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Brock K, Alpha KM, Brennan G, De Jong EP, Luke E, Turner CE. A comparative analysis of paxillin and Hic-5 proximity interactomes. Cytoskeleton (Hoboken) 2024. [PMID: 38801098 DOI: 10.1002/cm.21878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/18/2024] [Accepted: 05/06/2024] [Indexed: 05/29/2024]
Abstract
Focal adhesions serve as structural and signaling hubs, facilitating bidirectional communication at the cell-extracellular matrix interface. Paxillin and the related Hic-5 (TGFβ1i1) are adaptor/scaffold proteins that recruit numerous structural and regulatory proteins to focal adhesions, where they perform both overlapping and discrete functions. In this study, paxillin and Hic-5 were expressed in U2OS osteosarcoma cells as biotin ligase (BioID2) fusion proteins and used as bait proteins for proximity-dependent biotinylation in order to directly compare their respective interactomes. The fusion proteins localized to both focal adhesions and the centrosome, resulting in biotinylation of components of each of these structures. Biotinylated proteins were purified and analyzed by mass spectrometry. The list of proximity interactors for paxillin and Hic-5 comprised numerous shared core focal adhesion proteins that likely contribute to their similar functions in cell adhesion and migration, as well as proteins unique to paxillin and Hic-5 that have been previously localized to focal adhesions, the centrosome, or the nucleus. Western blotting confirmed biotinylation and enrichment of FAK and vinculin, known interactors of Hic-5 and paxillin, as well as several potentially unique proximity interactors of Hic-5 and paxillin, including septin 7 and ponsin, respectively. Further investigation into the functional relationship between the unique interactors and Hic-5 or paxillin may yield novel insights into their distinct roles in cell migration.
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Affiliation(s)
- Katia Brock
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kyle M Alpha
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Grant Brennan
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Ebbing P De Jong
- Proteomics Core Facility, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Elizabeth Luke
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Christopher E Turner
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
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2
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Watanabe H, Urano S, Kikuchi N, Kubo Y, Kikuchi A, Gomi K, Shintani T. Ykt6 functionally overlaps with vacuolar and exocytic R-SNAREs in the yeast Saccharomyces cerevisiae. J Biol Chem 2024; 300:107274. [PMID: 38588809 PMCID: PMC11091695 DOI: 10.1016/j.jbc.2024.107274] [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: 05/27/2023] [Revised: 03/17/2024] [Accepted: 03/31/2024] [Indexed: 04/10/2024] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex forms a 4-helix coiled-coil bundle consisting of 16 layers of interacting side chains upon membrane fusion. The central layer (layer 0) is highly conserved and comprises three glutamines (Q) and one arginine (R), and thus SNAREs are classified into Qa-, Qb-, Qc-, and R-SNAREs. Homotypic vacuolar fusion in Saccharomyces cerevisiae requires the SNAREs Vam3 (Qa), Vti1 (Qb), Vam7 (Qc), and Nyv1 (R). However, the yeast strain lacking NYV1 (nyv1Δ) shows no vacuole fragmentation, whereas the vam3Δ and vam7Δ strains display fragmented vacuoles. Here, we provide genetic evidence that the R-SNAREs Ykt6 and Nyv1 are functionally redundant in vacuole homotypic fusion in vivo using a newly isolated ykt6 mutant. We observed the ykt6-104 mutant showed no defect in vacuole morphology, but the ykt6-104 nyv1Δ double mutant had highly fragmented vacuoles. Furthermore, we show the defect in homotypic vacuole fusion caused by the vam7-Q284R mutation was compensated by the nyv1-R192Q or ykt6-R165Q mutations, which maintained the 3Q:1R ratio in the layer 0 of the SNARE complex, indicating that Nyv1 is exchangeable with Ykt6 in the vacuole SNARE complex. Unexpectedly, we found Ykt6 assembled with exocytic Q-SNAREs when the intrinsic exocytic R-SNAREs Snc1 and its paralog Snc2 lose their ability to assemble into the exocytic SNARE complex. These results suggest that Ykt6 may serve as a backup when other R-SNAREs become dysfunctional and that this flexible assembly of SNARE complexes may help cells maintain the robustness of the vesicular transport network.
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Affiliation(s)
- Hayate Watanabe
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Shingo Urano
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Nozomi Kikuchi
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Yurika Kubo
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Ayumi Kikuchi
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Katsuya Gomi
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Takahiro Shintani
- Department of Agricultural Chemistry, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
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3
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Herrmann E, Langemeyer L, Auffarth K, Ungermann C, Kümmel D. Targeting of the Mon1-Ccz1 Rab guanine nucleotide exchange factor to distinct organelles by a synergistic protein and lipid code. J Biol Chem 2023; 299:102915. [PMID: 36649906 PMCID: PMC10124900 DOI: 10.1016/j.jbc.2023.102915] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 01/01/2023] [Accepted: 01/05/2023] [Indexed: 01/16/2023] Open
Abstract
Activation of the small GTPase Rab7 by its cognate guanine nucleotide exchange factor Mon1-Ccz1 (MC1) is a key step in the maturation of endosomes and autophagosomes. This process is tightly regulated and subject to precise spatiotemporal control of MC1 localization, but the mechanisms that underly MC1 localization have not been fully elucidated. We here identify and characterize an amphipathic helix in Ccz1, which is required for the function of Mon-Ccz1 in autophagy, but not endosomal maturation. Furthermore, our data show that the interaction of the Ccz1 amphipathic helix with lipid packing defects, binding of Mon1 basic patches to positively charged lipids, and association of MC1 with recruiter proteins collectively govern membrane recruitment of the complex in a synergistic and redundant manner. Membrane binding enhances MC1 activity predominantly by increasing enzyme and substrate concentration on the membrane, but interaction with recruiter proteins can further stimulate the guanine nucleotide exchange factor. Our data demonstrate that specific protein and lipid cues convey the differential targeting of MC1 to endosomes and autophagosomes. In conclusion, we reveal the molecular basis for how MC1 is adapted to recognize distinct target compartments by exploiting the unique biophysical properties of organelle membranes and thus provide a model for how the complex is regulated and activated independently in different functional contexts.
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Affiliation(s)
- Eric Herrmann
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany; Center of Cellular Nanoanalytics (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, Münster, Germany.
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4
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Kruasuwan W, Puseenam A, Phithakrotchanakoon C, Tanapongpipat S, Roongsawang N. Modulation of heterologous protein secretion in the thermotolerant methylotrophic yeast Ogataea thermomethanolica TBRC 656 by CRISPR-Cas9 system. PLoS One 2021; 16:e0258005. [PMID: 34582499 PMCID: PMC8478189 DOI: 10.1371/journal.pone.0258005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/16/2021] [Indexed: 11/18/2022] Open
Abstract
The thermotolerant methylotrophic yeast Ogataea thermomethanolica TBRC 656 is a potential host strain for industrial protein production. Heterologous proteins are often retained intracellularly in yeast resulting in endoplasmic reticulum (ER) stress and poor secretion, and despite efforts to engineer protein secretory pathways, heterologous protein production is often lower than expected. We hypothesized that activation of genes involved in the secretory pathway could mitigate ER stress. In this study, we created mutants defective in protein secretory-related functions using clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) tools. Secretion of the model protein xylanase was significantly decreased in loss of function mutants for oxidative stress (sod1Δ) and vacuolar and protein sorting (vps1Δ and ypt7Δ) genes. However, xylanase secretion was unaffected in an autophagy related atg12Δ mutant. Then, we developed a system for sequence-specific activation of target gene expression (CRISPRa) in O. thermomethanolica and used it to activate SOD1, VPS1 and YPT7 genes. Production of both non-glycosylated xylanase and glycosylated phytase was enhanced in the gene activated mutants, demonstrating that CRISPR-Cas9 systems can be used as tools for understanding O. thermomethanolica genes involved in protein secretion, which could be applied for increasing heterologous protein secretion in this yeast.
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Affiliation(s)
- Worarat Kruasuwan
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Aekkachai Puseenam
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Chitwadee Phithakrotchanakoon
- Microbial Systems and Computational Biology Research Team, Thailand Bioresource Research Center, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Sutipa Tanapongpipat
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Niran Roongsawang
- Microbial Cell Factory Research Team, Microbial Biotechnology and Biochemicals Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
- * E-mail:
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5
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Soczewka P, Kolakowski D, Smaczynska-de Rooij I, Rzepnikowska W, Ayscough KR, Kaminska J, Zoladek T. Yeast-model-based study identified myosin- and calcium-dependent calmodulin signalling as a potential target for drug intervention in chorea-acanthocytosis. Dis Model Mech 2019; 12:dmm.036830. [PMID: 30635263 PMCID: PMC6361151 DOI: 10.1242/dmm.036830] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/07/2019] [Indexed: 01/03/2023] Open
Abstract
Chorea-acanthocytosis (ChAc) is a rare neurodegenerative disease associated with mutations in the human VPS13A gene. The mechanism of ChAc pathogenesis is unclear. A simple yeast model was used to investigate the function of the single yeast VSP13 orthologue, Vps13. Vps13, like human VPS13A, is involved in vesicular protein transport, actin cytoskeleton organisation and phospholipid metabolism. A newly identified phenotype of the vps13Δ mutant, sodium dodecyl sulphate (SDS) hypersensitivity, was used to screen a yeast genomic library for multicopy suppressors. A fragment of the MYO3 gene, encoding Myo3-N (the N-terminal part of myosin, a protein involved in the actin cytoskeleton and in endocytosis), was isolated. Myo3-N protein contains a motor head domain and a linker. The linker contains IQ motifs that mediate the binding of calmodulin, a negative regulator of myosin function. Amino acid substitutions that disrupt the interaction of Myo3-N with calmodulin resulted in the loss of vps13Δ suppression. Production of Myo3-N downregulated the activity of calcineurin, a protein phosphatase regulated by calmodulin, and alleviated some defects in early endocytosis events. Importantly, ethylene glycol tetraacetic acid (EGTA), which sequesters calcium and thus downregulates calmodulin and calcineurin, was a potent suppressor of vps13Δ. We propose that Myo3-N acts by sequestering calmodulin, downregulating calcineurin and increasing activity of Myo3, which is involved in endocytosis and, together with Osh2/3 proteins, functions in endoplasmic reticulum-plasma membrane contact sites. These results show that defects associated with vps13Δ could be overcome, and point to a functional connection between Vps13 and calcium signalling as a possible target for chemical intervention in ChAc. Yeast ChAc models may uncover the underlying pathological mechanisms, and may also serve as a platform for drug testing. This article has an associated First Person interview with the first author of the paper. Summary: Using the vps13Δ strain, a yeast model of the neurodegenerative disorder chorea-acanthocytosis, we found that its defects can be overcome by reduction of calcineurin activity and/or type-I-myosin activation.
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Affiliation(s)
- Piotr Soczewka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Genetics, Pawinskiego 5A, 02106 Warsaw, Poland
| | - Damian Kolakowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Genetics, Pawinskiego 5A, 02106 Warsaw, Poland
| | | | - Weronika Rzepnikowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Genetics, Pawinskiego 5A, 02106 Warsaw, Poland
| | - Kathryn R Ayscough
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Genetics, Pawinskiego 5A, 02106 Warsaw, Poland
| | - Teresa Zoladek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Department of Genetics, Pawinskiego 5A, 02106 Warsaw, Poland
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6
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Rab5-independent activation and function of yeast Rab7-like protein, Ypt7p, in the AP-3 pathway. PLoS One 2019; 14:e0210223. [PMID: 30682048 PMCID: PMC6347229 DOI: 10.1371/journal.pone.0210223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/18/2018] [Indexed: 11/19/2022] Open
Abstract
The small GTPases, Rab5 and Rab7, are key regulators at multiple stages of the endocytic/endolysosomal pathway, including fusion and maturation of endosomes. In yeast, Vps21p (Rab5 homolog) recruits a GEF for Rab7 and activates the downstream Ypt7p (Rab7 homolog) on endosomal membrane. Although the model of this sequential activation from Vps21p to Ypt7p in the endocytic pathway has been established, activation mechanism of Ypt7p in the Vps21p-independent pathway has not been completely clarified. Here we show that Ypt7p is activated and mediates vacuolar fusion in cells lacking all yeast Rab5 genes, VPS21, YPT52, and YPT53. We also demonstrate that deletion of both VPS21 and YPT7 genes cause severe defect in the AP-3 pathway as well as the CPY pathway although the AP-3 pathway is mostly intact in each vps21Δ or ypt7Δ mutant. Interestingly, in vps21Δ ypt7Δ mutant cargos trafficked via the VPS or endocytic pathway accumulate beside nucleus whereas cargo trafficked via the AP-3 pathway disperse in the cytosol. These findings suggest that Ypt7p is activated and plays a Rab5-independent role in the AP-3-mediated pathway.
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7
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Liu Z, Wang Z, Huang M, Yan L, Ma Z, Yin Y. The FgSsb-FgZuo-FgSsz complex regulates multiple stress responses and mycotoxin production via folding the soluble SNARE Vam7 and β2-tubulin in Fusarium graminearum. Environ Microbiol 2017; 19:5040-5059. [PMID: 29076607 DOI: 10.1111/1462-2920.13968] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 10/16/2017] [Accepted: 10/19/2017] [Indexed: 11/28/2022]
Abstract
Hsp70 proteins play important roles in protein folding in the budding yeast, but their functions in pathogenic fungi are largely unknown. Here, we found that Fusarium graminearum Hsp70 proteins FgSsb, FgSsz and their cochaperone FgZuo formed a complex. This complex was required for microtubule morphology, vacuole fusion and endocytosis. More importantly, the β2-tubulin FgTub2 and SNARE protein FgVam7 were identified as targeting proteins of this complex. We further found that the complex FgSsb-FgZuo-FgSsz controlled sensitivity of F. graminearum to the antimicrotubule drug carbendazim and cold stress via regulating the folding of FgTub2. Moreover, this complex assisted the folding of FgVam7, subsequently modulated vacuole fusion and responses to heavy metal, osmotic and oxidative stresses. In addition, the deletion of this complex led to dramatically decreased deoxynivalenol biosynthesis. This study uncovers a novel regulating mechanism of Hsp70 in multiple stress responses in a filamentous fungus.
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Affiliation(s)
- Zunyong Liu
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Zhihui Wang
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Mengmeng Huang
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Leiyan Yan
- Ningbo Academy of Agricultural Sciences, Ningbo, 315040, China
| | - Zhonghua Ma
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.,State Key Laboratory of Rice Biology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Yanni Yin
- Institute of Biotechnology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
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8
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Niedzwiecka K, Tisi R, Penna S, Lichocka M, Plochocka D, Kucharczyk R. Two mutations in mitochondrial ATP6 gene of ATP synthase, related to human cancer, affect ROS, calcium homeostasis and mitochondrial permeability transition in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1865:117-131. [PMID: 28986220 DOI: 10.1016/j.bbamcr.2017.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 09/15/2017] [Accepted: 10/02/2017] [Indexed: 02/06/2023]
Abstract
The relevance of mitochondrial DNA (mtDNA) mutations in cancer process is still unknown. Since the mutagenesis of mitochondrial genome in mammals is not possible yet, we have exploited budding yeast S. cerevisiae as a model to study the effects of tumor-associated mutations in the mitochondrial MTATP6 gene, encoding subunit 6 of ATP synthase, on the energy metabolism. We previously reported that four mutations in this gene have a limited impact on the production of cellular energy. Here we show that two mutations, Atp6-P163S and Atp6-K90E (human MTATP6-P136S and MTATP6-K64E, found in prostate and thyroid cancer samples, respectively), increase sensitivity of yeast cells both to compounds inducing oxidative stress and to high concentrations of calcium ions in the medium, when Om45p, the component of porin complex in outer mitochondrial membrane (OM), was fused to GFP. In OM45-GFP background, these mutations affect the activation of yeast permeability transition pore (yPTP, also called YMUC, yeast mitochondrial unspecific channel) upon calcium induction. Moreover, we show that calcium addition to isolated mitochondria heavily induced the formation of ATP synthase dimers and oligomers, recently proposed to form the core of PTP, which was slower in the mutants. We show the genetic evidence for involvement of mitochondrial ATP synthase in calcium homeostasis and permeability transition in yeast. This paper is a first to show, although in yeast model organism, that mitochondrial ATP synthase mutations, which accumulate during carcinogenesis process, may be significant for cancer cell escape from apoptosis.
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Affiliation(s)
- Katarzyna Niedzwiecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Renata Tisi
- Dept. Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy; Milan Center for Neuroscience, Milan, Italy
| | - Sara Penna
- Dept. Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Malgorzata Lichocka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Danuta Plochocka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
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9
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Dong Y, Yu Q, Chen Y, Xu N, Zhao Q, Jia C, Zhang B, Zhang K, Zhang B, Xing L, Li M. The Ccz1 mediates the autophagic clearance of damaged mitochondria in response to oxidative stress in Candida albicans. Int J Biochem Cell Biol 2015; 69:41-51. [PMID: 26471407 DOI: 10.1016/j.biocel.2015.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/28/2015] [Accepted: 10/07/2015] [Indexed: 10/25/2022]
Abstract
Autophagy plays a critical role in response to numerous cellular stresses, such as nutrient deprivation, hypoxia, starvation and organelle damage. The disruption of autophagy pathway affects multiple aspects of cellular stress response. Here we for the first time identified Ccz1 as an essential component for autophagy in Candida albicans. Our experiments demonstrated that loss of CCZ1 gene led to vacuolar fragmentation and disruption of the autophagy pathway. Our results also suggested that Ccz1 functioned in oxidative stress. In the ccz1Δ/Δ mutant, the levels of reactive oxidative species (ROS) sharply increased under H2O2 treatment. Further studies demonstrated that breakdown of the autophagic clearance pathway led to the accumulation of oxidative stress-damaged mitochondria, and consequently elevated cellular ROS levels in the ccz1Δ/Δ mutant. Furthermore, deletion of CCZ1 led to a significant defect in filamentous development at both 30°C and 37°C. The disruption of CCZ1 gene led to decreased capacity of macrophage killing and increased sensitivity to the macrophages. In addition, the ccz1Δ/Δ mutant exhibited attenuated virulence and decreased fungal burdens in the mouse systemic infection model, indicating that CCZ1 might provide a promising target for antifungal drugs development. In summary, our findings provide new insights into the understanding of autophagy-related gene in C. albicans.
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Affiliation(s)
- Yijie Dong
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Yulu Chen
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Ning Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, PR China.
| | - Qiang Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Chang Jia
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Bing Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Kai Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Biao Zhang
- Tianjin University of Traditional Chinese Medicine, Tianjin, PR China.
| | - Laijun Xing
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, PR China.
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10
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Liu XH, Chen SM, Gao HM, Ning GA, Shi HB, Wang Y, Dong B, Qi YY, Zhang DM, Lu GD, Wang ZH, Zhou J, Lin FC. The small GTPase MoYpt7 is required for membrane fusion in autophagy and pathogenicity ofMagnaporthe oryzae. Environ Microbiol 2015; 17:4495-510. [DOI: 10.1111/1462-2920.12903] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 05/07/2015] [Accepted: 05/10/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Xiao-Hong Liu
- State Key Laboratory for Rice Biology; Biotechnology Institute; Zhejiang University; Hangzhou 310058 China
| | - Si-Miao Chen
- College of Life Sciences; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
| | - Hui-Min Gao
- State Key Laboratory of Soil and Sustainable Agriculture; Institute of Soil Science; Chinese Academy Sciences; Nanjing 210008 China
| | - Guo-Ao Ning
- State Key Laboratory for Rice Biology; Biotechnology Institute; Zhejiang University; Hangzhou 310058 China
| | - Huan-Bin Shi
- State Key Laboratory for Rice Biology; Biotechnology Institute; Zhejiang University; Hangzhou 310058 China
| | - Yao Wang
- State Key Laboratory for Rice Biology; Biotechnology Institute; Zhejiang University; Hangzhou 310058 China
| | - Bo Dong
- Institute of Virology and Biotechnology; Zhejiang Academy of Agricultural Science; Hangzhou 310058 China
| | - Yao-Yao Qi
- Key Laboratory of Biopesticides and Chemical Biology; Ministry of Education; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
| | - Dong-Mei Zhang
- Key Laboratory of Biopesticides and Chemical Biology; Ministry of Education; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
| | - Guo-Dong Lu
- Key Laboratory of Biopesticides and Chemical Biology; Ministry of Education; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
| | - Zong-Hua Wang
- College of Life Sciences; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
- Key Laboratory of Biopesticides and Chemical Biology; Ministry of Education; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
| | - Jie Zhou
- College of Life Sciences; Fujian Agriculture and Forestry University; Fuzhou Fujian 350002 China
| | - Fu-Cheng Lin
- State Key Laboratory for Rice Biology; Biotechnology Institute; Zhejiang University; Hangzhou 310058 China
- China Tobacco Gene Research Center; Zhengzhou Tobacco Institute of CNTC; Zhengzhou 450001 China
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11
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CCZ1, MON1 and YPT7 genes are involved in pexophagy, the Cvt pathway and non-specific macroautophagy in the methylotrophic yeast Pichia pastoris. Cell Biol Int 2011; 35:311-9. [PMID: 21155714 DOI: 10.1042/cbi20100547] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Orthologues of Saccharomyces cerevisiae CCZ1, MON1 and YPT7 genes in the methylotrophic yeast, Pichia pastoris, have been identified. These genes encode proteins, which act as a complex, being involved in degradation of oleate-induced peroxisomes, Cvt (cytoplasm to vacuole targeting) pathway and non-specific macroautophagy in S. cerevisiae. CCZ1, MON1 and YPT7 gene orthologues are essential for multiple delivery pathways in P. pastoris. Strains with deletion of either of these genes displayed complete deficiency in pexophagy, non-specific macroautophagy and the biosynthetic Cvt pathway. The data suggest that CCZ1, MON1 and YPT7 genes are involved in degradation of both small oleate-induced and large methanol-induced peroxisomes. The data suggest conservative functions of CCZ1, MON1 and YPT7 genes among yeast species.
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Plemel RL, Lobingier BT, Brett CL, Angers CG, Nickerson DP, Paulsel A, Sprague D, Merz AJ. Subunit organization and Rab interactions of Vps-C protein complexes that control endolysosomal membrane traffic. Mol Biol Cell 2011; 22:1353-63. [PMID: 21325627 PMCID: PMC3078060 DOI: 10.1091/mbc.e10-03-0260] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The Vps-C complexes, CORVET and HOPS, are key regulators of membrane traffic through late endosomes and lysosomes. In this study Vps-C intersubunit contacts, domain architecture, and interactions with Rab G proteins are systematically dissected using genetic and biochemical approaches. Traffic through late endolysosomal compartments is regulated by sequential signaling of small G proteins of the Rab5 and Rab7 families. The Saccharomyces cerevisiae Vps-C protein complexes CORVET (class C core vacuole/endosome tethering complex) and HOPS (homotypic fusion and protein transport) interact with endolysosomal Rabs to coordinate their signaling activities. To better understand these large and intricate complexes, we performed interaction surveys to assemble domain-level interaction topologies for the eight Vps-C subunits. We identified numerous intersubunit interactions and up to six Rab-binding sites. Functional modules coordinate the major Rab interactions within CORVET and HOPS. The CORVET-specific subunits, Vps3 and Vps8, form a subcomplex and physically and genetically interact with the Rab5 orthologue Vps21. The HOPS-specific subunits, Vps39 and Vps41, also form a subcomplex. Both subunits bind the Rab7 orthologue Ypt7, but with distinct nucleotide specificities. The in vivo functions of four RING-like domains within Vps-C subunits were analyzed and shown to have distinct functions in endolysosomal transport. Finally, we show that the CORVET- and HOPS-specific subunits Vps3 and Vps39 bind the Vps-C core through a common region within the Vps11 C-terminal domain (CTD). Biochemical and genetic experiments demonstrate the importance of these regions, revealing the Vps11 CTD as a key integrator of Vps-C complex assembly, Rab signaling, and endosomal and lysosomal traffic.
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Affiliation(s)
- Rachael L Plemel
- Department of Biochemistry, University of Washington, Seattle, WA 98195-3750, USA
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13
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Nordmann M, Cabrera M, Perz A, Bröcker C, Ostrowicz C, Engelbrecht-Vandré S, Ungermann C. The Mon1-Ccz1 complex is the GEF of the late endosomal Rab7 homolog Ypt7. Curr Biol 2011; 20:1654-9. [PMID: 20797862 DOI: 10.1016/j.cub.2010.08.002] [Citation(s) in RCA: 279] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 06/18/2010] [Accepted: 08/03/2010] [Indexed: 11/16/2022]
Abstract
Rab GTPases coordinate membrane fusion reactions [1]. Rab-GDP requires a guanine nucleotide exchange factor (GEF) for its conversion to the active GTP form. It then binds to effectors such as multimeric tethering complexes and supports fusion [2]. GTPase-activating proteins (GAPs) promote GTP hydrolysis to inactivate the Rab. GEFs are thus critical activators of fusion reactions [3, 4]. The Rab GEF family is diverse, ranging from multimeric complexes [5] to monomeric GEFs [6-9]. At the late endosome, Rab7 activation is critical for endosomal maturation. The yeast Rab7 homolog Ypt7 binds to the homotypic fusion and protein sorting (HOPS) complex [10, 11]. Its subunit Vps39/Vam6 has been proposed as a GEF for Ypt7 [12] and the Rag GTPase Gtr1 [13], but other genetic evidence has implicated the endosomal protein Ccz1 as a GEF for Ypt7 [14]. Ccz1 and its binding partner Mon1 have been linked to endosomal transport and maturation [15-20]. We now provide evidence that the dimeric Mon1-Ccz1 complex is the Rab7/Ypt7 GEF. The Mon1-Ccz1 complex, but neither protein alone, counteracts GAP function in vivo, rescues in vitro fusion of vacuoles carrying Ypt7-GDP, and promotes nucleotide exchange on Ypt7 independently of Vps39/HOPS. Our data indicate that the Mon1-Ccz1 complex triggers endosomal maturation by activating Ypt7 on late endosomes.
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Affiliation(s)
- Mirjana Nordmann
- Department of Biology/Chemistry, University of Osnabrück, Germany
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14
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Piekarska I, Kucharczyk R, Mickowska B, Rytka J, Rempola B. Mutants of the Saccharomyces cerevisiae VPS genes CCZ1 and YPT7 are blocked in different stages of sporulation. Eur J Cell Biol 2010; 89:780-7. [DOI: 10.1016/j.ejcb.2010.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/24/2010] [Accepted: 06/28/2010] [Indexed: 11/30/2022] Open
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Tong J, Yan X, Yu L. The late stage of autophagy: cellular events and molecular regulation. Protein Cell 2010; 1:907-15. [PMID: 21204017 PMCID: PMC4875124 DOI: 10.1007/s13238-010-0121-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 10/18/2010] [Indexed: 12/28/2022] Open
Abstract
Autophagy is an intracellular degradation system that delivers cytoplasmic contents to the lysosome for degradation. It is a "self-eating" process and plays a "house-cleaner" role in cells. The complex process consists of several sequential steps-induction, autophagosome formation, fusion of lysosome and autophagosome, degradation, efflux transportation of degradation products, and autophagic lysosome reformation. In this review, the cellular and molecular regulations of late stage of autophagy, including cellular events after fusion step, are summarized.
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Affiliation(s)
- Jingjing Tong
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Science, Tsinghua University, Beijing, 100084 China
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Xianghua Yan
- College of Animal Sciences and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Li Yu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Science, Tsinghua University, Beijing, 100084 China
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Hoffman-Sommer M, Kucharczyk R, Piekarska I, Kozlowska E, Rytka J. Mutations in the Saccharomyces cerevisiae vacuolar fusion proteins Ccz1, Mon1 and Ypt7 cause defects in cell cycle progression in a num1Δ background. Eur J Cell Biol 2009; 88:639-52. [DOI: 10.1016/j.ejcb.2009.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 06/29/2009] [Accepted: 07/03/2009] [Indexed: 01/07/2023] Open
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17
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Kraft C, Reggiori F, Peter M. Selective types of autophagy in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1404-12. [PMID: 19264099 DOI: 10.1016/j.bbamcr.2009.02.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 02/17/2009] [Accepted: 02/18/2009] [Indexed: 12/19/2022]
Abstract
Autophagy is the process through which cytosol and organelles are sequestered into a double-membrane vesicle called an autophagosome and delivered to the vacuole/lysosome for breakdown and recycling. One of its primary roles in unicellular organisms is to regulate intracellular homeostasis and to adjust organelle numbers in response to stress such as changes in nutrient availability. In higher eukaryotes, autophagy plays also an important role in stress-response, development, cell differentiation, immunity and tumor suppression. Importantly, a misregulation in this catabolic pathway is associated with diseases such as cancer, neurodegeneration and myopathies. For a long time, starvation-induced autophagy has been considered a non-selective pathway, however, numerous recent observations revealed that autophagy can also selectively eliminate specific proteins, protein complexes and organelles. Most of these studies used yeast Saccharomyces cerevisiae as a model organism. In this compendium, we will review what is known about the mechanisms and roles of selective types of autophagy in yeast and highlight possible connections of these pathways with human diseases. In addition, we will discuss some selective types of autophagy, which have so far only been described in higher eukaryotes.
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Affiliation(s)
- Claudine Kraft
- Institute of Biochemistry, HPM, ETH Hönggerberg, 8093 Zürich, Switzerland.
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18
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Hoffman-Sommer M, Rytka J. The yeast protein sorting pathway as an experimental model for lysosomal trafficking. Expert Rev Clin Immunol 2007; 3:225-39. [PMID: 20477111 DOI: 10.1586/1744666x.3.2.225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lysosomes are conserved organelles that are present in all eukaryotic cells. They are part of a complicated network of intracellular trafficking routes - the lysosomal transport system. Lysosomes are necessary for the maintenance of cellular homeostasis and for many specialized functions, including the activity of many components of the mammalian immune system. Dysfunctions of the lysosomal system are associated with numerous diseases, such as storage disorders, neuro- and myopathies, cancer and some types of albinism and immunological deficiencies. High conservation of the processes of lysosomal biogenesis and transport enables the use of yeast as a model for studying the mechanisms that underlie these diseases. In this review, we discuss several examples of such models in an attempt to present an overview of the most important experimental methods available in yeast research.
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Affiliation(s)
- Marta Hoffman-Sommer
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland.
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Hoffman-Sommer M, Grynberg M, Kucharczyk R, Rytka J. The CHiPS Domain - Ancient Traces for the Hermansky-Pudlak Syndrome. Traffic 2005; 6:534-8. [PMID: 15941405 DOI: 10.1111/j.1600-0854.2005.00301.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hermansky-Pudlak syndrome (HPS) is a rare disorder caused by malfunctions of lysosomes and specialized lysosome-related organelles, resulting primarily in oculocutaneous albinism and bleeding diathesis. The majority of the HPS genes have been described as novel, but herein we report the identification of a conserved protein family which includes human HPS4, as well as distant homologs for other HPS genes. Our results suggest that the cellular machinery involved in the HPS syndrome is ancient.
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Affiliation(s)
- Marta Hoffman-Sommer
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, Warsaw 02-106, Poland
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20
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Hoffman-Sommer M, Migdalski A, Rytka J, Kucharczyk R. Multiple functions of the vacuolar sorting protein Ccz1p in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2005; 329:197-204. [PMID: 15721293 DOI: 10.1016/j.bbrc.2005.01.107] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Indexed: 10/25/2022]
Abstract
The CCZ1 (YBR131w) gene encodes a protein required for fusion of various transport intermediates with the vacuole. Ccz1p, in a complex with Mon1p, is a close partner of Ypt7p in the processes of fusion of endosomes to vacuoles and homotypic vacuole fusion. In this work, we exploited the Ca(2+)-sensitivity of the ccz1Delta mutant to identify genes specifically interacting with CCZ1, basing on functional multicopy suppression of calcium toxicity. The presented results indicate that Ccz1p functions in the cell either in association with Mon1p and Ypt7p in fusion at the vacuolar membrane, or--separately--with Arl1p at early steps of vacuolar transport. We also show that suppression of calcium toxicity by the calcium pumps Pmr1p and Pmc1p is restricted only to the subset of mutants defective in vacuole morphology. The mechanisms of Ca(2+)-pump-mediated suppression also differ from each other, since the action of Pmr1p, but not Pmc1p, appears to require Arl1p function.
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Affiliation(s)
- Marta Hoffman-Sommer
- Institute of Biochemistry and Biophysics PAS, Pawinskiego 5A, 02-106 Warsaw, Poland
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21
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Tedrick K, Trischuk T, Lehner R, Eitzen G. Enhanced membrane fusion in sterol-enriched vacuoles bypasses the Vrp1p requirement. Mol Biol Cell 2004; 15:4609-21. [PMID: 15254266 PMCID: PMC519153 DOI: 10.1091/mbc.e04-03-0194] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Organization of lipids into membrane microdomains is a vital mechanism of protein processing. Here we show that overexpression of ERG6, a gene involved in ergosterol synthesis, elevates sterol levels 1.5-fold on the vacuole membrane and enhances their homotypic fusion. The mechanism of sterol-enhanced fusion is not via more efficient sorting, but instead promotes increased kinetics of fusion subreactions. We initially isolated ERG6 as a suppressor of a vrp1Delta growth defect selective for vacuole function. VRP1 encodes verprolin, an actin-binding protein that colocalizes to vacuoles. The vrp1Delta mutant has fragmented vacuoles in vivo and isolated vacuoles do not fuse in vitro, indicative of a Vrp1p requirement for membrane fusion. ERG6 overexpression rescues vrp1Delta vacuole fusion in a cytosol-dependent manner. Cytosol prepared from the vrp1Delta strain remains active; therefore, cytosol is not resupplying Vrp1p. Las17p (Vrp1p functional partner) antibodies, which inhibit wild-type vacuole fusion, do not inhibit the fusion of vacuoles from the vrp1Delta-ERG6 overexpression strain. Vacuole-associated actin turnover is decreased in the vrp1Delta strain, but recovered by ERG6 overexpression linking sterol enrichment to actin remodeling. Therefore, the Vrp1p/Las17p requirement for membrane fusion is bypassed by increased sterols, which promotes actin remodeling as part the membrane fusion mechanism.
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Affiliation(s)
- Kelly Tedrick
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, T6G 2H7 Canada
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Love SL, Manlandro CMA, Testa CJ, Thomas AE, Tryggestad KE, Rosenwald AG. The yeast genes, ARL1 and CCZ1, interact to control membrane traffic and ion homeostasis. Biochem Biophys Res Commun 2004; 319:840-6. [PMID: 15184059 DOI: 10.1016/j.bbrc.2004.05.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Indexed: 10/26/2022]
Abstract
The yeast ARL1 gene, encoding a guanine-nucleotide binding protein of the Arf-like family, exhibits a synthetic genetic interaction with CCZ1. An arl1 Delta ccz1 Delta double mutant was viable but grew slowly, was more sensitive to caffeine, Ca(2+), Zn(2+), and hygromycin B than either single mutant, and had a more severe vacuolar protein sorting phenotype. Overexpression of ARL1 did not suppress ccz1 Delta mutant phenotypes, nor did overexpression of CCZ1 suppress arl1 Delta mutant phenotypes. We conclude that ARL1 and CCZ1 independently contribute to both ion homeostasis and protein sorting.
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Affiliation(s)
- Sherie L Love
- Department of Biology, Georgetown University, Washington, DC 20057, USA
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23
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Wang CW, Stromhaug PE, Kauffman EJ, Weisman LS, Klionsky DJ. Yeast homotypic vacuole fusion requires the Ccz1-Mon1 complex during the tethering/docking stage. ACTA ACUST UNITED AC 2004; 163:973-85. [PMID: 14662743 PMCID: PMC1705953 DOI: 10.1083/jcb.200308071] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The function of the yeast lysosome/vacuole is critically linked with the morphology of the organelle. Accordingly, highly regulated processes control vacuolar fission and fusion events. Analysis of homotypic vacuole fusion demonstrated that vacuoles from strains defective in the CCZ1 and MON1 genes could not fuse. Morphological evidence suggested that these mutant vacuoles could not proceed to the tethering/docking stage. Ccz1 and Mon1 form a stable protein complex that binds the vacuole membrane. In the absence of the Ccz1–Mon1 complex, the integrity of vacuole SNARE pairing and the unpaired SNARE class C Vps/HOPS complex interaction were both impaired. The Ccz1–Mon1 complex colocalized with other fusion components on the vacuole as part of the cis-SNARE complex, and the association of the Ccz1–Mon1 complex with the vacuole appeared to be regulated by the class C Vps/HOPS complex proteins. Accordingly, we propose that the Ccz1–Mon1 complex is critical for the Ypt7-dependent tethering/docking stage leading to the formation of a trans-SNARE complex and subsequent vacuole fusion.
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Affiliation(s)
- Chao-Wen Wang
- Life Sciences Institute, Department of Molecular, Cellular and Developmental Biology and Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-2216, USA
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Wang CW, Stromhaug PE, Shima J, Klionsky DJ. The Ccz1-Mon1 protein complex is required for the late step of multiple vacuole delivery pathways. J Biol Chem 2002; 277:47917-27. [PMID: 12364329 PMCID: PMC2754690 DOI: 10.1074/jbc.m208191200] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mon1 and Ccz1 were identified from a gene deletion library as mutants defective in the vacuolar import of aminopeptidase I (Ape1) via the cytoplasm to vacuole targeting (Cvt) pathway. The mon1Delta and ccz1Delta strains also displayed defects in autophagy and pexophagy, degradative pathways that share protein machinery and mechanistic features with the biosynthetic Cvt pathway. Further analyses indicated that Mon1, like Ccz1, was required in nearly all membrane-trafficking pathways where the vacuole represented the terminal acceptor compartment. Accordingly, both deletion strains had kinetic defects in the biosynthetic delivery of resident vacuolar hydrolases through the CPY, ALP, and MVB pathways. Biochemical and microscopy studies suggested that Mon1 and Ccz1 functioned after transport vesicle formation but before (or at) the fusion step with the vacuole. Thus, ccz1Delta and mon1Delta are the first mutants identified in screens for the Cvt and Apg pathways that accumulate precursor Ape1 within completed cytosolic vesicles. Subcellular fractionation and co-immunoprecipitation experiments confirm that Mon1 and Ccz1 physically interact as a stable protein complex termed the Ccz1-Mon1 complex. Microscopy of Ccz1 and Mon1 tagged with a fluorescent marker indicated that the Ccz1-Mon1 complex peripherally associated with a perivacuolar compartment and may attach to the vacuole membrane in agreement with their proposed function in fusion.
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Affiliation(s)
- Chao-Wen Wang
- Department of Molecular, Cellular, and Developmental Biology and the Department of Biological Chemistry and the Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Per E. Stromhaug
- Department of Molecular, Cellular, and Developmental Biology and the Department of Biological Chemistry and the Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Jun Shima
- Department of Molecular, Cellular, and Developmental Biology and the Department of Biological Chemistry and the Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Daniel J. Klionsky
- To whom correspondence should be addressed: University of Michigan, Dept. of Molecular, Cellular and Developmental Biology, Ann Arbor, MI 48109-1048. Tel.: 734-615-6556; Fax: 734-647-0884;
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Abstract
Autophagy is a membrane trafficking mechanism that delivers cytoplasmic cargo to the vacuole/lysosome for degradation and recycling. In addition to non-specific bulk cytosol, selective cargoes, such as peroxisomes, are sorted for autophagic transport under specific physiological conditions. In a nutrient-rich growth environment, many of the autophagic components are recruited for executing a biosynthetic trafficking process, the cytoplasm to vacuole targeting (Cvt) pathway, that transports the resident hydrolases aminopeptidase I and alpha-mannosidase to the vacuole in Saccharomyces cerevisiae. Recent studies have identified pathway-specific components that are necessary to divert a protein kinase and a lipid kinase complex to regulate the conversion between the Cvt pathway and autophagy. Downstream of these proteins, the general machinery for transport vesicle formation involves two novel conjugation systems and a putative membrane protein complex. Completed vesicles are targeted to, and fuse with, the vacuole under the control of machinery shared with other vacuolar trafficking pathways. Inside the vacuole, a potential lipase and several proteases are responsible for the final steps of vesicle breakdown, precursor enzyme processing and substrate turnover. In this review, we discuss the most recent developments in yeast autophagy and point out the challenges we face in the future.
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Affiliation(s)
- Wei-Pang Huang
- Departments of Molecular, Cellular and Developmental Biology and Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109-1048, USA
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26
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Meiling-Wesse K, Barth H, Voss C, Barmark G, Murén E, Ronne H, Thumm M. Yeast Mon1p/Aut12p functions in vacuolar fusion of autophagosomes and cvt-vesicles. FEBS Lett 2002; 530:174-80. [PMID: 12387888 DOI: 10.1016/s0014-5793(02)03456-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Here we identify Mon1p as being essential for the cvt-pathway and autophagy. Thus, mon1Delta cells are impaired in proaminopeptidase I maturation and homozygous diploid mon1Delta cells do not sporulate. Quantitative autophagy measurements suggest a complete autophagy block. The autophagosomal marker protein GFP-Aut7p accumulates in mon1Delta cells at punctate structures outside the vacuole. Furthermore, proaminopeptidase I accumulates in mon1Delta cells in a proteinase-protected form. Our data demonstrate that mon1Delta cells are defective in the fusion of cvt-vesicles and autophagosomes with the vacuole. Consistent with this, GFP-Mon1p localizes to the cytosol and to punctate structures within the cytosol.
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27
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Abstract
In a reverse genetics screen, we here identify Ccz1p as an essential component of the cvt pathway and autophagy. Ccz1p is identical with the so far unknown Cvt16p. GFP-Aut7p, a specific cargo of autophagosomes, accumulates in ccz1 Delta cells at punctate, vesicular structures in the cytosol, suggesting a block in the autophagic pathway prior to vacuolar fusion of autophagosomes. Proteinase protection experiments using hypotonically lysed ccz1 Delta spheroplasts demonstrate that proaminopeptidase I, another specific cargo of autophagy and the cvt pathway, is trapped inside membrane-enclosed vesicles. Taken together our findings are compatible with a function of Ccz1p in vacuolar fusion of cvt vesicles and autophagosomes.
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Affiliation(s)
- Khuyen Meiling-Wesse
- University of Stuttgart, Institute of Biochemistry, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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28
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Bonangelino CJ, Chavez EM, Bonifacino JS. Genomic screen for vacuolar protein sorting genes in Saccharomyces cerevisiae. Mol Biol Cell 2002; 13:2486-501. [PMID: 12134085 PMCID: PMC117329 DOI: 10.1091/mbc.02-01-0005] [Citation(s) in RCA: 266] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The biosynthetic sorting of hydrolases to the yeast vacuole involves transport along two distinct routes referred to as the carboxypeptidase Y and alkaline phosphatase pathways. To identify genes involved in sorting to the vacuole, we conducted a genome-wide screen of 4653 homozygous diploid gene deletion strains of Saccharomyces cerevisiae for missorting of carboxypeptidase Y. We identified 146 mutant strains that secreted strong-to-moderate levels of carboxypeptidase Y. Of these, only 53 of the corresponding genes had been previously implicated in vacuolar protein sorting, whereas the remaining 93 had either been identified in screens for other cellular processes or were only known as hypothetical open reading frames. Among these 93 were genes encoding: 1) the Ras-like GTP-binding proteins Arl1p and Arl3p, 2) actin-related proteins such as Arp5p and Arp6p, 3) the monensin and brefeldin A hypersensitivity proteins Mon1p and Mon2p, and 4) 15 novel proteins designated Vps61p-Vps75p. Most of the novel gene products were involved only in the carboxypeptidase Y pathway, whereas a few, including Mon1p, Mon2p, Vps61p, and Vps67p, appeared to be involved in both the carboxypeptidase Y and alkaline phosphatase pathways. Mutants lacking some of the novel gene products, including Arp5p, Arp6p, Vps64p, and Vps67p, were severely defective in secretion of mature alpha-factor. Others, such as Vps61p, Vps64p, and Vps67p, displayed defects in the actin cytoskeleton at 30 degrees C. The identification and phenotypic characterization of these novel mutants provide new insights into the mechanisms of vacuolar protein sorting, most notably the probable involvement of the actin cytoskeleton in this process.
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Affiliation(s)
- Cecilia J Bonangelino
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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29
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Briza P, Bogengruber E, Thür A, Rützler M, Münsterkötter M, Dawes IW, Breitenbach M. Systematic analysis of sporulation phenotypes in 624 non-lethal homozygous deletion strains of Saccharomyces cerevisiae. Yeast 2002; 19:403-22. [PMID: 11921089 DOI: 10.1002/yea.843] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A new high throughput mutant screening procedure for the detection of sporulation mutants was developed and used to analyse a set of 624 non-lethal homozygous deletion mutants created in the European joint research program EUROFAN. The screening procedure involved determination of LL- and DL-dityrosine, sporulation-specific compounds, which were shown to be robust markers of the extent and arrest stage of sporulation mutants. Secondary screens consisted of light microscopy to detect mature and immature spores and DAPI staining to monitor the progress of meiotic nuclear divisions. We discovered new phenotypic classes of mutants defective in spore wall synthesis that were not discovered by previous screens for sporulation mutants. The genes corresponding to the sporulation mutants fell in several functional classes, some of which were previously unknown to be involved in spore formation. Peroxisomes seem to play a role in spore wall synthesis. Mitochondria play a role in sporulation that is not simply restricted to supply of ATP from respiratory metabolism. The deletion mutants included in the set were functionally unknown at the start of EUROFAN; however, within the last few years the importance to sporulation of some of them was also reported by other authors. Taken together, about 8% of all single gene deletion mutants of non-essential genes of Saccharomyces cerevisiae seem to display a clear and reproducible sporulation phenotype.
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Affiliation(s)
- Peter Briza
- Institut für Genetik und Allgemeine Biologie, Universität Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria
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Kucharczyk R, Kierzek AM, Slonimski PP, Rytka J. The Ccz1 protein interacts with Ypt7 GTPase during fusion of multiple transport intermediates with the vacuole in S. cerevisiae. J Cell Sci 2001; 114:3137-45. [PMID: 11590240 DOI: 10.1242/jcs.114.17.3137] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously we have shown that the Saccharomyces cerevisiae CCZ1 (YBR131w) gene encodes a protein involved in protein trafficking. Deletion of this gene leads to fragmentation of the vacuole typical of the class B vps mutants. Genetic and biochemical data indicated that Ccz1p is required for fusion of various transport intermediates with the vacuole. Here we present data indicating that CCZ1 is a close partner of the YPT7 gene, which encodes Rab GTPase and is required for fusion of transport vesicles to vacuole and homotypic vacuole fusion. We isolated extragenic suppressors of CCZ1 deletion. All these suppressors belong to one complementation group and correspond to mutated alleles of the YPT7 gene. The mutated residues are located in two Ypt7p domains responsible for guanine binding. These data suggest that Ccz1p and Ypt7p interact physically. Coimmunoprecipitation experiments provide direct evidence that this indeed is the case. A possible mechanism of Ccz1p action is discussed.
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Affiliation(s)
- R Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland
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31
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Current awareness on yeast. Yeast 2001; 18:577-84. [PMID: 11284013 DOI: 10.1002/yea.684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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