P, Stockner T. Active transport of rhodamine 123 by the human multidrug transporter P-glycoprotein involves two independent outer gates. Pharmacol Res Perspect 2020; 8:e00572. [PMID: 32232949 PMCID: PMC7105846 DOI: 10.1002/prp2.572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 02/07/2020] [Indexed: 12/20/2022] Open
Abstract
Human P-glycoprotein (P-gp) is a multispecific drug-efflux transporter, which plays an important role in drug resistance and drug disposition. Recent cryo-electron microscopy structures confirmed its rotationally symmetric architecture, which allows dual interaction with ATP and substrates. We here report the existence of two distinct, symmetry-related outer gates. Experiments were aided by availability of the X-ray structure of a homodimeric eukaryotic homolog of P-gp from red alga (CmABCB1), which defined the role of an apical tyrosine residue (Y358) in outer gate formation. We mutated analogous tyrosine residues in each half of the human full-length transporter (Y310, Y953) to alanine. These mutants were introduced in engineered transporters which bind rhodamine 123 in one of two symmetry-related binding modes only. Outer gate dysfunction was detected by a loss of active transport characteristics, while these mutants retained the ability for outward downhill transport. Our data demonstrate that symmetric tyrosine residues Y310 and Y953 are involved in formation of two distinct symmetry-related outer gates, which operate contingent on the rhodamine 123 binding mode. Hence, the rotationally symmetric architecture of P-gp, which determines duality in ATP binding and rhodamine 123 interaction, also forms the basis for the existence of two independently operating outer gates.
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Affiliation(s)
- Fauzia Nasim
- Institute of Medical ChemistryCenter for Pathobiochemistry and GeneticsMedical University of ViennaViennaAustria
| | - Diethart Schmid
- Institute of PhysiologyCenter for Physiology and PharmacologyMedical University of ViennaViennaAustria
| | - Gergely Szakács
- Institute of Cancer ResearchMedical University of ViennaViennaAustria
| | - Azmat Sohail
- Institute of PharmacologyCenter for Physiology and PharmacologyMedical University of ViennaViennaAustria
| | - Harald H. Sitte
- Institute of PharmacologyCenter for Physiology and PharmacologyMedical University of ViennaViennaAustria
| | - Peter Chiba
- Institute of Medical ChemistryCenter for Pathobiochemistry and GeneticsMedical University of ViennaViennaAustria
| | - Thomas Stockner
- Institute of PharmacologyCenter for Physiology and PharmacologyMedical University of ViennaViennaAustria
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25
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Arnold FM, Weber MS, Gonda I, Gallenito MJ, Adenau S, Egloff P, Zimmermann I, Hutter CAJ, Hürlimann LM, Peters EE, Piel J, Meloni G, Medalia O, Seeger MA. The ABC exporter IrtAB imports and reduces mycobacterial siderophores. Nature 2020; 580:413-417. [PMID: 32296173 PMCID: PMC7170716 DOI: 10.1038/s41586-020-2136-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/24/2020] [Indexed: 12/17/2022]
Abstract
Intracellular replication of the deadly pathogen Mycobacterium tuberculosis relies on the production of small organic molecules called siderophores to scavenge iron from host proteins1. M. tuberculosis produces two classes of siderophores, lipid-bound mycobactin and soluble carboxymycobactin2, 3. Functional studies revealed that iron-loaded carboxymycobactin is imported into the cytoplasm by the ABC transporter IrtAB4, which features an additional cytoplasmic siderophore interaction domain (SID)5. However, IrtAB’s predicted ABC exporter fold seemingly contradicts its import function. Here, we show that membrane-reconstituted IrtAB is sufficient to import mycobactins, which are then reduced by the SID to facilitate iron release. Structure determination by X-ray crystallography and cryo-EM confirms IrtAB’s ABC exporter fold, but also reveals structural peculiarities at the transmembrane region of IrtAB resulting in a partially collapsed inward-facing substrate binding cavity. The SID is positioned in close proximity to the inner membrane leaflet, which allows the reduction of membrane-inserted mycobactin. Enzymatic ATPase activity and in vivo growth assays show that IrtAB prefers mycobactin over carboxymycobactin as its substrate. Our study provides insights into an unusual ABC exporter that evolved as highly specialized siderophore import machinery in mycobacteria.
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Affiliation(s)
- Fabian M Arnold
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Miriam S Weber
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Imre Gonda
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Marc J Gallenito
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, USA
| | - Sophia Adenau
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Pascal Egloff
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.,Linkster Therapeutics, Zurich, Switzerland
| | - Iwan Zimmermann
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.,Linkster Therapeutics, Zurich, Switzerland
| | - Cedric A J Hutter
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Lea M Hürlimann
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Eike E Peters
- Institute of Microbiology, ETH Zurich, Zurich, Switzerland
| | - Jörn Piel
- Institute of Microbiology, ETH Zurich, Zurich, Switzerland
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, USA
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
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26
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Hussey GA, Thomas NE, Henzler-Wildman KA. Highly coupled transport can be achieved in free-exchange transport models. J Gen Physiol 2020; 152:e201912437. [PMID: 31816638 PMCID: PMC7034097 DOI: 10.1085/jgp.201912437] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 11/04/2019] [Indexed: 02/04/2023] Open
Abstract
Secondary active transporters couple the transport of an ion species down its concentration gradient to the uphill transport of another substrate. Despite the importance of secondary active transport to multidrug resistance, metabolite transport, and nutrient acquisition, among other biological processes, the microscopic steps of the coupling mechanism are not well understood. Often, transport models illustrate coupling mechanisms through a limited number of "major" conformations or states, yet recent studies have indicated that at least some transporters violate these models. The small multidrug resistance transporter EmrE has been shown to couple proton influx to multidrug efflux via a mechanism that incorporates both "major" and "minor" conformational states and transitions. The resulting free exchange transport model includes multiple leak pathways and theoretically allows for both exchange and cotransport of ion and substrate. To better understand how coupled transport can be achieved in such a model, we numerically simulate a free-exchange model of transport to determine the step-by-step requirements for coupled transport. We find that only moderate biasing of rate constants for key transitions produce highly efficient net transport approaching a perfectly coupled, stoichiometric model. We show how a free-exchange model can enable complex phenotypes, including switching transport direction with changing environmental conditions or substrates. This research has broad implications for synthetic biology, as it demonstrates the utility of free-exchange transport models and the fine tuning required for perfectly coupled transport.
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27
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Dastvan R, Mishra S, Peskova YB, Nakamoto RK, Mchaourab HS. Mechanism of allosteric modulation of P-glycoprotein by transport substrates and inhibitors. Science 2019; 364:689-692. [PMID: 31097669 DOI: 10.1126/science.aav9406] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 04/17/2019] [Indexed: 01/15/2023]
Abstract
The ATP-binding cassette subfamily B member 1 (ABCB1) multidrug transporter P-glycoprotein plays a central role in clearance of xenobiotics in humans and is implicated in cancer resistance to chemotherapy. We used double electron electron resonance spectroscopy to uncover the basis of stimulation of P-glycoprotein adenosine 5'-triphosphate (ATP) hydrolysis by multiple substrates and illuminate how substrates and inhibitors differentially affect its transport function. Our results reveal that substrate-induced acceleration of ATP hydrolysis correlates with stabilization of a high-energy, post-ATP hydrolysis state characterized by structurally asymmetric nucleotide-binding sites. By contrast, this state is destabilized in the substrate-free cycle and by high-affinity inhibitors in favor of structurally symmetric nucleotide binding sites. Together with previous data, our findings lead to a general model of substrate and inhibitor coupling to P-glycoprotein.
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Affiliation(s)
- Reza Dastvan
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Smriti Mishra
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Yelena B Peskova
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Robert K Nakamoto
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
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28
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Models for Understanding Resistance to Chemotherapy in Liver Cancer. Cancers (Basel) 2019; 11:cancers11111677. [PMID: 31671735 PMCID: PMC6896032 DOI: 10.3390/cancers11111677] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
The lack of response to pharmacological treatment constitutes a substantial limitation in the handling of patients with primary liver cancers (PLCs). The existence of active mechanisms of chemoresistance (MOCs) in hepatocellular carcinoma, cholangiocarcinoma, and hepatoblastoma hampers the usefulness of chemotherapy. A better understanding of MOCs is needed to develop strategies able to overcome drug refractoriness in PLCs. With this aim, several experimental models are commonly used. These include in vitro cell-free assays using subcellular systems; studies with primary cell cultures; cancer cell lines or heterologous expression systems; multicellular models, such as spheroids and organoids; and a variety of in vivo models in rodents, such as subcutaneous and orthotopic tumor xenografts or chemically or genetically induced liver carcinogenesis. Novel methods to perform programmed genomic edition and more efficient techniques to isolate circulating microvesicles offer new opportunities for establishing useful experimental tools for understanding the resistance to chemotherapy in PLCs. In the present review, using three criteria for information organization: (1) level of research; (2) type of MOC; and (3) type of PLC, we have summarized the advantages and limitations of the armamentarium available in the field of pharmacological investigation of PLC chemoresistance.
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29
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Bock C, Zollmann T, Lindt KA, Tampé R, Abele R. Peptide translocation by the lysosomal ABC transporter TAPL is regulated by coupling efficiency and activation energy. Sci Rep 2019; 9:11884. [PMID: 31417173 PMCID: PMC6695453 DOI: 10.1038/s41598-019-48343-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 07/25/2019] [Indexed: 11/15/2022] Open
Abstract
The lysosomal polypeptide transporter TAPL belongs to the superfamily of ATP-binding cassette transporters. TAPL forms a homodimeric transport complex, which translocates oligo- and polypeptides into the lumen of lysosomes driven by ATP hydrolysis. Although the structure and the function of ABC transporters were intensively studied in the past, details about the single steps of the transport cycle are still elusive. Therefore, we analyzed the coupling of peptide binding, transport and ATP hydrolysis for different substrate sizes. Although longer and shorter peptides bind with the same affinity and are transported with identical Km values, they differ significantly in their transport rates. This difference can be attributed to a higher activation energy for the longer peptide. TAPL shows a basal ATPase activity, which is inhibited in the presence of longer peptides. Uncoupling between ATP hydrolysis and peptide transport increases with peptide length. Remarkably, also the type of nucleotide determines the uncoupling. While GTP is hydrolyzed as good as ATP, peptide transport is significantly reduced. In conclusion, TAPL does not differentiate between transport substrates in the binding process but during the following steps in the transport cycle, whereas, on the other hand, not only the coupling efficiency but also the activation energy varies depending on the size of peptide substrate.
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Affiliation(s)
- Christoph Bock
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt am Main, Germany
| | - Tina Zollmann
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt am Main, Germany
| | - Katharina-Astrid Lindt
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt am Main, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt am Main, Germany
| | - Rupert Abele
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438, Frankfurt am Main, Germany.
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30
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Characterization of Guided Entry of Tail-Anchored Proteins 3 Homologues in Mycobacterium tuberculosis. J Bacteriol 2019; 201:JB.00159-19. [PMID: 31036728 DOI: 10.1128/jb.00159-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/22/2019] [Indexed: 02/07/2023] Open
Abstract
We characterized an operon in Mycobacterium tuberculosis, Rv3679-Rv3680, in which each open reading frame is annotated to encode "anion transporter ATPase" homologues. Using structure prediction modeling, we found that Rv3679 and Rv3680 more closely resemble the guided entry of tail-anchored proteins 3 (Get3) chaperone in eukaryotes. Get3 delivers proteins into the membranes of the endoplasmic reticulum and is essential for the normal growth and physiology of some eukaryotes. We sought to characterize the structures of Rv3679 and Rv3680 and test if they have a role in M. tuberculosis pathogenesis. We solved crystal structures of the nucleotide-bound Rv3679-Rv3680 complex at 2.5 to 3.2 Å and show that while it has some similarities to Get3 and ArsA, there are notable differences, including that these proteins are unlikely to be involved in anion transport. Deletion of both genes did not reveal any conspicuous growth defects in vitro or in mice. Collectively, we identified a new class of proteins in bacteria with similarity to Get3 complexes, the functions of which remain to be determined.IMPORTANCE Numerous bacterial species encode proteins predicted to have similarity with Get3- and ArsA-type anion transporters. Our studies provide evidence that these proteins, which we named BagA and BagB, are unlikely to be involved in anion transport. In addition, BagA and BagB are conserved in all mycobacterial species, including the causative agent of leprosy, which has a highly decayed genome. This conservation suggests that BagAB constitutes a part of the core mycobacterial genome and is needed for some yet-to-be-determined part of the life cycle of these organisms.
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31
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Sachs J, Döhl K, Weber A, Bonus M, Ehlers F, Fleischer E, Klinger A, Gohlke H, Pietruszka J, Schmitt L, Teusch N. Novel 3,4-Dihydroisocoumarins Inhibit Human P-gp and BCRP in Multidrug Resistant Tumors and Demonstrate Substrate Inhibition of Yeast Pdr5. Front Pharmacol 2019; 10:400. [PMID: 31040786 PMCID: PMC6476959 DOI: 10.3389/fphar.2019.00400] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 04/01/2019] [Indexed: 12/15/2022] Open
Abstract
Multidrug resistance (MDR) in tumors and pathogens remains a major problem in the efficacious treatment of patients by reduction of therapy options and subsequent treatment failure. Various mechanisms are described to be involved in the development of MDR with overexpression of ATP-binding cassette (ABC) transporters reflecting the most extensively studied. These membrane transporters translocate a wide variety of substrates utilizing energy from ATP hydrolysis leading to decreased intracellular drug accumulation and impaired drug efficacy. One treatment strategy might be inhibition of transporter-mediated efflux by small molecules. Isocoumarins and 3,4-dihydroisocoumarins are a large group of natural products derived from various sources with great structural and functional variety, but have so far not been in the focus as potential MDR reversing agents. Thus, three natural products and nine novel 3,4-dihydroisocoumarins were designed and analyzed regarding cytotoxicity induction and inhibition of human ABC transporters P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) in a variety of human cancer cell lines as well as the yeast ABC transporter Pdr5 in Saccharomyces cerevisiae. Dual inhibitors of P-gp and BCRP and inhibitors of Pdr5 were identified, and distinct structure-activity relationships for transporter inhibition were revealed. The strongest inhibitor of P-gp and BCRP, which inhibited the transporters up to 80 to 90% compared to the respective positive controls, demonstrated the ability to reverse chemotherapy resistance in resistant cancer cell lines up to 5.6-fold. In the case of Pdr5, inhibitors were identified that prevented substrate transport and/or ATPase activity with IC50 values in the low micromolar range. However, cell toxicity was not observed. Molecular docking of the test compounds to P-gp revealed that differences in inhibition capacity were based on different binding affinities to the transporter. Thus, these small molecules provide novel lead structures for further optimization.
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Affiliation(s)
- Julia Sachs
- Bio-Pharmaceutical Chemistry and Molecular Pharmacology, Faculty of Applied Natural Sciences, Technische Hochschule Köln, Leverkusen, Germany
| | - Katja Döhl
- Institute of Biochemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Anja Weber
- Institute of Bioorganic Chemistry, Heinrich-Heine-Universität Düsseldorf im Forschungszentrum Jülich, Jülich, Germany
| | - Michele Bonus
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Ferdinand Ehlers
- Bio-Pharmaceutical Chemistry and Molecular Pharmacology, Faculty of Applied Natural Sciences, Technische Hochschule Köln, Leverkusen, Germany
| | | | | | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.,John von Neumann Institute for Computing, Jülich Supercomputing Centre and Institute for Complex Systems - Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Jörg Pietruszka
- Institute of Bioorganic Chemistry, Heinrich-Heine-Universität Düsseldorf im Forschungszentrum Jülich, Jülich, Germany.,IBG-1: Biotechnology, Forschungszentrum Jülich, Jülich, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Nicole Teusch
- Bio-Pharmaceutical Chemistry and Molecular Pharmacology, Faculty of Applied Natural Sciences, Technische Hochschule Köln, Leverkusen, Germany
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32
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Yang T, Wang S, Zheng H, Wang L, Liu D, Chen X, Li R. Understanding dihydro-β-agarofuran sesquiterpenes from Tripterygium hypoglaucum as the modulators of multi-drug resistance in HepG2/Adr cells. Biochem Biophys Res Commun 2019; 508:742-748. [DOI: 10.1016/j.bbrc.2018.11.188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 11/29/2018] [Indexed: 12/24/2022]
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33
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Muthiah D, Henshaw GK, DeBono AJ, Capuano B, Scammells PJ, Callaghan R. Overcoming P-Glycoprotein–Mediated Drug Resistance with Noscapine Derivatives. Drug Metab Dispos 2018; 47:164-172. [DOI: 10.1124/dmd.118.083188] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/20/2018] [Indexed: 12/15/2022] Open
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34
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Yakusheva EN, Titov DS. Structure and Function of Multidrug Resistance Protein 1. BIOCHEMISTRY (MOSCOW) 2018; 83:907-929. [DOI: 10.1134/s0006297918080047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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35
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Parreira B, Cardoso JCR, Costa R, Couto AR, Bruges-Armas J, Power DM. Persistence of the ABCC6 genes and the emergence of the bony skeleton in vertebrates. Sci Rep 2018; 8:6027. [PMID: 29662086 PMCID: PMC5902450 DOI: 10.1038/s41598-018-24370-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 03/22/2018] [Indexed: 12/18/2022] Open
Abstract
The ATP-binding cassette transporter 6 (ABCC6) gene encodes a cellular transmembrane protein transporter (MRP6) that is involved in the regulation of tissue calcification in mammals. Mutations in ABCC6 are associated with human ectopic calcification disorders. To gain insight into its evolution and involvement in tissue calcification we conducted a comparative analysis of the ABCC6 gene and the related gene ABCC1 from invertebrates to vertebrates where a bony endoskeleton first evolved. Taking into consideration the role of ABCC6 in ectopic calcification of human skin we analysed the involvement of both genes in the regeneration of scales, mineralized structures that develop in fish skin. The ABCC6 gene was only found in bony vertebrate genomes and was absent from Elasmobranchs, Agnatha and from invertebrates. In teleost fish the abcc6 gene duplicated but the two genes persisted only in some teleost genomes. Six disease causing amino acid mutations in human MRP6 are a normal feature of abcc6 in fish, suggesting they do not have a deleterious effect on the protein. After scale removal the abcc6 (5 and 10 days) and abcc1 (10 days) gene expression was up-regulated relative to the intact control skin and this coincided with a time of intense scale mineralization.
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Affiliation(s)
- Bruna Parreira
- Serviço Especializado de Epidemiologia e Biologia Molecular (SEEBMO), Hospital de Santo Espírito da Ilha Terceira, Azores, Portugal
| | - João C R Cardoso
- Centre of Marine Sciences (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Rita Costa
- Centre of Marine Sciences (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Ana Rita Couto
- Serviço Especializado de Epidemiologia e Biologia Molecular (SEEBMO), Hospital de Santo Espírito da Ilha Terceira, Azores, Portugal
| | - Jácome Bruges-Armas
- Serviço Especializado de Epidemiologia e Biologia Molecular (SEEBMO), Hospital de Santo Espírito da Ilha Terceira, Azores, Portugal.,CEDOC - Chronic Diseases Research Center, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Deborah M Power
- Centre of Marine Sciences (CCMAR), Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal. .,Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China.
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36
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Robin T, Reuveni S, Urbakh M. Single-molecule theory of enzymatic inhibition. Nat Commun 2018; 9:779. [PMID: 29472579 PMCID: PMC5823943 DOI: 10.1038/s41467-018-02995-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/12/2018] [Indexed: 12/19/2022] Open
Abstract
The classical theory of enzymatic inhibition takes a deterministic, bulk based approach to quantitatively describe how inhibitors affect the progression of enzymatic reactions. Catalysis at the single-enzyme level is, however, inherently stochastic which could lead to strong deviations from classical predictions. To explore this, we take the single-enzyme perspective and rebuild the theory of enzymatic inhibition from the bottom up. We find that accounting for multi-conformational enzyme structure and intrinsic randomness should strongly change our view on the uncompetitive and mixed modes of inhibition. There, stochastic fluctuations at the single-enzyme level could make inhibitors act as activators; and we state—in terms of experimentally measurable quantities—a mathematical condition for the emergence of this surprising phenomenon. Our findings could explain why certain molecules that inhibit enzymatic activity when substrate concentrations are high, elicit a non-monotonic dose response when substrate concentrations are low. Single molecule approaches demonstrated that enzymatic catalysis is stochastic which could lead to deviations from classical predictions. Here authors rebuild the theory of enzymatic inhibition to show that stochastic fluctuations on the single enzyme level could make inhibitors act as activators.
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Affiliation(s)
- Tal Robin
- School of Chemistry and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Shlomi Reuveni
- School of Chemistry and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, 6997801, Tel Aviv, Israel. .,Department of Systems Biology, HMS, Harvard University, 200 Longwood Avenue, Boston, MA, 02115, USA.
| | - Michael Urbakh
- School of Chemistry and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, 6997801, Tel Aviv, Israel
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37
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Karasik A, Ledwitch KV, Arányi T, Váradi A, Roberts A, Szeri F. Boosted coupling of ATP hydrolysis to substrate transport upon cooperative estradiol-17-β-D-glucuronide binding in a Drosophila ATP binding cassette type-C transporter. FASEB J 2018; 32:669-680. [PMID: 28939593 DOI: 10.1096/fj.201700606r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ATP binding cassette type-C (ABCC) transporters move molecules across cell membranes upon hydrolysis of ATP; however, their coupling of ATP hydrolysis to substrate transport remains elusive. Drosophila multidrug resistance-associated protein (DMRP) is the functional ortholog of human long ABCC transporters, with similar substrate and inhibitor specificity, but higher activity. Exploiting its high activity, we kinetically dissected the catalytic mechanism of DMRP by using E2-d-glucuronide (E2G), the physiologic substrate of human ABCC. We examined the DMRP-mediated interdependence of ATP and E2G in biochemical assays. We observed E2G-dependent ATPase activity to be biphasic at subsaturating ATP concentrations, which implies at least 2 E2G binding sites on DMRP. Furthermore, transport measurements indicated strong nonreciprocal cooperativity between ATP and E2G. In addition to confirming these findings, our kinetic modeling with the Complex Pathway Simulator indicated a 10-fold decrease in the E2G-mediated activation of ATP hydrolysis upon saturation of the second E2G binding site. Surprisingly, the binding of the second E2G allowed for substrate transport with a constant rate, which tightly coupled ATP hydrolysis to transport. In summary, we show that the second E2G binding-similar to human ABCC2-allosterically stimulates transport activity of DMRP. Our data suggest that this is achieved by a significant increase in the coupling of ATP hydrolysis to transport.-Karasik, A., Ledwitch, K. V., Arányi, T., Váradi, A., Roberts, A., Szeri, F. Boosted coupling of ATP hydrolysis to substrate transport upon cooperative estradiol-17-β-D-glucuronide binding in a Drosophila ATP binding cassette type-C transporter.
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Affiliation(s)
- Agnes Karasik
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - Tamás Arányi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - András Váradi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Arthur Roberts
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia, USA
| | - Flóra Szeri
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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38
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ATPase activity regulation by leader peptide processing of ABC transporter maturation and secretion protein, NukT, for lantibiotic nukacin ISK-1. Appl Microbiol Biotechnol 2017; 102:763-772. [DOI: 10.1007/s00253-017-8645-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/09/2017] [Accepted: 11/12/2017] [Indexed: 10/18/2022]
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39
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Abstract
EmrE is a small multidrug resistance transporter found in Escherichia coli that confers resistance to toxic polyaromatic cations due to its proton-coupled antiport of these substrates. Here we show that EmrE breaks the rules generally deemed essential for coupled antiport. NMR spectra reveal that EmrE can simultaneously bind and cotransport proton and drug. The functional consequence of this finding is an exceptionally promiscuous transporter: not only can EmrE export diverse drug substrates, it can couple antiport of a drug to either one or two protons, performing both electrogenic and electroneutral transport of a single substrate. We present a free-exchange model for EmrE antiport that is consistent with these results and recapitulates ∆pH-driven concentrative drug uptake. Kinetic modeling suggests that free exchange by EmrE sacrifices coupling efficiency but boosts initial transport speed and drug release rate, which may facilitate efficient multidrug efflux.
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40
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Zoghbi ME, Mok L, Swartz DJ, Singh A, Fendley GA, Urbatsch IL, Altenberg GA. Substrate-induced conformational changes in the nucleotide-binding domains of lipid bilayer-associated P-glycoprotein during ATP hydrolysis. J Biol Chem 2017; 292:20412-20424. [PMID: 29018094 DOI: 10.1074/jbc.m117.814186] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/25/2017] [Indexed: 11/06/2022] Open
Abstract
P-glycoprotein (Pgp) is an efflux pump important in multidrug resistance of cancer cells and in determining drug pharmacokinetics. Pgp is a prototype ATP-binding cassette transporter with two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP. Conformational changes at the NBDs (the Pgp engines) lead to changes across Pgp transmembrane domains that result in substrate translocation. According to current alternating access models (substrate-binding pocket accessible only to one side of the membrane at a time), binding of ATP promotes NBD dimerization, resulting in external accessibility of the drug-binding site (outward-facing, closed NBD conformation), and ATP hydrolysis leads to dissociation of the NBDs with the subsequent return of the accessibility of the binding site to the cytoplasmic side (inward-facing, open NBD conformation). However, previous work has not investigated these events under near-physiological conditions in a lipid bilayer and in the presence of transport substrate. Here, we used luminescence resonance energy transfer (LRET) to measure the distances between the two Pgp NBDs. Pgp was labeled with LRET probes, reconstituted in lipid nanodiscs, and the distance between the NBDs was measured at 37 °C. In the presence of verapamil, a substrate that activates ATP hydrolysis, the NBDs of Pgp reconstituted in nanodiscs were never far apart during the hydrolysis cycle, and we never observed the NBD-NBD distances of tens of Å that have previously been reported. However, we found two main conformations that coexist in a dynamic equilibrium under all conditions studied. Our observations highlight the importance of performing studies of efflux pumps under near-physiological conditions, in a lipid bilayer, at 37 °C, and during substrate-stimulated hydrolysis.
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Affiliation(s)
- Maria E Zoghbi
- From the Department of Cell Physiology and Molecular Biophysics
| | - Leo Mok
- Department of Cell Biology and Biochemistry, and
| | | | | | | | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, and .,Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
| | - Guillermo A Altenberg
- From the Department of Cell Physiology and Molecular Biophysics, .,Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas 79430
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41
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Loo TW, Clarke DM. A short cross-linker activates human P-glycoprotein missing a catalytic carboxylate. Biochem Pharmacol 2017; 145:27-33. [PMID: 28837794 DOI: 10.1016/j.bcp.2017.08.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 08/18/2017] [Indexed: 11/17/2022]
Abstract
P-glycoprotein (P-gp) is an ATP-dependent drug pump that protects us from toxic agents and confers multidrug resistance. It has a tweezer-like structure with each arm consisting of a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Drug substrates bind to sites within the TMDs to activate ATPase activity by promoting a tweezer-like closing of the gap between the NBDs. The catalytic carboxylates may be critical for NBD movements because the E556Q(NBD1) or E1201Q(NBD2) mutation inhibited drug-stimulated ATPase activity. If the catalytic carboxylates were components of the mechanism to bring the NBDs together, then we predicted that insertion of a flexible cross-linker between the arms would increase ATPase activity of the mutants. We found that cross-linking (between L175C(TMD1) and N820C(TMD2)) with a short flexible cross-linker (7.8Å maximum) restored high levels of drug-stimulated ATPase activity of the E556Q or E1201Q mutants. Cross-linking with a longer cross-linker (22Å maximum) however, did not restore activity. Cross-linking could not rescue all ATPase deficient mutants. For example, cross-linking L175C/N820C with short or long cross-linkers did not activate the H-loop mutants H587A or H1232A or the Walker A K433M or K1076M mutants. The results suggest that the E556 and E1201 catalytic carboxylates are part of a spring-like mechanism that is required to facilitate movements between the open and closed conformations of P-gp during ATP hydrolysis.
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Affiliation(s)
- Tip W Loo
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - David M Clarke
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.
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42
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Sohail MI, Schmid D, Wlcek K, Spork M, Szakács G, Trauner M, Stockner T, Chiba P. Molecular Mechanism of Taurocholate Transport by the Bile Salt Export Pump, an ABC Transporter Associated with Intrahepatic Cholestasis. Mol Pharmacol 2017; 92:401-413. [PMID: 28784620 DOI: 10.1124/mol.117.108688] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 07/31/2017] [Indexed: 12/12/2022] Open
Abstract
The bile salt export pump (BSEP/ABCB11) transports bile salts from hepatocytes into bile canaliculi. Its malfunction is associated with severe liver disease. One reason for functional impairment of BSEP is systemic administration of drugs, which as a side effect inhibit the transporter. Therefore, drug candidates are routinely screened for potential interaction with this transporter. Hence, understanding the functional biology of BSEP is of key importance. In this study, we engineered the transporter to dissect interdomain communication paths. We introduced mutations in noncanonical and in conserved residues of either of the two nucleotide binding domains and determined the effect on BSEP basal and substrate-stimulated ATPase activity as well as on taurocholate transport. Replacement of the noncanonical methionine residue M584 (Walker B sequence of nucleotide binding site 1) by glutamate imparted hydrolysis competency to this site. Importantly, this mutation was able to sustain 15% of wild-type transport activity, when the catalytic glutamate of the canonical nucleotide binding site 2 was mutated to glutamine. Kinetic modeling of experimental results for the ensuing M584E/E1244Q mutant suggests that a transfer of hydrolytic capacity from the canonical to the noncanonical nucleotide binding site results in loss of active and adoption of facilitative characteristics. This facilitative transport is ATP-gated. To the best of our knowledge, this result is unprecedented in ATP-binding cassette proteins with one noncanonical nucleotide binding site. Our study promotes an understanding of the domain interplay in BSEP as a basis for exploration of drug interactions with this transporter.
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Affiliation(s)
- Muhammad Imran Sohail
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Diethart Schmid
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Katrin Wlcek
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Matthias Spork
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Gergely Szakács
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Michael Trauner
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Thomas Stockner
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
| | - Peter Chiba
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics (M.I.S., M.S., P.C.), Institute of Physiology, Center for Physiology and Pharmacology (D.S.), Institute of Cancer Research (G.S.), Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III (M.T.), and Institute of Pharmacology, Center for Physiology and Pharmacology (T.S.), Medical University of Vienna, Vienna, Austria; Department of Zoology, Government College University Lahore, Lahore, Pakistan (M.I.S.); and Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, Vienna, Austria (K.W.)
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43
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Krapf MK, Gallus J, Wiese M. 4-Anilino-2-pyridylquinazolines and -pyrimidines as Highly Potent and Nontoxic Inhibitors of Breast Cancer Resistance Protein (ABCG2). J Med Chem 2017; 60:4474-4495. [PMID: 28471656 DOI: 10.1021/acs.jmedchem.7b00441] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transport proteins remains a major problem in the chemotherapeutic treatment of cancer and might be overcome by inhibition of the transporter. Because of the lack of understanding, the complex mechanisms involved in the transport process, in particular for breast cancer resistance protein (BCRP/ABCG2), there is a persistent need for studies of inhibitors of ABCG2. In this study, we investigated a systematic series of 4-substituted-2-pyridylquinazolines in terms of their inhibitory potency as well as selectivity toward ABCG2. For comparison, the quinazoline scaffold was reduced to the significantly smaller 4-methylpyrimidine basic structure. Furthermore, the cytotoxicity and the ability to reverse MDR was tested with the chemotherapeutic agents SN-38 and mitoxantrone (MX). Interaction of the compounds with ABCG2 was investigated by a colorimetric ATPase assay. Enzyme kinetic studies were carried out with Hoechst 33342 as fluorescent dye and substrate of ABCG2 to elucidate the compounds binding modes.
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Affiliation(s)
- Michael K Krapf
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
| | - Jennifer Gallus
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
| | - Michael Wiese
- Pharmaceutical Institute, University of Bonn , An der Immenburg 4, 53121 Bonn, Germany
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44
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Zhang YK, Zhang XY, Zhang GN, Wang YJ, Xu H, Zhang D, Shukla S, Liu L, Yang DH, Ambudkar SV, Chen ZS. Selective reversal of BCRP-mediated MDR by VEGFR-2 inhibitor ZM323881. Biochem Pharmacol 2017; 132:29-37. [PMID: 28242251 DOI: 10.1016/j.bcp.2017.02.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 02/22/2017] [Indexed: 10/20/2022]
Abstract
The expression of breast cancer resistant protein (BCRP) in lung cancer is correlated with development of multidrug resistance (MDR) and therefore leads to lower response to chemotherapy. ZM323881, a previously developed selective VEGFR-2 inhibitor, was found to have inhibitory effects on BCRP-mediated MDR in this investigation. ZM323881 significantly decreased the cytotoxic doses of mitoxantrone and SN-38 in BCRP-overexpressing NCI-H460/MX20 cells. Mechanistic studies revealed that ZM323881 effected by inhibiting BCRP-mediated drug efflux, leading to intracellular accumulation of BCRP substrates. No significant alteration in the expression levels and localization pattern of BCRP was observed when BCRP-overexpressing cells were exposed to ZM323881. Stimulated bell-shaped ATPase activities were observed. Molecular docking suggested that ZM323881 binds to the modulator site of BCRP and the binding pose is stable validated by 100ns molecular dynamic simulation. Overall, our results indicated that ZM323881 reversed BCRP-related MDR by inhibiting its efflux function. These findings might be useful in developing combination chemotherapy for MDR cancer treatment.
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Affiliation(s)
- Yun-Kai Zhang
- College of Pharmacy and Health Sciences, St. John's University, Queens, NY 11439, USA
| | - Xiao-Yu Zhang
- College of Pharmacy and Health Sciences, St. John's University, Queens, NY 11439, USA
| | - Guan-Nan Zhang
- College of Pharmacy and Health Sciences, St. John's University, Queens, NY 11439, USA
| | - Yi-Jun Wang
- College of Pharmacy and Health Sciences, St. John's University, Queens, NY 11439, USA
| | - Huizhong Xu
- College of Liberal Arts and Sciences, St. John's University, Queens, NY 11439, USA
| | - Dongmei Zhang
- College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Suneet Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lili Liu
- Guangdong Province Hospital for Occupational Disease Prevention and Treatment, Guangzhou 510300, China
| | - Dong-Hua Yang
- College of Pharmacy and Health Sciences, St. John's University, Queens, NY 11439, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhe-Sheng Chen
- College of Pharmacy and Health Sciences, St. John's University, Queens, NY 11439, USA.
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45
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Wang H, Chen X, Li T, Xu J, Ma Y. A myrsinol diterpene isolated from a traditional herbal medicine, LANGDU reverses multidrug resistance in breast cancer cells. JOURNAL OF ETHNOPHARMACOLOGY 2016; 194:1-5. [PMID: 27566201 DOI: 10.1016/j.jep.2016.08.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/12/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE LANGDU, a Chinese traditional herbal medicine, was the dried roots of Euphorbia prolifera Buch-Ham. The herbal medicine has been used as anti-cancer and anti-inflammatory drug in local folk medicine for several hundred years. AIM OF THE STUDY P-glycoprotein (P-gp) is a transmembrane exporter, which can expel a variety of anti-cancer drugs. Over-expressed P-glycoprotein in cancer cells impairs the effect of cancer chemotherapy and results in multidrug resistance (MDR). To elucidate the effect of LANGDU on MDR cancer cells, the constituents of Euphorbia prolifera Buch-Ham were analyzed. We found that a myrsinol diterpene, J196-10-1 could reverse multidrug resistance. MATERIALS AND METHODS Cytotoxicity assays were performed to measure reversal efficiency of J196-10-1. Efflux assay, ATPase assay, and real-time PCR were used to elucidate the mechanism of the chemical. RESULTS J196-10-1 could reverse the resistance to daunorubicin, vincristine, and topotecan effectively. The diterpene inhibited P-gp mediated efflux and did not alter transcription of the target gene significantly. The compound stimulated ATP hydrolysis at a low concentration and inhibited it at a high concentration. CONCLUSIONS J196-10-1 inhibits P-gp competitively and reverses P-gp induced MDR in breast cancer cells.
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Affiliation(s)
| | - Xiaobo Chen
- Union Stem Cell & Gene Engineering Co., Ltd, Tianjin, China
| | - Ting Li
- College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin, China
| | - Jing Xu
- College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin, China
| | - Yonggang Ma
- College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin, China.
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46
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Loo TW, Clarke DM. Attachment of a 'molecular spring' restores drug-stimulated ATPase activity to P-glycoprotein lacking both Q loop glutamines. Biochem Biophys Res Commun 2016; 483:366-370. [PMID: 28025146 DOI: 10.1016/j.bbrc.2016.12.137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 12/21/2016] [Indexed: 01/28/2023]
Abstract
P-glycoprotein (P-gp) is an ABC (ATP-Binding Cassette) drug pump that is clinically important because it confers multidrug resistance. Drugs bind at the interface between the transmembrane domains to activate ATPase activity at the two nucleotide-binding domains (NBDs). Drug transport involves ATP-dependent conformational changes between inward- (open, NBDs far apart) and outward-facing (closed, NBDs close together) conformations. Recently, it was reported that the conserved glutamines residues (Gln475 in NBD1 and Gln1118 in NBD2) in the Q loops of P-gp when mutated to alanine completely inhibited the drug-stimulated ATPase activity. It is unknown why the glutamine residues (Gln475 and Gln1118) in the Q loops of the NBDs of P-gp are required for drug-stimulated ATPase activity. Here we show that introduction of these mutations into the L175C/N820C mutant (L175C/N820C/Q475A/Q1118A) also abolished drug-stimulated ATPase activity. The ATPase activity was restored however, when the L175C/N820C/Q475A/Q1118A mutant was cross-linked with a flexible disulfide cross-linker. These results suggest that both Q-loop glutamines are not required for ATP hydrolysis and they might function as part of a spring-like mechanism in facilitating the open (inactive) to closed (active) conformational change during ATP hydrolysis. The molecular spring-like action of the Q-loop glutamines during drug-stimulated ATPase activity is likely mimicked by the attachment of the flexible cross-linker.
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Affiliation(s)
- Tip W Loo
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - David M Clarke
- Department of Medicine and Department of Biochemistry, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
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47
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Esser L, Zhou F, Pluchino KM, Shiloach J, Ma J, Tang WK, Gutierrez C, Zhang A, Shukla S, Madigan JP, Zhou T, Kwong PD, Ambudkar SV, Gottesman MM, Xia D. Structures of the Multidrug Transporter P-glycoprotein Reveal Asymmetric ATP Binding and the Mechanism of Polyspecificity. J Biol Chem 2016; 292:446-461. [PMID: 27864369 DOI: 10.1074/jbc.m116.755884] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/15/2016] [Indexed: 12/25/2022] Open
Abstract
P-glycoprotein (P-gp) is a polyspecific ATP-dependent transporter linked to multidrug resistance in cancer; it plays important roles in determining the pharmacokinetics of many drugs. Understanding the structural basis of P-gp, substrate polyspecificity has been hampered by its intrinsic flexibility, which is facilitated by a 75-residue linker that connects the two halves of P-gp. Here we constructed a mutant murine P-gp with a shortened linker to facilitate structural determination. Despite dramatic reduction in rhodamine 123 and calcein-AM transport, the linker-shortened mutant P-gp possesses basal ATPase activity and binds ATP only in its N-terminal nucleotide-binding domain. Nine independently determined structures of wild type, the linker mutant, and a methylated P-gp at up to 3.3 Å resolution display significant movements of individual transmembrane domain helices, which correlated with the opening and closing motion of the two halves of P-gp. The open-and-close motion alters the surface topology of P-gp within the drug-binding pocket, providing a mechanistic explanation for the polyspecificity of P-gp in substrate interactions.
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Affiliation(s)
- Lothar Esser
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - Fei Zhou
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | | | | | - Jichun Ma
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - Wai-Kwan Tang
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - Camilo Gutierrez
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - Alex Zhang
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - Suneet Shukla
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - James P Madigan
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | - Tongqing Zhou
- the Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Peter D Kwong
- the Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Suresh V Ambudkar
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI
| | | | - Di Xia
- From the Laboratory of Cell Biology, Center for Cancer Research, NCI,
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48
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Hürlimann LM, Corradi V, Hohl M, Bloemberg GV, Tieleman DP, Seeger MA. The Heterodimeric ABC Transporter EfrCD Mediates Multidrug Efflux in Enterococcus faecalis. Antimicrob Agents Chemother 2016; 60:5400-11. [PMID: 27381387 PMCID: PMC4997860 DOI: 10.1128/aac.00661-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/20/2016] [Indexed: 11/22/2022] Open
Abstract
Nosocomial infections with Enterococcus faecalis are an emerging health problem. However, drug efflux pumps contributing to intrinsic drug resistance are poorly studied in this Gram-positive pathogen. In this study, we functionally investigated seven heterodimeric ABC transporters of E. faecalis that are annotated as drug efflux pumps. Deletion of ef0789-ef0790 on the chromosome of E. faecalis resulted in increased susceptibility to daunorubicin, doxorubicin, ethidium, and Hoechst 33342, and the corresponding transporter was named EfrCD. Unexpectedly, the previously described heterodimeric multidrug ABC transporter EfrAB contributes marginally to drug efflux in the endogenous context of E. faecalis In contrast, heterologous expression in Lactococcus lactis revealed that EfrAB, EfrCD, and the product of ef2226-ef2227 (EfrEF) mediate the efflux of fluorescent substrates and confer resistance to multiple dyes and drugs, including fluoroquinolones. Four of seven transporters failed to exhibit drug efflux activity for the set of drugs and dyes tested, even upon overexpression in L. lactis Since all seven transporters were purified as heterodimers after overexpression in L. lactis, a lack of drug efflux activity is not attributed to poor expression or protein aggregation. Reconstitution of the purified multidrug transporters EfrAB, EfrCD, and EfrEF in proteoliposomes revealed functional coupling between ATP hydrolysis and drug binding. Our analysis creates an experimental basis for the accurate prediction of drug efflux transporters and indicates that many annotated multidrug efflux pumps might be incapable of drug transport and thus might fulfill other physiological functions in the cell.
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Affiliation(s)
- Lea M Hürlimann
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Michael Hohl
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Guido V Bloemberg
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
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49
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Zwick M, Esposito C, Hellstern M, Seelig A. How Phosphorylation and ATPase Activity Regulate Anion Flux though the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). J Biol Chem 2016; 291:14483-98. [PMID: 27226582 DOI: 10.1074/jbc.m116.721415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 01/25/2023] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR, ABCC7), mutations of which cause cystic fibrosis, belongs to the ATP-binding cassette (ABC) transporter family and works as a channel for small anions, such as chloride and bicarbonate. Anion channel activity is known to depend on phosphorylation by cAMP-dependent protein kinase A (PKA) and CFTR-ATPase activity. Whereas anion channel activity has been extensively investigated, phosphorylation and CFTR-ATPase activity are still poorly understood. Here, we show that the two processes can be measured in a label-free and non-invasive manner in real time in live cells, stably transfected with CFTR. This study reveals three key findings. (i) The major contribution (≥90%) to the total CFTR-related ATP hydrolysis rate is due to phosphorylation by PKA and the minor contribution (≤10%) to CFTR-ATPase activity. (ii) The mutant CFTR-E1371S that is still conductive, but defective in ATP hydrolysis, is not phosphorylated, suggesting that phosphorylation requires a functional nucleotide binding domain and occurs in the post-hydrolysis transition state. (iii) CFTR-ATPase activity is inversely related to CFTR anion flux. The present data are consistent with a model in which CFTR is in a closed conformation with two ATPs bound. The open conformation is induced by ATP hydrolysis and corresponds to the post-hydrolysis transition state that is stabilized by phosphorylation and binding of chloride channel potentiators.
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Affiliation(s)
- Matthias Zwick
- From the Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Cinzia Esposito
- From the Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Manuel Hellstern
- From the Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Anna Seelig
- From the Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
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50
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Macalou S, Robey RW, Jabor Gozzi G, Shukla S, Grosjean I, Hegedus T, Ambudkar SV, Bates SE, Di Pietro A. The linker region of breast cancer resistance protein ABCG2 is critical for coupling of ATP-dependent drug transport. Cell Mol Life Sci 2016; 73:1927-37. [PMID: 26708291 PMCID: PMC7477947 DOI: 10.1007/s00018-015-2118-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/21/2015] [Accepted: 12/14/2015] [Indexed: 10/22/2022]
Abstract
The ATP-binding cassette (ABC) transporters of class G display a different domain organisation than P-glycoprotein/ABCB1 and bacterial homologues with a nucleotide-binding domain preceding the transmembrane domain. The linker region connecting these domains is unique and its function and structure cannot be predicted. Sequence analysis revealed that the human ABCG2 linker contains a LSGGE sequence, homologous to the canonical C-motif/ABC signature present in all ABC nucleotide-binding domains. Predictions of disorder and of secondary structures indicated that this C2-sequence was highly mobile and located between an α-helix and a loop similarly to the C-motif. Point mutations of the two first residues of the C2-sequence fully abolished the transport-coupled ATPase activity, and led to the complete loss of cell resistance to mitoxantrone. The interaction with potent, selective and non-competitive, ABCG2 inhibitors was also significantly altered upon mutation. These results suggest an important mechanistic role for the C2-sequence of the ABCG2 linker region in ATP binding and/or hydrolysis coupled to drug efflux.
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Affiliation(s)
- S Macalou
- Equipe Labellisée Ligue 2014, BMSSI, UMR 5086 CNRS, Université Lyon 1, IBCP, 69007, Lyon, France
| | - R W Robey
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - G Jabor Gozzi
- Equipe Labellisée Ligue 2014, BMSSI, UMR 5086 CNRS, Université Lyon 1, IBCP, 69007, Lyon, France
| | - S Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - I Grosjean
- CelluloNet Biobank BB-0033-00072 Facility of UMS3444/US8/SFR Biosciences, IBCP, 69007, Lyon, France
| | - T Hegedus
- MTA-SE Molecular Biophysics Research Group, Hungarian Academy of Sciences and Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - S V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - S E Bates
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - A Di Pietro
- Equipe Labellisée Ligue 2014, BMSSI, UMR 5086 CNRS, Université Lyon 1, IBCP, 69007, Lyon, France.
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