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Kück U, Pöggeler S. STRIPAK, a fundamental signaling hub of eukaryotic development. Microbiol Mol Biol Rev 2024; 88:e0020523. [PMID: 39526753 DOI: 10.1128/mmbr.00205-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2024] Open
Abstract
SUMMARYThe striatin-interacting phosphatase and kinase (STRIPAK) complex is involved in the regulation of many developmental processes in eukaryotic microorganisms and all animals, including humans. STRIPAK is a component of protein phosphatase 2A (PP2A), a highly conserved serine-threonine phosphatase composed of catalytic subunits (PP2Ac), a scaffolding subunit (PP2AA) and various substrate-directing B regulatory subunits. In particular, the B''' regulatory subunit called striatin has evoked major interest over the last 20 years. Studies in fungal systems have contributed substantially to our current knowledge about STRIPAK composition, assembly, and cellular localization, as well as its regulatory role in autophagy and the morphology of fungal development. STRIPAK represents a signaling hub with many kinases and thus integrates upstream and downstream information from many conserved eukaryotic signaling pathways. A profound understanding of STRIPAK's regulatory role in fungi opens the gateway to understanding the multifarious functions carried out by STRIPAK in higher eukaryotes, including its contribution to malignant cell growth.
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Affiliation(s)
- Ulrich Kück
- Allgemeine & Molekulare Botanik, Ruhr-University, Bochum, Germany
| | - Stefanie Pöggeler
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University, Göttingen, Germany
- Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
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2
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Peterson PP, Choi JT, Fu C, Cowen LE, Sun S, Bahn YS, Heitman J. The Cryptococcus neoformans STRIPAK complex controls genome stability, sexual development, and virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.06.606879. [PMID: 39149236 PMCID: PMC11326274 DOI: 10.1101/2024.08.06.606879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
The eukaryotic serine/threonine protein phosphatase PP2A is a heterotrimeric enzyme composed of a scaffold A subunit, a regulatory B subunit, and a catalytic C subunit. Of the four known B subunits, the B"' subunit (known as striatin) interacts with the multi-protein striatin-interacting phosphatase and kinase (STRIPAK) complex. Orthologs of STRIPAK components were identified in Cryptococcus neoformans, namely PP2AA/Tpd3, PP2AC/Pph22, PP2AB/Far8, STRIP/Far11, SLMAP/Far9, and Mob3. Structural modeling, protein domain analysis, and detected protein-protein interactions suggest C. neoformans STRIPAK is assembled similarly to the human and fungal orthologs. Here, STRIPAK components Pph22, Far8, and Mob3 were functionally characterized. Whole-genome sequencing revealed that mutations in STRIPAK complex subunits lead to increased segmental and chromosomal aneuploidy, suggesting STRIPAK functions in maintaining genome stability. We demonstrate that PPH22 is a haploinsufficient gene: heterozygous PPH22/pph22Δ mutant diploid strains exhibit defects in hyphal growth and sporulation and have a significant fitness disadvantage when grown in competition against a wild-type diploid. Deletion mutants pph22Δ, far8Δ, and mob3Δ exhibit defects in mating and sexual differentiation, including impaired hyphae, basidia, and basidiospore production. Loss of either PPH22 or FAR8 in a haploid background leads to growth defects at 30°C, severely reduced growth at elevated temperature, abnormal cell morphology, and impaired virulence. Additionally, pph22Δ strains frequently accumulate suppressor mutations that result in overexpression of another putative PP2A catalytic subunit, PPG1. The pph22Δ and far8Δ mutants are also unable to grow in the presence of the calcineurin inhibitors cyclosporine A or FK506, and thus these mutations are synthetically lethal with loss of calcineurin activity. Conversely, mob3Δ mutants display increased thermotolerance, capsule production, and melanization, and are hypervirulent in a murine infection model. Taken together, these findings reveal that the C. neoformans STRIPAK complex plays an important role in genome stability, vegetative growth, sexual development, and virulence in this prominent human fungal pathogen.
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Affiliation(s)
- Patricia P. Peterson
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Jin-Tae Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Ci Fu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
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Peterson PP, Choi JT, Fu C, Cowen LE, Sun S, Bahn YS, Heitman J. The Cryptococcus neoformans STRIPAK complex controls genome stability, sexual development, and virulence. PLoS Pathog 2024; 20:e1012735. [PMID: 39561188 PMCID: PMC11614259 DOI: 10.1371/journal.ppat.1012735] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Revised: 12/03/2024] [Accepted: 11/07/2024] [Indexed: 11/21/2024] Open
Abstract
The eukaryotic serine/threonine protein phosphatase PP2A is a heterotrimeric enzyme composed of a scaffold A subunit, a regulatory B subunit, and a catalytic C subunit. Of the four known B subunits, the B"' subunit (known as striatin) interacts with the multi-protein striatin-interacting phosphatase and kinase (STRIPAK) complex. Orthologs of STRIPAK components were identified in Cryptococcus neoformans, namely PP2AA/Tpd3, PP2AC/Pph22, PP2AB/Far8, STRIP/Far11, SLMAP/Far9, and Mob3. Structural modeling, protein domain analysis, and detected protein-protein interactions suggest C. neoformans STRIPAK is assembled similarly to the human and fungal orthologs. Here, STRIPAK components Pph22, Far8, and Mob3 were functionally characterized. Whole-genome sequencing revealed that mutations in STRIPAK complex subunits lead to increased segmental and chromosomal aneuploidy, suggesting STRIPAK functions in maintaining genome stability. We demonstrate that PPH22 is a haploinsufficient gene: heterozygous PPH22/pph22Δ mutant diploid strains exhibit defects in hyphal growth and sporulation and have a significant fitness disadvantage when grown in competition against a wild-type diploid. Deletion mutants pph22Δ, far8Δ, and mob3Δ exhibit defects in mating and sexual differentiation, including impaired hyphae, basidia, and basidiospore production. Loss of either PPH22 or FAR8 in a haploid background leads to growth defects at 30°C, severely reduced growth at elevated temperature, abnormal cell morphology, and impaired virulence. Additionally, pph22Δ strains frequently accumulate suppressor mutations that result in overexpression of another putative PP2A catalytic subunit, PPG1. The pph22Δ and far8Δ mutants are also unable to grow in the presence of the calcineurin inhibitors cyclosporine A or FK506, and thus these mutations are synthetically lethal with loss of calcineurin activity. Conversely, mob3Δ mutants display increased thermotolerance, capsule production, and melanization, and are hypervirulent in a murine infection model. Taken together, these findings reveal that the C. neoformans STRIPAK complex plays an important role in genome stability, vegetative growth, sexual development, and virulence in this prominent human fungal pathogen.
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Affiliation(s)
- Patricia P. Peterson
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jin-Tae Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Ci Fu
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
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4
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Niphadkar S, Karinje L, Laxman S. The PP2A-like phosphatase Ppg1 mediates assembly of the Far complex to balance gluconeogenic outputs and enables adaptation to glucose depletion. PLoS Genet 2024; 20:e1011202. [PMID: 38452140 PMCID: PMC10950219 DOI: 10.1371/journal.pgen.1011202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/19/2024] [Accepted: 02/27/2024] [Indexed: 03/09/2024] Open
Abstract
To sustain growth in changing nutrient conditions, cells reorganize outputs of metabolic networks and appropriately reallocate resources. Signaling by reversible protein phosphorylation can control such metabolic adaptations. In contrast to kinases, the functions of phosphatases that enable metabolic adaptation as glucose depletes are poorly studied. Using a Saccharomyces cerevisiae deletion screen, we identified the PP2A-like phosphatase Ppg1 as required for appropriate carbon allocations towards gluconeogenic outputs-trehalose, glycogen, UDP-glucose, UDP-GlcNAc-after glucose depletion. This Ppg1 function is mediated via regulation of the assembly of the Far complex-a multi-subunit complex that tethers to the ER and mitochondrial outer membranes forming localized signaling hubs. The Far complex assembly is Ppg1 catalytic activity-dependent. Ppg1 regulates the phosphorylation status of multiple ser/thr residues on Far11 to enable the proper assembly of the Far complex. The assembled Far complex is required to maintain gluconeogenic outputs after glucose depletion. Glucose in turn regulates Far complex amounts. This Ppg1-mediated Far complex assembly, and Ppg1-Far complex dependent control of gluconeogenic outputs enables adaptive growth under glucose depletion. Our study illustrates how protein dephosphorylation is required for the assembly of a multi-protein scaffold present in localized cytosolic pools, to thereby alter gluconeogenic flux and enable cells to metabolically adapt to nutrient fluctuations.
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Affiliation(s)
- Shreyas Niphadkar
- Institute for Stem Cell Science and Regenerative Medicine (DBT-inStem) Bangalore, India
- Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Lavanya Karinje
- Institute for Stem Cell Science and Regenerative Medicine (DBT-inStem) Bangalore, India
| | - Sunil Laxman
- Institute for Stem Cell Science and Regenerative Medicine (DBT-inStem) Bangalore, India
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5
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Lind AC, David F, Siewers V. Evaluation and comparison of colorimetric outputs for yeast-based biosensors in laboratory and point-of-use settings. FEMS Microbiol Lett 2024; 371:fnae034. [PMID: 38782713 PMCID: PMC11166083 DOI: 10.1093/femsle/fnae034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/30/2024] [Accepted: 05/22/2024] [Indexed: 05/25/2024] Open
Abstract
Recent research has shown the potential of yeast-based biosensors (YBBs) for point-of-use detection of pathogens and target molecules in saliva, blood, and urine samples. The choice of output can greatly affect the sensitivity, dynamic range, detection time, and ease-of-use of a sensor. For visual detection without the need for additional reagents or machinery, colorimetric outputs have shown great potential. Here, we evaluated the inducible generation of prodeoxyviolacein and proviolacein as colorimetric YBB outputs and benchmarked these against lycopene. The outputs were induced via the yeast mating pathway and were compared on agar plates, in liquid culture, and on paper slips. We found that all three outputs produced comparable pigment intensity on agar plates, making them applicable for bioengineering settings. In liquid media and on paper slips, lycopene resulted in a higher intensity pigment and a decreased time-of-detection.
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Affiliation(s)
- Andrea Clausen Lind
- Department of Life Sciences, Chalmers University of Technology, 412 58 Gothenburg, Sweden
| | - Florian David
- Department of Life Sciences, Chalmers University of Technology, 412 58 Gothenburg, Sweden
| | - Verena Siewers
- Department of Life Sciences, Chalmers University of Technology, 412 58 Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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6
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Abeliovich H. Mitophagy in yeast: known unknowns and unknown unknowns. Biochem J 2023; 480:1639-1657. [PMID: 37850532 PMCID: PMC10586778 DOI: 10.1042/bcj20230279] [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: 07/12/2023] [Revised: 09/06/2023] [Accepted: 09/22/2023] [Indexed: 10/19/2023]
Abstract
Mitophagy, the autophagic breakdown of mitochondria, is observed in eukaryotic cells under various different physiological circumstances. These can be broadly categorized into two types: mitophagy related to quality control events and mitophagy induced during developmental transitions. Quality control mitophagy involves the lysosomal or vacuolar degradation of malfunctioning or superfluous mitochondria within lysosomes or vacuoles, and this is thought to serve as a vital maintenance function in respiring eukaryotic cells. It plays a crucial role in maintaining physiological balance, and its disruption has been associated with the progression of late-onset diseases. Developmentally induced mitophagy has been reported in the differentiation of metazoan tissues which undergo metabolic shifts upon developmental transitions, such as in the differentiation of red blood cells and muscle cells. Although the mechanistic studies of mitophagy in mammalian cells were initiated after the initial mechanistic findings in Saccharomyces cerevisiae, our current understanding of the physiological role of mitophagy in yeast remains more limited, despite the presence of better-defined assays and tools. In this review, I present my perspective on our present knowledge of mitophagy in yeast, focusing on physiological and mechanistic aspects. I aim to focus on areas where our understanding is still incomplete, such as the role of mitochondrial dynamics and the phenomenon of protein-level selectivity.
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Affiliation(s)
- Hagai Abeliovich
- Institute of Biochemistry, Food Science and Nutrition, Hebrew University of Jerusalem, 1 Hankin St, Rehovot 7610001, Israel
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Chen A, Liu N, Xu C, Wu S, Liu C, Qi H, Ren Y, Han X, Yang K, Liu X, Ma Z, Chen Y. The STRIPAK complex orchestrates cell wall integrity signalling to govern the fungal development and virulence of Fusarium graminearum. MOLECULAR PLANT PATHOLOGY 2023; 24:1139-1153. [PMID: 37278525 PMCID: PMC10423325 DOI: 10.1111/mpp.13359] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/04/2023] [Accepted: 05/16/2023] [Indexed: 06/07/2023]
Abstract
Striatin-interacting phosphatases and kinases (STRIPAKs) are evolutionarily conserved supramolecular complexes that control various important cellular processes such as signal transduction and development. However, the role of the STRIPAK complex in pathogenic fungi remains elusive. In this study, the components and function of the STRIPAK complex were investigated in Fusarium graminearum, an important plant-pathogenic fungus. The results obtained from bioinformatic analyses and the protein-protein interactome suggested that the fungal STRIPAK complex consisted of six proteins: Ham2, Ham3, Ham4, PP2Aa, Ppg1, and Mob3. Deletion mutations of individual components of the STRIPAK complex were created, and observed to cause a significant reduction in fungal vegetative growth and sexual development, and dramatically attenuae virulence, excluding the essential gene PP2Aa. Further results revealed that the STRIPAK complex interacted with the mitogen-activated protein kinase Mgv1, a key component in the cell wall integrity pathway, subsequently regulating the phosphorylation level and nuclear accumulation of Mgv1 to control the fungal stress response and virulence. Our results also suggested that the STRIPAK complex was interconnected with the target of rapamycin pathway through Tap42-PP2A cascade. Taken together, our findings revealed that the STRIPAK complex orchestrates cell wall integrity signalling to govern the fungal development and virulence of F. graminearum and highlighted the importance of the STRIPAK complex in fungal virulence.
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Affiliation(s)
- Ahai Chen
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Na Liu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
- College of Plant Health and MedicineQingdao Agricultural UniversityQingdaoChina
| | - Chenghui Xu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Siqi Wu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Chao Liu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Hao Qi
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Yiyi Ren
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Xingmin Han
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Kunlong Yang
- Department of Biomedicine and Food Science, School of Life ScienceJiangsu Normal UniversityXuzhouChina
| | - Xiao Liu
- State Key Laboratory of Mycology, Institute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Yun Chen
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
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8
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Su X, Pang YT, Li W, Gumbart JC, Kelley J, Torres M. N-terminal intrinsic disorder is an ancestral feature of Gγ subunits that influences the balance between different Gβγ signaling axes in yeast. J Biol Chem 2023; 299:104947. [PMID: 37354971 PMCID: PMC10393545 DOI: 10.1016/j.jbc.2023.104947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/02/2023] [Accepted: 06/16/2023] [Indexed: 06/26/2023] Open
Abstract
Activated G protein-coupled receptors promote the dissociation of heterotrimeric G proteins into Gα and Gβγ subunits that bind to effector proteins to drive intracellular signaling responses. In yeast, Gβγ subunits coordinate the simultaneous activation of multiple signaling axes in response to mating pheromones, including MAP kinase (MAPK)-dependent transcription, cell polarization, and cell cycle arrest responses. The Gγ subunit in this complex contains an N-terminal intrinsically disordered region that governs Gβγ-dependent signal transduction in yeast and mammals. Here, we demonstrate that N-terminal intrinsic disorder is likely an ancestral feature that has been conserved across different Gγ subtypes and organisms. To understand the functional contribution of structural disorder in this region, we introduced precise point mutations that produce a stepwise disorder-to-order transition in the N-terminal tail of the canonical yeast Gγ subunit, Ste18. Mutant tail structures were confirmed using circular dichroism and molecular dynamics and then substituted for the wildtype gene in yeast. We find that increasing the number of helix-stabilizing mutations, but not isometric mutation controls, has a negative and proteasome-independent effect on Ste18 protein levels as well as a differential effect on pheromone-induced levels of active MAPK/Fus3, but not MAPK/Kss1. When expressed at wildtype levels, we further show that mutants with an alpha-helical N terminus exhibit a counterintuitive shift in Gβγ signaling that reduces active MAPK/Fus3 levels whilst increasing cell polarization and cell cycle arrest. These data reveal a role for Gγ subunit intrinsically disordered regions in governing the balance between multiple Gβγ signaling axes.
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Affiliation(s)
- Xinya Su
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Yui Tik Pang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Wei Li
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA; Southeast Center for Mathematics and Biology, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - J C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Joshua Kelley
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, USA
| | - Matthew Torres
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA; Southeast Center for Mathematics and Biology, Georgia Institute of Technology, Atlanta, Georgia, USA.
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9
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Onishi M, Kubota M, Duan L, Tian Y, Okamoto K. The GET pathway serves to activate Atg32-mediated mitophagy by ER targeting of the Ppg1-Far complex. Life Sci Alliance 2023; 6:e202201640. [PMID: 36697253 PMCID: PMC9880027 DOI: 10.26508/lsa.202201640] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 01/27/2023] Open
Abstract
Mitophagy removes defective or superfluous mitochondria via selective autophagy. In yeast, the pro-mitophagic protein Atg32 localizes to the mitochondrial surface and interacts with the scaffold protein Atg11 to promote degradation of mitochondria. Although Atg32-Atg11 interactions are thought to be stabilized by Atg32 phosphorylation, how this posttranslational modification is regulated remains obscure. Here, we show that cells lacking the guided entry of the tail-anchored protein (GET) pathway exhibit reduced Atg32 phosphorylation and Atg32-Atg11 interactions, which can be rescued by additional loss of the ER-resident Ppg1-Far complex, a multi-subunit phosphatase negatively acting in mitophagy. In GET-deficient cells, Ppg1-Far is predominantly localized to mitochondria. An artificial ER anchoring of Ppg1-Far in GET-deficient cells significantly ameliorates defects in Atg32-Atg11 interactions and mitophagy. Moreover, disruption of GET and Msp1, an AAA-ATPase that extracts non-mitochondrial proteins localized to the mitochondrial surface, elicits synthetic defects in mitophagy. Collectively, we propose that the GET pathway mediates ER targeting of Ppg1-Far, thereby preventing dysregulated suppression of mitophagy activation.
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Affiliation(s)
- Mashun Onishi
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Mitsutaka Kubota
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Lan Duan
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yuan Tian
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Koji Okamoto
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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10
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Hall RA, Wallace EW. Post-transcriptional control of fungal cell wall synthesis. Cell Surf 2022; 8:100074. [PMID: 35097244 PMCID: PMC8783092 DOI: 10.1016/j.tcsw.2022.100074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 12/21/2022] Open
Abstract
Pathogenic fungi hide from their hosts by camouflage, obscuring immunogenic cell wall components such as beta-glucan with innocuous coverings such as mannoproteins and alpha-glucan that are less readily recognised by the host. Attempts to understand how such processes are regulated have met with varying success. Typically studies focus on understanding the transcriptional response of fungi to either their reservoir environment or the host. However, such approaches do not fully address this research question, due to the layers of post-transcriptional and post-translational regulation that occur within a cell. Although in animals the impact of post-transcriptional and post-translational regulation has been well characterised, our knowledge of these processes in the fungal kingdom is more limited. Mutations in RNA-binding proteins, like Ssd1 and Candida albicans Slr1, affect cell wall composition and fungal virulence indicating that post-transcriptional regulation plays a key role in these processes. Here, we review the current state of knowledge of fungal post-transcriptional regulation, and link this to potential mechanisms of immune evasion by drawing on studies from model yeast and plant pathogenic fungi. We highlight several RNA-binding proteins that regulate cell wall synthesis and could be involved in local translation of cell wall components. Expanding our knowledge on post-transcriptional regulation in human fungal pathogens is essential to fully comprehend fungal virulence strategies and for the design of novel antifungal therapies.
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Affiliation(s)
- Rebecca A. Hall
- Kent Fungal Group, Division of Natural Sciences, School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
| | - Edward W.J. Wallace
- Institute for Cell Biology and SynthSys, School of Biological Sciences, University of Edinburgh, EH9 3FF, United Kingdom
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11
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Afza F, Singh N, Shriya S, Bisoyi P, Kashyap AK, Jain BP. Genome wide identification and analysis of WD40 domain containing proteins in Danio rerio. GENE REPORTS 2022; 26:101426. [DOI: 10.1016/j.genrep.2021.101426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Wernet V, Wäckerle J, Fischer R. The STRIPAK component SipC is involved in morphology and cell-fate determination in the nematode-trapping fungus Duddingtonia flagrans. Genetics 2022; 220:iyab153. [PMID: 34849851 PMCID: PMC8733638 DOI: 10.1093/genetics/iyab153] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/20/2021] [Indexed: 11/29/2022] Open
Abstract
The striatin-interacting phosphatase and kinase (STRIPAK) complex is a highly conserved eukaryotic signaling hub involved in the regulation of many cellular processes. In filamentous fungi, STRIPAK controls multicellular development, hyphal fusion, septation, and pathogenicity. In this study, we analyzed the role of the STRIPAK complex in the nematode-trapping fungus Duddingtonia flagrans which forms three-dimensional, adhesive trapping networks to capture Caenorhabditis elegans. Trap networks consist of several hyphal loops which are morphologically and functionally different from vegetative hyphae. We show that lack of the STRIPAK component SipC (STRIP1/2/HAM-2/PRO22) results in incomplete loop formation and column-like trap structures with elongated compartments. The misshapen or incomplete traps lost their trap identity and continued growth as vegetative hyphae. The same effect was observed in the presence of the actin cytoskeleton drug cytochalasin A. These results could suggest a link between actin and STRIPAK complex functions.
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Affiliation(s)
- Valentin Wernet
- Department of Microbiology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT)—South Campus, D-76131 Karlsruhe, Germany
| | - Jan Wäckerle
- Department of Microbiology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT)—South Campus, D-76131 Karlsruhe, Germany
| | - Reinhard Fischer
- Department of Microbiology, Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT)—South Campus, D-76131 Karlsruhe, Germany
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13
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Kubota M, Okamoto K. The protein N-terminal acetyltransferase A complex contributes to yeast mitophagy via promoting expression and phosphorylation of Atg32. J Biochem 2021; 170:175-182. [PMID: 34115119 DOI: 10.1093/jb/mvab068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
Mitophagy is an evolutionarily conserved catabolic process that selectively degrades damaged or superfluous mitochondria via autophagy. Although mitophagy is considered to be critical to maintain cellular homeostasis, detailed mechanisms of mitophagy remain largely unknown. In the budding yeast Saccharomyces cerevisiae, the protein N-terminal acetyltransferase A (NatA) complex is important for transcriptional induction of the pro-mitophagic factor Atg32 and efficient degradation of mitochondria under prolonged respiratory conditions. Overexpression of Atg32 only partially recovers mitophagy in cells lacking NatA, raising the possibility that NatA may contribute to mitophagy via additional mechanisms. Here we demonstrate that Atg32 phosphorylation, which is required for facilitating mitophagy, is altered in respiring NatA-deficient cells. Hyperphosphorylation of Atg32 partially rescues mitophagy in cells lacking NatA. Notably, mitophagy is mostly restored in NatA-null cells overexpressing hyperphosphorylated Atg32. Loss of NatA does not impair the interaction of phosphorylated Atg32 with Atg11, a scaffold protein critical for selective autophagy, suggesting that NatA-dependent Atg32 phosphorylation promotes mitophagy independently of Atg32-Atg11 interactions. We propose that NatA-mediated protein N-terminal acetylation acts in Atg32 expression and phosphorylation to drive mitophagy.
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Affiliation(s)
- Mitsutaka Kubota
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Koji Okamoto
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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Zhang S, Dong Y, Qiang R, Zhang Y, Zhang X, Chen Y, Jiang P, Ma X, Wu L, Ai J, Gao X, Wang P, Chen J, Chai R. Characterization of Strip1 Expression in Mouse Cochlear Hair Cells. Front Genet 2021; 12:625867. [PMID: 33889175 PMCID: PMC8056008 DOI: 10.3389/fgene.2021.625867] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/12/2021] [Indexed: 12/13/2022] Open
Abstract
Striatin-interacting protein 1 (Strip1) is a core component of the striatin interacting phosphatase and kinase (STRIPAK) complex, which is involved in embryogenesis and development, circadian rhythms, type 2 diabetes, and cancer progression. However, the expression and role of Strip1 in the mammalian cochlea remains unclear. Here we studied the expression and function of Strip1 in the mouse cochlea by using Strip1 knockout mice. We first found that the mRNA and protein expression of Strip1 increases as mice age starting from postnatal day (P) 3 and reaches its highest expression level at P30 and that the expression of Strip1 can be detected by immunofluorescent staining starting from P14 only in cochlear HCs, and not in supporting cells (SCs). Next, we crossed Strip1 heterozygous knockout (Strip +/-) mice to obtain Strip1 homozygous knockout (Strip1-/-) mice for studying the role of Strip1 in cochlear HCs. However, no Strip1-/- mice were obtained and the ratio of Strip +/- to Strip1+/+ mice per litter was about 2:1, which suggested that homozygous Strip1 knockout is embryonic lethal. We measured hearing function and counted the HC number in P30 and P60 Strip +/- mice and found that they had normal hearing ability and HC numbers compared to Strip1+/+ mice. Our study suggested that Strip1 probably play important roles in HC development and maturation, which needs further study in the future.
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Affiliation(s)
- Shasha Zhang
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Ying Dong
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Ruiying Qiang
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Yuan Zhang
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Xiaoli Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Yin Chen
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Pei Jiang
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Xiangyu Ma
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Leilei Wu
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Jingru Ai
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Xia Gao
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Pengjun Wang
- Department of Otorhinolaryngology, Affiliated Sixth People’s Hospital of Shanghai Jiao Tong University, Shanghai, China
| | - Jie Chen
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
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15
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Vještica A, Bérard M, Liu G, Merlini L, Nkosi PJ, Martin SG. Cell cycle-dependent and independent mating blocks ensure fungal zygote survival and ploidy maintenance. PLoS Biol 2021; 19:e3001067. [PMID: 33406066 PMCID: PMC7815208 DOI: 10.1371/journal.pbio.3001067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 01/19/2021] [Accepted: 12/22/2020] [Indexed: 12/22/2022] Open
Abstract
To ensure genome stability, sexually reproducing organisms require that mating brings together exactly 2 haploid gametes and that meiosis occurs only in diploid zygotes. In the fission yeast Schizosaccharomyces pombe, fertilization triggers the Mei3-Pat1-Mei2 signaling cascade, which represses subsequent mating and initiates meiosis. Here, we establish a degron system to specifically degrade proteins postfusion and demonstrate that mating blocks not only safeguard zygote ploidy but also prevent lysis caused by aberrant fusion attempts. Using long-term imaging and flow-cytometry approaches, we identify previously unrecognized and independent roles for Mei3 and Mei2 in zygotes. We show that Mei3 promotes premeiotic S-phase independently of Mei2 and that cell cycle progression is both necessary and sufficient to reduce zygotic mating behaviors. Mei2 not only imposes the meiotic program and promotes the meiotic cycle, but also blocks mating behaviors independently of Mei3 and cell cycle progression. Thus, we find that fungi preserve zygote ploidy and survival by at least 2 mechanisms where the zygotic fate imposed by Mei2 and the cell cycle reentry triggered by Mei3 synergize to prevent zygotic mating. During sexual reproduction, fertilization must happen between exactly two gametes to ensure genome stability. This study shows that two mechanisms – establishment of zygotic fate and re-entry to the cell cycle – combine to prevent fission yeast zygotes fusing with further gametes.
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Affiliation(s)
- Aleksandar Vještica
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- * E-mail: (AV); (SGM)
| | - Melvin Bérard
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Gaowen Liu
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Laura Merlini
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Pedro Junior Nkosi
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Sophie G. Martin
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
- * E-mail: (AV); (SGM)
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Innokentev A, Furukawa K, Fukuda T, Saigusa T, Inoue K, Yamashita SI, Kanki T. Association and dissociation between the mitochondrial Far complex and Atg32 regulate mitophagy. eLife 2020; 9:63694. [PMID: 33317697 PMCID: PMC7738187 DOI: 10.7554/elife.63694] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 11/27/2020] [Indexed: 12/17/2022] Open
Abstract
Mitophagy plays an important role in mitochondrial homeostasis. In yeast, the phosphorylation of the mitophagy receptor Atg32 by casein kinase 2 is essential for mitophagy. This phosphorylation is counteracted by the yeast equivalent of the STRIPAK complex consisting of the PP2A-like protein phosphatase Ppg1 and Far3-7-8-9-10-11 (Far complex), but the underlying mechanism remains elusive. Here we show that two subpopulations of the Far complex reside in the mitochondria and endoplasmic reticulum, respectively, and play distinct roles; the former inhibits mitophagy via Atg32 dephosphorylation, and the latter regulates TORC2 signaling. Ppg1 and Far11 form a subcomplex, and Ppg1 activity is required for the assembling integrity of Ppg1-Far11-Far8. The Far complex preferentially interacts with phosphorylated Atg32, and this interaction is weakened by mitophagy induction. Furthermore, the artificial tethering of Far8 to Atg32 prevents mitophagy. Taken together, the Ppg1-mediated Far complex formation and its dissociation from Atg32 are crucial for mitophagy regulation.
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Affiliation(s)
- Aleksei Innokentev
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kentaro Furukawa
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Tomoyuki Fukuda
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Tetsu Saigusa
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Keiichi Inoue
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Shun-Ichi Yamashita
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Tomotake Kanki
- Department of Cellular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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17
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Rodriguez-Cupello C, Dam M, Serini L, Wang S, Lindgren D, Englund E, Kjellman P, Axelson H, García-Mariscal A, Madsen CD. The STRIPAK Complex Regulates Response to Chemotherapy Through p21 and p27. Front Cell Dev Biol 2020; 8:146. [PMID: 32258031 PMCID: PMC7089963 DOI: 10.3389/fcell.2020.00146] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/21/2020] [Indexed: 12/18/2022] Open
Abstract
The STRIPAK complex has been linked to a variety of biological processes taking place during embryogenesis and development, but its role in cancer has only just started to be defined. Here, we expand on previous work indicating a role for the scaffolding protein STRIP1 in cancer cell migration and metastasis. We show that cell cycle arrest and decreased proliferation are seen upon loss of STRIP1 in MDA-MB-231 cells due to the induction of cyclin dependent kinase inhibitors, including p21 and p27. We demonstrate that p21 and p27 induction is observed in a subpopulation of cells having low DNA damage response and that the p21high/γH2AXlow ratio within single cells can be rescued by depleting MST3&4 kinases. While the loss of STRIP1 decreases cell proliferation and tumor growth, cells treated with low dosage of chemotherapeutics in vitro paradoxically escape therapy-induced senescence and begin to proliferate after recovery. This corroborates with already known research on the dual role of p21 and indicates that STRIP1 also plays a contradictory role in breast cancer, suppressing tumor growth, but once treated with chemotherapeutics, allowing for possible recurrence and decreased patient survival.
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Affiliation(s)
- Carmen Rodriguez-Cupello
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Monica Dam
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Laura Serini
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Shan Wang
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - David Lindgren
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Emelie Englund
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Pontus Kjellman
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Håkan Axelson
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Alberto García-Mariscal
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Chris D Madsen
- Division of Translational Cancer Research, Department of Laboratory Medicine, Lund University, Lund, Sweden
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Prabhakar A, Vadaie N, Krzystek T, Cullen PJ. Proteins That Interact with the Mucin-Type Glycoprotein Msb2p Include a Regulator of the Actin Cytoskeleton. Biochemistry 2019; 58:4842-4856. [PMID: 31710471 DOI: 10.1021/acs.biochem.9b00725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Transmembrane mucin-type glycoproteins can regulate signal transduction pathways. In yeast, signaling mucins regulate mitogen-activated protein kinase (MAPK) pathways that induce cell differentiation to filamentous growth (fMAPK pathway) and the response to osmotic stress (HOG pathway). To explore regulatory aspects of signaling mucin function, protein microarrays were used to identify proteins that interact with the cytoplasmic domain of the mucin-like glycoprotein Msb2p. Eighteen proteins were identified that comprised functional categories of metabolism, actin filament capping and depolymerization, aerobic and anaerobic growth, chromatin organization and bud growth, sporulation, ribosome biogenesis, protein modification by iron-sulfur clusters, RNA catabolism, and DNA replication and DNA repair. A subunit of actin capping protein, Cap2p, interacted with the cytoplasmic domain of Msb2p. Cells lacking Cap2p showed altered localization of Msb2p and increased levels of shedding of Msb2p's N-terminal glycosylated domain. Consistent with its role in regulating the actin cytoskeleton, Cap2p was required for enhanced cell polarization during filamentous growth. Our study identifies proteins that connect a signaling mucin to diverse cellular processes and may provide insight into new aspects of mucin function.
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Affiliation(s)
- Aditi Prabhakar
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
| | - Nadia Vadaie
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
| | - Thomas Krzystek
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
| | - Paul J Cullen
- Department of Biological Sciences , State University of New York at Buffalo , Buffalo , New York 14260-1300 , United States
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19
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Kück U, Radchenko D, Teichert I. STRIPAK, a highly conserved signaling complex, controls multiple eukaryotic cellular and developmental processes and is linked with human diseases. Biol Chem 2019; 400:1005-1022. [PMID: 31042639 DOI: 10.1515/hsz-2019-0173] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 03/28/2019] [Indexed: 01/17/2023]
Abstract
The striatin-interacting phosphatases and kinases (STRIPAK) complex is evolutionary highly conserved and has been structurally and functionally described in diverse lower and higher eukaryotes. In recent years, this complex has been biochemically characterized better and further analyses in different model systems have shown that it is also involved in numerous cellular and developmental processes in eukaryotic organisms. Further recent results have shown that the STRIPAK complex functions as a macromolecular assembly communicating through physical interaction with other conserved signaling protein complexes to constitute larger dynamic protein networks. Here, we will provide a comprehensive and up-to-date overview of the architecture, function and regulation of the STRIPAK complex and discuss key issues and future perspectives, linked with human diseases, which may form the basis of further research endeavors in this area. In particular, the investigation of bi-directional interactions between STRIPAK and other signaling pathways should elucidate upstream regulators and downstream targets as fundamental parts of a complex cellular network.
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Affiliation(s)
- Ulrich Kück
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Daria Radchenko
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Ines Teichert
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
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20
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La Marca JE, Diepstraten ST, Hodge AL, Wang H, Hart AH, Richardson HE, Somers WG. Strip and Cka negatively regulate JNK signalling during Drosophila spermatogenesis. Development 2019; 146:dev.174292. [PMID: 31164352 DOI: 10.1242/dev.174292] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/24/2019] [Indexed: 12/16/2022]
Abstract
One fundamental property of a stem cell niche is the exchange of molecular signals between its component cells. Niche models, such as the Drosophila melanogaster testis, have been instrumental in identifying and studying the conserved genetic factors that contribute to niche molecular signalling. Here, we identify jam packed (jam), an allele of Striatin interacting protein (Strip), which is a core member of the highly conserved Striatin-interacting phosphatase and kinase (STRIPAK) complex. In the developing Drosophila testis, Strip cell-autonomously regulates the differentiation and morphology of the somatic lineage, and non-cell-autonomously regulates the proliferation and differentiation of the germline lineage. Mechanistically, Strip acts in the somatic lineage with its STRIPAK partner, Connector of kinase to AP-1 (Cka), where they negatively regulate the Jun N-terminal kinase (JNK) signalling pathway. Our study reveals a novel role for Strip/Cka in JNK pathway regulation during spermatogenesis within the developing Drosophila testis.
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Affiliation(s)
- John E La Marca
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia 3086
| | - Sarah T Diepstraten
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia 3086
| | - Amy L Hodge
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia 3086
| | - Hongyan Wang
- Neuroscience and Behavioral Disorders Program, Duke-National University of Singapore Graduate Medical School, Singapore 169857.,National University of Singapore Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - Adam H Hart
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia 3086
| | - Helena E Richardson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia 3086
| | - W Gregory Somers
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia 3086
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21
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Phospho-peptide binding domains in S. cerevisiae model organism. Biochimie 2019; 163:117-127. [PMID: 31194995 DOI: 10.1016/j.biochi.2019.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 06/06/2019] [Indexed: 02/07/2023]
Abstract
Protein phosphorylation is one of the main mechanisms by which signals are transmitted in eukaryotic cells, and it plays a crucial regulatory role in almost all cellular processes. In yeast, more than half of the proteins are phosphorylated in at least one site, and over 20,000 phosphopeptides have been experimentally verified. However, the functional consequences of these phosphorylation events for most of the identified phosphosites are unknown. A family of protein interaction domains selectively recognises phosphorylated motifs to recruit regulatory proteins and activate signalling pathways. Nine classes of dedicated modules are coded by the yeast genome: 14-3-3, FHA, WD40, BRCT, WW, PBD, and SH2. The recognition specificity relies on a few residues on the target protein and has coevolved with kinase specificity. In the present study, we review the current knowledge concerning yeast phospho-binding domains and their networks. We emphasise the relevance of both positive and negative amino acid selection to orchestrate the highly regulated outcomes of inter- and intra-molecular interactions. Finally, we hypothesise that only a small fraction of yeast phosphorylation events leads to the creation of a docking site on the target molecule, while many have a direct effect on the protein or, as has been proposed, have no function at all.
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Assembly of a heptameric STRIPAK complex is required for coordination of light-dependent multicellular fungal development with secondary metabolism in Aspergillus nidulans. PLoS Genet 2019; 15:e1008053. [PMID: 30883543 PMCID: PMC6438568 DOI: 10.1371/journal.pgen.1008053] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/28/2019] [Accepted: 02/28/2019] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic striatin forms striatin-interacting phosphatase and kinase (STRIPAK) complexes that control many cellular processes including development, cellular transport, signal transduction, stem cell differentiation and cardiac functions. However, detailed knowledge of complex assembly and its roles in stress responses are currently poorly understood. Here, we discovered six striatin (StrA) interacting proteins (Sips), which form a heptameric complex in the filamentous fungus Aspergillus nidulans. The complex consists of the striatin scaffold StrA, the Mob3-type kinase coactivator SipA, the SIKE-like protein SipB, the STRIP1/2 homolog SipC, the SLMAP-related protein SipD and the catalytic and regulatory phosphatase 2A subunits SipE (PpgA), and SipF, respectively. Single and double deletions of the complex components result in loss of multicellular light-dependent fungal development, secondary metabolite production (e.g. mycotoxin Sterigmatocystin) and reduced stress responses. sipA (Mob3) deletion is epistatic to strA deletion by supressing all the defects caused by the lack of striatin. The STRIPAK complex, which is established during vegetative growth and maintained during the early hours of light and dark development, is mainly formed on the nuclear envelope in the presence of the scaffold StrA. The loss of the scaffold revealed three STRIPAK subcomplexes: (I) SipA only interacts with StrA, (II) SipB-SipD is found as a heterodimer, (III) SipC, SipE and SipF exist as a heterotrimeric complex. The STRIPAK complex is required for proper expression of the heterotrimeric VeA-VelB-LaeA complex which coordinates fungal development and secondary metabolism. Furthermore, the STRIPAK complex modulates two important MAPK pathways by promoting phosphorylation of MpkB and restricting nuclear shuttling of MpkC in the absence of stress conditions. SipB in A. nidulans is similar to human suppressor of IKK-ε(SIKE) protein which supresses antiviral responses in mammals, while velvet family proteins show strong similarity to mammalian proinflammatory NF-KB proteins. The presence of these proteins in A. nidulans further strengthens the hypothesis that mammals and fungi use similar proteins for their immune response and secondary metabolite production, respectively. The multisubunit STRIPAK complex has been studied from yeast to human and plays a range of roles from cell-cycle arrest, fruit body formation to neuronal functions. Molecular assembly of the STRIPAK complex and its roles in stress responses are not well-documented. Fungi, with an estimated 1.5 million members are friends and foes of mankind, acting as pathogens, natural product and enzyme producers. In filamentous fungus Aspergillus nidulans, we found a heptameric STRIPAK core complex made from three subcomplexes, which sits on the nuclear envelope and coordinates signal influx for light-dependent fungal development, secondary metabolism and stress responses. STRIPAK complex controls activities of two major Mitogen Activated Protein Kinase (MAPK) signaling pathways through either promoting their phosphorylation or limiting their nuclear localization under resting conditions. These findings establish a basis for how fungi govern signal influx by using multimeric scaffold protein complexes on the nuclear envelope to control different downstream pathways.
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Chen Z, Zhang Y, Zhao X. FAM40A alters the cytoskeleton of podocytes in familial focal and segmental glomerulosclerosis by regulating F-actin and nephrin. Arch Med Sci 2019; 15:165-173. [PMID: 30697267 PMCID: PMC6348344 DOI: 10.5114/aoms.2018.73138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/29/2017] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Familial focal and segmental glomerulosclerosis (FFSGS) was found in a large cohort of patients in our previous study. Under the sponsorship of the National Natural Science Foundation of China, we conducted linkage analysis and full exon sequencing on the genomes of 54 patients diagnosed with FFSGS. The results revealed a FAM40A gene signature in those patients. To determine whether FAM40A was associated with podocyte lesions and whether changes in the podocyte cytoskeleton could affect podocyte function, mouse podocytes (MPs) were used in this study. MATERIAL AND METHODS FAM40A silencing, over-expression and mutant-type over-expression models of renal MPs were established, whereby roles of wild-type FAM40A and mutant FAM40A (c.1562T>C, p521M>T) in regulating the function of the MP cytoskeleton were explored by using cellular immunofluorescence, RT-qPCR and Western blot. RESULTS FAM40A was expressed and localized in MPs and significantly enriched in the nucleus and perinuclear zone. Changes of FAM40A expression altered the morphology of the MPs and their cytoskeletal organization, which was characterized by disordered distribution of F-actin, loss of the foot process architecture and the functional protein of the slit diaphragm nephrin (p < 0.05 or p < 0.01). FAM40A mutation (p521M>T) led to the formation of round and blunt morphology of the MPs and loss of the foot-process structure. In addition, expression of the cytoskeletal protein F-actin was increased and concentrated in FAM40A mutated cells, whereas the expression of nephrin decreased in those cells (p < 0.01). CONCLUSIONS FAM40A played an important role in maintaining the normal morphology and function of MPs by stabilizing the cytoskeleton of MPs. Moreover, mutant FAM40A (p521M>T) was able to alter the morphology and cytoskeleton of the MPs, and to decrease the expression of nephrin, which may be the main factor contributing to FSGS.
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Affiliation(s)
- Zhou Chen
- Division of Nephrology, Shanghai Changzheng Hospital of Second Military Medical University, Kidney Institute of Chinese People’s Liberation Army, Shanghai, China
- Department of Nephrology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Yinghui Zhang
- Division of Nephrology, Shanghai Changzheng Hospital of Second Military Medical University, Kidney Institute of Chinese People’s Liberation Army, Shanghai, China
- Department of Nephrology, Shanghai Yangpu District Central Hospital of Tongji University, Shanghai, China
| | - Xuezhi Zhao
- Division of Nephrology, Shanghai Changzheng Hospital of Second Military Medical University, Kidney Institute of Chinese People’s Liberation Army, Shanghai, China
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Suryavanshi N, Furmston J, Ridley AJ. The STRIPAK complex components FAM40A and FAM40B regulate endothelial cell contractility via ROCKs. BMC Cell Biol 2018; 19:26. [PMID: 30509168 PMCID: PMC6276190 DOI: 10.1186/s12860-018-0175-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 10/12/2018] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Endothelial cells provide a barrier between blood and tissues, which is regulated to allow molecules and cells in out of tissues. Patients with cerebral cavernous malformations (CCM) have dilated leaky blood vessels, especially in the central nervous system. A subset of these patients has loss-of-function mutations in CCM3. CCM3 is part of the STRIPAK protein complex that includes the little-characterized proteins FAM40A and FAM40B. RESULTS We show here that FAM40A and FAM40B can interact with CCM3. Knockdown of CCM3, FAM40A or FAM40B in endothelial cells by RNAi causes an increase in stress fibers and a reduction in loop formation in an in vitro angiogenesis assay, which can be reverted by inhibiting the Rho-regulated ROCK kinases. FAM40B depletion also increases endothelial permeability. CONCLUSIONS These results demonstrate the importance of the FAM40 proteins for endothelial cell physiology, and suggest that they act as part of the CCM3-containing STRIPAK complex.
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Affiliation(s)
- Narendra Suryavanshi
- Randall Centre for Cell and Molecular Biophysics, King’s College London, New Hunt’s House, Guy’s Campus, London, SE1 1UL UK
| | - Joanna Furmston
- Randall Centre for Cell and Molecular Biophysics, King’s College London, New Hunt’s House, Guy’s Campus, London, SE1 1UL UK
| | - Anne J. Ridley
- Randall Centre for Cell and Molecular Biophysics, King’s College London, New Hunt’s House, Guy’s Campus, London, SE1 1UL UK
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University Walk, University of Bristol, Bristol, BS8 1TD UK
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J Reschka E, Nordzieke S, Valerius O, Braus GH, Pöggeler S. A novel STRIPAK complex component mediates hyphal fusion and fruiting-body development in filamentous fungi. Mol Microbiol 2018; 110:513-532. [PMID: 30107058 DOI: 10.1111/mmi.14106] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2018] [Indexed: 01/17/2023]
Abstract
The STRIPAK complex is involved in growth, cell fusion, development and signaling pathways, and thus malfunctions in the human STRIPAK complex often result in severe neuronal diseases and cancer. Despite the high degree of general conservation throughout the complex, several STRIPAK complex-associated small coiled-coil proteins of animals and yeasts are not conserved across species. As there are no data for filamentous ascomycetes, we addressed this through affinity purification with HA-tagged striatin ortholog PRO11 in Sordaria macrospora. Combining the method with liquid chromatography-mass spectrometry, we were able to co-purify STRIPAK complex interactor 1 (SCI1), the first STRIPAK-associated small coiled-coil protein in filamentous ascomycetes. Using yeast two-hybrid experiments, we identified SCI1 protein regions required for SCI1-PRO11 interaction, dimerization of SCI1 and interaction with other STRIPAK components. Further, both proteins PRO11 and SCI1 co-localize with the nuclear basket protein SmPOM152 at the nuclear envelope. Expression of the gene sci1 occurs during early developmental stages of S. macrospora, and the protein SCI1 in combination with PRO11 is required for cell fusion, vegetative growth and sexual development. The results of the present study will help to understand the underlying molecular mechanisms of STRIPAK signaling and function in cellular development and diseases in higher eukaryotes.
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Affiliation(s)
- Eva J Reschka
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany
| | - Steffen Nordzieke
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany
| | - Oliver Valerius
- Institute of Microbiology and Genetics, Department of Molecular Microbiology & Genetics, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August University, Göttingen, Germany
| | - Gerhard H Braus
- Institute of Microbiology and Genetics, Department of Molecular Microbiology & Genetics, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August University, Göttingen, Germany
| | - Stefanie Pöggeler
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August University, Göttingen, Germany
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Arellano VJ, Martinell García P, Rodríguez Plaza JG, Lara Ortiz MT, Schreiber G, Volkmer R, Klipp E, Rio GD. An Antimicrobial Peptide Induces FIG1-Dependent Cell Death During Cell Cycle Arrest in Yeast. Front Microbiol 2018; 9:1240. [PMID: 29963019 PMCID: PMC6010521 DOI: 10.3389/fmicb.2018.01240] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 05/23/2018] [Indexed: 12/30/2022] Open
Abstract
Although most antibiotics act on cells that are actively dividing and non-dividing cells such as in microbe sporulation or cancer stem cells represent a new paradigm for the control of disease. In addition to their relevance to health, such antibiotics may promote our understanding of the relationship between the cell cycle and cell death. No antibiotic specifically acting on microbial cells arrested in their cell cycle has been identified until the present time. In this study we used an antimicrobial peptide derived from α-pheromone, IP-1, targeted against MATa Saccharomyces cerevisiae cells in order to assess its dependence on cell cycle arrest to kill cells. Analysis by flow cytometry and fluorescence microscopy of various null mutations of genes involved in biological processes activated by the pheromone pathway (the mitogen-activated protein kinase pathway, cell cycle arrest, cell proliferation, autophagy, calcium influx) showed that IP-1 requires arrest in G0/G1 in order to kill yeast cells. Isolating cells in different cell cycle phases by elutriation provided further evidence that entry into cell cycle arrest, and not into G1 phase, is necessary if our peptide is to kill yeast cells. We also describe a variant of IP-1 that does not activate the pheromone pathway and consequently does not kill yeast cells that express the pheromone’s receptor; the use of this variant peptide in combination with different cell cycle inhibitors that induce cell cycle arrest independently of the pheromone pathway confirmed that it is cell cycle arrest that is required for the cell death induced by this peptide in yeast. We show that the cell death induced by IP-1 differs from that induced by α-pheromone and depends on FIG1 in a way independent of the cell cycle arrest induced by the pheromone. Thus, IP-1 is the first molecule described that specifically kills microbial cells during cell cycle arrest, a subject of interest beyond the process of mating in yeast cells. The experimental system described in this study should be useful in the study of the mechanisms at play in the communication between cell cycle arrest and cell death on other organisms, hence promoting the development of new antibiotics.
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Affiliation(s)
- Vladimir J Arellano
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Paula Martinell García
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Theoretische Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Maria T Lara Ortiz
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Rudolf Volkmer
- Institut für Medizinische Immunologie, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
| | - Edda Klipp
- Theoretische Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gabriel Del Rio
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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The PP2A-like Protein Phosphatase Ppg1 and the Far Complex Cooperatively Counteract CK2-Mediated Phosphorylation of Atg32 to Inhibit Mitophagy. Cell Rep 2018; 23:3579-3590. [DOI: 10.1016/j.celrep.2018.05.064] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/07/2018] [Accepted: 05/17/2018] [Indexed: 12/13/2022] Open
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Campos SE, Avelar-Rivas JA, Garay E, Juárez-Reyes A, DeLuna A. Genomewide mechanisms of chronological longevity by dietary restriction in budding yeast. Aging Cell 2018; 17:e12749. [PMID: 29575540 PMCID: PMC5946063 DOI: 10.1111/acel.12749] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 12/16/2022] Open
Abstract
Dietary restriction is arguably the most promising nonpharmacological intervention to extend human life and health span. Yet, only few genetic regulators mediating the cellular response to dietary restriction are known, and the question remains which other regulatory factors are involved. Here, we measured at the genomewide level the chronological lifespan of Saccharomyces cerevisiae gene deletion strains under two nitrogen source regimens, glutamine (nonrestricted) and γ‐aminobutyric acid (restricted). We identified 473 mutants with diminished or enhanced extension of lifespan. Functional analysis of such dietary restriction genes revealed novel processes underlying longevity by the nitrogen source quality, which also allowed us to generate a prioritized catalogue of transcription factors orchestrating the dietary restriction response. Importantly, deletions of transcription factors Msn2, Msn4, Snf6, Tec1, and Ste12 resulted in diminished lifespan extension and defects in cell cycle arrest upon nutrient starvation, suggesting that regulation of the cell cycle is a major mechanism of chronological longevity. We further show that STE12 overexpression is enough to extend lifespan, linking the pheromone/invasive growth pathway with cell survivorship. Our global picture of the genetic players of longevity by dietary restriction highlights intricate regulatory cross‐talks in aging cells.
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Affiliation(s)
- Sergio E. Campos
- Unidad de Genómica Avanzada (Langebio); Centro de Investigación y de Estudios Avanzados del IPN; Irapuato Guanajuato Mexico
| | - J. Abraham Avelar-Rivas
- Unidad de Genómica Avanzada (Langebio); Centro de Investigación y de Estudios Avanzados del IPN; Irapuato Guanajuato Mexico
| | - Erika Garay
- Unidad de Genómica Avanzada (Langebio); Centro de Investigación y de Estudios Avanzados del IPN; Irapuato Guanajuato Mexico
| | - Alejandro Juárez-Reyes
- Unidad de Genómica Avanzada (Langebio); Centro de Investigación y de Estudios Avanzados del IPN; Irapuato Guanajuato Mexico
| | - Alexander DeLuna
- Unidad de Genómica Avanzada (Langebio); Centro de Investigación y de Estudios Avanzados del IPN; Irapuato Guanajuato Mexico
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Zhang H, Mukherjee M, Kim J, Yu W, Shim W. Fsr1, a striatin homologue, forms an endomembrane-associated complex that regulates virulence in the maize pathogen Fusarium verticillioides. MOLECULAR PLANT PATHOLOGY 2018; 19:812-826. [PMID: 28467007 PMCID: PMC6638083 DOI: 10.1111/mpp.12562] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/06/2017] [Indexed: 05/09/2023]
Abstract
Fsr1, a homologue of mammalian striatin, containing multiple protein-binding domains and a coiled-coil (CC) domain, is critical for Fusarium verticillioides virulence. In mammals, striatin interacts with multiple proteins to form a STRIPAK (striatin-interacting phosphatase and kinase) complex that regulates a variety of developmental processes and cellular mechanisms. In this study, we identified the homologue of a key mammalian STRIPAK component STRIP1/2 (striatin-interacting proteins 1 and 2) in F. verticillioides, FvStp1, which interacts with Fsr1 in vivo. Gene deletion analysis indicates that FvStp1 is critical for F. verticillioides stalk rot virulence. In addition, we identified three proteins, designated FvCyp1, FvScp1 and FvSel1, which interact with the Fsr1 CC domain via a yeast two-hybrid screen. Importantly, FvCyp1, FvScp1 and FvSel1 co-localize to endomembrane structures, each having a preferred localization in the cell, and they are all required for F. verticillioides stalk rot virulence. Moreover, these proteins are necessary for the correct localization of Fsr1 to the endoplasmic reticulum (ER) and nuclear envelope. Thus, we identified several novel components in the STRIPAK complex that regulates F. verticillioides virulence, and propose that the correct organization and localization of Fsr1 are critical for STRIPAK complex function.
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Affiliation(s)
- Huan Zhang
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Mala Mukherjee
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Jung‐Eun Kim
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Wenying Yu
- College of Life Science, Fujian Agricultural and Forestry UniversityFuzhou 350002China
| | - Won‐Bo Shim
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
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STRIP1, a core component of STRIPAK complexes, is essential for normal mesoderm migration in the mouse embryo. Proc Natl Acad Sci U S A 2017; 114:E10928-E10936. [PMID: 29203676 PMCID: PMC5754794 DOI: 10.1073/pnas.1713535114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Striatin-interacting phosphatases and kinases (STRIPAK) complexes can regulate the cytoskeleton and cell migration in cell lines, but their roles in vivo in mammals are not known. Here, we show that mouse embryos that lack striatin-interacting protein 1 (STRIP1), a core component of STRIPAK complexes, arrest at midgestation with striking morphological defects. Strip1 mutants lack a trunk, and both paraxial and axial mesoderm fail to elongate along the anterior–posterior body axis. Mesodermal cells from Strip1 mutants have defects in actin organization, focal adhesions, and cell migration that can account for the failure of normal mesoderm migration. The findings demonstrate that STRIPAK is a critical regulator of mammalian cell migration and is likely to have important roles in tumor progression as well as development. Regulated mesoderm migration is necessary for the proper morphogenesis and organ formation during embryonic development. Cell migration and its dependence on the cytoskeleton and signaling machines have been studied extensively in cultured cells; in contrast, remarkably little is known about the mechanisms that regulate mesoderm cell migration in vivo. Here, we report the identification and characterization of a mouse mutation in striatin-interacting protein 1 (Strip1) that disrupts migration of the mesoderm after the gastrulation epithelial-to-mesenchymal transition (EMT). STRIP1 is a core component of the biochemically defined mammalian striatin-interacting phosphatases and kinase (STRIPAK) complexes that appear to act through regulation of protein phosphatase 2A (PP2A), but their functions in mammals in vivo have not been examined. Strip1-null mutants arrest development at midgestation with profound disruptions in the organization of the mesoderm and its derivatives, including a complete failure of the anterior extension of axial mesoderm. Analysis of cultured mesoderm explants and mouse embryonic fibroblasts from null mutants shows that the mesoderm migration defect is correlated with decreased cell spreading, abnormal focal adhesions, changes in the organization of the actin cytoskeleton, and decreased velocity of cell migration. The results show that STRIPAK complexes are essential for cell migration and tissue morphogenesis in vivo.
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Maheshwari R, Pushpa K, Subramaniam K. A role for post-transcriptional control of endoplasmic reticulum dynamics and function in C. elegans germline stem cell maintenance. Development 2016; 143:3097-108. [PMID: 27510976 DOI: 10.1242/dev.134056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 07/21/2016] [Indexed: 01/02/2023]
Abstract
Membrane-bound receptors, which are crucial for mediating several key developmental signals, are synthesized on endoplasmic reticulum (ER). The functional integrity of ER must therefore be important for the regulation of at least some developmental programs. However, the developmental control of ER function is not well understood. Here, we identify the C. elegans protein FARL-11, an ortholog of the mammalian STRIPAK complex component STRIP1/2 (FAM40A/B), as an ER protein. In the C. elegans embryo, we find that FARL-11 is essential for the cell cycle-dependent morphological changes of ER and for embryonic viability. In the germline, FARL-11 is required for normal ER morphology and for membrane localization of the GLP-1/Notch receptor involved in germline stem cell (GSC) maintenance. Furthermore, we provide evidence that PUF-8, a key translational regulator in the germline, promotes the translation of farl-11 mRNA. These findings reveal that ER form and function in the C. elegans germline are post-transcriptionally regulated and essential for the niche-GSC signaling mediated by GLP-1.
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Affiliation(s)
- Richa Maheshwari
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Kumari Pushpa
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Kuppuswamy Subramaniam
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India Department of Biotechnology, Indian Institute of Technology - Madras, Chennai 600036, India
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Wang CL, Shim WB, Shaw BD. The Colletotrichum graminicola striatin orthologue Str1 is necessary for anastomosis and is a virulence factor. MOLECULAR PLANT PATHOLOGY 2016; 17:931-42. [PMID: 26576029 PMCID: PMC6638439 DOI: 10.1111/mpp.12339] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 05/24/2023]
Abstract
Striatin family proteins are key regulators in signalling pathways in fungi and animals. These scaffold proteins contain four conserved domains: a caveolin-binding domain, a coiled-coil motif and a calmodulin-binding domain at the N-terminus, and a WD-repeat domain at the C-terminus. Fungal striatin orthologues are associated with sexual development, hyphal growth and plant pathogenesis. In Fusarium verticillioides, the striatin orthologue Fsr1 promotes virulence in the maize stalk. The relationship between fungal striatins and pathogenicity remains largely unexplored. In this study, we demonstrate that the Colletotrichum graminicola striatin orthologue Str1 is required for full stalk rot and leaf blight virulence in maize. Pathogenicity assays show that the striatin mutant strain (Δstr1) produces functional appressoria, but infection and colonization are attenuated. Additional phenotypes of the Δstr1 mutant include reduced radial growth and compromised hyphal fusion. In comparison with the wild-type, Δstr1 also shows a defect in sexual development and produces fewer and shorter conidia. Together with the fact that F. verticillioides fsr1 can complement Δstr1, our results indicate that C. graminicola Str1 shares five phenotypes with striatin orthologues in other fungal species: hyphal growth, hyphal fusion, conidiation, sexual development and virulence. We propose that fungal striatins, like mammalian striatins, act as scaffolding molecules that cross-link multiple signal transduction pathways.
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Affiliation(s)
- Chih-Li Wang
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, TX, USA
- Department of Plant Pathology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Won-Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, TX, USA
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, TX, USA
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Beier A, Teichert I, Krisp C, Wolters DA, Kück U. Catalytic Subunit 1 of Protein Phosphatase 2A Is a Subunit of the STRIPAK Complex and Governs Fungal Sexual Development. mBio 2016; 7:e00870-16. [PMID: 27329756 PMCID: PMC4916389 DOI: 10.1128/mbio.00870-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED The generation of complex three-dimensional structures is a key developmental step for most eukaryotic organisms. The details of the molecular machinery controlling this step remain to be determined. An excellent model system to study this general process is the generation of three-dimensional fruiting bodies in filamentous fungi like Sordaria macrospora Fruiting body development is controlled by subunits of the highly conserved striatin-interacting phosphatase and kinase (STRIPAK) complex, which has been described in organisms ranging from yeasts to humans. The highly conserved heterotrimeric protein phosphatase PP2A is a subunit of STRIPAK. Here, catalytic subunit 1 of PP2A was functionally characterized. The Δpp2Ac1 strain is sterile, unable to undergo hyphal fusion, and devoid of ascogonial septation. Further, PP2Ac1, together with STRIPAK subunit PRO22, governs vegetative and stress-related growth. We revealed in vitro catalytic activity of wild-type PP2Ac1, and our in vivo analysis showed that inactive PP2Ac1 blocks the complementation of the sterile deletion strain. Tandem affinity purification, followed by mass spectrometry and yeast two-hybrid analysis, verified that PP2Ac1 is a subunit of STRIPAK. Further, these data indicate links between the STRIPAK complex and other developmental signaling pathways, implying the presence of a large interconnected signaling network that controls eukaryotic developmental processes. The insights gained in our study can be transferred to higher eukaryotes and will be important for understanding eukaryotic cellular development in general. IMPORTANCE The striatin-interacting phosphatase and kinase (STRIPAK) complex is highly conserved from yeasts to humans and is an important regulator of numerous eukaryotic developmental processes, such as cellular signaling and cell development. Although functional insights into the STRIPAK complex are accumulating, the detailed molecular mechanisms of single subunits are only partially understood. The first fungal STRIPAK was described in Sordaria macrospora, which is a well-established model organism used to study the formation of fungal fruiting bodies, three-dimensional organ-like structures. We analyzed STRIPAK subunit PP2Ac1, catalytic subunit 1 of protein phosphatase PP2A, to study the importance of the catalytic activity of this protein during sexual development. The results of our yeast two-hybrid analysis and tandem affinity purification, followed by mass spectrometry, indicate that PP2Ac1 activity connects STRIPAK with other signaling pathways and thus forms a large interconnected signaling network.
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Affiliation(s)
- Anna Beier
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
| | - Ines Teichert
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
| | - Christoph Krisp
- Lehrstuhl für Analytische Chemie, Ruhr-Universität, Bochum, Germany
| | - Dirk A Wolters
- Lehrstuhl für Analytische Chemie, Ruhr-Universität, Bochum, Germany
| | - Ulrich Kück
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
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Kück U, Beier AM, Teichert I. The composition and function of the striatin-interacting phosphatases and kinases (STRIPAK) complex in fungi. Fungal Genet Biol 2015; 90:31-38. [PMID: 26439752 DOI: 10.1016/j.fgb.2015.10.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 09/30/2015] [Accepted: 10/02/2015] [Indexed: 02/06/2023]
Abstract
The striatin-interacting phosphatases and kinases (STRIPAK) complex is a highly conserved eukaryotic protein complex that was recently described for diverse animal and fungal species. Here, we summarize our current knowledge about the composition and function of the STRIPAK complex from the ascomycete Sordaria macrospora, which we discovered by investigating sexually sterile mutants (pro), having a defect in fruiting body development. Mass spectrometry and yeast two-hybrid analysis defined core subunits of the STRIPAK complex, which have structural homologs in animal and other fungal organisms. These subunits (and their mammalian homologs) are PRO11 (striatin), PRO22 (STRIP1/2), SmMOB3 (Mob3), PRO45 (SLMAP), and PP2AA, the structural, and PP2Ac, the catalytic subunits of protein phosphatase 2A (PP2A). Beside fruiting body formation, the STRIPAK complex controls vegetative growth and hyphal fusion in S. macrospora. Although the contribution of single subunits to diverse cellular and developmental processes is not yet fully understood, functional analysis has already shown that mammalian homologs are able to substitute the function of distinct fungal STRIPAK subunits. This underscores the view that fungal model organisms serve as useful tools to get a molecular insight into cellular and developmental processes of eukaryotes in general. Future work will unravel the precise localization of single subunits within the cell and decipher their STRIPAK-related and STRIPAK-independent functions. Finally, evidence is accumulating that there is a crosstalk between STRIPAK and various signaling pathways, suggesting that eukaryotic development is dependent on STRIPAK signaling.
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Affiliation(s)
- Ulrich Kück
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Anna M Beier
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
| | - Ines Teichert
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
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Frey S, Reschka EJ, Pöggeler S. Germinal Center Kinases SmKIN3 and SmKIN24 Are Associated with the Sordaria macrospora Striatin-Interacting Phosphatase and Kinase (STRIPAK) Complex. PLoS One 2015; 10:e0139163. [PMID: 26418262 PMCID: PMC4587736 DOI: 10.1371/journal.pone.0139163] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/08/2015] [Indexed: 11/18/2022] Open
Abstract
The striatin-interacting phosphatase and kinase (STRIPAK) complex is composed of striatin, protein phosphatase PP2A and protein kinases that regulate development in animals and fungi. In the filamentous ascomycete Sordaria macrospora, it is required for fruiting-body development and cell fusion. Here, we report on the presence and function of STRIPAK-associated kinases in ascomycetes. Using the mammalian germinal center kinases (GCKs) MST4, STK24, STK25 and MINK1 as query, we identified the two putative homologs SmKIN3 and SmKIN24 in S. macrospora. A BLASTP search revealed that both kinases are conserved among filamentous ascomycetes. The physical interaction of the striatin homolog PRO11 with SmKIN3 and SmKIN24 were verified by yeast two-hybrid (Y2H) interaction studies and for SmKIN3 by co-Immunoprecipitation (co-IP). In vivo localization found that both kinases were present at the septa and deletion of both Smkin3 and Smkin24 led to abnormal septum distribution. While deletion of Smkin3 caused larger distances between adjacent septa and increased aerial hyphae, deletion of Smkin24 led to closer spacing of septa and to sterility. Although phenotypically distinct, both kinases appear to function independently because the double-knockout strain ΔSmkin3/ΔSmkin24 displayed the combined phenotypes of each single-deletion strain.
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Affiliation(s)
- Stefan Frey
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August-University Göttingen, Göttingen, Germany
| | - Eva J. Reschka
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August-University Göttingen, Göttingen, Germany
| | - Stefanie Pöggeler
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August-University Göttingen, Göttingen, Germany
- Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, Göttingen, Germany
- * E-mail:
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Comparative Analysis of Transmembrane Regulators of the Filamentous Growth Mitogen-Activated Protein Kinase Pathway Uncovers Functional and Regulatory Differences. EUKARYOTIC CELL 2015; 14:868-83. [PMID: 26116211 DOI: 10.1128/ec.00085-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 06/17/2015] [Indexed: 12/14/2022]
Abstract
Filamentous growth is a microbial differentiation response that involves the concerted action of multiple signaling pathways. In budding yeast, one pathway that regulates filamentous growth is a Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway. Several transmembrane (TM) proteins regulate the filamentous growth pathway, including the signaling mucin Msb2p, the tetraspan osmosensor Sho1p, and an adaptor Opy2p. The TM proteins were compared to identify common and unique features. Msb2p, Sho1p, and Opy2p associated by coimmunoprecipitation analysis but showed predominantly different localization patterns. The different localization patterns of the proteins resulted in part from different rates of turnover from the plasma membrane (PM). In particular, Msb2p (and Opy2p) were turned over rapidly compared to Sho1p. Msb2p signaled from the PM, and its turnover was a rate-limiting step in MAPK signaling. Genetic analysis identified unique phenotypes of cells overexpressing the TM proteins. Therefore, each TM regulator of the filamentous growth pathway has its own regulatory pattern and specific function in regulating filamentous growth. This specialization may be important for fine-tuning and potentially diversifying the filamentation response.
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Draheim KM, Li X, Zhang R, Fisher OS, Villari G, Boggon TJ, Calderwood DA. CCM2-CCM3 interaction stabilizes their protein expression and permits endothelial network formation. ACTA ACUST UNITED AC 2015; 208:987-1001. [PMID: 25825518 PMCID: PMC4384732 DOI: 10.1083/jcb.201407129] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CCM2–CCM3 interactions protect CCM2 and CCM3 from proteasomal degradation, and both CCM2 and CCM3 are required for normal endothelial cell network formation. Mutations in the essential adaptor proteins CCM2 or CCM3 lead to cerebral cavernous malformations (CCM), vascular lesions that most frequently occur in the brain and are strongly associated with hemorrhagic stroke, seizures, and other neurological disorders. CCM2 binds CCM3, but the molecular basis of this interaction, and its functional significance, have not been elucidated. Here, we used x-ray crystallography and structure-guided mutagenesis to show that an α-helical LD-like motif within CCM2 binds the highly conserved “HP1” pocket of the CCM3 focal adhesion targeting (FAT) homology domain. By knocking down CCM2 or CCM3 and rescuing with binding-deficient mutants, we establish that CCM2–CCM3 interactions protect CCM2 and CCM3 proteins from proteasomal degradation and show that both CCM2 and CCM3 are required for normal endothelial cell network formation. However, CCM3 expression in the absence of CCM2 is sufficient to support normal cell growth, revealing complex-independent roles for CCM3.
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Affiliation(s)
- Kyle M Draheim
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Xiaofeng Li
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Rong Zhang
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Oriana S Fisher
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Giulia Villari
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
| | - Titus J Boggon
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
| | - David A Calderwood
- Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520 Department of Pharmacology and Department of Cell Biology, Yale University, New Haven, CT 06520
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Ford CB, Funt JM, Abbey D, Issi L, Guiducci C, Martinez DA, Delorey T, Li BY, White TC, Cuomo C, Rao RP, Berman J, Thompson DA, Regev A. The evolution of drug resistance in clinical isolates of Candida albicans. eLife 2015; 4:e00662. [PMID: 25646566 PMCID: PMC4383195 DOI: 10.7554/elife.00662] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 12/18/2014] [Indexed: 12/31/2022] Open
Abstract
Candida albicans is both a member of the healthy human microbiome
and a major pathogen in immunocompromised individuals. Infections are typically
treated with azole inhibitors of ergosterol biosynthesis often leading to drug
resistance. Studies in clinical isolates have implicated multiple mechanisms in
resistance, but have focused on large-scale aberrations or candidate genes, and do
not comprehensively chart the genetic basis of adaptation. Here, we leveraged
next-generation sequencing to analyze 43 isolates from 11 oral candidiasis patients.
We detected newly selected mutations, including single-nucleotide polymorphisms
(SNPs), copy-number variations and loss-of-heterozygosity (LOH) events. LOH events
were commonly associated with acquired resistance, and SNPs in 240 genes may be
related to host adaptation. Conversely, most aneuploidies were transient and did not
correlate with drug resistance. Our analysis also shows that isolates also varied in
adherence, filamentation, and virulence. Our work reveals new molecular mechanisms
underlying the evolution of drug resistance and host adaptation. DOI:http://dx.doi.org/10.7554/eLife.00662.001 Nearly all humans are infected with the fungus Candida albicans. In
most people, the infection does not produce any symptoms because their immune system
is able to counteract the fungus' attempts to spread around the body. However, if the
balance between fungal attack and body defence fails, the fungus is able to spread,
which can lead to serious disease that is fatal in 42% of cases. How does C. albicans outcompete the body's defences to cause
disease? This is a pertinent question because the most effective antifungal
medicines—including the drug fluconazole—do not kill the fungus; they
only stop it from growing. This gives the fungus time to develop resistance to the
drug by becoming able to quickly replace the fungal proteins the drug destroys, or to
efficiently remove the drug from its cells. In this study, Ford et al. studied the changes that occur in the DNA of C.
albicans over time in patients who are being treated with fluconazole.
Ford et al. took 43 samples of C. albicans from 11 patients with
weakened immune systems. The experiments show that the fungus samples collected early
on were more sensitive to the drug than the samples collected later. In most cases, the genetic data suggest that the infections begin with a single
fungal cell; the cells in the later samples are its offspring. Despite this, there is
a lot of genetic variation between samples from the same patient, which indicates
that the fungus is under pressure to become more resistant to the drug. There were
240 genes—including those that can alter the surface on the fungus cells to
make it better at evading the host immune system—in which small changes
occurred over time in three or more patients. Laboratory tests revealed that many of
these genes are likely important for the fungus to survive in an animal host in the
presence of the drug. C. albicans cells usually have two genetically distinct copies of
every gene. Ford et al. found that for some genes—including some that make
surface components or are involved in expelling drugs from cells—the loss of
genetic information from one copy, so that both copies become identical, is linked to
resistance to fluconazole. However, the gain of whole or partial
chromosomes—which contain large numbers of genes—is not linked to
resistance, but may provide additional genetic material for generating diversity in
the yeast population that may help the cells to evolve resistance in the future. These experiments have identified many new candidate genes that are important for
drug resistance and evading the host immune system, and which could be used to guide
the development of new therapeutics to treat these life-threatening infections. DOI:http://dx.doi.org/10.7554/eLife.00662.002
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Affiliation(s)
- Christopher B Ford
- Department of Biology, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Jason M Funt
- Department of Biology, Broad Institute of MIT and Harvard, Cambridge, United States
| | - Darren Abbey
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, United States
| | - Luca Issi
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, United States
| | | | | | - Toni Delorey
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Bi Yu Li
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Theodore C White
- School of Biological Sciences, University of Missouri at Kansas City, Kansas City, United States
| | - Christina Cuomo
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Reeta P Rao
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, United States
| | - Judith Berman
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, United States
| | - Dawn A Thompson
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Aviv Regev
- Department of Biology, Broad Institute of MIT and Harvard, Cambridge, United States
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A fungal sarcolemmal membrane-associated protein (SLMAP) homolog plays a fundamental role in development and localizes to the nuclear envelope, endoplasmic reticulum, and mitochondria. EUKARYOTIC CELL 2014; 14:345-58. [PMID: 25527523 DOI: 10.1128/ec.00241-14] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 12/13/2014] [Indexed: 11/20/2022]
Abstract
Sarcolemmal membrane-associated protein (SLMAP) is a tail-anchored protein involved in fundamental cellular processes, such as myoblast fusion, cell cycle progression, and chromosomal inheritance. Further, SLMAP misexpression is associated with endothelial dysfunctions in diabetes and cancer. SLMAP is part of the conserved striatin-interacting phosphatase and kinase (STRIPAK) complex required for specific signaling pathways in yeasts, filamentous fungi, insects, and mammals. In filamentous fungi, STRIPAK was initially discovered in Sordaria macrospora, a model system for fungal differentiation. Here, we functionally characterize the STRIPAK subunit PRO45, a homolog of human SLMAP. We show that PRO45 is required for sexual propagation and cell-to-cell fusion and that its forkhead-associated (FHA) domain is essential for these processes. Protein-protein interaction studies revealed that PRO45 binds to STRIPAK subunits PRO11 and SmMOB3, which are also required for sexual propagation. Superresolution structured-illumination microscopy (SIM) further established that PRO45 localizes to the nuclear envelope, endoplasmic reticulum, and mitochondria. SIM also showed that localization to the nuclear envelope requires STRIPAK subunits PRO11 and PRO22, whereas for mitochondria it does not. Taken together, our study provides important insights into fundamental roles of the fungal SLMAP homolog PRO45 and suggests STRIPAK-related and STRIPAK-unrelated functions.
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Barozai MYK, Bashir F, Muzaffar S, Afzal S, Behlil F, Khan M. In-silico identification and characterization of organic and inorganic chemical stress responding genes in yeast (Saccharomyces cerevisiae). Gene 2014; 550:74-80. [PMID: 25111117 DOI: 10.1016/j.gene.2014.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/31/2014] [Accepted: 08/08/2014] [Indexed: 10/24/2022]
Abstract
To study the life processes of all eukaryotes, yeast (Saccharomyces cerevisiae) is a significant model organism. It is also one of the best models to study the responses of genes at transcriptional level. In a living organism, gene expression is changed by chemical stresses. The genes that give response to chemical stresses will provide good source for the strategies in engineering and formulating mechanisms which are chemical stress resistant in the eukaryotic organisms. The data available through microarray under the chemical stresses like lithium chloride, lactic acid, weak organic acids and tomatidine were studied by using computational tools. Out of 9335 yeast genes, 388 chemical stress responding genes were identified and characterized under different chemical stresses. Some of these are: Enolases 1 and 2, heat shock protein-82, Yeast Elongation Factor 3, Beta Glucanase Protein, Histone H2A1 and Histone H2A2 Proteins, Benign Prostatic Hyperplasia, ras GTPase activating protein, Establishes Silent Chromatin protein, Mei5 Protein, Nondisjunction Protein and Specific Mitogen Activated Protein Kinase. Characterization of these genes was also made on the basis of their molecular functions, biological processes and cellular components.
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Affiliation(s)
| | - Farrukh Bashir
- Department of Chemistry, Sardar Bahadur Khan Women's University, Quetta, Pakistan
| | - Shafia Muzaffar
- Department of Chemistry, Sardar Bahadur Khan Women's University, Quetta, Pakistan
| | - Saba Afzal
- Department of Chemistry, Sardar Bahadur Khan Women's University, Quetta, Pakistan
| | - Farida Behlil
- Department of Chemistry, Sardar Bahadur Khan Women's University, Quetta, Pakistan
| | - Muzaffar Khan
- Department of Chemistry, Sardar Bahadur Khan Women's University, Quetta, Pakistan
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42
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Ashton-Beaucage D, Udell CM, Gendron P, Sahmi M, Lefrançois M, Baril C, Guenier AS, Duchaine J, Lamarre D, Lemieux S, Therrien M. A functional screen reveals an extensive layer of transcriptional and splicing control underlying RAS/MAPK signaling in Drosophila. PLoS Biol 2014; 12:e1001809. [PMID: 24643257 PMCID: PMC3958334 DOI: 10.1371/journal.pbio.1001809] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/05/2014] [Indexed: 12/11/2022] Open
Abstract
A global RNAi screening approach in Drosophila cells identifies a large group of transcription and splicing factors that modulate RAS/MAPK signaling by altering the expression of MAPK. The small GTPase RAS is among the most prevalent oncogenes. The evolutionarily conserved RAF-MEK-MAPK module that lies downstream of RAS is one of the main conduits through which RAS transmits proliferative signals in normal and cancer cells. Genetic and biochemical studies conducted over the last two decades uncovered a small set of factors regulating RAS/MAPK signaling. Interestingly, most of these were found to control RAF activation, thus suggesting a central regulatory role for this event. Whether additional factors are required at this level or further downstream remains an open question. To obtain a comprehensive view of the elements functionally linked to the RAS/MAPK cascade, we used a quantitative assay in Drosophila S2 cells to conduct a genome-wide RNAi screen for factors impacting RAS-mediated MAPK activation. The screen led to the identification of 101 validated hits, including most of the previously known factors associated to this pathway. Epistasis experiments were then carried out on individual candidates to determine their position relative to core pathway components. While this revealed several new factors acting at different steps along the pathway—including a new protein complex modulating RAF activation—we found that most hits unexpectedly work downstream of MEK and specifically influence MAPK expression. These hits mainly consist of constitutive splicing factors and thereby suggest that splicing plays a specific role in establishing MAPK levels. We further characterized two representative members of this group and surprisingly found that they act by regulating mapk alternative splicing. This study provides an unprecedented assessment of the factors modulating RAS/MAPK signaling in Drosophila. In addition, it suggests that pathway output does not solely rely on classical signaling events, such as those controlling RAF activation, but also on the regulation of MAPK levels. Finally, it indicates that core splicing components can also specifically impact alternative splicing. The RAS/MAPK pathway is a cornerstone of the cell proliferation signaling apparatus. It has a notable involvement in cancer as mutations in the components of the pathway are associated with aberrant proliferation. Previous work has focused predominantly on post-translational regulation of RAS/MAPK signaling such that a large and intricate network of factors is now known to act on core pathway components. However, regulation at the pre-translational level has not been examined nearly as extensively and is comparatively poorly understood. In this study, we used an unbiased and global screening approach to survey the Drosophila genome—using Drosophila cultured cells—for novel regulators of this pathway. Surprisingly, a majority of our hits were associated to either transcription or mRNA splicing. We used a series of secondary screening assays to determine which part of the RAS/MAPK pathway these candidates target. We found that these factors were not equally distributed along the pathway, but rather converged predominantly on mapk mRNA expression and processing. Our findings raise the intriguing possibility that regulation of mapk transcript production is a key step for a diverse set of regulatory inputs, and may play an important part in RAS/MAPK signaling dynamics.
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Affiliation(s)
- Dariel Ashton-Beaucage
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Christian M. Udell
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Patrick Gendron
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Malha Sahmi
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Martin Lefrançois
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Caroline Baril
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Anne-Sophie Guenier
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Jean Duchaine
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
| | - Daniel Lamarre
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
- Département de médecine, Université de Montréal, Montréal, Québec, Canada
| | - Sébastien Lemieux
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
- Département d'informatique et de recherche opérationnelle, Université de Montréal, Montréal, Québec, Canada
| | - Marc Therrien
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Québec, Canada
- Département de pathologie et de biologie cellulaire, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
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43
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Insight into Tor2, a budding yeast microdomain protein. Eur J Cell Biol 2014; 93:87-97. [DOI: 10.1016/j.ejcb.2014.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/03/2014] [Accepted: 01/06/2014] [Indexed: 11/20/2022] Open
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Hwang J, Pallas DC. STRIPAK complexes: structure, biological function, and involvement in human diseases. Int J Biochem Cell Biol 2014; 47:118-48. [PMID: 24333164 PMCID: PMC3927685 DOI: 10.1016/j.biocel.2013.11.021] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 11/18/2013] [Accepted: 11/28/2013] [Indexed: 12/31/2022]
Abstract
The mammalian striatin family consists of three proteins, striatin, S/G2 nuclear autoantigen, and zinedin. Striatin family members have no intrinsic catalytic activity, but rather function as scaffolding proteins. Remarkably, they organize multiple diverse, large signaling complexes that participate in a variety of cellular processes. Moreover, they appear to be regulatory/targeting subunits for the major eukaryotic serine/threonine protein phosphatase 2A. In addition, striatin family members associate with germinal center kinase III kinases as well as other novel components, earning these assemblies the name striatin-interacting phosphatase and kinase (STRIPAK) complexes. Recently, there has been a great increase in functional and mechanistic studies aimed at identifying and understanding the roles of STRIPAK and STRIPAK-like complexes in cellular processes of multiple organisms. These studies have identified novel STRIPAK and STRIPAK-like complexes and have explored their roles in specific signaling pathways. Together, the results of these studies have sparked increased interest in striatin family complexes because they have revealed roles in signaling, cell cycle control, apoptosis, vesicular trafficking, Golgi assembly, cell polarity, cell migration, neural and vascular development, and cardiac function. Moreover, STRIPAK complexes have been connected to clinical conditions, including cardiac disease, diabetes, autism, and cerebral cavernous malformation. In this review, we discuss the expression, localization, and protein domain structure of striatin family members. Then we consider the diverse complexes these proteins and their homologs form in various organisms, emphasizing what is known regarding function and regulation. Finally, we explore possible roles of striatin family complexes in disease, especially cerebral cavernous malformation.
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Affiliation(s)
- Juyeon Hwang
- Department of Biochemistry and Winship Cancer Institute, and Biochemistry, Cell, Developmental Biology Graduate Program, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.
| | - David C Pallas
- Department of Biochemistry and Winship Cancer Institute, and Biochemistry, Cell, Developmental Biology Graduate Program, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.
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45
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He CH, Xie LX, Allan CM, Tran UC, Clarke CF. Coenzyme Q supplementation or over-expression of the yeast Coq8 putative kinase stabilizes multi-subunit Coq polypeptide complexes in yeast coq null mutants. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:630-44. [PMID: 24406904 DOI: 10.1016/j.bbalip.2013.12.017] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/17/2013] [Accepted: 12/30/2013] [Indexed: 12/17/2022]
Abstract
Coenzyme Q biosynthesis in yeast requires a multi-subunit Coq polypeptide complex. Deletion of any one of the COQ genes leads to respiratory deficiency and decreased levels of the Coq4, Coq6, Coq7, and Coq9 polypeptides, suggesting that their association in a high molecular mass complex is required for stability. Over-expression of the putative Coq8 kinase in certain coq null mutants restores steady-state levels of the sensitive Coq polypeptides and promotes the synthesis of late-stage Q-intermediates. Here we show that over-expression of Coq8 in yeast coq null mutants profoundly affects the association of several of the Coq polypeptides in high molecular mass complexes, as assayed by separation of digitonin extracts of mitochondria by two-dimensional blue-native/SDS PAGE. The Coq4 polypeptide persists at high molecular mass with over-expression of Coq8 in coq3, coq5, coq6, coq7, coq9, and coq10 mutants, indicating that Coq4 is a central organizer of the Coq complex. Supplementation with exogenous Q6 increased the steady-state levels of Coq4, Coq7, and Coq9, and several other mitochondrial polypeptides in select coq null mutants, and also promoted the formation of late-stage Q-intermediates. Q supplementation may stabilize this complex by interacting with one or more of the Coq polypeptides. The stabilizing effects of exogenously added Q6 or over-expression of Coq8 depend on Coq1 and Coq2 production of a polyisoprenyl intermediate. Based on the observed interdependence of the Coq polypeptides, the effect of exogenous Q6, and the requirement for an endogenously produced polyisoprenyl intermediate, we propose a new model for the Q-biosynthetic complex, termed the CoQ-synthome.
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Affiliation(s)
- Cuiwen H He
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
| | - Letian X Xie
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
| | - Christopher M Allan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
| | - Uyenphuong C Tran
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA
| | - Catherine F Clarke
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, CA 90095-1569, USA.
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Teichert I, Nowrousian M, Pöggeler S, Kück U. The filamentous fungus Sordaria macrospora as a genetic model to study fruiting body development. ADVANCES IN GENETICS 2014; 87:199-244. [PMID: 25311923 DOI: 10.1016/b978-0-12-800149-3.00004-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Filamentous fungi are excellent experimental systems due to their short life cycles as well as easy and safe manipulation in the laboratory. They form three-dimensional structures with numerous different cell types and have a long tradition as genetic model organisms used to unravel basic mechanisms underlying eukaryotic cell differentiation. The filamentous ascomycete Sordaria macrospora is a model system for sexual fruiting body (perithecia) formation. S. macrospora is homothallic, i.e., self-fertile, easily genetically tractable, and well suited for large-scale genomics, transcriptomics, and proteomics studies. Specific features of its life cycle and the availability of a developmental mutant library make it an excellent system for studying cellular differentiation at the molecular level. In this review, we focus on recent developments in identifying gene and protein regulatory networks governing perithecia formation. A number of tools have been developed to genetically analyze developmental mutants and dissect transcriptional profiles at different developmental stages. Protein interaction studies allowed us to identify a highly conserved eukaryotic multisubunit protein complex, the striatin-interacting phosphatase and kinase complex and its role in sexual development. We have further identified a number of proteins involved in chromatin remodeling and transcriptional regulation of fruiting body development. Furthermore, we review the involvement of metabolic processes from both primary and secondary metabolism, and the role of nutrient recycling by autophagy in perithecia formation. Our research has uncovered numerous players regulating multicellular development in S. macrospora. Future research will focus on mechanistically understanding how these players are orchestrated in this fungal model system.
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Affiliation(s)
- Ines Teichert
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, Germany
| | - Minou Nowrousian
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, Germany
| | - Stefanie Pöggeler
- Abteilung Genetik eukaryotischer Mikroorganismen, Institut für Mikrobiologie und Genetik, Georg-August Universität Göttingen, Göttingen, Germany
| | - Ulrich Kück
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Bochum, Germany
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Dettmann A, Heilig Y, Ludwig S, Schmitt K, Illgen J, Fleißner A, Valerius O, Seiler S. HAM-2 and HAM-3 are central for the assembly of the Neurospora STRIPAK complex at the nuclear envelope and regulate nuclear accumulation of the MAP kinase MAK-1 in a MAK-2-dependent manner. Mol Microbiol 2013; 90:796-812. [PMID: 24028079 DOI: 10.1111/mmi.12399] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2013] [Indexed: 12/20/2022]
Abstract
Intercellular communication and somatic cell fusion are important for fungal colony establishment, multicellular differentiation and have been associated with host colonization and virulence of pathogenic species. By a combination of genetic, biochemical and live cell imaging techniques, we characterized the Neurospora crassa STRIPAK complex that is essential for self-signalling and consists of the six proteins HAM-2/STRIP, HAM-3/striatin, HAM-4/SLMAP, MOB-3/phocein, PPG-1/PP2A-C and PP2A-A. We describe that the core STRIPAK components HAM-2 and HAM-3 are central for the assembly of the complex at the nuclear envelope, while the phosphatase PPG-1 only transiently associates with this central subcomplex. Our data connect the STRIPAK complex with two MAP kinase pathways: (i) nuclear accumulation of the cell wall integrity MAP kinase MAK-1 depends on the functional integrity of the STRIPAK complex at the nuclear envelope, and (ii) phosphorylation of MOB-3 by the MAP kinase MAK-2 impacts the nuclear accumulation of MAK-1. In summary, these data support a model, in which MAK-2-dependent phosphorylation of MOB-3 is part of a MAK-1 import mechanism. Although self-communication remained intact in the absence of nuclear MAK-1 accumulation, supporting the presence of multiple mechanisms that co-ordinate robust intercellular communication, proper fruiting body morphology was dependent on the MAK-2-phosphorylated N-terminus of MOB-3.
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Affiliation(s)
- Anne Dettmann
- Institute for Biology II - Molecular Plant Physiology, Albert-Ludwigs University Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany
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Pracheil T, Liu Z. Tiered assembly of the yeast Far3-7-8-9-10-11 complex at the endoplasmic reticulum. J Biol Chem 2013; 288:16986-16997. [PMID: 23625923 DOI: 10.1074/jbc.m113.451674] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Target of rapamycin signaling is a conserved, essential pathway integrating nutritional cues with cell growth and proliferation. The target of rapamycin kinase exists in two distinct complexes, TORC1 and TORC2. It has been reported that protein phosphatase 2A (PP2A) and the Far3-7-8-9-10-11 complex (Far complex) negatively regulate TORC2 signaling in yeast. The Far complex, originally identified as factors required for pheromone-induced cell cycle arrest, and PP2A form the yeast counterpart of the STRIPAK complex, which was first isolated in mammals. The cellular localization of the Far complex has yet to be fully characterized. Here, we show that the Far complex localizes to the endoplasmic reticulum (ER) by analyzing functional GFP-tagged Far proteins in vivo. We found that Far9 and Far10, two homologous proteins each with a tail-anchor domain, localize to the ER in mutant cells lacking the other Far complex components. Far3, Far7, and Far8 form a subcomplex, which is recruited to the ER by Far9/10. The Far3-7-8- complex in turn recruits Far11 to the ER. Finally, we show that the tail-anchor domain of Far9 is required for its optimal function in TORC2 signaling. Our study reveals tiered assembly of the yeast Far complex at the ER and a function for Far complex's ER localization in TORC2 signaling.
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Affiliation(s)
- Tammy Pracheil
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana 70148
| | - Zhengchang Liu
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana 70148.
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Williams TC, Nielsen LK, Vickers CE. Engineered quorum sensing using pheromone-mediated cell-to-cell communication in Saccharomyces cerevisiae. ACS Synth Biol 2013; 2:136-49. [PMID: 23656437 DOI: 10.1021/sb300110b] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Population-density-dependent control of gene expression, or quorum sensing, is widespread in nature and is used to coordinate complex population-wide phenotypes through space and time. We have engineered quorum sensing in S. cerevisiae by rewiring the native pheromone communication system that is normally used by haploid cells to detect potential mating partners. In our system, populations consisting of only mating type "a" cells produce and respond to extracellular α-type pheromone by arresting growth and expressing GFP in a population-density-dependent manner. Positive feedback quorum sensing dynamics were tuned by varying α-pheromone production levels using different versions of the pheromone-responsive FUS1 promoter as well as different versions of pheromone genes (mfα1 or mfα2). In a second system, pheromone communication was rendered conditional upon the presence of aromatic amino acids in the growth medium by controlling α-pheromone expression with the aromatic amino acid responsive ARO9 promoter. In these circuits, pheromone communication and response could be fine-tuned according to aromatic amino acid type and concentration. The genetic control programs developed here are responsive to dynamic spatiotemporal and chemical cellular environments, resulting in up-regulation of gene expression. These programs could be used to control biochemical pathways for the production of fuels and chemicals that are toxic or place a heavy metabolic burden on cell growth.
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Affiliation(s)
- Thomas C. Williams
- Australian Institute for
Bioengineering and Nanotechnology
(AIBN), The University of Queensland, St.
Lucia, QLD 4072, Australia
| | - Lars K. Nielsen
- Australian Institute for
Bioengineering and Nanotechnology
(AIBN), The University of Queensland, St.
Lucia, QLD 4072, Australia
| | - Claudia E. Vickers
- Australian Institute for
Bioengineering and Nanotechnology
(AIBN), The University of Queensland, St.
Lucia, QLD 4072, Australia
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Functional repurposing revealed by comparing S. pombe and S. cerevisiae genetic interactions. Cell 2012; 149:1339-52. [PMID: 22682253 PMCID: PMC3613983 DOI: 10.1016/j.cell.2012.04.028] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 03/08/2012] [Accepted: 04/02/2012] [Indexed: 12/12/2022]
Abstract
We present a genetic interaction map of pairwise measures including ∼40% of nonessential S. pombe genes. By comparing interaction maps for fission and budding yeast, we confirmed widespread conservation of genetic relationships within and between complexes and pathways. However, we identified an important subset of orthologous complexes that have undergone functional "repurposing": the evolution of divergent functions and partnerships. We validated three functional repurposing events in S. pombe and mammalian cells and discovered that (1) two lumenal sensors of misfolded ER proteins, the kinase/nuclease Ire1 and the glucosyltransferase Gpt1, act together to mount an ER stress response; (2) ESCRT factors regulate spindle-pole-body duplication; and (3) a membrane-protein phosphatase and kinase complex, the STRIPAK complex, bridges the cis-Golgi, the centrosome, and the outer nuclear membrane to direct mitotic progression. Each discovery opens new areas of inquiry and-together-have implications for model organism-based research and the evolution of genetic systems.
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