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Zbieralski K, Staszewski J, Konczak J, Lazarewicz N, Nowicka-Kazmierczak M, Wawrzycka D, Maciaszczyk-Dziubinska E. Multilevel Regulation of Membrane Proteins in Response to Metal and Metalloid Stress: A Lesson from Yeast. Int J Mol Sci 2024; 25:4450. [PMID: 38674035 PMCID: PMC11050377 DOI: 10.3390/ijms25084450] [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: 03/07/2024] [Revised: 04/06/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
In the face of flourishing industrialization and global trade, heavy metal and metalloid contamination of the environment is a growing concern throughout the world. The widespread presence of highly toxic compounds of arsenic, antimony, and cadmium in nature poses a particular threat to human health. Prolonged exposure to these toxins has been associated with severe human diseases, including cancer, diabetes, and neurodegenerative disorders. These toxins are known to induce analogous cellular stresses, such as DNA damage, disturbance of redox homeostasis, and proteotoxicity. To overcome these threats and improve or devise treatment methods, it is crucial to understand the mechanisms of cellular detoxification in metal and metalloid stress. Membrane proteins are key cellular components involved in the uptake, vacuolar/lysosomal sequestration, and efflux of these compounds; thus, deciphering the multilevel regulation of these proteins is of the utmost importance. In this review, we summarize data on the mechanisms of arsenic, antimony, and cadmium detoxification in the context of membrane proteome. We used yeast Saccharomyces cerevisiae as a eukaryotic model to elucidate the complex mechanisms of the production, regulation, and degradation of selected membrane transporters under metal(loid)-induced stress conditions. Additionally, we present data on orthologues membrane proteins involved in metal(loid)-associated diseases in humans.
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Affiliation(s)
| | | | | | | | | | | | - Ewa Maciaszczyk-Dziubinska
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland; (K.Z.); (J.S.); (J.K.); (N.L.); (M.N.-K.); (D.W.)
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2
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Hammond N, Snider J, Stagljar I, Mitchell K, Lagutin K, Jessulat M, Babu M, Teesdale-Spittle PH, Sheridan JP, Sturley SL, Munkacsi AB. Identification and characterization of protein interactions with the major Niemann-Pick type C disease protein in yeast reveals pathways of therapeutic potential. Genetics 2023; 225:iyad129. [PMID: 37440478 PMCID: PMC10471228 DOI: 10.1093/genetics/iyad129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 01/12/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Niemann-Pick type C (NP-C) disease is a rare lysosomal storage disease caused by mutations in NPC1 (95% cases) or NPC2 (5% cases). These proteins function together in cholesterol egress from the lysosome, whereby upon mutation, cholesterol and other lipids accumulate causing major pathologies. However, it is not fully understood how cholesterol is transported from NPC1 residing at the lysosomal membrane to the endoplasmic reticulum (ER) and plasma membrane. The yeast ortholog of NPC1, Niemann-Pick type C-related protein-1 (Ncr1), functions similarly to NPC1; when transfected into a mammalian cell lacking NPC1, Ncr1 rescues the diagnostic hallmarks of cholesterol and sphingolipid accumulation. Here, we aimed to identify and characterize protein-protein interactions (PPIs) with the yeast Ncr1 protein. A genome-wide split-ubiquitin membrane yeast two-hybrid (MYTH) protein interaction screen identified 11 ER membrane-localized, full-length proteins interacting with Ncr1 at the lysosomal/vacuolar membrane. These highlight the importance of ER-vacuole membrane interface and include PPIs with the Cyb5/Cbr1 electron transfer system, the ceramide synthase complex, and the Sec61/Sbh1 protein translocation complex. These PPIs were not detected in a sterol auxotrophy condition and thus depend on normal sterol metabolism. To provide biological context for the Ncr1-Cyb5 PPI, a yeast strain lacking this PPI (via gene deletions) exhibited altered levels of sterols and sphingolipids including increased levels of glucosylceramide that mimic NP-C disease. Overall, the results herein provide new physical and genetic interaction models to further use the yeast model of NP-C disease to better understand human NP-C disease.
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Affiliation(s)
- Natalie Hammond
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jamie Snider
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Mediterranean Institute for Life Sciences, Meštrovićevo Šetalište 45, HR-21000 Split, Croatia
| | | | | | - Matthew Jessulat
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Paul H Teesdale-Spittle
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Jeffrey P Sheridan
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Stephen L Sturley
- Department of Biology, Barnard College-Columbia University, New York, NY 10027, USA
| | - Andrew B Munkacsi
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
- Centre for Biodiscovery, Victoria University of Wellington, Wellington 6012, New Zealand
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3
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Pathmanathan S, Yao Z, Coelho P, Valla R, Drecun L, Benz C, Snider J, Saraon P, Grozavu I, Kotlyar M, Jurisica I, Park M, Stagljar I. B cell linker protein (BLNK) is a regulator of Met receptor signaling and trafficking in non-small cell lung cancer. iScience 2022; 25:105419. [DOI: 10.1016/j.isci.2022.105419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/16/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
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4
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Khandelwal NK, Millan CR, Zangari SI, Avila S, Williams D, Thaker TM, Tomasiak TM. The structural basis for regulation of the glutathione transporter Ycf1 by regulatory domain phosphorylation. Nat Commun 2022; 13:1278. [PMID: 35277487 PMCID: PMC8917219 DOI: 10.1038/s41467-022-28811-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 02/07/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractYeast Cadmium Factor 1 (Ycf1) sequesters heavy metals and glutathione into the vacuole to counter cell stress. Ycf1 belongs to the ATP binding cassette C-subfamily (ABCC) of transporters, many of which are regulated by phosphorylation on intrinsically-disordered domains. The regulatory mechanism of phosphorylation is still poorly understood. Here, we report two cryo-EM structures of Ycf1 at 3.4 Å and 4.0 Å resolution in inward-facing open conformations that capture previously unobserved ordered states of the intrinsically disordered regulatory domain (R-domain). R-domain phosphorylation is clearly evident and induces a topology promoting electrostatic and hydrophobic interactions with Nucleotide Binding Domain 1 (NBD1) and the Lasso motif. These interactions stay constant between the structures and are related by rigid body movements of the NBD1/R-domain complex. Biochemical data further show R-domain phosphorylation reorganizes the Ycf1 architecture and is required for maximal ATPase activity. Together, we provide insights into how R-domains control ABCC transporter activity.
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5
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Lim SH, Snider J, Birimberg‐Schwartz L, Ip W, Serralha JC, Botelho HM, Lopes‐Pacheco M, Pinto MC, Moutaoufik MT, Zilocchi M, Laselva O, Esmaeili M, Kotlyar M, Lyakisheva A, Tang P, López Vázquez L, Akula I, Aboualizadeh F, Wong V, Grozavu I, Opacak‐Bernardi T, Yao Z, Mendoza M, Babu M, Jurisica I, Gonska T, Bear CE, Amaral MD, Stagljar I. CFTR interactome mapping using the mammalian membrane two-hybrid high-throughput screening system. Mol Syst Biol 2022; 18:e10629. [PMID: 35156780 PMCID: PMC8842165 DOI: 10.15252/msb.202110629] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/16/2022] [Accepted: 01/19/2022] [Indexed: 12/19/2022] Open
Abstract
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a chloride and bicarbonate channel in secretory epithelia with a critical role in maintaining fluid homeostasis. Mutations in CFTR are associated with Cystic Fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasians. While remarkable treatment advances have been made recently in the form of modulator drugs directly rescuing CFTR dysfunction, there is still considerable scope for improvement of therapeutic effectiveness. Here, we report the application of a high-throughput screening variant of the Mammalian Membrane Two-Hybrid (MaMTH-HTS) to map the protein-protein interactions of wild-type (wt) and mutant CFTR (F508del), in an effort to better understand CF cellular effects and identify new drug targets for patient-specific treatments. Combined with functional validation in multiple disease models, we have uncovered candidate proteins with potential roles in CFTR function/CF pathophysiology, including Fibrinogen Like 2 (FGL2), which we demonstrate in patient-derived intestinal organoids has a significant effect on CFTR functional expression.
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Affiliation(s)
- Sang Hyun Lim
- Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of BiochemistryUniversity of TorontoTorontoONCanada
| | - Jamie Snider
- Donnelly CentreUniversity of TorontoTorontoONCanada
| | - Liron Birimberg‐Schwartz
- Programme in Translational MedicineThe Hospital for Sick ChildrenTorontoONCanada
- Division of Gastroenterology, Hepatology and NutritionDepartment of PediatricsUniversity of TorontoTorontoONCanada
| | - Wan Ip
- Programme in Translational MedicineThe Hospital for Sick ChildrenTorontoONCanada
| | - Joana C Serralha
- Faculty of SciencesBioISI‐Biosystems and Integrative Sciences InstituteUniversity of LisboaLisboaPortugal
- Faculty of Life Sciences and MedicineSchool of Bioscience EducationKing’s College LondonLondonUK
| | - Hugo M Botelho
- Faculty of SciencesBioISI‐Biosystems and Integrative Sciences InstituteUniversity of LisboaLisboaPortugal
| | - Miquéias Lopes‐Pacheco
- Faculty of SciencesBioISI‐Biosystems and Integrative Sciences InstituteUniversity of LisboaLisboaPortugal
| | - Madalena C Pinto
- Faculty of SciencesBioISI‐Biosystems and Integrative Sciences InstituteUniversity of LisboaLisboaPortugal
| | - Mohamed Taha Moutaoufik
- Department of Biochemistry, Research and Innovation CentreUniversity of ReginaReginaSKCanada
| | - Mara Zilocchi
- Department of Biochemistry, Research and Innovation CentreUniversity of ReginaReginaSKCanada
| | - Onofrio Laselva
- Department of PhysiologyUniversity of TorontoTorontoONCanada
| | - Mohsen Esmaeili
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoONCanada
| | - Max Kotlyar
- Osteoarthritis Research ProgramDivision of Orthopedic SurgerySchroeder Arthritis InstituteUniversity Health NetworkTorontoONCanada
- Data Science Discovery Centre for Chronic DiseasesKrembil Research InstituteUniversity Health NetworkTorontoONCanada
| | | | | | | | - Indira Akula
- Donnelly CentreUniversity of TorontoTorontoONCanada
| | | | | | - Ingrid Grozavu
- Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of BiochemistryUniversity of TorontoTorontoONCanada
| | | | - Zhong Yao
- Donnelly CentreUniversity of TorontoTorontoONCanada
| | - Meg Mendoza
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation CentreUniversity of ReginaReginaSKCanada
| | - Igor Jurisica
- Osteoarthritis Research ProgramDivision of Orthopedic SurgerySchroeder Arthritis InstituteUniversity Health NetworkTorontoONCanada
- Data Science Discovery Centre for Chronic DiseasesKrembil Research InstituteUniversity Health NetworkTorontoONCanada
- Departments of Medical Biophysics and Computer ScienceUniversity of TorontoTorontoONCanada
- Institute of NeuroimmunologySlovak Academy of SciencesBratislavaSlovakia
| | - Tanja Gonska
- Programme in Translational MedicineThe Hospital for Sick ChildrenTorontoONCanada
- Division of Gastroenterology, Hepatology and NutritionDepartment of PediatricsUniversity of TorontoTorontoONCanada
| | - Christine E Bear
- Department of BiochemistryUniversity of TorontoTorontoONCanada
- Department of PhysiologyUniversity of TorontoTorontoONCanada
| | - Margarida D Amaral
- Faculty of SciencesBioISI‐Biosystems and Integrative Sciences InstituteUniversity of LisboaLisboaPortugal
| | - Igor Stagljar
- Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of BiochemistryUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
- Mediterranean Institute for Life SciencesSplitCroatia
- School of MedicineUniversity of SplitSplitCroatia
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6
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Grozavu I, Stuart S, Lyakisheva A, Yao Z, Pathmanathan S, Ohh M, Stagljar I. D154Q Mutation does not Alter KRAS Dimerization. J Mol Biol 2021; 434:167392. [PMID: 34896362 DOI: 10.1016/j.jmb.2021.167392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 10/19/2022]
Abstract
KRAS is one of the most frequently mutated oncogenes in human cancers. Despite nearly 40 years of research, KRAS remains largely undruggable, in part due to an incomplete understanding of its biology. Recently, KRAS dimerization was discovered to play an important role in its signalling function. The KRAS D154Q mutant was described as a dimer-deficient variant that can be used to study the effect of dimerization in KRAS oncogenicity. However, we show here that KRAS D154Q homo- and heterodimerized with KRAS WT using three separate protein-protein interaction assays, and that oncogenic KRAS dimerization was not negatively impacted by the presence of a secondary D154Q mutation. In conclusion, we advise caution in using this variant to study the purpose of dimerization in KRAS oncogenic behaviour.
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Affiliation(s)
- Ingrid Grozavu
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Sarah Stuart
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Anna Lyakisheva
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Zhong Yao
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Shivanthy Pathmanathan
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Michael Ohh
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada; Mediterranean Institute for Life Sciences (MedILS), Split, Croatia; School of Medicine, University of Split, Croatia.
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7
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Bickers SC, Benlekbir S, Rubinstein JL, Kanelis V. Structure of Ycf1p reveals the transmembrane domain TMD0 and the regulatory region of ABCC transporters. Proc Natl Acad Sci U S A 2021; 118:e2025853118. [PMID: 34021087 PMCID: PMC8166025 DOI: 10.1073/pnas.2025853118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
ATP binding cassette (ABC) proteins typically function in active transport of solutes across membranes. The ABC core structure is composed of two transmembrane domains (TMD1 and TMD2) and two cytosolic nucleotide binding domains (NBD1 and NBD2). Some members of the C-subfamily of ABC (ABCC) proteins, including human multidrug resistance proteins (MRPs), also possess an N-terminal transmembrane domain (TMD0) that contains five transmembrane α-helices and is connected to the ABC core by the L0 linker. While TMD0 was resolved in SUR1, the atypical ABCC protein that is part of the hetero-octameric ATP-sensitive K+ channel, little is known about the structure of TMD0 in monomeric ABC transporters. Here, we present the structure of yeast cadmium factor 1 protein (Ycf1p), a homolog of human MRP1, determined by electron cryo-microscopy (cryo-EM). A comparison of Ycf1p, SUR1, and a structure of MRP1 that showed TMD0 at low resolution demonstrates that TMD0 can adopt different orientations relative to the ABC core, including a ∼145° rotation between Ycf1p and SUR1. The cryo-EM map also reveals that segments of the regulatory (R) region, which links NBD1 to TMD2 and was poorly resolved in earlier ABCC structures, interacts with the L0 linker, NBD1, and TMD2. These interactions, combined with fluorescence quenching experiments of isolated NBD1 with and without the R region, suggest how posttranslational modifications of the R region modulate ABC protein activity. Mapping known mutations from MRP2 and MRP6 onto the Ycf1p structure explains how mutations involving TMD0 and the R region of these proteins lead to disease.
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Affiliation(s)
- Sarah C Bickers
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada
- Department of Chemical and Physical Sciences, University of Toronto, Mississauga, ON L5L 1C6, Canada
| | - Samir Benlekbir
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - John L Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Voula Kanelis
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada;
- Department of Chemical and Physical Sciences, University of Toronto, Mississauga, ON L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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8
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Buechel ER, Pinkett HW. Transcription factors and ABC transporters: from pleiotropic drug resistance to cellular signaling in yeast. FEBS Lett 2020; 594:3943-3964. [PMID: 33089887 DOI: 10.1002/1873-3468.13964] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/07/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022]
Abstract
Budding yeast Saccharomyces cerevisiae survives in microenvironments utilizing networks of regulators and ATP-binding cassette (ABC) transporters to circumvent toxins and a variety of drugs. Our understanding of transcriptional regulation of ABC transporters in yeast is mainly derived from the study of multidrug resistance protein networks. Over the past two decades, this research has not only expanded the role of transcriptional regulators in pleiotropic drug resistance (PDR) but evolved to include the role that regulators play in cellular signaling and environmental adaptation. Inspection of the gene networks of the transcriptional regulators and characterization of the ABC transporters has clarified that they also contribute to environmental adaptation by controlling plasma membrane composition, toxic-metal sequestration, and oxidative stress adaptation. Additionally, ABC transporters and their regulators appear to be involved in cellular signaling for adaptation of S. cerevisiae populations to nutrient availability. In this review, we summarize the current understanding of the S. cerevisiae transcriptional regulatory networks and highlight recent work in other notable fungal organisms, underlining the expansion of the study of these gene networks across the kingdom fungi.
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Affiliation(s)
- Evan R Buechel
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Heather W Pinkett
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
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9
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Celaj A, Gebbia M, Musa L, Cote AG, Snider J, Wong V, Ko M, Fong T, Bansal P, Mellor JC, Seesankar G, Nguyen M, Zhou S, Wang L, Kishore N, Stagljar I, Suzuki Y, Yachie N, Roth FP. Highly Combinatorial Genetic Interaction Analysis Reveals a Multi-Drug Transporter Influence Network. Cell Syst 2019; 10:25-38.e10. [PMID: 31668799 PMCID: PMC6989212 DOI: 10.1016/j.cels.2019.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 08/14/2019] [Accepted: 09/17/2019] [Indexed: 12/18/2022]
Abstract
Many traits are complex, depending non-additively on variant combinations. Even in model systems, such as the yeast S. cerevisiae, carrying out the high-order variant-combination testing needed to dissect complex traits remains a daunting challenge. Here, we describe “X-gene” genetic analysis (XGA), a strategy for engineering and profiling highly combinatorial gene perturbations. We demonstrate XGA on yeast ABC transporters by engineering 5,353 strains, each deleted for a random subset of 16 transporters, and profiling each strain’s resistance to 16 compounds. XGA yielded 85,648 genotype-to-resistance observations, revealing high-order genetic interactions for 13 of the 16 transporters studied. Neural networks yielded intuitive functional models and guided exploration of fluconazole resistance, which was influenced non-additively by five genes. Together, our results showed that highly combinatorial genetic perturbation can functionally dissect complex traits, supporting pursuit of analogous strategies in human cells and other model systems. Celaj et al. introduce “X-gene” genetic analysis (XGA), a strategy for modeling complex systems by engineering and profiling highly combinatorial genetic perturbations. They apply XGA to 16 yeast ABC transporters, revealing many high-order genetic interactions. Neural network models yielded intuitive functional models and illuminated an ABC transporter influence network, supporting application of XGA to other organisms and processes.
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Affiliation(s)
- Albi Celaj
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5T 3A1, Canada
| | - Marinella Gebbia
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Louai Musa
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Atina G Cote
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Jamie Snider
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Victoria Wong
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Minjeong Ko
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5T 3A1, Canada
| | - Tiffany Fong
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Paul Bansal
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Joseph C Mellor
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Gireesh Seesankar
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Maria Nguyen
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Shijie Zhou
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Liangxi Wang
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5T 3A1, Canada
| | - Nishka Kishore
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Igor Stagljar
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Mediterranean Institute for Life Sciences, Split 21 000, Croatia
| | - Yo Suzuki
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Nozomu Yachie
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Synthetic Biology Division, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan; Department of Biological Sciences, School of Science, University of Tokyo, Tokyo 113-0033, Japan; Institute for Advanced Biosciences, Keio University, Yamagata 997-0035, Japan; PRESTO, Japan Science and Technology Agency, Tokyo 153-8904, Japan.
| | - Frederick P Roth
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5T 3A1, Canada; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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10
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Zhang Z, Ke D, Hu M, Zhang C, Deng L, Li Y, Li J, Zhao H, Cheng L, Wang L, Yuan H. Quantitative phosphoproteomic analyses provide evidence for extensive phosphorylation of regulatory proteins in the rhizobia-legume symbiosis. PLANT MOLECULAR BIOLOGY 2019; 100:265-283. [PMID: 30989446 DOI: 10.1007/s11103-019-00857-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
Symbiotic nitrogen fixation in root nodules of grain legumes is essential for high yielding. Protein phosphorylation/dephosphorylation plays important role in root nodule development. Differences in the phosphoproteomes may either be developmental specific and related to nitrogen fixation activity. An iTRAQ-based quantitative phosphoproteomic analyses during nodule development enables identification of specific phosphorylation signaling in the Lotus-rhizobia symbiosis. During evolution, legumes (Fabaceae) have evolved a symbiotic relationship with rhizobia, which fix atmospheric nitrogen and produce ammonia that host plants can then absorb. Root nodule development depends on the activation of protein phosphorylation-mediated signal transduction cascades. To investigate possible molecular mechanisms of protein modulation during nodule development, we used iTRAQ-based quantitative proteomic analyses to identify root phosphoproteins during rhizobial colonization and infection of Lotus japonicus. 1154 phosphoproteins with 2957 high-confidence phosphorylation sites were identified. Gene ontology enrichment analysis of functional groups of these genes revealed that the biological processes mediated by these proteins included cellular processes, signal transduction, and transporter activity. Quantitative data highlighted the dynamics of protein phosphorylation during nodule development and, based on regulatory trends, seven groups were identified. RNA splicing and brassinosteroid (BR) signaling pathways were extensively affected by phosphorylation, and most Ser/Arg-rich (SR) proteins were multiply phosphorylated. In addition, many proposed kinase-substrate pairs were predicted, and in these MAPK6 substrates were found to be highly enriched. This study offers insights into the regulatory processes underlying nodule development, provides an accessible resource cataloging the phosphorylation status of thousands of Lotus proteins during nodule development, and develops our understanding of post-translational regulatory mechanisms in the Lotus-rhizobia symbiosis.
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Affiliation(s)
- Zaibao Zhang
- Henan Key Laboratory of Tea Plant Biology, Xinyang Normal University, Xinyang, Henan, China
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Danxia Ke
- Henan Key Laboratory of Tea Plant Biology, Xinyang Normal University, Xinyang, Henan, China
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Menghui Hu
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Chi Zhang
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Lijun Deng
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Yuting Li
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Jiuli Li
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Hai Zhao
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Lin Cheng
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China
| | - Lei Wang
- Henan Key Laboratory of Tea Plant Biology, Xinyang Normal University, Xinyang, Henan, China.
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China.
| | - Hongyu Yuan
- Henan Key Laboratory of Tea Plant Biology, Xinyang Normal University, Xinyang, Henan, China.
- College of Life Science, Xinyang Normal University, Xinyang, Henan, China.
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11
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Identification and Functional Testing of Novel Interacting Protein Partners for the Stress Sensors Wsc1p and Mid2p of Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2019; 9:1085-1102. [PMID: 30733383 PMCID: PMC6469404 DOI: 10.1534/g3.118.200985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Wsc1p and Mid2p are transmembrane signaling proteins of cell wall stress in the budding yeast Saccharomyces cerevisiae. When an environmental stress compromises cell wall integrity, they activate a cell response through the Cell Wall Integrity (CWI) pathway. Studies have shown that the cytoplasmic domain of Wsc1p initiates the CWI signaling cascade by interacting with Rom2p, a Rho1-GDP-GTP exchange factor. Binding of Rom2p to the cytoplasmic tail of Wsc1p requires dephosphorylation of specific serine residues but the mechanism by which the sensor is dephosphorylated and how it subsequently interacts with Rom2p remains unclear. We hypothesize that Wsc1p and Mid2p must be physically associated with interacting proteins other than Rom2p that facilitate its interaction and regulate the activation of CWI pathway. To address this, a cDNA plasmid library of yeast proteins was expressed in bait strains bearing membrane yeast two-hybrid (MYTH) reporter modules of Wsc1p and Mid2p, and their interacting preys were recovered and sequenced. 14 previously unreported interactors were confirmed for Wsc1p and 29 for Mid2p. The interactors’ functionality were assessed by cell growth assays and CWI pathway activation by western blot analysis of Slt2p/Mpk1p phosphorylation in null mutants of each interactor under defined stress conditions. The susceptibility of these strains to different stresses were tested against antifungal agents and chemicals. This study reports important novel protein interactions of Wsc1p and Mid2p that are associated with the cellular response to oxidative stress induced by Hydrogen Peroxide and cell wall stress induced by Caspofungin.
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12
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Vacuolar Sequestration of Azoles, a Novel Strategy of Azole Antifungal Resistance Conserved across Pathogenic and Nonpathogenic Yeast. Antimicrob Agents Chemother 2019; 63:AAC.01347-18. [PMID: 30642932 DOI: 10.1128/aac.01347-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/29/2018] [Indexed: 11/20/2022] Open
Abstract
Target alteration and overproduction and drug efflux through overexpression of multidrug transporters localized in the plasma membrane represent the conventional mechanisms of azole antifungal resistance. Here, we identify a novel conserved mechanism of azole resistance not only in the budding yeast Saccharomyces cerevisiae but also in the pathogenic yeast Candida albicans We observed that the vacuolar-membrane-localized, multidrug resistance protein (MRP) subfamily, ATP-binding cassette (ABC) transporter of S. cerevisiae, Ybt1, could import azoles into vacuoles. Interestingly, the Ybt1 homologue in C. albicans, Mlt1p, could also fulfill this function. Evidence that the process is energy dependent comes from the finding that a Mlt1p mutant version made by converting a critical lysine residue in the Walker A motif of nucleotide-binding domain 1 (required for ATP hydrolysis) to alanine (K710A) was not able to transport azoles. Additionally, we have shown that, as for other eukaryotic MRP subfamily members, deletion of the conserved phenylalanine amino acid at position 765 (F765Δ) results in mislocalization of the Mlt1 protein; this mislocalized protein was devoid of the azole-resistant attribute. This finding suggests that the presence of this protein on vacuolar membranes is an important factor in azole resistance. Further, we report the importance of conserved residues, because conversion of two serines (positions 973 and 976, in the regulatory domain and in the casein kinase I [CKI] consensus sequence, respectively) to alanine severely affected the drug resistance. Hence, the present study reveals vacuolar sequestration of azoles by the ABC transporter Ybt1 and its homologue Mlt1 as an alternative strategy to circumvent drug toxicity among pathogenic and nonpathogenic yeasts.
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13
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Oestreicher J, Morgan B. Glutathione: subcellular distribution and membrane transport 1. Biochem Cell Biol 2018; 97:270-289. [PMID: 30427707 DOI: 10.1139/bcb-2018-0189] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glutathione (γ-l-glutamyl-l-cysteinylglycine) is a small tripeptide found at millimolar concentrations in nearly all eukaryotes as well as many prokaryotic cells. Glutathione synthesis is restricted to the cytosol in animals and fungi and to the cytosol and plastids in plants. Nonetheless, glutathione is found in virtually all subcellular compartments. This implies that transporters must exist that facilitate glutathione transport into and out of the various subcellular compartments. Glutathione may also be exported and imported across the plasma membrane in many cells. However, in most cases, the molecular identity of these transporters remains unclear. Whilst glutathione transport is essential for the supply and replenishment of subcellular glutathione pools, recent evidence supports a more active role for glutathione transport in the regulation of subcellular glutathione redox homeostasis. However, our knowledge of glutathione redox homeostasis at the level of specific subcellular compartments remains remarkably limited and the role of glutathione transport remains largely unclear. In this review, we discuss how new tools and techniques have begun to yield insights into subcellular glutathione distribution and glutathione redox homeostasis. In particular, we discuss the known and putative glutathione transporters and examine their contribution to the regulation of subcellular glutathione redox homeostasis.
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Affiliation(s)
- Julian Oestreicher
- a Cellular Biochemistry, University of Kaiserslautern, 67663 Kaiserslautern, Germany.,b Institute of Biochemistry, Center of Human and Molecular Biology (ZHMB), University of the Saarland, Campus B 2.2, D-66123 Saarbrücken, Germany
| | - Bruce Morgan
- a Cellular Biochemistry, University of Kaiserslautern, 67663 Kaiserslautern, Germany.,b Institute of Biochemistry, Center of Human and Molecular Biology (ZHMB), University of the Saarland, Campus B 2.2, D-66123 Saarbrücken, Germany
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14
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Sooklal CR, López-Alonso JP, Papp N, Kanelis V. Phosphorylation Alters the Residual Structure and Interactions of the Regulatory L1 Linker Connecting NBD1 to the Membrane-Bound Domain in SUR2B. Biochemistry 2018; 57:6278-6292. [PMID: 30273482 DOI: 10.1021/acs.biochem.8b00503] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
ATP-sensitive potassium (KATP) channels in vascular smooth muscle are comprised of four pore-forming Kir6.1 subunits and four copies of the sulfonylurea receptor 2B (SUR2B), which acts as a regulator of channel gating. Recent electron cryo-microscopy (cryo-EM) structures of the pancreatic KATP channel show a central Kir6.2 pore that is surrounded by the SUR1 subunits. Mutations in the L1 linker connecting the first membrane-spanning domain and the first nucleotide binding domain (NBD1) in SUR2B cause cardiac disease; however, this part of the protein is not resolved in the cryo-EM structures. Phosphorylation of the L1 linker, by protein kinase A, disrupts its interactions with NBD1, which increases the MgATP affinity of NBD1 and KATP channel gating. To elucidate the mode by which the L1 linker regulates KATP channels, we have probed the effects of phosphorylation on its structure and interactions using nuclear magnetic resonance (NMR) spectroscopy and other techniques. We demonstrate that the L1 linker is an intrinsically disordered region of SUR2B but possesses residual secondary and compact structure, both of which are disrupted with phosphorylation. NMR binding studies demonstrate that phosphorylation alters the mode by which the L1 linker interacts with NBD1. The data show that L1 linker residues with the greatest α-helical propensity also form the most stable interaction with NBD1, highlighting a hot spot within the L1 linker. This hot spot is the site of disease-causing mutations and is associated with other processes that regulate KATP channel gating. These data provide insights into the mode by which the phospho-regulatory L1 linker regulates KATP channels.
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Affiliation(s)
- Clarissa R Sooklal
- Department of Chemistry , University of Toronto , Toronto , ON , Canada M5S 3H8.,Department of Chemical and Physical Sciences , University of Toronto Mississauga , Mississauga , ON , Canada L5L 1C6
| | - Jorge P López-Alonso
- Department of Chemistry , University of Toronto , Toronto , ON , Canada M5S 3H8.,Department of Chemical and Physical Sciences , University of Toronto Mississauga , Mississauga , ON , Canada L5L 1C6
| | - Natalia Papp
- Department of Chemical and Physical Sciences , University of Toronto Mississauga , Mississauga , ON , Canada L5L 1C6
| | - Voula Kanelis
- Department of Chemistry , University of Toronto , Toronto , ON , Canada M5S 3H8.,Department of Chemical and Physical Sciences , University of Toronto Mississauga , Mississauga , ON , Canada L5L 1C6.,Department of Cell and Systems Biology , University of Toronto , Toronto , ON , Canada M5S 3G5
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15
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Yin Y, Wang Z, Cheng D, Chen X, Chen Y, Ma Z. The ATP-binding protein FgArb1 is essential for penetration, infectious and normal growth of Fusarium graminearum. THE NEW PHYTOLOGIST 2018; 219:1447-1466. [PMID: 29932228 DOI: 10.1111/nph.15261] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
ATP-binding cassette (ABC) transporters act mainly to transport compounds across cellular membranes and are important for diverse biological processes. However, their roles in pathogenesis have not been well-characterized in Fusarium graminearum. Sixty F. graminearum ABC protein genes were functionally characterized. Among them, FgArb1 regulates normal growth and importantly is essential for pathogenicity. Thus, the regulatory mechanisms of FgArb1 in pathogenicity were analyzed in this study. FgArb1 interacts with the mitogen-activated protein kinase (MAPK) FgSte7, and partially modulates plant penetration by regulating the phosphorylation of FgGpmk1 (the downstream kinase of FgSte7). The FgArb1 mutant exhibited dramatically reduced infective growth within wounded host tissues, likely resulting from its increased sensitivity to oxidative stresses, defective cell wall integrity and reduced deoxynivalenol (DON) production. FgArb1 also is important for the production of sexual and asexual spores that are important propagules for plant infection. In addition, FgArb1 is involved in the regulation of protein biosynthesis through impeding nuclear export of small ribosomal subunit. Finally, acetylation modification at sites K28, K65, K341 and K525 in FgArb1 is required for its biological functions. Taken together, results of this study provide a novel insight into functions of the ABC transporter in fungal pathogenesis.
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Affiliation(s)
- Yanni Yin
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Zhihui Wang
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Danni Cheng
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Xiang Chen
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Yun Chen
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, The Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
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16
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Crawford RR, Potukuchi PK, Schuetz EG, Schuetz JD. Beyond Competitive Inhibition: Regulation of ABC Transporters by Kinases and Protein-Protein Interactions as Potential Mechanisms of Drug-Drug Interactions. Drug Metab Dispos 2018. [PMID: 29514827 DOI: 10.1124/dmd.118.080663] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
ATP-binding cassette (ABC) transporters are transmembrane efflux transporters mediating the extrusion of an array of substrates ranging from amino acids and lipids to xenobiotics, and many therapeutic compounds, including anticancer drugs. The ABC transporters are also recognized as important contributors to pharmacokinetics, especially in drug-drug interactions and adverse drug effects. Drugs and xenobiotics, as well as pathologic conditions, can influence the transcription of ABC transporters, or modify their activity or intracellular localization. Kinases can affect the aforementioned processes for ABC transporters as do protein interactions. In this review, we focus on the ABC transporters ABCB1, ABCB11, ABCC1, ABCC4, and ABCG2 and illustrate how kinases and protein-protein interactions affect these transporters. The clinical relevance of these factors is currently unknown; however, these examples suggest that our understanding of drug-drug interactions will benefit from further knowledge of how kinases and protein-protein interactions affect ABC transporters.
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Affiliation(s)
- Rebecca R Crawford
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Praveen K Potukuchi
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Erin G Schuetz
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - John D Schuetz
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee
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17
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Chen Y, Nielsen J. Flux control through protein phosphorylation in yeast. FEMS Yeast Res 2017; 16:fow096. [PMID: 27797916 DOI: 10.1093/femsyr/fow096] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2016] [Indexed: 01/26/2023] Open
Abstract
Protein phosphorylation is one of the most important mechanisms regulating metabolism as it can directly modify metabolic enzymes by the addition of phosphate groups. Attributed to such a rapid and reversible mechanism, cells can adjust metabolism rapidly in response to temporal changes. The yeast Saccharomyces cerevisiae, a widely used cell factory and model organism, is reported to show frequent phosphorylation events in metabolism. Studying protein phosphorylation in S. cerevisiae allows for gaining new insight into the function of regulatory networks, which may enable improved metabolic engineering as well as identify mechanisms underlying human metabolic diseases. Here we collect functional phosphorylation events of 41 enzymes involved in yeast metabolism and demonstrate functional mechanisms and the application of this information in metabolic engineering. From a systems biology perspective, we describe the development of phosphoproteomics in yeast as well as approaches to analysing the phosphoproteomics data. Finally, we focus on integrated analyses with other omics data sets and genome-scale metabolic models. Despite the advances, future studies improving both experimental technologies and computational approaches are imperative to expand the current knowledge of protein phosphorylation in S. cerevisiae.
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Affiliation(s)
- Yu Chen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Department of Biology and Biological Engineering, Chalmers University of Technology, SE412 96 Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, SE412 96 Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK2800 Kgs. Lyngby, Denmark
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18
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Zhang J, Hwang JU, Song WY, Martinoia E, Lee Y. Identification of amino acid residues important for the arsenic resistance function of Arabidopsis ABCC1. FEBS Lett 2017; 591:656-666. [PMID: 28130831 DOI: 10.1002/1873-3468.12576] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/22/2017] [Accepted: 01/23/2017] [Indexed: 11/11/2022]
Abstract
The Arabidopsis ATP-Binding Cassette (ABC) transporter ABCC1 sequesters arsenic (As)-phytochelatin conjugates into the vacuole, thereby conferring As resistance. Here, we report the results of a screen for phosphorylation-dependent regulation sites of AtABCC1. Variants of AtABCC1 harboring mutations that replaced amino acid residues Tyr682 , Tyr709 , Tyr822 , Ser846 , Ser1278 , or Thr1408 with alanine confer reduced resistance and decrease the intracellular As content relative to wild-type AtABCC1 when heterologously expressed in the SM7 yeast strain. This suggests that these mutations compromise the vacuolar sequestration of As by AtABCC1. Furthermore, through a phosphomimic mutant study, we found that phosphorylation of Ser846 is required for the As resistance function of AtABCC1. Our analysis provides a first clue as to the phosphorylation-mediated regulation of AtABCC1 activity.
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Affiliation(s)
- Jie Zhang
- Department of Life Science, Pohang University of Science and Technology, Korea
| | - Jae-Ung Hwang
- Department of Life Science, Pohang University of Science and Technology, Korea
| | - Won-Yong Song
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Korea
| | - Enrico Martinoia
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Korea.,Institut für Pflanzenbiologie, Universität Zürich, Switzerland
| | - Youngsook Lee
- Department of Life Science, Pohang University of Science and Technology, Korea.,Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Korea
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19
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Raichaudhuri A. Arabidopsis thaliana MRP1 (AtABCC1) nucleotide binding domain contributes to arsenic stress tolerance with serine triad phosphorylation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 108:109-120. [PMID: 27428365 DOI: 10.1016/j.plaphy.2016.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 07/07/2016] [Indexed: 05/20/2023]
Abstract
Multidrug resistance protein AtMRPs belong to the ATP binding cassette (ABC) transporter super family. ABC proteins are membrane proteins involved in the transport of a broad range of amphipathic organic anions across membranes. MRPs (ABCCs) are one of the highly represented subfamilies of ABC transporters. Plant MRPs also transport various glutathione conjugates across membranes. Arabidopsis thaliana MRP1 is already known to be involved in vacuolar storage of folates. Using heterologously expressed AtMRP1 in yeast and its C-terminal nucleotide binding domain (NBD2) in Escherichia coli, it has been shown that Casein kinase II (CKII) mediated phosphorylation is a potential regulator of AtMRP1 function. AtMRP1 showed enhanced tolerance towards arsenite As(III) in yeast. CKIIII/CKII mediated phosphorylation of AtMRP1 was found to be involved in As(III) mediated signaling. AtMRP1-NBD2 and its serine mutants showed distinct change in secondary structure in the presence of arsenite and methotrexate (MTX) controlled by serine triad phosphorylation. Results showed that AtMRP1 is important for vacuolar accumulation of antifolates as well as tolerance against arsenic, both of which involved phosphorylation in the serine triads at the C terminal NBD of AtMRP1. The experiments provide an important insight into the role of AtMRP1 serine triad phosphorylation under AsIII stress conditions.
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Affiliation(s)
- Ayan Raichaudhuri
- Department of Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
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20
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Development of a membrane-anchored ligand and receptor yeast two-hybrid system for ligand-receptor interaction identification. Sci Rep 2016; 6:35631. [PMID: 27762338 PMCID: PMC5071910 DOI: 10.1038/srep35631] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 10/03/2016] [Indexed: 12/25/2022] Open
Abstract
Identifying interactions between ligands and transmembrane receptors is crucial for understanding the endocrine system. However, the present approaches for this purpose are still not capable of high-throughput screening. In this report, a membrane-anchored ligand and receptor yeast two-hybrid (MALAR-Y2H) system was established. In the method, an extracellular ligand is linked with an intracellular split-ubiquitin reporter system via a chimeric transmembrane structure. Meanwhile, the prey proteins of transmembrane receptors are fused to the other half of the split-ubiquitin reporter system. The extracellular interaction of ligands and receptors can lead to the functional recovery of the ubiquitin reporter system in yeast, and eventually lead to the expression of report genes. Consequently, the system can be used to detect the interactions between extracellular ligands and their transmembrane receptors. To test the efficiency and universality of the method, interactions between several pairs of ligands and receptors of mouse were analyzed. The detecting results were shown to be thoroughly consistent with the present knowledge, indicating MALAR-Y2H can be utilized for such purpose with high precision, high efficiency and strong universality. The characteristics of the simple procedure and high-throughput potential make MALAR-Y2H a powerful platform to study protein-protein interaction networks between secreted proteins and transmembrane proteins.
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21
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Learning from each other: ABC transporter regulation by protein phosphorylation in plant and mammalian systems. Biochem Soc Trans 2016; 43:966-74. [PMID: 26517911 DOI: 10.1042/bst20150128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ABC (ATP-binding cassette) transporter family in higher plants is highly expanded compared with those of mammalians. Moreover, some members of the plant ABC subfamily B (ABCB) display very high substrate specificity compared with their mammalian counterparts that are often associated with multi-drug resistance phenomena. In this review, we highlight prominent functions of plant and mammalian ABC transporters and summarize our knowledge on their post-transcriptional regulation with a focus on protein phosphorylation. A deeper comparison of regulatory events of human cystic fibrosis transmembrane conductance regulator (CFTR) and ABCB1 from the model plant Arabidopsis reveals a surprisingly high degree of similarity. Both physically interact with orthologues of the FK506-binding proteins that chaperon both transporters to the plasma membrane in an action that seems to involve heat shock protein (Hsp)90. Further, both transporters are phosphorylated at regulatory domains that connect both nt-binding folds. Taken together, it appears that ABC transporters exhibit an evolutionary conserved but complex regulation by protein phosphorylation, which apparently is, at least in some cases, tightly connected with protein-protein interactions (PPI).
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22
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Tsao S, Weber S, Cameron C, Nehme D, Ahmadzadeh E, Raymond M. Positive regulation of the Candida albicans multidrug efflux pump Cdr1p function by phosphorylation of its N-terminal extension. J Antimicrob Chemother 2016; 71:3125-3134. [PMID: 27402010 DOI: 10.1093/jac/dkw252] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/10/2016] [Accepted: 05/24/2016] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES Overexpression of ATP-binding cassette (ABC) transporters is a frequent cause of multidrug resistance in cancer cells and pathogenic microorganisms. One example is the Cdr1p transporter from the human fungal pathogen Candida albicans that belongs to the pleiotropic drug resistance (PDR) subfamily of ABC transporters found in fungi and plants. Cdr1p is overexpressed in several azole-resistant clinical isolates, causing azole efflux and treatment failure. Cdr1p appears as a doublet band in western blot analyses, suggesting that the protein is post-translationally modified. We investigated whether Cdr1p is phosphorylated and the function of this modification. METHODS Phosphorylated residues were identified by MS. Their function was investigated by site-directed mutagenesis and expression of the mutants in a C. albicans endogenous system that exploits a hyperactive allele of the Tac1p transcription factor to drive high levels of Cdr1p expression. Fluconazole resistance was measured by microtitre plate and spot assays and transport activity by Nile red accumulation. RESULTS We identified a cluster of seven phosphorylated amino acids in the N-terminal extension (NTE) of Cdr1p. Mutating all seven sites to alanine dramatically diminished the ability of Cdr1p to confer fluconazole resistance and transport Nile red, without affecting Cdr1p localization. Conversely, a Cdr1p mutant in which the seven amino acids were replaced by glutamate was able to confer high levels of fluconazole resistance and to export Nile red. CONCLUSIONS Our results demonstrate that the NTE of Cdr1p is phosphorylated and that NTE phosphorylation plays a major role in regulating Cdr1p and possibly other PDR transporter function.
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Affiliation(s)
- Sarah Tsao
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Sandra Weber
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Christine Cameron
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Dominic Nehme
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Elaheh Ahmadzadeh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Martine Raymond
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC H3T 1J4, Canada .,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
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23
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Correction: Learning from each other: ABC transporter regulation by protein phosphorylation in plant and mammalian systems. Biochem Soc Trans 2016; 44:663-73. [DOI: 10.1042/bst20150128_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Indexed: 12/31/2022]
Abstract
The ABC (ATP-binding cassette) transporter family in higher plants is highly expanded compared with those of mammalians. Moreover, some members of the plant ABCB subfamily display very high substrate specificity compared with their mammalian counterparts that are often associated with multidrug resistance (MDR) phenomena. In this review we highlight prominent functions of plant and mammalian ABC transporters and summarize our knowledge on their post-transcriptional regulation with a focus on protein phosphorylation. A deeper comparison of regulatory events of human cystic fibrosis transmembrane conductance regulator (CFTR) and ABCB1 from the model plant Arabidopsis reveals a surprisingly high degree of similarity. Both physically interact with orthologues of the FK506-binding proteins (FKBPs) that chaperon both transporters to the plasma membrane in an action that seems to involve Hsp90. Further both transporters are phosphorylated at regulatory domains that connect both nucleotide-binding folds. Taken together it appears that ABC transporters exhibit an evolutionary conserved but complex regulation by protein phosphorylation, which apparently is, at least in some cases, tightly connected with protein–protein interactions (PPI).
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New insights into the roles of the N-terminal region of the ABCC6 transporter. J Bioenerg Biomembr 2016; 48:259-67. [PMID: 26942607 DOI: 10.1007/s10863-016-9654-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/23/2016] [Indexed: 01/07/2023]
Abstract
ABCC6 is a human ATP binding cassette (ABC) transporter of the plasma membrane associated with Pseudoxanthoma elasticum (PXE), an autosomal recessive disease characterized by ectopic calcification of elastic fibers in dermal, ocular and vascular tissues. Similar to other ABC transporters, ABCC6 encloses the core structure of four domains: two transmembrane domains (TMDs) and two nucleotide binding domains (NBDs) but also an additional N-terminal extension, including a transmembrane domain (TMD0) and a cytosolic loop (L0), which is only found in some members of ABCC subfamily, and for which the function remains to be established. To investigate the functional roles of this N-terminal region, we generated several domain deletion constructs of ABCC6, expressed in HEK293 and polarized LLC-PK1 cells. ABCC6 lacking TMD0 displayed full transport activity as the wild type protein. Unlike the wild type protein, ABCC6 without L0 was not targeted to the basolateral membrane. Moreover, homology modeling of L0 suggests that it forms an ATPase regulatory domain. Furthermore, we show that the expression of ABCC6 is linked to a cellular influx of Ca(2+). The results suggest that TMD0 is not required for transport function and that L0 maintains ABCC6 in a targeting-competent state for the basolateral membrane and might be involved in regulating the NBDs. These findings shed new light on a possible physiological function of ABCC6 and may explain some of the hallmarks of the clinical features associated with PXE that could contribute to the identification of novel pharmacological targets.
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Miller KE, Kim Y, Huh WK, Park HO. Bimolecular Fluorescence Complementation (BiFC) Analysis: Advances and Recent Applications for Genome-Wide Interaction Studies. J Mol Biol 2015; 427:2039-2055. [PMID: 25772494 DOI: 10.1016/j.jmb.2015.03.005] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/09/2022]
Abstract
Complex protein networks are involved in nearly all cellular processes. To uncover these vast networks of protein interactions, various high-throughput screening technologies have been developed. Over the last decade, bimolecular fluorescence complementation (BiFC) assay has been widely used to detect protein-protein interactions (PPIs) in living cells. This technique is based on the reconstitution of a fluorescent protein in vivo. Easy quantification of the BiFC signals allows effective cell-based high-throughput screenings for protein binding partners and drugs that modulate PPIs. Recently, with the development of large screening libraries, BiFC has been effectively applied for genome-wide PPI studies and has uncovered novel protein interactions, providing new insight into protein functions. In this review, we describe the development of reagents and methods used for BiFC-based screens in yeast, plants, and mammalian cells. We also discuss the advantages and drawbacks of these methods and highlight the application of BiFC in large-scale studies.
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Affiliation(s)
- Kristi E Miller
- Molecular Cellular Developmental Biology Program, Ohio State University, OH, USA
| | - Yeonsoo Kim
- Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
| | - Won-Ki Huh
- Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
| | - Hay-Oak Park
- Molecular Cellular Developmental Biology Program, Ohio State University, OH, USA
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A Comprehensive Membrane Interactome Mapping of Sho1p Reveals Fps1p as a Novel Key Player in the Regulation of the HOG Pathway in S. cerevisiae. J Mol Biol 2015; 427:2088-103. [PMID: 25644660 DOI: 10.1016/j.jmb.2015.01.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 01/21/2015] [Accepted: 01/24/2015] [Indexed: 01/05/2023]
Abstract
Sho1p, an integral membrane protein, plays a vital role in the high-osmolarity glycerol (HOG) mitogen-activated protein kinase pathway in the yeast Saccharomyces cerevisiae. Activated under conditions of high osmotic stress, it interacts with other HOG pathway proteins to mediate cell signaling events, ensuring that yeast cells can adapt and remain viable. In an attempt to further understand how the function of Sho1p is regulated through its protein-protein interactions (PPIs), we identified 49 unique Sho1p PPIs through the use of membrane yeast two-hybrid (MYTH), an assay specifically suited to identify PPIs of full-length integral membrane proteins in their native membrane environment. Secondary validation by literature search, or two complementary PPI assays, confirmed 80% of these interactions, resulting in a high-quality Sho1p interactome. This set of putative PPIs included both previously characterized interactors, along with a large subset of interactors that have not been previously identified as binding to Sho1p. The SH3 domain of Sho1p was found to be important for binding to many of these interactors. One particular novel interactor of interest is the glycerol transporter Fps1p, which was shown to require the SH3 domain of Sho1p for binding via its N-terminal soluble regulatory domain. Furthermore, we found that Fps1p is involved in the positive regulation of Sho1p function and plays a role in the phosphorylation of the downstream kinase Hog1p. This study represents the largest membrane interactome analysis of Sho1p to date and complements past studies on the HOG pathway by increasing our understanding of Sho1p regulation.
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de Paula DAJ, Rosa e Silva LK, Staats CC, Vainstein MH, Joanoni ALP, Nakazato L, Dutra V. Identification of genes expressed by Cryptococcus gattii during iron deprivation. Braz J Microbiol 2014; 45:813-20. [PMID: 25477912 PMCID: PMC4204963 DOI: 10.1590/s1517-83822014000300008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 12/13/2013] [Indexed: 11/23/2022] Open
Abstract
Cryptococcus neoformans and C. gattii are pathogenic yeasts that cause life-threatening diseases in humans and animals. Iron is an essential nutrient for virtually every organism as it functions as a cofactor in numerous essential enzymatic reactions. In the literature, the competition for iron between microbes and mammalian hosts during infection is well documented. In this study, we used representational difference analysis (RDA) in order to gain a better understanding of how C. gattii responds to iron starvation. A total of 15 and 29 genes were identified as having altered expression levels due to iron depletion after 3 h and 12 h, respectively. Of these, eight genes were identified in both libraries. The transcripts were related to many biological processes, such as cell cycle, ergosterol metabolism, cell wall organization, transportation, translation, cell respiration and the stress response. These data suggest a remodeling of C. gattii metabolism during conditions of iron deprivation.
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Affiliation(s)
| | - Lívia Kmetzsch Rosa e Silva
- Centro de Biotecnologia Universidade Federal do Rio Grande do Sul Porto AlegreRS Brazil Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Charley Christian Staats
- Centro de Biotecnologia Universidade Federal do Rio Grande do Sul Porto AlegreRS Brazil Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marilene H Vainstein
- Centro de Biotecnologia Universidade Federal do Rio Grande do Sul Porto AlegreRS Brazil Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ana Lúcia Pinto Joanoni
- Universidade Federal de Mato Grosso CuiabáMT Brazil Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Luciano Nakazato
- Universidade Federal de Mato Grosso CuiabáMT Brazil Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Valéria Dutra
- Universidade Federal de Mato Grosso CuiabáMT Brazil Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
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Wei W, Smith N, Wu X, Kim H, Seravalli J, Khalimonchuk O, Lee J. YCF1-mediated cadmium resistance in yeast is dependent on copper metabolism and antioxidant enzymes. Antioxid Redox Signal 2014; 21:1475-89. [PMID: 24444374 PMCID: PMC4158973 DOI: 10.1089/ars.2013.5436] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIMS Acquisition and detoxification of metal ions are vital biological processes. Given the requirement of metallochaperones in cellular copper distribution and metallation of cuproproteins, this study investigates whether the metallochaperones also deliver metal ions for transporters functioning in metal detoxification. RESULTS Resistance to excess cadmium and copper of the yeast Saccharomyces cerevisiae, which is conferred by PCA1 and CaCRP1 metal efflux P-type ATPases, respectively, does not rely on known metallochaperones, Atx1p, Ccs1p, and Cox17p. Copper deficiency induced by the expression of CaCRP1 encoding a copper exporter occurs in the absence of Atx1p. Intriguingly, CCS1 encoding the copper chaperone for superoxide dismutase 1 (Sod1p) is necessary for cadmium resistance that is mediated by Ycf1p, a vacuolar cadmium sequestration transporter. This is attributed to Ccs1p's role in the maturation of Sod1p rather than its direct interaction with Ycf1p for cadmium transfer. Functional defect in Ycf1p associated with the absence of Sod1p as well as another antioxidant enzyme Glr1p is rescued by anaerobic growth or substitutions of specific cysteine residues of Ycf1p to alanine or serine. This further supports oxidative inactivation of Ycf1p in the absence of Ccs1p, Sod1p, or Glr1p. INNOVATION These results provide new insights into the mechanisms of metal metabolism, interaction among metal ions, and the roles for antioxidant systems in metal detoxification. CONCLUSION Copper metabolism and antioxidant enzymes maintain the function of Ycf1p for cadmium defense.
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Affiliation(s)
- Wenzhong Wei
- Department of Biochemistry, Redox Biology Center, University of Nebraska-Lincoln , Lincoln, Nebraska
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Labbé S, Khan MGM, Jacques JF. Iron uptake and regulation in Schizosaccharomyces pombe. Curr Opin Microbiol 2013; 16:669-76. [PMID: 23916750 DOI: 10.1016/j.mib.2013.07.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 11/16/2022]
Abstract
Schizosaccharomyces pombe is a useful model system for understanding many aspects of eukaryotic cell growth. Studies of S. pombe have identified novel genes that function in the regulation of iron homeostasis. In response to high levels of iron, Fep1 represses the expression of several genes involved in the acquisition of iron. When iron levels are limited, optimization of cellular iron utilization is coordinated by Php4, which represses genes encoding iron-using proteins. Results from studies in yeast have shed new light on the role of monothiol glutaredoxins (Grxs) in iron homeostasis. In S. pombe, the Grx4 protein serves as an inhibitory partner for Fep1 in response to iron deficiency, whereas it is required for the inhibition of Php4 under iron-replete conditions.
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Affiliation(s)
- Simon Labbé
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
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Kimura S, Kawarazaki T, Nibori H, Michikawa M, Imai A, Kaya H, Kuchitsu K. The CBL-interacting protein kinase CIPK26 is a novel interactor of Arabidopsis NADPH oxidase AtRbohF that negatively modulates its ROS-producing activity in a heterologous expression system. J Biochem 2012; 153:191-5. [DOI: 10.1093/jb/mvs132] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Nguyen THN, Brechenmacher L, Aldrich JT, Clauss TR, Gritsenko MA, Hixson KK, Libault M, Tanaka K, Yang F, Yao Q, Paša-Tolić L, Xu D, Nguyen HT, Stacey G. Quantitative phosphoproteomic analysis of soybean root hairs inoculated with Bradyrhizobium japonicum. Mol Cell Proteomics 2012; 11:1140-55. [PMID: 22843990 PMCID: PMC3494206 DOI: 10.1074/mcp.m112.018028] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 06/05/2012] [Indexed: 11/06/2022] Open
Abstract
Root hairs are single hair-forming cells on roots that function to increase root surface area, enhancing water and nutrient uptake. In leguminous plants, root hairs also play a critical role as the site of infection by symbiotic nitrogen fixing rhizobia, leading to the formation of a novel organ, the nodule. The initial steps in the rhizobia-root hair infection process are known to involve specific receptor kinases and subsequent kinase cascades. Here, we characterize the phosphoproteome of the root hairs and the corresponding stripped roots (i.e. roots from which root hairs were removed) during rhizobial colonization and infection to gain insight into the molecular mechanism of root hair cell biology. We chose soybean (Glycine max L.), one of the most important crop plants in the legume family, for this study because of its larger root size, which permits isolation of sufficient root hair material for phosphoproteomic analysis. Phosphopeptides derived from root hairs and stripped roots, mock inoculated or inoculated with the soybean-specific rhizobium Bradyrhizobium japonicum, were labeled with the isobaric tag eight-plex iTRAQ, enriched using Ni-NTA magnetic beads and subjected to nanoRPLC-MS/MS1 analysis using HCD and decision tree guided CID/ETD strategy. A total of 1625 unique phosphopeptides, spanning 1659 nonredundant phosphorylation sites, were detected from 1126 soybean phosphoproteins. Among them, 273 phosphopeptides corresponding to 240 phosphoproteins were found to be significantly regulated (>1.5-fold abundance change) in response to inoculation with B. japonicum. The data reveal unique features of the soybean root hair phosphoproteome, including root hair and stripped root-specific phosphorylation suggesting a complex network of kinase-substrate and phosphatase-substrate interactions in response to rhizobial inoculation.
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Affiliation(s)
- Tran Hong Nha Nguyen
- From the ‡Division of Plant Sciences, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
- §National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri 65211
- ¶Vietnam Education Foundation
| | - Laurent Brechenmacher
- From the ‡Division of Plant Sciences, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
- §National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri 65211
| | - Joshua T. Aldrich
- ‖Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Therese R. Clauss
- **Fundamental and Computational Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Marina A. Gritsenko
- **Fundamental and Computational Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Kim K. Hixson
- ‖Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Marc Libault
- ‡‡Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73019
| | - Kiwamu Tanaka
- From the ‡Division of Plant Sciences, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
- §National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri 65211
| | - Feng Yang
- **Fundamental and Computational Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Qiuming Yao
- §§Department of Computer Science, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Ljiljana Paša-Tolić
- ‖Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Dong Xu
- §§Department of Computer Science, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Henry T. Nguyen
- From the ‡Division of Plant Sciences, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
- §National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri 65211
| | - Gary Stacey
- From the ‡Division of Plant Sciences, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
- §National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri 65211
- ¶¶Division of Biochemistry, University of Missouri, Columbia, Missouri 65211
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Stolarczyk EI, Reiling CJ, Pickin KA, Coppage R, Knecht MR, Paumi CM. Casein kinase 2α regulates multidrug resistance-associated protein 1 function via phosphorylation of Thr249. Mol Pharmacol 2012; 82:488-99. [PMID: 22695718 DOI: 10.1124/mol.112.078295] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have shown previously that the function of Ycf1p, yeast ortholog of multidrug resistance-associated protein 1 (MRP1), is regulated by yeast casein kinase 2α (Cka1p) via phosphorylation at Ser251. In this study, we explored whether casein kinase 2α (CK2α), the human homolog of Cka1p, regulates MRP1 by phosphorylation at the semiconserved site Thr249. Knockdown of CK2α in MCF7-derived cells expressing MRP1 [MRP1 CK2α(-)] resulted in increased doxorubicin sensitivity. MRP1-dependent transport of leukotriene C(4) and estradiol-17β-d-glucuronide into vesicles derived from MRP1 CK2α(-) cells was decreased compared with MRP1 vesicles. Moreover, mutation of Thr249 to alanine (MRP1-T249A) also resulted in decreased MRP1-dependent transport, whereas a phosphomimicking mutation (MRP1-T249E) led to dramatic increase in MRP1-dependent transport. Studies in tissue culture confirmed these findings, showing increased intracellular doxorubicin accumulation in MRP1 CK2α(-) and MRP1-T249A cells compared with MRP1 cells. Inhibition of CK2 kinase by 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole resulted in increased doxorubicin accumulation in MRP1 cells, but not in MRP1 CK2α(-), MRP1-T249A, or MRP1-T249E cells, suggesting that CK2α regulates MRP1 function via phosphorylation of Thr249. Indeed, CK2α and MRP1 interact physically, and recombinant CK2 phosphorylates MRP1-derived peptide in vitro in a Thr249-dependent manner, whereas knockdown of CK2α results in decreased phosphorylation at MRP1-Thr249. The role of CK2 in regulating MRP1 was confirmed in other cancer cell lines where CK2 inhibition decreased MRP1-mediated efflux of doxorubicin and increased doxorubicin cytotoxicity. This study supports a model in which CK2α potentiates MRP1 function via direct phosphorylation of Thr249.
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Ycf1p attenuates basal level oxidative stress response in Saccharomyces cerevisiae. FEBS Lett 2012; 586:847-53. [PMID: 22449970 DOI: 10.1016/j.febslet.2012.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 02/06/2012] [Accepted: 02/08/2012] [Indexed: 11/22/2022]
Abstract
Ycf1p function is regulated by casein kinase 2α, Cka1p, via phosphorylation of Ser251. Cka1p-mediated phosphorylation of Ycf1p is attenuated in response to high salt stress. Previous results from our lab suggest a role for Ycf1p in cellular resistance to salt stress. Here, we show that Ycf1p plays an important role in cellular resistance to salt stress by maintaining the cellular redox balance via glutathione recycling. Our results suggest that during acute salt stress increased Sod1p, Sod2p and Ctt1p activity is the main compensatory for the loss in Ycf1p function that results from reduced Ycf1p-dependent recycling of cellular GSH levels.
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Petschnigg J, Wong V, Snider J, Stagljar I. Investigation of membrane protein interactions using the split-ubiquitin membrane yeast two-hybrid system. Methods Mol Biol 2012; 812:225-44. [PMID: 22218863 DOI: 10.1007/978-1-61779-455-1_13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Proteins are generally organized into molecular complexes, in which multiple interaction partners collaborate to carry out cellular processes. Thus, techniques to map protein-protein interactions have become pivotal for biological studies of as yet uncharacterized proteins. Investigation of interaction partners of membrane proteins is of special interest, as they play a major role in cellular processes and are often directly linked to human diseases. Owing to their hydrophobic nature, however, it has proven difficult to study their interaction partners. To circumvent this problem, a yeast-based genetic technology for the in vivo detection of membrane protein interactions, the split-ubiquitin membrane yeast two-hybrid (MYTH) system, has been developed. MYTH allows for detection of both stable and transient interactions and can be applied to large- and small-scale screens. It uses the split-ubiquitin approach, in which the reconstitution of two ubiquitin halves is mediated by a specific protein-protein interaction. Briefly, the bait membrane protein is fused to the C-terminal half of ubiquitin and an artificial transcription factor. The mutated N-terminal moiety of ubiquitin is fused to the prey protein. Upon interaction of bait and prey proteins, ubiquitin is reconstituted and further recognized by ubiquitin-specific proteases, which subsequently cleave off the transcription factor, thus resulting in reporter gene activation. To date, MYTH has been successfully applied to study interactions of membrane proteins from various organisms and has only recently been adapted for the identification of interaction partners of mammalian receptor tyrosine kinases.
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Affiliation(s)
- Julia Petschnigg
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
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Mielniczki-Pereira AA, Hahn ABB, Bonatto D, Riger CJ, Eleutherio ECA, Henriques JAP. New insights into the Ca2+-ATPases that contribute to cadmium tolerance in yeast. Toxicol Lett 2011; 207:104-11. [PMID: 21911041 DOI: 10.1016/j.toxlet.2011.08.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/29/2011] [Accepted: 08/29/2011] [Indexed: 01/16/2023]
Abstract
Cadmium (Cd(2+)) is a toxic heavy metal which triggers several toxic effects in eukaryotes, including neurotoxicity and impaired calcium metabolism. In the model organism Saccharomyces cerevisiae, the best characterized pathway for Cd(2+) detoxification involves conjugation with glutathione (GSH) and subsequent transport to vacuoles by Ycf1p, an ATPase homologous to human MRP1 (Multidrug resistance associated protein 1). However, Cd(2+) tolerance also can be mediated by Pmr1p, a Ca(2+) pump located in the Golgi membrane, possibly through to the secretory pathway. Herein, we showed that inactivation of the PMR1 gene, alone or simultaneously with YCF1, delayed initial Cd(2+) capture compared to wild-type (WT) cells. In addition, Cd(2+) treatment altered the expression profile of yeast internal Ca(2+) transporters; specifically, PMC1 gene expression is induced substantially by the metal in WT cells, and this induction is stronger in mutants lacking YCF1. Taken together, these results indicate that, in addition to Pmr1p, the vacuolar Ca(2+)-ATPase Pmc1p also helps yeast cells cope with Cd(2+) toxicity. We propose a model where Pmc1p and Pmr1p Ca(2+)-ATPase function in cooperation with Ycf1p to promote Cd(2+) detoxification.
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Stolarczyk EI, Reiling CJ, Paumi CM. Regulation of ABC transporter function via phosphorylation by protein kinases. Curr Pharm Biotechnol 2011; 12:621-35. [PMID: 21118091 DOI: 10.2174/138920111795164075] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Accepted: 04/07/2010] [Indexed: 11/22/2022]
Abstract
ATP-binding cassette (ABC) transporters are multispanning membrane proteins that utilize ATP to move a broad range of substrates across cellular membranes. ABC transporters are involved in a number of human disorders and diseases. Overexpression of a subset of the transporters has been closely linked to multidrug resistance in both bacteria and viruses and in cancer. A poorly understood and important aspect of ABC transporter biology is the role of phosphorylation as a mechanism to regulate transporter function. In this review, we summarize the current literature addressing the role of phosphorylation in regulating ABC transporter function. A comprehensive list of all the phosphorylation sites that have been identified for the human ABC transporters is presented, and we discuss the role of individual kinases in regulating transporter function. We address the potential pitfalls and difficulties associated with identifying phosphorylation sites and the corresponding kinase(s), and we discuss novel techniques that may circumvent these problems. We conclude by providing a brief perspective on studying ABC transporter phosphorylation.
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Wysocki R, Tamás MJ. How Saccharomyces cerevisiae copes with toxic metals and metalloids. FEMS Microbiol Rev 2011; 34:925-51. [PMID: 20374295 DOI: 10.1111/j.1574-6976.2010.00217.x] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Toxic metals and metalloids are widespread in nature and can locally reach fairly high concentrations. To ensure cellular protection and survival in such environments, all organisms possess systems to evade toxicity and acquire tolerance. This review provides an overview of the molecular mechanisms that contribute to metal toxicity, detoxification and tolerance acquisition in budding yeast Saccharomyces cerevisiae. We mainly focus on the metals/metalloids arsenic, cadmium, antimony, mercury, chromium and selenium, and emphasize recent findings on sensing and signalling mechanisms and on the regulation of tolerance and detoxification systems that safeguard cellular and genetic integrity.
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Affiliation(s)
- Robert Wysocki
- Institute of Genetics and Microbiology, University of Wroclaw, Wroclaw, Poland
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Arsenic transport in prokaryotes and eukaryotic microbes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 679:47-55. [PMID: 20666223 DOI: 10.1007/978-1-4419-6315-4_4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Aquaporins (AQPs) and aquaglyceroporins facilitate transport of a broad spectrum of substrates such as water, glycerol and other small uncharged solutes. More recently, AQPs ave also been shown to facilitate diffusion of metalloids such as arsenic (As) and antimony (Sb). At neutral pH, the trivalent forms of these metalloids are structurally similar to glycerol and hence they can enter cells through AQPs. As- and Sb-containing compounds are toxic to cells, yet both metalloids are used as chemotherapeutic agents for treating acute promyelocytic leukemia and diseases caused by protozoan parasites. In this chapter, we will review the role of AQPs and other proteins in metalloid transport in prokaryotes and eukaryotic microbes.
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Pickin KA, Ezenwajiaku N, Overcash H, Sethi M, Knecht MR, Paumi CM. Suppression of Ycf1p function by Cka1p-dependent phosphorylation is attenuated in response to salt stress. FEMS Yeast Res 2010; 10:839-57. [PMID: 20812950 DOI: 10.1111/j.1567-1364.2010.00677.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The yeast vacuolar membrane protein Ycf1p and its mammalian counterpart, MRP1, belong to the ABCC subfamily of ATP-binding cassette transporters. Genetic evidence suggests that the yeast casein kinase 2α, Cka1p, negatively regulates Ycf1p function via phosphorylation of Ser251 within the N-terminus. In this study, we provide strong evidence that Cka1p regulates Ycf1p function via phosphorylation of Ser251. We show that the CK2 holoenzyme interacts with Ycf1p. However, genetic analysis suggests that only Cka1p is required for Ser251 phosphorylation, as the deletion of CKA1 significantly reduces Ser251 phosphorylation in vivo. Furthermore, purified recombinant Cka1p phosphorylates a Ycf1p-derived peptide containing Ser251. We also demonstrate that Ycf1p function is induced in response to high salt stress. Induction of the Ycf1p function strongly correlates with reduced phosphorylation of Ser251. Importantly, Cka1p activity in vivo is similarly reduced in response to salt stress, consistent with our finding that Cka1p directly phosphorylates Ser251 of Ycf1p. We provide genetic and biochemical evidence that strongly suggests that the induction of Ycf1p function is the result of decreased phosphorylation of Ser251. In conclusion, our work demonstrates a novel biochemical role for Cka1p regulation of Ycf1p function in the cellular response of yeast to salt stress.
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Affiliation(s)
- Kerry A Pickin
- Department of Toxicology, University of Kentucky, Lexington, KY 40536, USA
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ABC transporters in Saccharomyces cerevisiae and their interactors: new technology advances the biology of the ABCC (MRP) subfamily. Microbiol Mol Biol Rev 2010; 73:577-93. [PMID: 19946134 DOI: 10.1128/mmbr.00020-09] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Members of the ATP-binding cassette (ABC) transporter superfamily exist in bacteria, fungi, plants, and animals and play key roles in the efflux of xenobiotic compounds, physiological substrates, and toxic intracellular metabolites. Based on sequence relatedness, mammalian ABC proteins have been divided into seven subfamilies, ABC subfamily A (ABCA) to ABCG. This review focuses on recent advances in our understanding of ABC transporters in the model organism Saccharomyces cerevisiae. We propose a revised unified nomenclature for the six yeast ABC subfamilies to reflect the current mammalian designations ABCA to ABCG. In addition, we specifically review the well-studied yeast ABCC subfamily (formerly designated the MRP/CFTR subfamily), which includes six members (Ycf1p, Bpt1p, Ybt1p/Bat1p, Nft1p, Vmr1p, and Yor1p). We focus on Ycf1p, the best-characterized yeast ABCC transporter. Ycf1p is located in the vacuolar membrane in yeast and functions in a manner analogous to that of the human multidrug resistance-related protein (MRP1, also called ABCC1), mediating the transport of glutathione-conjugated toxic compounds. We review what is known about Ycf1p substrates, trafficking, processing, posttranslational modifications, regulation, and interactors. Finally, we discuss a powerful new yeast two-hybrid technology called integrated membrane yeast two-hybrid (iMYTH) technology, which was designed to identify interactors of membrane proteins. iMYTH technology has successfully identified novel interactors of Ycf1p and promises to be an invaluable tool in future efforts to comprehensively define the yeast ABC interactome.
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abc3+ encodes an iron-regulated vacuolar ABC-type transporter in Schizosaccharomyces pombe. EUKARYOTIC CELL 2009; 9:59-73. [PMID: 19915076 DOI: 10.1128/ec.00262-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Studies have shown the fundamental contribution of the yeast vacuole as a site for storage and detoxification of metals. Whereas the transmembrane proteins responsible for iron transport into and out of the vacuole have been identified in Saccharomyces cerevisiae, less information is available concerning the mobilization of vacuolar iron stores in Schizosaccharomyces pombe. In this study, we report the identification of a gene designated abc3(+) that encodes a protein which exhibits sequence homology with the ABCC subfamily of ATP-binding cassette transporters. The transcription of abc3(+) is induced by low concentrations of iron but repressed by high levels of iron. The iron-mediated repression of abc3(+) required a functional fep1(+) gene. Chromatin immunoprecipitation assays showed that Fep1 associates with the abc3(+) promoter in vivo, in an iron-dependent manner. Microscopic analyses revealed that a functional Abc3-green fluorescent protein localizes to the membrane vacuole when iron levels were low. Abc3 was required for growth in low-iron medium in the absence of the transport system mediated by Fio1 and Fip1. abc3Delta cells exhibited increased levels of expression of the frp1(+)-encoded ferric reductase, suggesting a loss of Fep1 repression and, consequently, the activation of Fep1-regulated genes. When abc3(+) was expressed using the nmt1(+) promoter system, its induction led to a reduced transcriptional activity of the frp1(+) gene. Because S. pombe does not possess vacuolar membrane-localized orthologs to S. cerevisiae Fth1, Fet5, and Smf3, our findings suggested that Abc3 may be responsible for mobilizing stored iron from the vacuole to the cytosol in response to iron deficiency.
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Angiotensin II triggers release of leukotriene C4 in vascular smooth muscle cells via the multidrug resistance-related protein 1. Mol Cell Biochem 2009; 333:261-7. [PMID: 19685171 DOI: 10.1007/s11010-009-0227-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 08/06/2009] [Indexed: 10/20/2022]
Abstract
The multidrug resistance-related protein-1 (MRP1) is important for the management of oxidative stress in vascular cells in vivo. Substrates of MRP1 are, among others, glutathione and the leukotriene C(4) (LTC(4)), an eicosanoid and mediator of inflammation. Angiotensin (Ang) II infusion results in MRP1(-/-) mice compared to wild-type mice in improved endothelial function and reduced reactive oxygen species (ROS) formation. However, the interaction between Ang II, LTC(4) and MRP1 is not completely understood and has never been investigated in vitro. Ang II induced in vascular smooth muscle cells (VSMC) the release of LTC(4) and the generation of ROS. Pharmacologic inhibition of MRP1 via MK 571 significantly reduced Ang II-induced ROS release (L012-luminescence) in VSMC. The release of ROS after Ang II stimulation is inhibited, to a comparable degree, by blockade of the Cys-LT1 receptor with montelukast. Incubation of VSMC with recombined LTC(4) and Ang II caused enhanced rates of proliferation in VSMC. This effect can be rescued by either MRP1 or Cys-LT1 receptor inhibition. Accordingly, stimulation of VSMC with LTC(4) reduces intracellular levels of glutathione, but does not affect apoptosis. LTC(4) stimulation results in a significant activation of MRP1, but does not alter MRP1 expression. These findings indicate a connection between Ang II, MRP1 and LTC(4). Both, MRP1 and LTC(4), are potentially promising targets for atheroprotective therapy.
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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