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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [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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Tanti GK, Pandey P, Shreya S, Jain BP. Striatin family proteins: The neglected scaffolds. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119430. [PMID: 36638846 DOI: 10.1016/j.bbamcr.2023.119430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/19/2022] [Accepted: 12/31/2022] [Indexed: 01/12/2023]
Abstract
The Striatin family of proteins constitutes Striatin, SG2NA, and Zinedin. Members of this family of proteins act as a signaling scaffold due to the presence of multiple protein-protein interaction domains. At least two members of this family, namely Zinedin and SG2NA, have a proven role in cancer cell proliferation. SG2NA, the second member of this family, undergoes alternative splicing and gives rise to several isoforms which are differentially regulated in a tissue-dependent manner. SG2NA evolved earlier than the other two members of the family, and SG2NA undergoes not only alternative splicing but also other posttranscriptional gene regulation. Striatin also undergoes alternative splicing, and as a result, it gives rise to multiple isoforms. It has been shown that this family of proteins plays a significant role in estrogen signaling, neuroprotection, cancer as well as in cell cycle regulation. Members of the striatin family form a complex network of signaling hubs with different kinases and phosphatases, and other signaling proteins named STRIPAK. Here, in the present manuscript, we thoroughly reviewed the findings on striatin family members to elaborate on the overall structural and functional idea of this family of proteins. We also commented on the involvement of these proteins in STRIPAK complexes and their functional relevance.
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Affiliation(s)
- Goutam Kumar Tanti
- Department of Neurology, School of Medicine, Technical University of Munich, Germany.
| | - Prachi Pandey
- National Institute of Plant Genome Research, New Delhi, India
| | - Smriti Shreya
- Department of Zoology, Mahatma Gandhi Central University, Motihari, Bihar, India
| | - Buddhi Prakash Jain
- Department of Zoology, Mahatma Gandhi Central University, Motihari, Bihar, India.
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Peroxin Pex14/17 Is Required for Trap Formation, and Plays Pleiotropic Roles in Mycelial Development, Stress Response, and Secondary Metabolism in Arthrobotrys oligospora. mSphere 2023; 8:e0001223. [PMID: 36786584 PMCID: PMC10117088 DOI: 10.1128/msphere.00012-23] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
The peroxins encoded by PEX genes involved in peroxisome biogenesis play a crucial role in cellular metabolism and pathogenicity in fungi. Herein, we characterized a filamentous fungus-specific peroxin Pex14/17 in the Arthrobotrys oligospora, a representative species of nematode-trapping fungi. The deletion of AoPEX14/17 resulted in a remarkable reduction in mycelial growth, conidia yield, trap formation, and pathogenicity. Compared with the wild-type strain, the ΔAopex14/17 mutant exhibited more lipid droplet and reactive oxygen species accumulation accompanied with a significant decrease in fatty acid utilization and tolerance to oxidative stress. Transcriptomic analysis indicated that AoPEX14/17 was involved in the regulation of metabolism, genetic information processing, environmental information processing, and cellular processes. In subcellular morphology, the deletion of AoPEX14/17 resulted in a decrease in the number of cell nuclei, autophagosomes, and Woronin bodies. Metabolic profile analysis showed that AoPex14/17 affects the biosynthesis of secondary metabolites. Yeast two-hybrid assay revealed that AoPex14/17 interacted with AoPex14 but not with AoPex13. Taken together, our results suggest that Pex14/17 is the main factor for modulating growth, development, and pathogenicity in A. oligospora. IMPORTANCE Peroxisome biogenesis genes (PEX) play an important role in growth, development, and pathogenicity in pathogenic fungi. However, the roles of PEX genes remain largely unknown in nematode-trapping (NT) fungi. Here, we provide direct evidence that AoPex14/17 regulates mycelial growth, conidiation, trap formation, autophagy, endocytosis, catalase activity, stress response to oxidants, lipid metabolism, and reactive oxygen species production. Transcriptome analysis and metabolic profile suggested that AoPex14/17 is involved in multiple cellular processes and the regulation of secondary metabolism. Therefore, our study extends the functions of PEX genes, which helps to elucidate the mechanism of organelle development and trap formation in NT fungi and lays the foundation for the development of efficient nematode biocontrol agents.
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Sordaria macrospora Sterile Mutant pro34 Is Impaired in Respiratory Complex I Assembly. J Fungi (Basel) 2022; 8:jof8101015. [PMID: 36294581 PMCID: PMC9605262 DOI: 10.3390/jof8101015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/21/2022] Open
Abstract
The formation of fruiting bodies is a highly regulated process that requires the coordinated formation of different cell types. By analyzing developmental mutants, many developmental factors have already been identified. Yet, a complete understanding of fruiting body formation is still lacking. In this study, we analyzed developmental mutant pro34 of the filamentous ascomycete Sordaria macrospora. Genome sequencing revealed a deletion in the pro34 gene encoding a putative mitochondrial complex I assembly factor homologous to Neurospora crassa CIA84. We show that PRO34 is required for fast vegetative growth, fruiting body and ascospore formation. The pro34 transcript undergoes adenosine to inosine editing, a process correlated with sexual development in fruiting body-forming ascomycetes. Fluorescence microscopy and western blot analysis showed that PRO34 is a mitochondrial protein, and blue-native PAGE revealed that the pro34 mutant lacks mitochondrial complex I. Inhibitor experiments revealed that pro34 respires via complexes III and IV, but also shows induction of alternative oxidase, a shunt pathway to bypass complexes III and IV. We discuss the hypothesis that alternative oxidase is induced to prevent retrograde electron transport to complex I intermediates, thereby protecting from oxidative stress.
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Groth A, Ahlmann S, Werner A, Pöggeler S. The vacuolar morphology protein VAC14 plays an important role in sexual development in the filamentous ascomycete Sordaria macrospora. Curr Genet 2022; 68:407-427. [PMID: 35776170 PMCID: PMC9279277 DOI: 10.1007/s00294-022-01244-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 11/29/2022]
Abstract
The multiprotein Fab1p/PIKfyve-complex regulating the abundance of the phospholipid phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2) is highly conserved among eukaryotes. In yeast/mammals, it is composed of the phosphatidylinositol 3-phosphate 5-kinase Fab1p/PIKfyve, the PtdIns(3,5)P2 phosphatase Fig4p/Sac3 and the scaffolding subunit Vac14p/ArPIKfyve. The complex is located to vacuolar membranes in yeast and to endosomal membranes in mammals, where it controls the synthesis and turnover of PtdIns(3,5)P2. In this study, we analyzed the role and function of the Fab1p/PIKfyve-complex scaffold protein SmVAC14 in the filamentous ascomycete Sordaria macrospora (Sm). We generated the Smvac14 deletion strain ∆vac14 and performed phenotypic analysis of the mutant. Furthermore, we conducted fluorescence microscopic localization studies of fluorescently labeled SmVAC14 with vacuolar and late endosomal marker proteins. Our results revealed that SmVAC14 is important for maintaining vacuolar size and appearance as well as proper sexual development in S. macrospora. In addition, SmVAC14 plays an important role in starvation stress response. Accordingly, our results propose that the turnover of PtdIns(3,5)P2 is of great significance for developmental processes in filamentous fungi.
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Affiliation(s)
- Anika Groth
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Svenja Ahlmann
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Antonia Werner
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Stefanie Pöggeler
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany.
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Hyphal Fusions Enable Efficient Nutrient Distribution in Colletotrichum graminicola Conidiation and Symptom Development on Maize. Microorganisms 2022; 10:microorganisms10061146. [PMID: 35744664 PMCID: PMC9231406 DOI: 10.3390/microorganisms10061146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 02/01/2023] Open
Abstract
Hyphal and germling fusion is a common phenomenon in ascomycetous fungi. Due to the formed hyphal network, this process enables a coordinated development as well as an interaction with plant hosts and efficient nutrient distribution. Recently, our laboratory work demonstrated a positive correlation between germling fusion and the formation of penetrating hyphopodia on maize leaves outgoing from Colletotrichum graminicola oval conidia. To investigate the probable interconnectivity of these processes, we generated a deletion mutant in Cgso, in which homologs are essential for cellular fusion in other fungal species. However, hyphopodia development was not affected, indicating that both processes are not directly connected. Instead, we were able to link the cellular fusion defect in ∆Cgso to a decreased formation of asexual fruiting bodies of C. graminicola on the leaves. The monitoring of a fluorescent-labelled autophagy marker, eGFP-CgAtg8, revealed a high autophagy activity in the hyphae surrounding the acervuli. These results support the hypothesis that the efficient nutrient transport of degraded cellular material by hyphal fusions enables proper acervuli maturation and, therefore, symptom development on the leaves.
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AoPEX1 and AoPEX6 Are Required for Mycelial Growth, Conidiation, Stress Response, Fatty Acid Utilization, and Trap Formation in Arthrobotrys oligospora. Microbiol Spectr 2022; 10:e0027522. [PMID: 35323036 PMCID: PMC9045386 DOI: 10.1128/spectrum.00275-22] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Arthrobotrys oligospora (A. oligospora) is a typical nematode-trapping (NT) fungus that can capture nematodes by producing adhesive networks. Peroxisomes are single membrane-bound organelles that perform multiple physiological functions in filamentous fungi. Peroxisome biogenesis proteins are encoded by PEX genes, and the functions of PEX genes in A. oligospora and other NT fungi remain largely unknown. Here, our results demonstrated that two PEX genes (AoPEX1 and AoPEX6) are essential for mycelial growth, conidiation, fatty acid utilization, stress tolerance, and pathogenicity in A. oligospora. AoPEX1 and AoPEX6 knockout resulted in a failure to produce traps, conidia, peroxisomes, and Woronin bodies and damaged cell walls, reduced autophagosome levels, and increased lipid droplet size. Transcriptome data analysis showed that AoPEX1 and AoPEX6 deletion resulted in the upregulation of the proteasome, membranes, ribosomes, DNA replication, and cell cycle functions, and the downregulation of MAPK signaling and nitrogen metabolism. In summary, our results provide novel insights into the functions of PEX genes in the growth, development, and pathogenicity of A. oligospora and contribute to the elucidation of the regulatory mechanism of peroxisomes in trap formation and lifestyle switching in NT fungi. IMPORTANCE Nematode-trapping (NT) fungi are important resources for the biological control of plant-parasitic nematodes. They are widely distributed in various ecological environments and capture nematodes by producing unique predatory organs (traps). However, the molecular mechanisms of trap formation and lifestyle switching in NT fungi are still unclear. Here, we provided experimental evidence that the AoPEX1 and AoPEX6 genes could regulate mycelial growth and development, trap formation, and nematode predation of A. oligospora. We further analyzed the global transcription level changes of wild-type and mutant strains using RNA-seq. This study highlights the important role of peroxisome biogenesis genes in vegetative growth, conidiation, trap formation, and pathogenicity, which contribute to probing the mechanism of organelle development and trap formation of NT fungi and lays a foundation for developing high-efficiency nematode biocontrol agents.
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Wilson AM, Wilken PM, Wingfield MJ, Wingfield BD. Genetic Networks That Govern Sexual Reproduction in the Pezizomycotina. Microbiol Mol Biol Rev 2021; 85:e0002021. [PMID: 34585983 PMCID: PMC8485983 DOI: 10.1128/mmbr.00020-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Sexual development in filamentous fungi is a complex process that relies on the precise control of and interaction between a variety of genetic networks and pathways. The mating-type (MAT) genes are the master regulators of this process and typically act as transcription factors, which control the expression of genes involved at all stages of the sexual cycle. In many fungi, the sexual cycle typically begins when the mating pheromones of one mating type are recognized by a compatible partner, followed by physical interaction and fertilization. Subsequently, highly specialized sexual structures are formed, within which the sexual spores develop after rounds of meiosis and mitosis. These spores are then released and germinate, forming new individuals that initiate new cycles of growth. This review provides an overview of the known genetic networks and pathways that are involved in each major stage of the sexual cycle in filamentous ascomycete fungi.
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Affiliation(s)
- Andi M. Wilson
- Forestry and Agricultural Biotechnology Institute, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa
| | - P. Markus Wilken
- Forestry and Agricultural Biotechnology Institute, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa
| | - Michael J. Wingfield
- Forestry and Agricultural Biotechnology Institute, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa
| | - Brenda D. Wingfield
- Forestry and Agricultural Biotechnology Institute, Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Pretoria, Gauteng, South Africa
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Groth A, Schmitt K, Valerius O, Herzog B, Pöggeler S. Analysis of the Putative Nucleoporin POM33 in the Filamentous Fungus Sordaria macrospora. J Fungi (Basel) 2021; 7:jof7090682. [PMID: 34575720 PMCID: PMC8468769 DOI: 10.3390/jof7090682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/09/2021] [Accepted: 08/17/2021] [Indexed: 02/07/2023] Open
Abstract
In the filamentous fungus Sordaria macrospora (Sm), the STRIPAK complex is required for vegetative growth, fruiting-body development and hyphal fusion. The SmSTRIPAK core consists of the striatin homolog PRO11, the scaffolding subunit of phosphatase PP2A, SmPP2AA, and its catalytic subunit SmPP2Ac1. Among other STRIPAK proteins, the recently identified coiled-coil protein SCI1 was demonstrated to co-localize around the nucleus. Pulldown experiments with SCI identified the transmembrane nucleoporin (TM Nup) SmPOM33 as a potential nuclear-anchor of SmSTRIPAK. Localization studies revealed that SmPOM33 partially localizes to the nuclear envelope (NE), but mainly to the endoplasmic reticulum (ER). We succeeded to generate a Δpom33 deletion mutant by homologous recombination in a new S. macrospora Δku80 recipient strain, which is defective in non-homologous end joining. Deletion of Smpom33 did neither impair vegetative growth nor sexual development. In pulldown experiments of SmPOM33 followed by LC/MS analysis, ER-membrane proteins involved in ER morphology, protein translocation, glycosylation, sterol biosynthesis and Ca2+-transport were significantly enriched. Data are available via ProteomeXchange with identifier PXD026253. Although no SmSTRIPAK components were identified as putative interaction partners, it cannot be excluded that SmPOM33 is involved in temporarily anchoring the SmSTRIPAK to the NE or other sites in the cell.
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Affiliation(s)
- Anika Groth
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany; (A.G.); (B.H.)
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics, Service Unit LCMS Protein Analytics, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany; (K.S.); (O.V.)
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics, Service Unit LCMS Protein Analytics, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany; (K.S.); (O.V.)
| | - Britta Herzog
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany; (A.G.); (B.H.)
| | - Stefanie Pöggeler
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany; (A.G.); (B.H.)
- Correspondence: ; Tel.: +49-551-391-3930
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Tracking Fungal Growth: Establishment of Arp1 as a Marker for Polarity Establishment and Active Hyphal Growth in Filamentous Ascomycetes. J Fungi (Basel) 2021; 7:jof7070580. [PMID: 34356959 PMCID: PMC8304394 DOI: 10.3390/jof7070580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/16/2021] [Accepted: 07/18/2021] [Indexed: 12/20/2022] Open
Abstract
Polar growth is a key characteristic of all filamentous fungi. It allows these eukaryotes to not only effectively explore organic matter but also interact within its own colony, mating partners, and hosts. Therefore, a detailed understanding of the dynamics in polar growth establishment and maintenance is crucial for several fields of fungal research. We developed a new marker protein, the actin-related protein 1 (Arp1) fused to red and green fluorescent proteins, which allows for the tracking of polar axis establishment and active hyphal growth in microscopy approaches. To exclude a probable redundancy with known polarity markers, we compared the localizations of the Spitzenkörper (SPK) and Arp1 using an FM4-64 staining approach. As we show in applications with the coprophilous fungus Sordaria macrospora and the hemibiotrophic plant pathogen Colletotrichum graminicola, the monitoring of Arp1 can be used for detailed studies of hyphal growth dynamics and ascospore germination, the interpretation of chemotropic growth processes, and the tracking of elongating penetration pegs into plant material. Since the Arp1 marker showed the same dynamics in both fungi tested, we believe this marker can be broadly applied in fungal research to study the manifold polar growth processes determining fungal life.
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STRIPAK, a Key Regulator of Fungal Development, Operates as a Multifunctional Signaling Hub. J Fungi (Basel) 2021; 7:jof7060443. [PMID: 34206073 PMCID: PMC8226480 DOI: 10.3390/jof7060443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/26/2021] [Accepted: 05/29/2021] [Indexed: 01/26/2023] Open
Abstract
The striatin-interacting phosphatases and kinases (STRIPAK) multi subunit complex is a highly conserved signaling complex that controls diverse developmental processes in higher and lower eukaryotes. In this perspective article, we summarize how STRIPAK controls diverse developmental processes in euascomycetes, such as fruiting body formation, cell fusion, sexual and vegetative development, pathogenicity, symbiosis, as well as secondary metabolism. Recent structural investigations revealed information about the assembly and stoichiometry of the complex enabling it to act as a signaling hub. Multiple organellar targeting of STRIPAK subunits suggests how this complex connects several signaling transduction pathways involved in diverse cellular developmental processes. Furthermore, recent phosphoproteomic analysis shows that STRIPAK controls the dephosphorylation of subunits from several signaling complexes. We also refer to recent findings in yeast, where the STRIPAK homologue connects conserved signaling pathways, and based on this we suggest how so far non-characterized proteins may functions as receptors connecting mitophagy with the STRIPAK signaling complex. Such lines of investigation should contribute to the overall mechanistic understanding of how STRIPAK controls development in euascomycetes and beyond.
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The Glyoxysomal Protease LON2 Is Involved in Fruiting-Body Development, Ascosporogenesis and Stress Resistance in Sordaria macrospora. J Fungi (Basel) 2021; 7:jof7020082. [PMID: 33530609 PMCID: PMC7911957 DOI: 10.3390/jof7020082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 01/05/2023] Open
Abstract
Microbodies, including peroxisomes, glyoxysomes and Woronin bodies, are ubiquitous dynamic organelles that play important roles in fungal development. The ATP-dependent chaperone and protease family Lon that maintain protein quality control within the organelle significantly regulate the functionality of microbodies. The filamentous ascomycete Sordaria macrospora is a model organism for studying fruiting-body development. The genome of S. macrospora encodes one Lon protease with the C-terminal peroxisomal targeting signal (PTS1) serine-arginine-leucine (SRL) for import into microbodies. Here, we investigated the function of the protease SmLON2 in sexual development and during growth under stress conditions. Localization studies revealed a predominant localization of SmLON2 in glyoxysomes. This localization depends on PTS1, since a variant without the C-terminal SRL motif was localized in the cytoplasm. A ΔSmlon2 mutant displayed a massive production of aerial hyphae, and produced a reduced number of fruiting bodies and ascospores. In addition, the growth of the ΔSmlon2 mutant was completely blocked under mild oxidative stress conditions. Most of the defects could be complemented with both variants of SmLON2, with and without PTS1, suggesting a dual function of SmLON2, not only in microbody, but also in cytosolic protein quality control.
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Werner A, Otte KL, Stahlhut G, Pöggeler S. Establishment of the monomeric yellow-green fluorescent protein mNeonGreen for life cell imaging in mycelial fungi. AMB Express 2020; 10:222. [PMID: 33349910 PMCID: PMC7752937 DOI: 10.1186/s13568-020-01160-x] [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: 10/22/2020] [Accepted: 12/07/2020] [Indexed: 12/28/2022] Open
Abstract
The engineered monomeric version of the lancelet Branchiostoma lanceolatum fluorescent protein, mNeonGreen (mNG), has several positive characteristics, such as a very bright fluorescence, high photostability and fast maturation. These features make it a good candidate for the utilization as fluorescent tool for cell biology and biochemical applications in filamentous fungi. We report the generation of plasmids for the expression of the heterologous mNG gene under the control of an inducible and a constitutive promoter in the filamentous ascomycete Sordaria macrospora and display a stable expression of mNG in the cytoplasm. To demonstrate its usefulness for labeling of organelles, the peroxisomal targeting sequence serine-lysine-leucine (SKL) was fused to mNG. Expression of this tagged version led to protein import of mNG into peroxisomes and their bright fluorescence in life cell imaging.
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Affiliation(s)
- Antonia Werner
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Kolja L. Otte
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Gertrud Stahlhut
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Stefanie Pöggeler
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
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Zhou D, Xie M, Bai N, Yang L, Zhang KQ, Yang J. The Autophagy-Related Gene Aolatg4 Regulates Hyphal Growth, Sporulation, Autophagosome Formation, and Pathogenicity in Arthrobotrys oligospora. Front Microbiol 2020; 11:592524. [PMID: 33304340 PMCID: PMC7701090 DOI: 10.3389/fmicb.2020.592524] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/28/2020] [Indexed: 12/30/2022] Open
Abstract
Autophagy plays an important role in cell growth and development. The autophagy-related gene atg4 encodes a cysteine protease, which can cleave the carboxyl terminus of Atg8, thus plays a role in autophagosome formation in yeast and filamentous fungi. Arthrobotrys oligospora is well known for producing special trapping-devices (traps) and capturing nematodes. In this study, two ΔAolatg4 mutants were generated using targeted gene replacement and were used to investigate the biological functions of autophagy in A. oligospora. Autophagic process was observed using the AoAtg8-GFP fusion protein. The mutants showed a defective in hyphal growth and sporulation and were sensitive to chemical stressors, including menadione and Congo red. The spore yield of the ΔAolatg4 mutants was decreased by 88.5% compared to the wild type (WT), and the transcript levels of six sporulation-related genes, such as abaA, fluG, brlA, and wetA, were significantly downregulated during the conidiation stage. Deletion of Aolatg4 also affected the cell nuclei and mycelial septal development in A. oligospora. Importantly, autophagosome formation and the autophagic process were impaired in the ΔAolatg4 mutant. Moreover, the ΔAolatg4 mutant lost its ability to form mature traps. Our results provide novel insights into the roles of autophagy in A. oligospora.
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Affiliation(s)
- Duanxu Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
| | - Meihua Xie
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
| | - Na Bai
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
| | - Le Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
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Delgado ILS, Carmona B, Nolasco S, Santos D, Leitão A, Soares H. MOB: Pivotal Conserved Proteins in Cytokinesis, Cell Architecture and Tissue Homeostasis. BIOLOGY 2020; 9:biology9120413. [PMID: 33255245 PMCID: PMC7761452 DOI: 10.3390/biology9120413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/20/2020] [Accepted: 11/21/2020] [Indexed: 01/08/2023]
Abstract
The MOB family proteins are constituted by highly conserved eukaryote kinase signal adaptors that are often essential both for cell and organism survival. Historically, MOB family proteins have been described as kinase activators participating in Hippo and Mitotic Exit Network/ Septation Initiation Network (MEN/SIN) signaling pathways that have central roles in regulating cytokinesis, cell polarity, cell proliferation and cell fate to control organ growth and regeneration. In metazoans, MOB proteins act as central signal adaptors of the core kinase module MST1/2, LATS1/2, and NDR1/2 kinases that phosphorylate the YAP/TAZ transcriptional co-activators, effectors of the Hippo signaling pathway. More recently, MOBs have been shown to also have non-kinase partners and to be involved in cilia biology, indicating that its activity and regulation is more diverse than expected. In this review, we explore the possible ancestral role of MEN/SIN pathways on the built-in nature of a more complex and functionally expanded Hippo pathway, by focusing on the most conserved components of these pathways, the MOB proteins. We discuss the current knowledge of MOBs-regulated signaling, with emphasis on its evolutionary history and role in morphogenesis, cytokinesis, and cell polarity from unicellular to multicellular organisms.
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Affiliation(s)
- Inês L. S. Delgado
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
- Faculdade de Medicina Veterinária, Universidade Lusófona de Humanidades e Tecnologias, 1749-024 Lisboa, Portugal
| | - Bruno Carmona
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Centro de Química Estrutural–Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Sofia Nolasco
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
| | - Dulce Santos
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
| | - Alexandre Leitão
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
| | - Helena Soares
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Centro de Química Estrutural–Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
- Correspondence: or
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16
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Teichert I, Pöggeler S, Nowrousian M. Sordaria macrospora: 25 years as a model organism for studying the molecular mechanisms of fruiting body development. Appl Microbiol Biotechnol 2020; 104:3691-3704. [PMID: 32162092 PMCID: PMC7162830 DOI: 10.1007/s00253-020-10504-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/19/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023]
Abstract
Abstract Fruiting bodies are among the most complex multicellular structures formed by fungi, and the molecular mechanisms that regulate their development are far from understood. However, studies with a number of fungal model organisms have started to shed light on this developmental process. One of these model organisms is Sordaria macrospora, a filamentous ascomycete from the order Sordariales. This fungus has been a genetic model organism since the 1950s, but its career as a model organism for molecular genetics really took off in the 1990s, when the establishment of a transformation protocol, a mutant collection, and an indexed cosmid library provided the methods and resources to start revealing the molecular mechanisms of fruiting body development. In the 2000s, “omics” methods were added to the S. macrospora tool box, and by 2020, 58 developmental genes have been identified in this fungus. This review gives a brief overview of major method developments for S. macrospora, and then focuses on recent results characterizing different processes involved in regulating development including several regulatory protein complexes, autophagy, transcriptional and chromatin regulation, and RNA editing. Key points •Sordaria macrospora is a model system for analyzing fungal fruiting body development. •More than 100 developmental mutants are available for S. macrospora. •More than 50 developmental genes have been characterized in S. macrospora.
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Affiliation(s)
- Ines Teichert
- General and Molecular Botany, Ruhr-University Bochum, 44780, Bochum, Germany
| | - Stefanie Pöggeler
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany
| | - Minou Nowrousian
- Department of Molecular and Cellular Botany, Ruhr-University Bochum, ND 7/176 Universitätsstr. 150, 44780, Bochum, Germany.
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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: 58] [Impact Index Per Article: 11.6] [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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18
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It's All in the Genes: The Regulatory Pathways of Sexual Reproduction in Filamentous Ascomycetes. Genes (Basel) 2019; 10:genes10050330. [PMID: 31052334 PMCID: PMC6562746 DOI: 10.3390/genes10050330] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/17/2019] [Accepted: 04/24/2019] [Indexed: 12/23/2022] Open
Abstract
Sexual reproduction in filamentous ascomycete fungi results in the production of highly specialized sexual tissues, which arise from relatively simple, vegetative mycelia. This conversion takes place after the recognition of and response to a variety of exogenous and endogenous cues, and relies on very strictly regulated gene, protein, and metabolite pathways. This makes studying sexual development in fungi an interesting tool in which to study gene-gene, gene-protein, and protein-metabolite interactions. This review provides an overview of some of the most important genes involved in this process; from those involved in the conversion of mycelia into sexually-competent tissue, to those involved in the development of the ascomata, the asci, and ultimately, the ascospores.
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19
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He J, Cui Z, Ji X, Luo Y, Wei Y, Zhang Q. Novel Histidine Kinase Gene HisK2301 from Rhodosporidium kratochvilovae Contributes to Cold Adaption by Promoting Biosynthesis of Polyunsaturated Fatty Acids and Glycerol. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:653-660. [PMID: 30558417 DOI: 10.1021/acs.jafc.8b04859] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hybrid histidine kinase (HHKs) are widespread in fungi, but their roles in the regulation of fungal adaptation to environmental stresses remain largely unclear. To elucidate this, we cloned HisK2301 from Rhodosporidium kratochvilovae strain YM25235, characterized HisK2301 as a novel HHK, and further investigated the role of HisK2301 by overexpressing it in YM25235. Our results revealed that HisK2301 can promote adaptation of YM25235 to cold, osmotic, and salt stresses. During cold stress, HisK2301 significantly enhanced the biosynthesis of polyunsaturated fatty acids (PUFA) and intracellular glycerol. HisK2301 also augmented the expression levels of Δ12/Δ15 fatty acid desaturase ( RKD12) and glycerol-3-phosphate dehydrogenase1 ( GPD1), which are responsible for PUFA and glycerol biosynthesis, respectively. To conclude, our findings give the first insight into the defense and mechanisms of HisK2301 in fungi against cold stress and suggest the potential use of the novel cold-adapted HHK HisK2301 in industrial processes, such as large-scale production of PUFA.
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Affiliation(s)
- Jing He
- Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan 650500 , PR China
- Genetic Diagnosis Center, Yunnan Provincial Key Laboratory for Birth Defects and Genetic Diseases , The First People's Hospital of Yunnan Province , Kunming , Yunnan 650032 , PR China
| | - Zhicheng Cui
- Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan 650500 , PR China
| | - Xiuling Ji
- Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan 650500 , PR China
| | - Yiyong Luo
- Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan 650500 , PR China
| | - Yunlin Wei
- Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan 650500 , PR China
| | - Qi Zhang
- Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan 650500 , PR China
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20
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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: 13] [Impact Index Per Article: 2.2] [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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21
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Regulation of Cell-to-Cell Communication and Cell Wall Integrity by a Network of MAP Kinase Pathways and Transcription Factors in Neurospora crassa. Genetics 2018; 209:489-506. [PMID: 29678830 DOI: 10.1534/genetics.118.300904] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/18/2018] [Indexed: 11/18/2022] Open
Abstract
Maintenance of cell integrity and cell-to-cell communication are fundamental biological processes. Filamentous fungi, such as Neurospora crassa, depend on communication to locate compatible cells, coordinate cell fusion, and establish a robust hyphal network. Two MAP kinase (MAPK) pathways are essential for communication and cell fusion in N. crassa: the cell wall integrity/MAK-1 pathway and the MAK-2 (signal response) pathway. Previous studies have demonstrated several points of cross-talk between the MAK-1 and MAK-2 pathways, which is likely necessary for coordinating chemotropic growth toward an extracellular signal, and then mediating cell fusion. Canonical MAPK pathways begin with signal reception and end with a transcriptional response. Two transcription factors, ADV-1 and PP-1, are essential for communication and cell fusion. PP-1 is the conserved target of MAK-2, but it is unclear what targets ADV-1. We did RNA sequencing on Δadv-1, Δpp-1, and wild-type cells and found that ADV-1 and PP-1 have a shared regulon including many genes required for communication, cell fusion, growth, development, and stress response. We identified ADV-1 and PP-1 binding sites across the genome by adapting the in vitro method of DNA-affinity purification sequencing for N. crassa To elucidate the regulatory network, we misexpressed each transcription factor in each upstream MAPK deletion mutant. Misexpression of adv-1 was sufficient to fully suppress the phenotype of the Δpp-1 mutant and partially suppress the phenotype of the Δmak-1 mutant. Collectively, our data demonstrate that the MAK-1/ADV-1 and MAK-2/PP-1 pathways form a tight regulatory network that maintains cell integrity and mediates communication and cell fusion.
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22
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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: 12] [Impact Index Per Article: 2.0] [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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23
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Aharoni-Kats L, Zelinger E, Chen S, Yarden O. Altering Neurospora crassa MOB2A exposes its functions in development and affects its interaction with the NDR kinase COT1. Mol Microbiol 2018; 108:641-660. [PMID: 29600559 DOI: 10.1111/mmi.13954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2018] [Indexed: 12/30/2022]
Abstract
The Neurospora crassa Mps One Binder (MOB) proteins MOB2A and MOB2B physically interact with the Nuclear Dbf2 Related (NDR) kinase COT1 and have been shown to have overlapping functions in various aspects of asexual development. Here, we identified two N. crassa MOB2A residues, Tyr117 and Tyr119, which are potentially phosphorylated. Using phosphomimetic mob-2a mutants we have been able to establish that apart from their previously described roles, MOB2A/B are involved in additional developmental processes. Enhanced conidial germination, accompanied by conidial agglutination, in the phosphomimetic mutants indicated that MOB2A is a negative regulator of germination. Thick-section imaging of perithecia revealed slow maturation and a lack of asci alignment in the mutant strains demonstrating a role for MOB2A in sexual development. We demonstrate that even though MOB2A and MOB2B have some overlapping functions, MOB2B cannot compensate for the roles MOB2A has in conidiation and germination. Altering Tyr residues 117 and 119 impaired the physical interactions between MOB2A and COT1, most likely contributing to some of the observed effects. As cot-1 and the phosphomimetic mutants share an extragenic suppressor (gul-1), we concluded that at least some of the effects imposed by altering Tyr117 and Tyr119 are mediated by the NDR kinase.
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Affiliation(s)
- Liran Aharoni-Kats
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - Einat Zelinger
- Centre for Scientific Imaging, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel
| | - She Chen
- Proteomics Centre, The National Institute of Biological Sciences, Beijing 102206, China
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel
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24
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Islam KT, Bond JP, Fakhoury AM. FvSTR1, a striatin orthologue in Fusarium virguliforme, is required for asexual development and virulence. Appl Microbiol Biotechnol 2017; 101:6431-6445. [PMID: 28643182 DOI: 10.1007/s00253-017-8387-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/07/2017] [Accepted: 06/10/2017] [Indexed: 02/07/2023]
Abstract
The soil-borne fungus Fusarium virguliforme causes sudden death syndrome (SDS), one of the most devastating diseases of soybean in North and South America. Despite the importance of SDS, a clear understanding of the fungal pathogenicity factors that affect the development of this disease is still lacking. We have identified FvSTR1, a F. virguliforme gene, which encodes a protein similar to a family of striatin proteins previously reported to regulate signalling pathways, cell differentiation, conidiation, sexual development, and virulence in filamentous fungi. Striatins are multi-domain proteins that serve as scaffolding units in the striatin-interacting phosphatase and kinase (STRIPAK) complex in fungi and animals. To address the function of a striatin homologue in F. virguliforme, FvSTR1 was disrupted and functionally characterized using a gene knock out strategy. The resulting Fvstr1 mutants were largely impaired in conidiation and pigmentation, and displayed defective conidia and conidiophore morphology compared to the wild-type and ectopic transformants. Greenhouse virulence assays revealed that the disruption of FvSTR1 resulted in complete loss of virulence in F. virguliforme. Microtome studies using fluorescence microscopy showed that the Fvstr1 mutants were defective in their ability to colonize the vascular system. The Fvstr1 mutants also showed a reduced transcript level of genes involved in asexual reproduction and in the production of secondary metabolites. These results suggest that FvSTR1 has a critical role in asexual development and virulence in F. virguliforme.
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Affiliation(s)
- Kazi T Islam
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Jason P Bond
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Ahmad M Fakhoury
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA.
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25
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Schmidpeter J, Dahl M, Hofmann J, Koch C. ChMob2 binds to ChCbk1 and promotes virulence and conidiation of the fungal pathogen Colletotrichum higginsianum. BMC Microbiol 2017; 17:22. [PMID: 28103800 PMCID: PMC5248491 DOI: 10.1186/s12866-017-0932-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/12/2017] [Indexed: 01/11/2023] Open
Abstract
Background Mob family proteins are conserved between animals, plants and fungi and are essential for the activation of NDR kinases that control crucial cellular processes like cytokinesis, proliferation and morphology. Results We identified a hypomorphic allele of ChMOB2 in a random insertional mutant (vir-88) of the hemibiotrophic ascomycete fungus Colletotrichum higginsianum. The mutant is impaired in conidiation, host penetration and virulence on Arabidopsis thaliana. ChMob2 binds to and co-localizes with the NDR/LATS kinase homolog ChCbk1. Mutants in the two potential ChCbk1 downstream targets ChSSD1 and ChACE2 show defects in pathogenicity. The genome of C. higginsianum encodes two more Mob proteins. While we could not detect any effect on pathogenicity in ΔChmob3 mutants, ChMob1 is involved in conidiation, septae formation and virulence. Conclusion This study shows that ChMob2 binds to the conserved NDR/LATS Kinase ChCbk1 and plays an important role in pathogenicity of Colletotrichum higginsianum on Arabidopsis thaliana. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-0932-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Johannes Schmidpeter
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Marlis Dahl
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Jörg Hofmann
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Christian Koch
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany.
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Green KA, Becker Y, Tanaka A, Takemoto D, Fitzsimons HL, Seiler S, Lalucque H, Silar P, Scott B. SymB and SymC, two membrane associated proteins, are required forEpichloë festucaehyphal cell-cell fusion and maintenance of a mutualistic interaction withLolium perenne. Mol Microbiol 2016; 103:657-677. [DOI: 10.1111/mmi.13580] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Kimberly A. Green
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
- Bioprotection Research Centre, Massey University; Palmerston North 4442 New Zealand
| | - Yvonne Becker
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
- Leibniz Institute of Vegetable and Ornamental Crops; Großbeeren 14979 Germany
| | - Aiko Tanaka
- Graduate School of Bioagricultural Sciences; Nagoya University; Nagoya 464-8601 Japan
| | - Daigo Takemoto
- Graduate School of Bioagricultural Sciences; Nagoya University; Nagoya 464-8601 Japan
| | - Helen L. Fitzsimons
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
| | - Stephan Seiler
- Freiburg Institute for Advanced Studies, Albert-Ludwigs Universität Freiburg; Freiburg Germany
| | - Hervé Lalucque
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire des Energies de Demain; Paris 75205 France
| | - Philippe Silar
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire des Energies de Demain; Paris 75205 France
| | - Barry Scott
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
- Bioprotection Research Centre, Massey University; Palmerston North 4442 New Zealand
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Green KA, Becker Y, Fitzsimons HL, Scott B. An Epichloë festucae homologue of MOB3, a component of the STRIPAK complex, is required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. MOLECULAR PLANT PATHOLOGY 2016; 17:1480-1492. [PMID: 27277141 PMCID: PMC5132070 DOI: 10.1111/mpp.12443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/04/2016] [Accepted: 06/06/2016] [Indexed: 05/13/2023]
Abstract
In both Sordaria macrospora and Neurospora crassa, components of the conserved STRIPAK (striatin-interacting phosphatase and kinase) complex regulate cell-cell fusion, hyphal network development and fruiting body formation. Interestingly, a number of Epichloë festucae genes that are required for hyphal cell-cell fusion, such as noxA, noxR, proA, mpkA and mkkA, are also required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. To determine whether MobC, a homologue of the STRIPAK complex component MOB3 in S. macrospora and N. crassa, is required for E. festucae hyphal fusion and symbiosis, a mobC deletion strain was generated. The ΔmobC mutant showed reduced rates of hyphal cell-cell fusion, formed intrahyphal hyphae and exhibited enhanced conidiation. Plants infected with ΔmobC were severely stunted. Hyphae of ΔmobC showed a proliferative pattern of growth within the leaves of Lolium perenne with increased colonization of the intercellular spaces and vascular bundles. Although hyphae were still able to form expressoria, structures allowing the colonization of the leaf surface, the frequency of formation was significantly reduced. Collectively, these results show that the STRIPAK component MobC is required for the establishment of a mutualistic symbiotic association between E. festucae and L. perenne, and plays an accessory role in the regulation of hyphal cell-cell fusion and expressorium development in E. festucae.
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Affiliation(s)
- Kimberly A. Green
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Yvonne Becker
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Helen L. Fitzsimons
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Barry Scott
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
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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: 1.4] [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: 2.5] [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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Turrà D, Nordzieke D, Vitale S, El Ghalid M, Di Pietro A. Hyphal chemotropism in fungal pathogenicity. Semin Cell Dev Biol 2016; 57:69-75. [PMID: 27150623 DOI: 10.1016/j.semcdb.2016.04.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 10/21/2022]
Abstract
The ability to grow as filamentous hyphae defines the lifestyle of fungi. Hyphae are exposed to a variety of chemical stimuli such as nutrients or signal molecules from mating partners and host organisms. How fungi sense and process this chemical information to steer hyphal growth is poorly understood. Saccharomyces cerevisiae and Neurospora crassa have served as genetic models for the identification of cellular components functioning in chemotropism. A recent study in the pathogen Fusarium oxysporum revealed distinct MAPK pathways governing hyphal growth towards nutrient sources and sex pheromones or plant signals, suggesting an unanticipated complexity of chemosensing during fungus-host interactions.
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Affiliation(s)
- David Turrà
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Daniela Nordzieke
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Stefania Vitale
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Mennat El Ghalid
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Antonio Di Pietro
- Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, 14071 Córdoba, Spain.
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Heller J, Zhao J, Rosenfield G, Kowbel DJ, Gladieux P, Glass NL. Characterization of Greenbeard Genes Involved in Long-Distance Kind Discrimination in a Microbial Eukaryote. PLoS Biol 2016; 14:e1002431. [PMID: 27077707 PMCID: PMC4831770 DOI: 10.1371/journal.pbio.1002431] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/11/2016] [Indexed: 01/09/2023] Open
Abstract
Microorganisms are capable of communication and cooperation to perform social activities. Cooperation can be enforced using kind discrimination mechanisms in which individuals preferentially help or punish others, depending on genetic relatedness only at certain loci. In the filamentous fungus Neurospora crassa, genetically identical asexual spores (germlings) communicate and fuse in a highly regulated process, which is associated with fitness benefits during colony establishment. Recognition and chemotropic interactions between isogenic germlings requires oscillation of the mitogen-activated protein kinase (MAPK) signal transduction protein complex (NRC-1, MEK-2, MAK-2, and the scaffold protein HAM-5) to specialized cell fusion structures termed conidial anastomosis tubes. Using a population of 110 wild N. crassa isolates, we investigated germling fusion between genetically unrelated individuals and discovered that chemotropic interactions are regulated by kind discrimination. Distinct communication groups were identified, in which germlings within one communication group interacted at high frequency, while germlings from different communication groups avoided each other. Bulk segregant analysis followed by whole genome resequencing identified three linked genes (doc-1, doc-2, and doc-3), which were associated with communication group phenotype. Alleles at doc-1, doc-2, and doc-3 fell into five haplotypes that showed transspecies polymorphism. Swapping doc-1 and doc-2 alleles from different communication group strains was necessary and sufficient to confer communication group affiliation. During chemotropic interactions, DOC-1 oscillated with MAK-2 to the tips of conidial anastomosis tubes, while DOC-2 was statically localized to the plasma membrane. Our data indicate that doc-1, doc-2, and doc-3 function as "greenbeard" genes, involved in mediating long-distance kind recognition that involves actively searching for one's own type, resulting in cooperation between non-genealogical relatives. Our findings serve as a basis for investigations into the mechanisms associated with attraction, fusion, and kind recognition in other eukaryotic species.
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Affiliation(s)
- Jens Heller
- The Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
| | - Jiuhai Zhao
- The Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
| | - Gabriel Rosenfield
- The Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
| | - David J. Kowbel
- The Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
| | | | - N. Louise Glass
- The Plant and Microbial Biology Department, The University of California, Berkeley, California, United States of America
- * E-mail:
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Cell fusion in Neurospora crassa. Curr Opin Microbiol 2015; 28:53-9. [DOI: 10.1016/j.mib.2015.08.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 12/22/2022]
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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: 36] [Impact Index Per Article: 4.0] [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: 2.7] [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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Frey S, Lahmann Y, Hartmann T, Seiler S, Pöggeler S. Deletion of Smgpi1 encoding a GPI-anchored protein suppresses sterility of the STRIPAK mutant ΔSmmob3 in the filamentous ascomycete Sordaria macrospora. Mol Microbiol 2015; 97:676-97. [PMID: 25989468 DOI: 10.1111/mmi.13054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2015] [Indexed: 01/06/2023]
Abstract
The striatin interacting phosphatase and kinase (STRIPAK) complex, which is composed of striatin, protein phosphatase PP2A and kinases, is required for fruiting-body development and cell fusion in the filamentous ascomycete Sordaria macrospora. Here, we report on the interplay of the glycosylphosphatidylinositol (GPI)-anchored protein SmGPI1 with the kinase activator SmMOB3, a core component of human and fungal STRIPAK complexes. SmGPI1 is conserved among filamentous ascomycetes and was first identified in a yeast two-hybrid screen using SmMOB3 as bait. The physical interaction of SmMOB3 and SmGPI1 was verified by co-immunoprecipitation. In vivo localization and differential centrifugation revealed that SmGPI1 is predominantly secreted and attached to the cell wall but is also associated with mitochondria and appears to be a dual-targeted protein. Deletion of Smgpi1 led to an increased number of fruiting bodies that were normally shaped but reduced in size. In addition, Smmob3 and Smgpi1 genetically interact. In the sterile ΔSmmob3 background deletion of Smgpi1 restores fertility, vegetative growth as well as hyphal-fusion defects. The suppression effect was specific for the ΔSmmob3 mutant as deletion of Smgpi1 in other STRIPAK mutants does not restore fertility.
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Affiliation(s)
- Stefan Frey
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August-University, Göttingen, Germany
| | - Yasmine Lahmann
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August-University, Göttingen, Germany
| | - Thomas Hartmann
- Institute of Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August-University, Göttingen, Germany
| | - Stephan Seiler
- Institute of Microbiology and Genetics, Department of Molecular Microbiology and 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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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: 46] [Impact Index Per Article: 4.6] [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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Teichert I, Steffens EK, Schnaß N, Fränzel B, Krisp C, Wolters DA, Kück U. PRO40 is a scaffold protein of the cell wall integrity pathway, linking the MAP kinase module to the upstream activator protein kinase C. PLoS Genet 2014; 10:e1004582. [PMID: 25188365 PMCID: PMC4154660 DOI: 10.1371/journal.pgen.1004582] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/02/2014] [Indexed: 12/21/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathways are crucial signaling instruments in eukaryotes. Most ascomycetes possess three MAPK modules that are involved in key developmental processes like sexual propagation or pathogenesis. However, the regulation of these modules by adapters or scaffolds is largely unknown. Here, we studied the function of the cell wall integrity (CWI) MAPK module in the model fungus Sordaria macrospora. Using a forward genetic approach, we found that sterile mutant pro30 has a mutated mik1 gene that encodes the MAPK kinase kinase (MAPKKK) of the proposed CWI pathway. We generated single deletion mutants lacking MAPKKK MIK1, MAPK kinase (MAPKK) MEK1, or MAPK MAK1 and found them all to be sterile, cell fusion-deficient and highly impaired in vegetative growth and cell wall stress response. By searching for MEK1 interaction partners via tandem affinity purification and mass spectrometry, we identified previously characterized developmental protein PRO40 as a MEK1 interaction partner. Although fungal PRO40 homologs have been implicated in diverse developmental processes, their molecular function is currently unknown. Extensive affinity purification, mass spectrometry, and yeast two-hybrid experiments showed that PRO40 is able to bind MIK1, MEK1, and the upstream activator protein kinase C (PKC1). We further found that the PRO40 N-terminal disordered region and the central region encompassing a WW interaction domain are sufficient to govern interaction with MEK1. Most importantly, time- and stress-dependent phosphorylation studies showed that PRO40 is required for MAK1 activity. The sum of our results implies that PRO40 is a scaffold protein for the CWI pathway, linking the MAPK module to the upstream activator PKC1. Our data provide important insights into the mechanistic role of a protein that has been implicated in sexual and asexual development, cell fusion, symbiosis, and pathogenicity in different fungal systems. The specific response to environmental cues is crucial for cell differentiation and is often mediated by highly conserved eukaryotic MAP kinase (MAPK) pathways. How these pathways react specifically to huge numbers of different cues is still unclear, and current literature about adapter and scaffolding proteins remains scarce. However, gaining fundamental insight into molecular signaling determinants is pivotal for combating diseases with impaired signal transduction processes, such as Alzheimer's disease or cancer. Importantly, signal transduction can easily be studied in lower eukaryotes like filamentous fungi that are readily genetically tractable. The fungus Sordaria macrospora has a long history as an ideal model system for cell differentiation, and we show here that the proposed cell wall integrity (CWI) MAPK module of this fungus controls differentiation of sexual fruiting bodies, cell fusion, polar growth and cell wall stress response. We further discovered that developmental protein PRO40 binds the MAPK kinase kinase (MAPKKK), the MAPK kinase (MAPKK) and upstream activator protein kinase C (PKC1) of the CWI pathway and is required for MAK1 activity, thereby providing evidence that PRO40 is a scaffold protein. Collectively, our findings reveal a molecular role for a protein implicated in development, cell fusion, symbiosis, and pathogenicity in different fungi.
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Affiliation(s)
- Ines Teichert
- Department for General and Molecular Botany, Ruhr-University Bochum, Bochum, Germany
| | | | - Nicole Schnaß
- Department for General and Molecular Botany, Ruhr-University Bochum, Bochum, Germany
| | - Benjamin Fränzel
- Department of Analytical Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Christoph Krisp
- Department of Analytical Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Dirk A. Wolters
- Department of Analytical Chemistry, Ruhr-University Bochum, Bochum, Germany
| | - Ulrich Kück
- Department for General and Molecular Botany, Ruhr-University Bochum, Bochum, Germany
- * E-mail:
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Lehneck R, Elleuche S, Pöggeler S. The filamentous ascomyceteSordaria macrosporacan survive in ambient air without carbonic anhydrases. Mol Microbiol 2014; 92:931-44. [DOI: 10.1111/mmi.12607] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2014] [Indexed: 10/25/2022]
Affiliation(s)
- Ronny Lehneck
- Institute of Microbiology and Genetics; Department of Genetics of Eukaryotic Microorganisms; Georg-August-University Göttingen; Göttingen Germany
| | - Skander Elleuche
- Institute of Technical Microbiology; Hamburg University of Technology; Hamburg Germany
| | - Stefanie Pöggeler
- Institute of Microbiology and Genetics; Department of Genetics of Eukaryotic Microorganisms; Georg-August-University Göttingen; Göttingen Germany
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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: 170] [Impact Index Per Article: 17.0] [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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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: 4.8] [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: 5.5] [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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Voigt O, Pöggeler S. Autophagy genes Smatg8 and Smatg4 are required for fruiting-body development, vegetative growth and ascospore germination in the filamentous ascomycete Sordaria macrospora. Autophagy 2012; 9:33-49. [PMID: 23064313 DOI: 10.4161/auto.22398] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Autophagy is a tightly controlled degradation process involved in various developmental aspects of eukaryotes. However, its involvement in developmental processes of multicellular filamentous ascomycetes is largely unknown. Here, we analyzed the impact of the autophagic proteins SmATG8 and SmATG4 on the sexual and vegetative development of the filamentous ascomycete Sordaria macrospora. A Saccharomyces cerevisiae complementation assay demonstrated that the S. macrospora Smatg8 and Smatg4 genes can functionally replace the yeast homologs. By generating homokaryotic deletion mutants, we showed that the S. macrospora SmATG8 and SmATG4 orthologs were associated with autophagy-dependent processes. Smatg8 and Smatg4 deletions abolished fruiting-body formation and impaired vegetative growth and ascospore germination, but not hyphal fusion. We demonstrated that SmATG4 was capable of processing the SmATG8 precursor. SmATG8 was localized to autophagosomes, whereas SmATG4 was distributed throughout the cytoplasm of S. macrospora. Furthermore, we could show that Smatg8 and Smatg4 are not only required for nonselective macroautophagy, but for selective macropexophagy as well. Taken together, our results suggest that in S. macrospora, autophagy seems to be an essential and constitutively active process to sustain high energy levels for filamentous growth and multicellular development even under nonstarvation conditions.
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Affiliation(s)
- Oliver Voigt
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany
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Bloemendal S, Bernhards Y, Bartho K, Dettmann A, Voigt O, Teichert I, Seiler S, Wolters DA, Pöggeler S, Kück U. A homologue of the human STRIPAK complex controls sexual development in fungi. Mol Microbiol 2012; 84:310-23. [PMID: 22375702 DOI: 10.1111/j.1365-2958.2012.08024.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sexual development in fungi is a complex process involving the generation of new cell types and tissues - an essential step for all eukaryotic life. The characterization of sterile mutants in the ascomycete Sordaria macrospora has led to a number of proteins involved in sexual development, but a link between these proteins is still missing. Using a combined tandem-affinity purification/mass spectrometry approach, we showed in vivo association of developmental protein PRO22 with PRO11, homologue of mammalian striatin, and SmPP2AA, scaffolding subunit of protein phosphatase 2A. Further experiments extended the protein network to the putative kinase activator SmMOB3, known to be involved in sexual development. Extensive yeast two-hybrid studies allowed us to pinpoint functional domains involved in protein-protein interaction. We show for the first time that a number of already known factors together with new components associate in vivo to form a highly conserved multi-subunit complex. Strikingly, a similar complex has been described in humans, but the function of this so-called striatin interacting phosphatase and kinase (STRIPAK) complex is largely unknown. In S. macrospora, truncation of PRO11 and PRO22 leads to distinct defects in sexual development and cell fusion, indicating a role for the fungal STRIPAK complex in both processes.
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Affiliation(s)
- Sandra Bloemendal
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany
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Identification and characterization of genes required for cell-to-cell fusion in Neurospora crassa. EUKARYOTIC CELL 2011; 10:1100-9. [PMID: 21666072 DOI: 10.1128/ec.05003-11] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A screening procedure was used to identify cell fusion (hyphal anastomosis) mutants in the Neurospora crassa single gene deletion library. Mutants with alterations in 24 cell fusion genes required for cell fusion between conidial anastomosis tubes (CATs) were identified and characterized. The cell fusion genes identified included 14 genes that are likely to function in signal transduction pathways needed for cell fusion to occur (mik-1, mek-1, mak-1, nrc-1, mek-2, mak-2, rac-1, pp2A, so/ham-1, ham-2, ham-3, ham-5, ham-9, and mob3). The screening experiments also identified four transcription factors that are required for cell fusion (adv-1, ada-3, rco-1, and snf5). Three genes encoding proteins likely to be involved in the process of vesicular trafficking were also identified as needed for cell fusion during the screening (amph-1, ham-10, pkr1). Three of the genes identified by the screening procedure, ham-6, ham-7, and ham-8, encode proteins that might function in mediating the plasma membrane fusion event. Three of the putative signal transduction proteins, three of the transcription factors, the three putative vesicular trafficking proteins, and the three proteins that might function in mediating cell fusion had not been identified previously as required for cell fusion.
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