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Yang C, Zheng B, Wang R, Chang H, Liu P, Li B, Norvienyeku J, Chen Q. A Putative P-Type ATPase Regulates the Secretion of Hydrolytic Enzymes, Phospholipid Transport, Morphogenesis, and Pathogenesis in Phytophthora capsici. FRONTIERS IN PLANT SCIENCE 2022; 13:852500. [PMID: 35620687 PMCID: PMC9127794 DOI: 10.3389/fpls.2022.852500] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/11/2022] [Indexed: 05/17/2023]
Abstract
Phytophthora capsici is an important plant pathogenic oomycete with multiple hosts. The P4-ATPases, aminophospholipid translocases (APTs), play essential roles in the growth and pathogenesis of fungal pathogens. However, the function of P4-ATPase in P. capsici remains unclear. This study identified and characterized PcApt1, a P4-ATPase Drs2 homolog, in P. capsici. Deletion of PcAPT1 by CRISPR/Cas9 knock-out strategy impaired hyphal growth, extracellular laccase activity. Cytological analyses have shown that PcApt1 participates in phosphatidylserine (PS) transport across the plasma membrane. Also, we showed that targeted deletion of PcAPT1 triggered a significant reduction in the virulence of P. capsici. Secretome analyses have demonstrated that secretion of hydrolytic enzymes decreased considerably in the PcAPT1 gene deletion strains compared to the wild-type. Overall, our results showed that PcApt1 plays a pivotal role in promoting morphological development, phospholipid transport, secretion of hydrolytic enzymes, and the pathogenicity of the polycyclic phytopathogenic oomycete P. capsici. This study underscores the need for comprehensive evaluation of subsequent members of the P-type ATPase family to provide enhanced insights into the dynamic contributions to the pathogenesis of P. capsici and their possible deployment in the formulation of effective control strategies.
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Affiliation(s)
- Chengdong Yang
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Bowen Zheng
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Rongbo Wang
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Hongyang Chang
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Peiqing Liu
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Benjin Li
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
| | - Justice Norvienyeku
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
- Justice Norvienyeku,
| | - Qinghe Chen
- Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests, Ministry of Education, College of Plant Protection, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, China
- *Correspondence: Qinghe Chen,
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Yun Y, Guo P, Zhang J, You H, Guo P, Deng H, Hao Y, Zhang L, Wang X, Abubakar YS, Zhou J, Lu G, Wang Z, Zheng W. Flippases play specific but distinct roles in the development, pathogenicity, and secondary metabolism of Fusarium graminearum. MOLECULAR PLANT PATHOLOGY 2020; 21:1307-1321. [PMID: 32881238 PMCID: PMC7488471 DOI: 10.1111/mpp.12985] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/12/2020] [Accepted: 08/03/2020] [Indexed: 05/03/2023]
Abstract
The membrane trafficking system is important for compartmentalization of the biosynthesis pathway and secretion of deoxynivalenol (DON) mycotoxin (a virulence factor) in Fusarium graminearum. Flippases are transmembrane lipid transporters and mediate a number of essential physiological steps of membrane trafficking, including vesicle budding, charging, and protein diffusion within the membrane. However, the roles of flippases in secondary metabolism remain unknown in filamentous fungi. Herein, we identified five flippases (FgDnfA, FgDnfB, FgDnfC1, FgDnfC2, and FgDnfD) in F. graminearum and established their specific and redundant functions in the development and pathogenicity of this phytopathogenic fungus. Our results demonstrate that FgDnfA is critical for normal vegetative growth while the other flippases are dispensable. FgDnfA and FgDnfD were found crucial for the fungal pathogenesis, and a remarkable reduction in DON production was observed in ΔFgDNFA and ΔFgDNFD. Deletion of the FgDNFB gene increased DON production to about 30 times that produced by the wild type. Further analysis showed that FgDnfA and FgDnfD have positive roles in the regulation of trichothecene (TRI) genes (TRI1, TRI4, TRI5, TRI6, TRI12, and TRI101) expression and toxisome reorganization, while FgDnfB acts as a negative regulator of DON synthesis. In addition, FgDnfB and FgDnfD have redundant functions in the regulation of phosphatidylcholine transport, and double deletion of FgDNFB and FgDNFD showed serious defects in fungal development, DON synthesis, and virulence. Collectively, our findings reveal the distinct and specific functions of flippase family members in F. graminearum and principally demonstrate that FgDnfA, FgDnfD, and FgDnfB have specific spatiotemporal roles during toxisome biogenesis.
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Affiliation(s)
- Yingzi Yun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Pusheng Guo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Jing Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Haixia You
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Pingting Guo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Huobin Deng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Yixin Hao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Limei Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Xueyu Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | | | - Jie Zhou
- College of Life ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Guodong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
- Institute of Ocean ScienceMinjiang UniversityFuzhouChina
| | - Wenhui Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan CropsCollege of Plant ProtectionFujian Agriculture and Forestry UniversityFuzhouChina
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Mioka T, Fujimura-Kamada K, Mizugaki N, Kishimoto T, Sano T, Nunome H, Williams DE, Andersen RJ, Tanaka K. Phospholipid flippases and Sfk1p, a novel regulator of phospholipid asymmetry, contribute to low permeability of the plasma membrane. Mol Biol Cell 2018. [PMID: 29540528 PMCID: PMC5935070 DOI: 10.1091/mbc.e17-04-0217] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Phospholipid flippase (type 4 P-type ATPase) plays a major role in the generation of phospholipid asymmetry in eukaryotic cell membranes. Loss of Lem3p-Dnf1/2p flippases leads to the exposure of phosphatidylserine (PS) and phosphatidylethanolamine (PE) on the cell surface in yeast, resulting in sensitivity to PS- or PE-binding peptides. We isolated Sfk1p, a conserved membrane protein in the TMEM150/FRAG1/DRAM family, as a multicopy suppressor of this sensitivity. Overexpression of SFK1 decreased PS/PE exposure in lem3Δ mutant cells. Consistent with this, lem3Δ sfk1Δ double mutant cells exposed more PS/PE than the lem3Δ mutant. Sfk1p was previously implicated in the regulation of the phosphatidylinositol-4 kinase Stt4p, but the effect of Sfk1p on PS/PE exposure in lem3Δ was independent of Stt4p. Surprisingly, Sfk1p did not facilitate phospholipid flipping but instead repressed it, even under ATP-depleted conditions. We propose that Sfk1p negatively regulates transbilayer movement of phospholipids irrespective of directions. In addition, we showed that the permeability of the plasma membrane was dramatically elevated in the lem3Δ sfk1Δ double mutant in comparison with the corresponding single mutants. Interestingly, total ergosterol was decreased in the lem3Δ sfk1Δ mutant. Our results suggest that phospholipid asymmetry is required for the maintenance of low plasma membrane permeability.
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Affiliation(s)
- Tetsuo Mioka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Konomi Fujimura-Kamada
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Nahiro Mizugaki
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Takamitsu Sano
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - Hitoshi Nunome
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
| | - David E Williams
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Raymond J Andersen
- Departments of Chemistry and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Kazuma Tanaka
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Life Science, Kita-ku, Sapporo 060-0815, Japan
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Srivastava A, Sircaik S, Husain F, Thomas E, Ror S, Rastogi S, Alim D, Bapat P, Andes DR, Nobile CJ, Panwar SL. Distinct roles of the 7-transmembrane receptor protein Rta3 in regulating the asymmetric distribution of phosphatidylcholine across the plasma membrane and biofilm formation in Candida albicans. Cell Microbiol 2017; 19. [PMID: 28745020 DOI: 10.1111/cmi.12767] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/10/2017] [Accepted: 07/14/2017] [Indexed: 12/17/2022]
Abstract
Fungal pathogens such as Candida albicans exhibit several survival mechanisms to evade attack by antifungals and colonise host tissues. Rta3, a member of the Rta1-like family of lipid-translocating exporters has a 7-transmembrane domain topology, similar to the G-protein-coupled receptors and is unique to the fungal kingdom. Our findings point towards a role for the plasma membrane localised Rta3 in providing tolerance to miltefosine, an analogue of alkylphosphocholine, by maintaining mitochondrial energetics. Concurrent with miltefosine susceptibility, the rta3Δ/Δ strain displays increased inward translocation (flip) of fluorophore-labelled phosphatidylcholine (PC) across the plasma membrane attributed to enhanced PC-specific flippase activity. We also assign a novel role to Rta3 in the Bcr1-regulated pathway for in vivo biofilm development. Transcriptome analysis reveals that Rta3 regulates expression of Bcr1 target genes involved in cell surface properties, adhesion, and hyphal growth. We show that rta3Δ/Δ mutant is biofilm-defective in a rat venous catheter model of infection and that BCR1 overexpression rescues this defect, indicating that Bcr1 functions downstream of Rta3 to mediate biofilm formation in C. albicans. The identification of this novel Rta3-dependent regulatory network that governs biofilm formation and PC asymmetry across the plasma membrane will provide important insights into C. albicans pathogenesis.
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Affiliation(s)
- Archita Srivastava
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Shabnam Sircaik
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Farha Husain
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Edwina Thomas
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Shivani Ror
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sumit Rastogi
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Darakshan Alim
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Priyanka Bapat
- Department of Molecular and Cell Biology, University of California, Merced, California, USA.,Quantitative and System Biology Graduate Program, University of California, Merced, California, USA
| | - David R Andes
- Department of Medicine, Section of Infectious Diseases, University of Wisconsin, Madison, Wisconsin, USA
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, University of California, Merced, California, USA
| | - Sneh L Panwar
- Yeast Molecular Genetics Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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5
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Cell-sized asymmetric lipid vesicles facilitate the investigation of asymmetric membranes. Nat Chem 2016; 8:881-9. [DOI: 10.1038/nchem.2537] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/27/2016] [Indexed: 11/09/2022]
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Baldridge RD, Xu P, Graham TR. Type IV P-type ATPases distinguish mono- versus diacyl phosphatidylserine using a cytofacial exit gate in the membrane domain. J Biol Chem 2013; 288:19516-27. [PMID: 23709217 PMCID: PMC3707653 DOI: 10.1074/jbc.m113.476911] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/09/2013] [Indexed: 12/22/2022] Open
Abstract
Type IV P-type ATPases (P4-ATPases) use the energy from ATP to "flip" phospholipid across a lipid bilayer, facilitating membrane trafficking events and maintaining the characteristic plasma membrane phospholipid asymmetry. Preferred translocation substrates for the budding yeast P4-ATPases Dnf1 and Dnf2 include lysophosphatidylcholine, lysophosphatidylethanolamine, derivatives of phosphatidylcholine and phosphatidylethanolamine containing a 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD) group on the sn-2 C6 position, and were presumed to include phosphatidylcholine and phosphatidylethanolamine species with two intact acyl chains. We previously identified several mutations in Dnf1 transmembrane (TM) segments 1 through 4 that greatly enhance recognition and transport of NBD phosphatidylserine (NBD-PS). Here we show that most of these Dnf1 mutants cannot flip diacylated PS to the cytosolic leaflet to establish PS asymmetry. However, mutation of a highly conserved asparagine (Asn-550) in TM3 allowed Dnf1 to restore plasma membrane PS asymmetry in a strain deficient for the P4-ATPase Drs2, the primary PS flippase. Moreover, Dnf1 N550 mutants could replace the Drs2 requirement for growth at low temperature. A screen for additional Dnf1 mutants capable of replacing Drs2 function identified substitutions of TM1 and 2 residues, within a region called the exit gate, that permit recognition of dually acylated PS. These TM1, 2, and 3 residues coordinate with the "proline + 4" residue within TM4 to determine substrate preference at the exit gate. Moreover, residues from Atp8a1, a mammalian ortholog of Drs2, in these positions allow PS recognition by Dnf1. These studies indicate that Dnf1 poorly recognizes diacylated phospholipid and define key substitutions enabling recognition of endogenous PS.
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Affiliation(s)
- Ryan D. Baldridge
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Peng Xu
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Todd R. Graham
- From the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
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7
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Obara K, Yamamoto H, Kihara A. Membrane protein Rim21 plays a central role in sensing ambient pH in Saccharomyces cerevisiae. J Biol Chem 2012; 287:38473-81. [PMID: 23019326 DOI: 10.1074/jbc.m112.394205] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
External alkalization activates the Rim101 pathway in Saccharomyces cerevisiae. In this pathway, three integral membrane proteins, Rim21, Dfg16, and Rim9, are considered to be the components of the pH sensor machinery. However, how these proteins are involved in pH sensing is totally unknown. In this work, we investigated the localization, physical interaction, and interrelationship of Rim21, Dfg16, and Rim9. These proteins were found to form a complex and to localize to the plasma membrane in a patchy and mutually dependent manner. Their cellular level was also mutually dependent. In particular, the Rim21 level was significantly decreased in dfg16Δ and rim9Δ cells. Upon external alkalization, the proteins were internalized and degraded. We also demonstrate that the transient degradation of Rim21 completely suppressed the Rim101 pathway but that the degradation of Dfg16 or Rim9 did not. This finding strongly suggests that Rim21 is the pH sensor protein and that Dfg16 and Rim9 play auxiliary functions through maintaining the level of Rim21 and assisting in its plasma membrane localization. Even without external alkalization, the Rim101 pathway was activated in a Rim21-dependent manner by either protonophore treatment or depletion of phosphatidylserine in the inner leaflet of the plasma membrane, both of which caused plasma membrane depolarization like the external alkalization. Therefore, plasma membrane depolarization seems to be one of the key signals for the pH sensor molecule Rim21.
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Affiliation(s)
- Keisuke Obara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 062-0812, Japan
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8
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Identification of residues defining phospholipid flippase substrate specificity of type IV P-type ATPases. Proc Natl Acad Sci U S A 2012; 109:E290-8. [PMID: 22308393 DOI: 10.1073/pnas.1115725109] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Type IV P-type ATPases (P4-ATPases) catalyze translocation of phospholipid across a membrane to establish an asymmetric bilayer structure with phosphatidylserine (PS) and phosphatidylethanolamine (PE) restricted to the cytosolic leaflet. The mechanism for how P4-ATPases recognize and flip phospholipid is unknown, and is described as the "giant substrate problem" because the canonical substrate binding pockets of homologous cation pumps are too small to accommodate a bulky phospholipid. Here, we identify residues that confer differences in substrate specificity between Drs2 and Dnf1, Saccharomyces cerevisiae P4-ATPases that preferentially flip PS and phosphatidylcholine (PC), respectively. Transplanting transmembrane segments 3 and 4 (TM3-4) of Drs2 into Dnf1 alters the substrate preference of Dnf1 from PC to PS. Acquisition of the PS substrate maps to a Tyr618Phe substitution in TM4 of Dnf1, representing the loss of a single hydroxyl group. The reciprocal Phe511Tyr substitution in Drs2 specifically abrogates PS recognition by this flippase causing PS exposure on the outer leaflet of the plasma membrane without disrupting PE asymmetry. TM3 and the adjoining lumenal loop contribute residues important for Dnf1 PC preference, including Phe587. Modeling of residues involved in substrate selection suggests a novel P-type ATPase transport pathway at the protein/lipid interface and a potential solution to the giant substrate problem.
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Gulshan K, Moye-Rowley WS. Vacuolar import of phosphatidylcholine requires the ATP-binding cassette transporter Ybt1. Traffic 2011; 12:1257-68. [PMID: 21649806 DOI: 10.1111/j.1600-0854.2011.01228.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
ATP-binding cassette (ABC) transporters are well known for their roles as multidrug resistance determinants but also play important roles in regulation of lipid levels. In the yeast Saccharomyces cerevisiae, the plasma membrane ABC transporter proteins Pdr5 and Yor1 are required for normal rates of transport of phosphatidyethanolamine to the surface of the cell. Loss of these ABC transporters causes a defect in phospholipid asymmetry across the plasma membrane and has been linked with slowed rates of trafficking of other membrane proteins. Four ABC transporter proteins are found on the limiting membrane of the yeast vacuole and loss of one of these vacuolar ABC transporters, Ybt1, caused a major defect in the normal delivery of the phosphatidylcholine (PC) analog NBD-PC (7-nitro-2,1,3-benzoxadiazol-PC) to the lumen of the vacuole. NBD-PC accumulates on cytosolic membranes in an ybt1Δ strain. We demonstrated that Ybt1 is required to import NBD-PC into vacuoles in the presence of ATP in vitro. Loss of Ybt1 prevented vacuolar remodeling of PC analogs. Turnover of Ybt1 was reduced under conditions in which function of this vacuolar remodeling pathway was required. Our data describe a novel vacuolar route for lipid remodeling and reutilization in addition to previously described enzymatic avenues in the cytoplasm.
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Affiliation(s)
- Kailash Gulshan
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, 6-530 Bowen Science Building, University of Iowa, Iowa City, IA 52246, USA
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10
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Stevens HC, Malone L, Nichols JW. The putative aminophospholipid translocases, DNF1 and DNF2, are not required for 7-nitrobenz-2-oxa-1,3-diazol-4-yl-phosphatidylserine flip across the plasma membrane of Saccharomyces cerevisiae. J Biol Chem 2008; 283:35060-9. [PMID: 18931395 DOI: 10.1074/jbc.m802379200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The regulation of phosphatidylserine (PS) distribution across the plasma membrane of eukaryotic cells has been implicated in numerous cell functions (e.g. apoptosis and coagulation). In a recent study, fluorescent phospholipids labeled in the acyl chain with 7-nitrobenz-2-oxa-1, 3-diazol-4-yl (NBD) were used to identify two members of the P4 subfamily of P-type ATPases, Dnf1p and Dnf2p, that are necessary for the inward-directed transport of phospholipids across the plasma membrane (flip) of yeast ( Pomorski, T., Lombardi, R., Riezman, H., Devaux, P. F., Van Meer, G., and Holthuis, J. C. (2003) Mol. Biol. Cell 14, 1240-1254 ). Herein, we present evidence that the flip of NBD-labeled PS (NBD-PS) across the plasma membrane does not require the expression of Dnf1p or Dnf2p. In strains in which DNF1 and DNF2 are both deleted, the flip of NBD-PS is increased approximately 2-fold over that of the isogenic parent strain, whereas the flip of NBD-labeled phosphatidylcholine and NBD-labeled phosphatidylethanolamine are reduced to approximately 20 and approximately 50%, respectively. The mechanism responsible for NBD-PS flip is similar to that for NBD-labeled phosphatidylcholine and NBD-labeled phosphatidylethanolamine in its dependence on cellular ATP and the plasma membrane proton electrochemical gradient, as well as its regulation by the transcription factors Pdr1p and Pdr3p. Based on the observation that deletion or inactivation of all four members of the DRS2/DNF essential subfamily of P-type ATPases does not affect NBD-PS flip, we conclude that the activity reflected by NBD-PS internalization is not the essential function of the DRS2/DNF subfamily of P-type ATPases.
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Affiliation(s)
- Haley C Stevens
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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11
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Nakano K, Yamamoto T, Kishimoto T, Noji T, Tanaka K. Protein kinases Fpk1p and Fpk2p are novel regulators of phospholipid asymmetry. Mol Biol Cell 2008; 19:1783-97. [PMID: 18199685 PMCID: PMC2291408 DOI: 10.1091/mbc.e07-07-0646] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 12/20/2007] [Accepted: 01/08/2008] [Indexed: 11/11/2022] Open
Abstract
Type 4 P-type ATPases (flippases) are implicated in the generation of phospholipid asymmetry in membranes by the inward translocation of phospholipids. In budding yeast, the DRS2/DNF family members Lem3p-Dnf1p/Dnf2p and Cdc50p-Drs2p are putative flippases that are localized, respectively, to the plasma membrane and endosomal/trans-Golgi network (TGN) compartments. Herein, we identified a protein kinase gene, FPK1, as a mutation that exhibited synthetic lethality with the cdc50Delta mutation. The kinase domain of Fpk1p exhibits high homology to plant phototropins and the fungus Neurospora crassa NRC-2, both of which have membrane-associated functions. Simultaneous disruption of FPK1 and its homolog FPK2 phenocopied the lem3Delta/dnf1Delta dnf2Delta mutants, exhibiting the impaired NBD-labeled phospholipid uptake, defects in the early endosome-to-TGN pathway in the absence of CDC50, and hyperpolarized bud growth after exposure of phosphatidylethanolamine at the bud tip. The fpk1Delta fpk2Delta mutation did not affect the subcellular localization of Lem3p-Dnf1p or Lem3p-Dnf2p. Further, the purified glutathione S-transferase (GST)-fused kinase domain of Fpk1p phosphorylated immunoprecipitated Dnf1p and Dnf2p to a greater extent than Drs2p. We propose that Fpk1p/Fpk2p are upstream activating protein kinases for Lem3p-Dnf1p/Dnf2p.
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Affiliation(s)
- Kenzi Nakano
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate Schools of *Medicine and
| | | | - Takuma Kishimoto
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate Schools of *Medicine and
| | - Takehiro Noji
- Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate Schools of *Medicine and
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12
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Znaidi S, De Deken X, Weber S, Rigby T, Nantel A, Raymond M. The zinc cluster transcription factor Tac1p regulates
PDR16
expression in
Candida albicans. Mol Microbiol 2007; 66:440-52. [PMID: 17897373 DOI: 10.1111/j.1365-2958.2007.05931.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Candida albicans PDR16 gene, encoding a putative phosphatidylinositol transfer protein, is co-induced with the multidrug transporter genes CDR1 and CDR2 in azole-resistant (A(R)) clinical isolates and upon fluphenazine exposure of azole-susceptible (A(S)) cells, suggesting that it is regulated by Tac1p, the transcriptional activator of CDR genes. Deleting TAC1 in an A(R) isolate (5674) overexpressing PDR16, CDR1 and CDR2 decreased the expression of the three genes and fluconazole resistance to levels similar to those detected in the matched A(S) isolate (5457), demonstrating that Tac1p is responsible for PDR16 upregulation in that strain. Deleting TAC1 in the A(S) strain SC5314 abolished CDR2 induction by fluphenazine and decreased that of PDR16 and CDR1, uncovering the participation of an additional factor in the regulation of PDR16 and CDR1 expression. Sequencing of the TAC1 alleles identified one homozygous mutation in strain 5674, an Asn to Asp substitution at position 972 in the C-terminus of Tac1p. Introduction of the Asp(972) allele in a tac1Delta/Delta mutant caused high levels of fluconazole resistance and TAC1, PDR16, CDR1 and CDR2 constitutive induction. These results demonstrate that: (i) Tac1p controls PDR16 expression; (ii) Asn(972) to Asp(972) is a gain-of-function mutation; and (iii) Tac1p is positively autoregulated, directly or indirectly.
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Affiliation(s)
- Sadri Znaidi
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada H3C 3J7
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13
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Stevens HC, Nichols JW. The proton electrochemical gradient across the plasma membrane of yeast is necessary for phospholipid flip. J Biol Chem 2007; 282:17563-7. [PMID: 17452326 DOI: 10.1074/jbc.m700454200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recently, two members of the P4 family of P-type ATPases, Dnf1p and Dnf2p, were shown to be necessary for the internalization (flip) of fluorescent, 7-nitrobenz-2-oxa-1,3-diazol-4-yl(NBD)-labeled phospholipids across the plasma membrane of Saccharomyces cerevisiae. In the current study, we have demonstrated that ATP hydrolysis is not sufficient for phospholipid flip in the absence of the proton electrochemical gradient across the plasma membrane. This requirement was demonstrated by two independent means. First, collapse of the plasma membrane proton electrochemical gradient by the protonophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP) almost completely blocked NBD-phospholipid flip while only moderately reducing the cytosolic ATP concentration. Second, strains with point mutations in PMA1, which encodes the plasma membrane proton pump that generates the proton electrochemical gradient, are defective in NBD-PC flip, whereas their cytosolic ATP content is actually increased. These results establish that the proton electrochemical gradient is required for NBD-phospholipid flip across the plasma membrane of yeast and raise the question whether it contributes an additional required driving force or whether it functions as a regulatory signal.
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Affiliation(s)
- Haley C Stevens
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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14
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Berger AC, Vanderford TH, Gernert KM, Nichols JW, Faundez V, Corbett AH. Saccharomyces cerevisiae Npc2p is a functionally conserved homologue of the human Niemann-Pick disease type C 2 protein, hNPC2. EUKARYOTIC CELL 2006; 4:1851-62. [PMID: 16278452 PMCID: PMC1287848 DOI: 10.1128/ec.4.11.1851-1862.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Niemann-Pick Disease Type C (NP-C) is a fatal neurodegenerative disease, which is biochemically distinguished by the lysosomal accumulation of exogenously derived cholesterol. Mutation of either the hNPC1 or hNPC2 gene is causative for NP-C. We report the identification of the yeast homologue of human NPC2, Saccharomyces cerevisiae Npc2p. We demonstrate that scNpc2p is evolutionarily related to the mammalian NPC2 family of proteins. We also show, through colocalization, subcellular fractionation, and secretion analyses, that yeast Npc2p is treated similarly to human NPC2 when expressed in mammalian cells. Importantly, we show that yeast Npc2p can efficiently revert the unesterified cholesterol and GM1 accumulation seen in hNPC2-/- patient fibroblasts demonstrating that it is a functional homologue of human NPC2. The present study reveals that the fundamental process of NPC2-mediated lipid transport has been maintained throughout evolution.
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Affiliation(s)
- Adam C Berger
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Rd., NE, Atlanta, GA 30322, USA
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15
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Elvington SM, Bu F, Nichols JW. Fluorescent, acyl chain-labeled phosphatidylcholine analogs reveal novel transport pathways across the plasma membrane of yeast. J Biol Chem 2005; 280:40957-64. [PMID: 16204231 DOI: 10.1074/jbc.m507926200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acyl chain-labeled NBD-phosphatidylcholine (NBD-PC) has been used to identify three gene products (Lem3p, Dnf1p, and Dnf2p) that are required for normal levels of inward-directed phospholipid transport (flip) across the plasma membrane of yeast. Although the head group structure of acyl chain-labeled NBD phospholipids has been shown to influence the mechanism of flip across the plasma membrane, the extent to which the acyl chain region and the associated fluorophore affect flip has not been assessed. Given the identification of these proteins required for NBD-PC flip, it is now possible to determine whether the fluorophore attached to a phospholipid acyl chain influences the mechanism of flip. Thus, flip of phosphatidylcholine molecules with three different Bodipy fluorophores (Bodipy FL, Bodipy 530, and Bodipy 581) was tested and compared with that of NBD-PC in strains carrying deletions in LEM3, DNF1, and DNF2. Deletion of these genes significantly reduced the flip of NBD-PC and Bodipy FL-PC but had no effect on that of Bodipy 581-PC and Bodipy 530-PC. These data, in combination with comparisons of the effect of ATP depletion, collapse of the proton electrochemical gradient across the plasma membrane, and culture density led to the conclusion that at least three different flip pathways exist in yeast that are selective for the structure of the fluorophore attached to the acyl chain of phosphatidylcholine molecules.
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Affiliation(s)
- Shelley M Elvington
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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16
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Berger AC, Hanson PK, Wylie Nichols J, Corbett AH. A Yeast Model System for Functional Analysis of the Niemann-Pick Type C Protein 1 Homolog, Ncr1p. Traffic 2005; 6:907-17. [PMID: 16138904 DOI: 10.1111/j.1600-0854.2005.00327.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Niemann-Pick disease type C (NP-C) is a progressive, ultimately fatal, autosomal recessive neurodegenerative disorder. The major biochemical hallmark of the disease is the endocytic accumulation of low-density lipoprotein-derived cholesterol. The majority of NP-C patients have mutations in the Niemann-Pick type C1 gene, NPC1. This study focuses on the Saccharomyces cerevisiae homolog of the human NPC1 protein encoded by the NCR1 gene. Ncr1p localizes to the vacuole, the yeast equivalent to the mammalian endosome-lysosome system. Here, we identify the first phenotype caused by deletion of NCR1 from the yeast genome, resistance to the ether lipid drug, edelfosine. Our results indicate that edelfosine has a cytotoxic, rather than cytostatic, effect on wildtype yeast cells. We exploit the edelfosine resistance phenotype to assess the function of yeast Ncr1 proteins carrying amino acid changes corresponding to human NPC1 patient mutations. We find that one of these amino acid changes severely compromises Ncr1p function as assessed using the edelfosine resistance assay. These findings establish S. cerevisiae as a model system that can be exploited to analyze the molecular consequences of patient mutations in NPC1 and provide the basis for future genetic studies using yeast.
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Affiliation(s)
- Adam C Berger
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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17
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Ernst R, Klemm R, Schmitt L, Kuchler K. Yeast ATP-binding cassette transporters: cellular cleaning pumps. Methods Enzymol 2005; 400:460-84. [PMID: 16399365 DOI: 10.1016/s0076-6879(05)00026-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Numerous ATP-binding cassette (ABC) proteins have been implicated in multidrug resistance, and some are also intimately connected to genetic diseases. For example, mammalian ABC proteins such as P-glycoproteins or multidrug resistance-associated proteins are associated with multidrug resistance phenomena (MDR), thus hampering anticancer therapy. Likewise, homologues in bacteria, fungi, or parasites are tightly associated with multidrug and antibiotic resistance. Several orthologues of mammalian MDR genes operate in the unicellular eukaryote Saccharomyces cerevisiae. Their functions have been linked to stress response, cellular detoxification, and drug resistance. This chapter discusses those yeast ABC transporters implicated in pleiotropic drug resistance and cellular detoxification. We describe strategies for their overexpression, biochemical purification, functional analysis, and a reconstitution in phospholipid vesicles, all of which are instrumental to better understanding their mechanisms of action and perhaps their physiological function.
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Affiliation(s)
- Robert Ernst
- Institute of Biochemistry, Membrane Transport Group, Heinrich-Heine University of Düsseldorf, Germany
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18
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Abstract
The best-understood mechanisms for generating transport vesicles in the secretory and endocytic pathways involve the localized assembly of cytosolic coat proteins such as clathrin, coat protein complex (COP)I and COPII onto membranes. These coat proteins can deform membranes by themselves, but accessory proteins might help to generate the tight curvature needed to form a vesicle. Enzymes that pump phospholipid from one leaflet of the bilayer to the other (flippases) can deform membranes by creating an imbalance in the phospholipid number between the two leaflets. Recent studies describe a requirement for the yeast Drs2p family of P-type ATPases in both phospholipid translocation and protein transport in the secretory and endocytic pathways. This indicates that flippases work with coat proteins to form vesicles.
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Affiliation(s)
- Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634, USA.
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19
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Kihara A, Igarashi Y. Cross talk between sphingolipids and glycerophospholipids in the establishment of plasma membrane asymmetry. Mol Biol Cell 2004; 15:4949-59. [PMID: 15342785 PMCID: PMC524749 DOI: 10.1091/mbc.e04-06-0458] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glycerophospholipids and sphingolipids are distributed asymmetrically between the two leaflets of the lipid bilayer. Recent studies revealed that certain P-type ATPases and ATP-binding cassette (ABC) transporters are involved in the inward movement (flip) and outward movement (flop) of glycerophospholipids, respectively. In this study of phytosphingosine (PHS)-resistant yeast mutants, we isolated mutants for PDR5, an ABC transporter involved in drug efflux as well as in the flop of phosphatidylethanolamine. The pdr5 mutants exhibited an increase in the efflux of sphingoid long-chain bases (LCBs). Genetic analysis revealed that the PHS-resistant phenotypes exhibited by the pdr5 mutants were dependent on Rsb1p, a putative LCB-specific transporter/translocase. We found that the expression of Rsb1p was increased in the pdr5 mutants. We also demonstrated that expression of RSB1 is under the control of the transcriptional factor Pdr1p. Expression of Rsb1p also was enhanced in mutants for the genes involved in the flip of glycerophospholipids, including ROS3, DNF1, and DNF2. These results suggest that altered glycerophospholipid asymmetry induces the expression of Rsb1p. Conversely, overexpression of Rsb1p resulted in increased flip and decreased flop of fluorescence-labeled glycerophospholipids. Thus, there seems to be cross talk between sphingolipids and glycerophospholipids in maintaining the functional lipid asymmetry of the plasma membrane.
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Affiliation(s)
- Akio Kihara
- Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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20
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Abstract
Inter- and intramembrane phospholipid transport processes are central features of membrane biogenesis and homeostasis. Relatively recent successes in the molecular genetic analysis of aminoglycerophospholipid transport processes in both yeast and mammalian cells are now providing important new information defining specific protein and lipid components that participate in these reactions. Studies focused on phosphatidylserine (PtdSer) transport to the mitochondria reveal that the process is regulated by ubiquitination. In addition, a specific mutation disrupts PtdSer transport between mitochondrial membranes. Analysis of PtdSer transport from the endoplasmic reticulum to the locus of PtdSer decarboxylase 2 demonstrates the requirement for a phosphatidylinositol-4-kinase, a phosphatidylinositol-binding protein, and the C2 domain of the decarboxylase. Examination of NBD-phosphatidylcholine transport demonstrates the involvement of the prevacuolar compartment and a requirement for multiple genes involved in regulating vacuolar protein sorting for transport of the lipid to the vacuole. In intramembrane transport, multiple genes are now identified including those encoding multidrug resistant protein family members, DNF family members, ATP binding cassette transporters, and pleiotropic drug resistance family members. The scramblase family constitutes a collection of putative transmembrane transporters that function in an ATP-independent manner. The genetic analysis of lipid traffic is uncovering new molecules involved in all aspects of the regulation and execution of the transport steps and also providing essential tools to critically test the involvement of numerous candidate molecules.Key words: lipid transport, lipid sorting, membrane biogenesis, organelles, flippase.
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Affiliation(s)
- Dennis R Voelker
- Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA.
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21
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Wolfger H, Mamnun YM, Kuchler K. The yeast Pdr15p ATP-binding cassette (ABC) protein is a general stress response factor implicated in cellular detoxification. J Biol Chem 2003; 279:11593-9. [PMID: 14699125 DOI: 10.1074/jbc.m311282200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-binding cassette (ABC) transporters play important roles in drug efflux, but some may also function in cellular detoxification. The Pdr15p ABC protein is the closest homologue of the multidrug efflux transporter Pdr5p, which mediates pleiotropic drug resistance to hundreds of unrelated compounds. In this study, we show that the plasma membrane protein Pdr15p displays limited drug transport capacity, mediating chloramphenicol and detergent tolerance. Interestingly, Pdr15p becomes most abundant when cells exit the exponential growth phase, whereas its closest homologue, Pdr5p, disappears after exponential growth. Furthermore, in contrast to Pdr5p, Pdr15p is strongly induced by various stress conditions including heat shock, low pH, weak acids, or high osmolarity. PDR15 induction bypasses the Pdr1p/Pdr3p regulators but requires the general stress regulator Msn2p, which directly decorates the stress response elements in the PDR15 promoter. Remarkably, however, Pdr15p induction bypasses upstream components of the high osmolarity glycerol (HOG) pathway including the Hog1p and Pbs2p kinases as well as the dedicated HOG cell surface sensors. Our data provide evidence for a novel upstream branch of the general stress response pathway activating Msn2p. In addition, the results demonstrate a cross-talk between stress response and the pleiotropic drug resistance network.
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Affiliation(s)
- Hubert Wolfger
- Department of Medical Biochemistry, Division of Molecular Genetics, Max F. Perutz Laboratories, Medical University and Biocenter of Vienna, A-1030 Vienna, Austria
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22
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Birner R, Daum G. Biogenesis and cellular dynamics of aminoglycerophospholipids. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 225:273-323. [PMID: 12696595 DOI: 10.1016/s0074-7696(05)25007-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aminoglycerophospholipids phosphatidylserine (PtdSer), phosphatidylethanolamine (PtdEtn), and phosphatidylcholine (PtdCho) comprise about 80% of total cellular phospholipids in most cell types. While the major function of PtdCho in eukaryotes and PtdEtn in prokaryotes is that of bulk membrane lipids, PtdSer is a minor component and appears to play a more specialized role in the plasma membrane of eukaryotes, e.g., in cell recognition processes. All three aminoglycerophospholipid classes are essential in mammals, whereas prokaryotes and lower eukaryotes such as yeast appear to be more flexible regarding their aminoglycerophospholipid requirement. Since different subcellular compartments of eukaryotes, namely the endoplasmic reticulum and mitochondria, contribute to the biosynthetic sequence of aminoglycerophospholipid formation, intracellular transport, sorting, and specific function of these lipids in different organelles are of special interest.
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Affiliation(s)
- Ruth Birner
- Institut für Biochemie, Technische Universität Graz, Petersgasse 12/2, A-8010 Graz, Austria
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23
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Hanson PK, Malone L, Birchmore JL, Nichols JW. Lem3p is essential for the uptake and potency of alkylphosphocholine drugs, edelfosine and miltefosine. J Biol Chem 2003; 278:36041-50. [PMID: 12842877 DOI: 10.1074/jbc.m305263200] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alkylphosphocholine class of drugs, including edelfosine and miltefosine, has recently shown promise in the treatment of protozoal and fungal diseases, most notably, leishmaniasis. One of the major barriers to successful treatment of these infections is the development of drug resistance. To understand better the mechanisms underlying the development of drug resistance, we performed a combined mutant selection and screen in Saccharomyces cerevisiae, designed to identify genes that confer resistance to the alkylphosphocholine drugs by inhibiting their transport across the plasma membrane. Mutagenized cells were first selected for resistance to edelfosine, and the initial collection of mutants was screened a second time for defects in internalization of a short chain, fluorescent (7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD))-labeled phosphatidylcholine reporter. This approach identified mutations in a single gene, YNL323W/LEM3, that conferred resistance to alkylphosphocholine drugs and inhibited internalization of NBD-labeled phosphatidylcholine. Loss of YNL323W/LEM3 does not confer resistance to N-nitroquinilone N-oxide or ketoconazole and actually increases sensitivity to cycloheximide. The defect in internalization is specific to NBD-labeled phosphatidylcholine and phosphatidylethanolamine. Labeled phosphatidylserine is internalized at normal levels in lem3 strains. LEM3 is a member of an evolutionarily conserved family and has two homologues in S. cerevisiae. Single point mutations that produce resistance to alkylphosphocholine drugs and inhibition of NBD-labeled phosphatidylcholine internalization were identified in several highly conserved domains. These data demonstrate a requirement for Lem3p expression for normal phosphatidylcholine and alkylphosphocholine drug transport across the plasma membrane of yeast.
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Affiliation(s)
- Pamela K Hanson
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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24
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Pomorski T, Lombardi R, Riezman H, Devaux PF, van Meer G, Holthuis JCM. Drs2p-related P-type ATPases Dnf1p and Dnf2p are required for phospholipid translocation across the yeast plasma membrane and serve a role in endocytosis. Mol Biol Cell 2003; 14:1240-54. [PMID: 12631737 PMCID: PMC151593 DOI: 10.1091/mbc.e02-08-0501] [Citation(s) in RCA: 285] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Plasma membranes in eukaryotic cells display asymmetric lipid distributions with aminophospholipids concentrated in the inner and sphingolipids in the outer leaflet. This asymmetry is maintained by ATP-driven lipid transporters whose identities are unknown. The yeast plasma membrane contains two P-type ATPases, Dnf1p and Dnf2p, with structural similarity to ATPase II, a candidate aminophospholipid translocase from bovine chromaffin granules. Loss of Dnf1p and Dnf2p virtually abolished ATP-dependent transport of NBD-labeled phosphatidylethanolamine, phosphatidylserine, and phosphatidylcholine from the outer to the inner plasma membrane leaflet, leaving transport of sphingolipid analogs unaffected. Labeling with trinitrobenzene sulfonic acid revealed that the amount of phosphatidylethanolamine exposed on the surface of Deltadnf1Deltadnf2 cells increased twofold relative to wild-type cells. Phosphatidylethanolamine exposure by Deltadnf1Deltadnf2 cells further increased upon removal of Drs2p, an ATPase II homolog in the yeast Golgi. These changes in lipid topology were accompanied by a cold-sensitive defect in the uptake of markers for bulk-phase and receptor-mediated endocytosis. Our findings demonstrate a requirement for Dnf1p and Dnf2p in lipid translocation across the yeast plasma membrane. Moreover, it appears that Dnf1p, Dnf2p and Drs2p each help regulate the transbilayer lipid arrangement in the plasma membrane, and that this regulation is critical for budding endocytic vesicles.
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Affiliation(s)
- Thomas Pomorski
- Department of Membrane Enzymology, Center for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands
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25
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Abstract
In view of the increasing threat posed by fungal infections in immunocompromised patients and due to the non-availability of effective treatments, it has become imperative to find novel antifungals and vigorously search for new drug targets. Fungal pathogens acquire resistance to drugs (antifungals), a well-established phenomenon termed multidrug resistance (MDR), which hampers effective treatment strategies. The MDR phenomenon is spread throughout the evolutionary scale. Accordingly, a host of responsible genes have been identified in the genetically tractable budding yeast Saccharomyces cerevisiae, as well as in a pathogenic yeast Candida albicans. Studies so far suggest that, while antifungal resistance is the culmination of multiple factors, there may be a unifying mechanism of drug resistance in these pathogens. ABC (ATP binding cassette) and MFS (major facilitator superfamily) drug transporters belonging to two different superfamilies, are the most prominent contributors to MDR in yeasts. Considering the abundance of the drug transporters and their wider specificity, it is believed that these drug transporters may not exclusively export drugs in fungi. It has become apparent that the drug transporters of the ABC superfamily of S. cerevisiae and C. albicans are multifunctional proteins, which mediate important physiological functions. This review summarizes current research on the molecular mechanisms underlying drug resistance, the emerging regulatory circuits of MDR genes, and the physiological relevance of drug transporters.
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Affiliation(s)
- Rajendra Prasad
- Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi-110067, India
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26
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Kato U, Emoto K, Fredriksson C, Nakamura H, Ohta A, Kobayashi T, Murakami-Murofushi K, Kobayashi T, Umeda M. A novel membrane protein, Ros3p, is required for phospholipid translocation across the plasma membrane in Saccharomyces cerevisiae. J Biol Chem 2002; 277:37855-62. [PMID: 12133835 DOI: 10.1074/jbc.m205564200] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ro09-0198 (Ro) is a tetracyclic peptide antibiotic that binds specifically to phosphatidylethanolamine (PE) and causes cytolysis. To investigate the molecular basis of transbilayer movement of PE in biological membranes, we have isolated a series of budding yeast mutants that are hypersensitive to the Ro peptide. One of the most sensitive mutants, designated ros3 (Ro-sensitive 3), showed no significant change in the cellular phospholipid composition or in the sensitivity to amphotericin B, a sterol-binding polyene macrolide antibiotic. These results suggest that the mutation of ros3 affects the PE organization on the plasma membrane, rather than PE synthesis or overall organization of the membrane structures. By functional complementation screening, we identified the gene ROS3 affected in the mutant, and we showed that the hypersensitive phenotype was caused by the defective expression of the ROS3 gene product, Ros3p, an evolutionarily conserved protein with two putative transmembrane domains. Disruption of the ROS3 gene resulted in a marked decrease in the internalization of fluorescence-labeled analogs of PE and phosphatidylcholine, whereas the uptake of fluorescence-labeled phosphatidylserine and endocytic markers was not affected. Neither expression levels nor activities of ATP-binding cassette transporters of the ros3Delta cells differed from those of wild type cells, suggesting that Ros3p is not related to the multidrug resistance activities. Immunochemical analyses of the structure and subcellular localization showed that Ros3p was a glycosylated membrane protein localized in both the plasma membrane and the endoplasmic reticulum, and that a part of Ros3p was associated with the detergent-insoluble glycolipid-enriched complexes. These results indicate that Ros3p is a membrane glycoprotein that plays an important role in the phospholipid translocation across the plasma membrane.
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Affiliation(s)
- Utako Kato
- Department of Molecular Biodynamics, the Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo, Japan
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27
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Pohl A, Lage H, Müller P, Pomorski T, Herrmann A. Transport of phosphatidylserine via MDR1 (multidrug resistance 1)P-glycoprotein in a human gastric carcinoma cell line. Biochem J 2002; 365:259-68. [PMID: 12071854 PMCID: PMC1222671 DOI: 10.1042/bj20011880] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The ATP-binding cassette transporter multidrug resistance 1 P-glycoprotein (MDR1 Pgp) has been implicated with the transport of lipids from the inner to the outer leaflet of the plasma membrane. While this has been unambigously shown for the fluorescent lipid analogues [N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]hexanoyl (C6-NBD)-phosphatidylcholine, -phosphatidylethanolamine, -sphingomyelin and -glucosylceramide, by using a novel approach we have now found significantly increased outward transport also for C6-NBD-phosphatidylserine (C6-NBD-PS) in EPG85-257 human gastric carcinoma cells overexpressing MDR1 (coding for MDR1 Pgp). The increased transport of C6-NBD-PS is mediated by MDR1 Pgp, shown by transport reduction nearly to the level of controls in the presence of MDR1 Pgp inhibitors [PSC 833, cyclosporin A and dexniguldipine hydrochloride (Dex)]. Addition of MK 571, a specific inhibitor of the MDR protein MRP1, does not decrease transport in either of the two cell lines. The plasma-membrane association of FITC-annexin V, a fluorescent protein conjugate binding PS, is significantly increased in MDR1-overexpressing cells as compared with controls, and can be reduced by an MDR1 Pgp inhibitor. This suggests that MDR1 Pgp transports endogenous PS, the lipid exhibiting the most pronounced transverse asymmetry in the plasma membrane.
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Affiliation(s)
- Antje Pohl
- Institute of Biology/Biophysics, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany
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28
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Hanson PK, Grant AM, Nichols JW. NBD-labeled phosphatidylcholine enters the yeast vacuole via the pre-vacuolar compartment. J Cell Sci 2002; 115:2725-33. [PMID: 12077363 DOI: 10.1242/jcs.115.13.2725] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At low temperature, the short-chain fluorescent-labeled phospholipids,1-myristoyl-2-[6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)aminocaproyl]-phosphatidylcholine (M-C6-NBD-PC) and its phosphatidylethanolamine analog, M-C6-NBD-PE, are internalized by flip across the plasma membrane of S. cerevisiae and show similar enrichment in intracellular membranes including the mitochondria and nuclear envelope/ER. At higher temperatures (24-37°C), or if low temperature internalization is followed by warming, M-C6-NBD-PC, but not M-C6-NBD-PE, is trafficked to the lumen of the vacuole. Sorting of M-C6-NBD-PC to the vacuole is blocked by energy-depletion and by null mutations in the VPS4 and VPS28 genes required for vesicular traffic from the pre-vacuolar compartment (PVC) to the vacuole. This sorting is not blocked by a temperature-sensitive mutation in SEC12,which inhibits ER to Golgi transport, a null mutation in VPS8, which inhibits Golgi to PVC transport, or temperature-sensitive and null mutations in END4, which inhibit endocytosis from the plasma membrane. Monomethylation or dimethylation of the primary amine head-group of M-C6-NBD-PE is sufficient for sorting to the yeast vacuole in both wild-type yeast and in strains defective in the phosphatidylethanolamine methylation pathway. These data indicate that methylation of M-C6-NBD-PE produces the crucial structural component required to sort these phospholipid analogues to the vacuole via the PVC.
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Affiliation(s)
- Pamela K Hanson
- Department of Physiology, 615 Michael St, 605G Whitehead Building, Emory University School of Medicine, Atlanta, GA 30322, USA
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29
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Abstract
Phospholipid reporter molecules, containing a fluorescent group attached to a short, acyl chain, spontaneously insert into the plasma membrane of yeast cells allowing retrograde trafficking to intracellular organelles as well as their metabolic fates to be monitored. This approach provides the framework for determining the dependence of particular phospholipid trafficking and metabolic steps on a wide range of genes known to be required for related membrane transport functions as well as for developing genetic screens to identify novel genes required for these processes. This review presents an overview of insights gained into phospholipid trafficking and metabolism using this approach.
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Affiliation(s)
- J Wylie Nichols
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Owsianik G, Balzi l L, Ghislain M. Control of 26S proteasome expression by transcription factors regulating multidrug resistance in Saccharomyces cerevisiae. Mol Microbiol 2002; 43:1295-308. [PMID: 11918814 DOI: 10.1046/j.1365-2958.2002.02823.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In eukaryotic cells, intracellular proteolysis occurs mainly via the ubiquitin-proteasome system. Expression of the yeast proteasome is under the control of the transcription factor, Rpn4p (also known as Son1p/Ufd5p). We show here that the RPN4 gene promoter contains regulatory sequences that bind Pdr1p and Pdr3p, two homologous zinc finger-containing transcription factors, which mediate multiple drug resistance through the expression of membrane transporter proteins. Mutations in the RPN4 Pdr1p/Pdr3p binding sites lead to decreased expression of the proteasome RPT6 gene and to defective ubiquitin-mediated proteolysis. Pdr3p, but not Pdr1p, is required for normal levels of intracellular proteolysis, indicating that the two transcription factors have distinct functions in the control of RPN4 expression. The RPN4 promoter contains an additional sequence that binds Yap1p, a bZIP-type transcription factor that plays an important role in the oxidative stress response and multidrug resistance. We also show that the Yap1p response element is important in the transactivation of RPN4 by Yap1p. In yeast cells lacking Pdr1p, ubiquitin-Pro-beta-galactosidase, a short-lived protein used to assay proteasome activity, is stabilized by the loss of Yap1p. These data demonstrate that the ubiquitin-proteasome system is controlled by transcriptional regulators of multidrug resistance via RPN4 expression.
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Affiliation(s)
- Grzegorz Owsianik
- Unité de Biochimie Physiologique, Université Catholique de Louvain, Croix du Sud 2-20, B-1348 Louvain-la-Neuve, Belgium
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Heun P, Laroche T, Shimada K, Furrer P, Gasser SM. Chromosome dynamics in the yeast interphase nucleus. Science 2001; 294:2181-6. [PMID: 11739961 DOI: 10.1126/science.1065366] [Citation(s) in RCA: 374] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Little is known about the dynamics of chromosomes in interphase nuclei. By tagging four chromosomal regions with a green fluorescent protein fusion to lac repressor, we monitored the movement and subnuclear position of specific sites in the yeast genome, sampling at short time intervals. We found that early and late origins of replication are highly mobile in G1 phase, frequently moving at or faster than 0.5 micrometers/10 seconds, in an energy-dependent fashion. The rapid diffusive movement of chromatin detected in G1 becomes constrained in S phase through a mechanism dependent on active DNA replication. In contrast, telomeres and centromeres provide replication-independent constraint on chromatin movement in both G1 and S phases.
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Affiliation(s)
- P Heun
- University of Geneva, Department of Molecular Biology, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland
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