1
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Kourkoulou A, Martzoukou O, Fischer R, Amillis S. A type II phosphatidylinositol-4-kinase coordinates sorting of cargo polarizing by endocytic recycling. Commun Biol 2024; 7:855. [PMID: 38997419 PMCID: PMC11245547 DOI: 10.1038/s42003-024-06553-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 07/04/2024] [Indexed: 07/14/2024] Open
Abstract
Depending on their phosphorylation status, derivatives of phosphatidylinositol play important roles in vesicle identity, recognition and intracellular trafficking processes. In eukaryotic cells, phosphatidylinositol-4 phosphate pools generated by specific kinases are key determinants of the conventional secretion pathways. Earlier work in yeast has classified phosphatidylinositol-4 kinases in two types, Stt4p and Pik1p belonging to type III and Lsb6p to type II, with distinct cellular localizations and functions. Eurotiomycetes appear to lack Pik1p homologues. In Aspergillus nidulans, unlike homologues in other fungi, AnLsb6 is associated to late Golgi membranes and when heterologously overexpressed, it compensates for the thermosensitive phenotype in a Saccharomyces cerevisiae pik1 mutant, whereas its depletion leads to disorganization of Golgi-associated PHOSBP-labelled membranes, that tend to aggregate dependent on functional Rab5 GTPases. Evidence provided herein, indicates that the single type II phosphatidylinositol-4 kinase AnLsb6 is the main contributor for decorating secretory vesicles with relevant phosphatidylinositol-phosphate species, which navigate essential cargoes following the route of apical polarization via endocytic recycling.
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Affiliation(s)
- Anezia Kourkoulou
- National and Kapodistrian University of Athens, Department of Biology, Athens, Hellas, Greece
| | - Olga Martzoukou
- National and Kapodistrian University of Athens, Department of Biology, Athens, Hellas, Greece
| | - Reinhard Fischer
- Karlsruhe Institute of Technology - South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Sotiris Amillis
- National and Kapodistrian University of Athens, Department of Biology, Athens, Hellas, Greece.
- Karlsruhe Institute of Technology - South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany.
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2
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Yan Q, Han L, Liu Z, Zhou S, Zhou Z. Stepwise genetic modification for efficient expression of heterologous proteins in Aspergillus nidulans. Appl Microbiol Biotechnol 2023; 107:6923-6935. [PMID: 37698610 DOI: 10.1007/s00253-023-12755-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/09/2023] [Accepted: 08/26/2023] [Indexed: 09/13/2023]
Abstract
Filamentous fungi are widely used in food fermentation and therapeutic protein production due to their prominent protein secretion and post-translational modification system. Aspergillus nidulans is an important model strain of filamentous fungi, but not a fully developed cell factory for heterologous protein expression. One of the limitations is its relatively low capacity of protein secretion. To alleviate this limitation, in this study, the protein secretory pathway and mycelium morphology were stepwise modified. With eGFP as a reporter protein, protein secretion was significantly enhanced through reducing the degradation of heterologous proteins by endoplasmic reticulum-associated protein degradation (ERAD) and vacuoles in the secretory pathway. Elimination of mycelial aggregation resulted in a 1.5-fold and 1.3-fold increase in secretory expression of eGFP in typical constitutive and inducible expression systems, respectively. Combined with these modifications, high secretory expression of human interleukin-6 (HuIL-6) was achieved. Consequently, a higher yield of secretory HuIL-6 was realized by further disruption of extracellular proteases. Overall, a superior chassis cell of A. nidulans suitable for efficient secretory expression of heterologous proteins was successfully obtained, providing a promising platform for biosynthesis using filamentous fungi as hosts. KEY POINTS: • Elimination of mycelial aggregation and decreasing the degradation of heterologous protein are effective strategies for improving the heterologous protein expression. • The work provides a high-performance chassis host △agsB-derA for heterologous protein secretory expression. • Human interleukin-6 (HuIL-6) was expressed efficiently in the high-performance chassis host △agsB-derA.
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Affiliation(s)
- Qin Yan
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Laichuang Han
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Zhongmei Liu
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Shengmin Zhou
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, China.
| | - Zhemin Zhou
- School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.
- Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, 214122, China.
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3
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Bravo-Plaza I, Tagua VG, Arst HN, Alonso A, Pinar M, Monterroso B, Galindo A, Peñalva MA. The Uso1 globular head interacts with SNAREs to maintain viability even in the absence of the coiled-coil domain. eLife 2023; 12:e85079. [PMID: 37249218 PMCID: PMC10275640 DOI: 10.7554/elife.85079] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/29/2023] [Indexed: 05/31/2023] Open
Abstract
Uso1/p115 and RAB1 tether ER-derived vesicles to the Golgi. Uso1/p115 contains a globular-head-domain (GHD), a coiled-coil (CC) mediating dimerization/tethering, and a C-terminal region (CTR) interacting with golgins. Uso1/p115 is recruited to vesicles by RAB1. Genetic studies placed Uso1 paradoxically acting upstream of, or in conjunction with RAB1 (Sapperstein et al., 1996). We selected two missense mutations in uso1 resulting in E6K and G540S in the GHD that rescued lethality of rab1-deficient Aspergillus nidulans. The mutations are phenotypically additive, their combination suppressing the complete absence of RAB1, which emphasizes the key physiological role of the GHD. In living hyphae Uso1 recurs on puncta (60 s half-life) colocalizing partially with the Golgi markers RAB1, Sed5, and GeaA/Gea1/Gea2, and totally with the retrograde cargo receptor Rer1, consistent with Uso1 dwelling in a very early Golgi compartment from which ER residents reaching the Golgi recycle back to the ER. Localization of Uso1, but not of Uso1E6K/G540S, to puncta is abolished by compromising RAB1 function, indicating that E6K/G540S creates interactions bypassing RAB1. That Uso1 delocalization correlates with a decrease in the number of Gea1 cisternae supports that Uso1-and-Rer1-containing puncta are where the protein exerts its physiological role. In S-tag-coprecipitation experiments, Uso1 is an associate of the Sed5/Bos1/Bet1/Sec22 SNARE complex zippering vesicles with the Golgi, with Uso1E6K/G540S showing a stronger association. Using purified proteins, we show that Bos1 and Bet1 bind the Uso1 GHD directly. However, Bet1 is a strong E6K/G540S-independent binder, whereas Bos1 is weaker but becomes as strong as Bet1 when the GHD carries E6K/G540S. G540S alone markedly increases GHD binding to Bos1, whereas E6K causes a weaker effect, correlating with their phenotypic contributions. AlphaFold2 predicts that G540S increases the binding of the GHD to the Bos1 Habc domain. In contrast, E6K lies in an N-terminal, potentially alpha-helical, region that sensitive genetic tests indicate as required for full Uso1 function. Remarkably, this region is at the end of the GHD basket opposite to the end predicted to interact with Bos1. We show that, unlike dimeric full-length and CTR∆ Uso1 proteins, the GHD lacking the CC/CTR dimerization domain, whether originating from bacteria or Aspergillus extracts and irrespective of whether it carries or not E6K/G540S, would appear to be monomeric. With the finding that overexpression of E6K/G540S and wild-type GHD complement uso1∆, our data indicate that the GHD monomer is capable of providing, at least partially, the essential Uso1 functions, and that long-range tethering activity is dispensable. Rather, these findings strongly suggest that the essential role of Uso1 involves the regulation of SNAREs.
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Affiliation(s)
- Ignacio Bravo-Plaza
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Victor G Tagua
- Instituto de Tecnologías Biomédicas, Hospital Universitario Nuestra Señora de CandelariaSanta Cruz de TenerifeSpain
| | - Herbert N Arst
- Department of Infectious Diseases, Faculty of Medicine, Flowers Building, Imperial CollegeLondonUnited Kingdom
| | - Ana Alonso
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Mario Pinar
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Begoña Monterroso
- Department of Structural and Chemical Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
| | - Antonio Galindo
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Francis Crick AvenueCambridgeUnited Kingdom
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, CSIC Centro de Investigaciones BiológicasMadridSpain
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4
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Dimou S, Dionysopoulou M, Sagia GM, Diallinas G. Golgi-Bypass Is a Major Unconventional Route for Translocation to the Plasma Membrane of Non-Apical Membrane Cargoes in Aspergillus nidulans. Front Cell Dev Biol 2022; 10:852028. [PMID: 35465316 PMCID: PMC9021693 DOI: 10.3389/fcell.2022.852028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
Nutrient transporters have been shown to translocate to the plasma membrane (PM) of the filamentous fungus Aspergillus nidulans via an unconventional trafficking route that bypasses the Golgi. This finding strongly suggests the existence of distinct COPII vesicle subpopulations, one following Golgi-dependent conventional secretion and the other directed towards the PM. Here, we address whether Golgi-bypass concerns cargoes other than nutrient transporters and whether Golgi-bypass is related to cargo structure, size, abundance, physiological function, or polar vs. non-polar distribution in the PM. To address these questions, we followed the dynamic subcellular localization of two selected membrane cargoes differing in several of the aforementioned aspects. These are the proton-pump ATPase PmaA and the PalI pH signaling component. Our results show that neosynthesized PmaA and PalI are translocated to the PM via Golgi-bypass, similar to nutrient transporters. In addition, we showed that the COPII-dependent exit of PmaA from the ER requires the alternative COPII coat subunit LstA, rather than Sec24, whereas PalI requires the ER cargo adaptor Erv14. These findings strengthen the evidence of distinct cargo-specific COPII subpopulations and extend the concept of Golgi-independent biogenesis to essential transmembrane proteins, other than nutrient transporters. Overall, our findings point to the idea that Golgi-bypass might not constitute a fungal-specific peculiarity, but rather a novel major and cargo-specific sorting route in eukaryotic cells that has been largely ignored.
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Affiliation(s)
- Sofia Dimou
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, Athens, Greece
| | - Mariangela Dionysopoulou
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, Athens, Greece
| | - Georgia Maria Sagia
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, Athens, Greece
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, Athens, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Greece
- *Correspondence: George Diallinas,
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5
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Hiasa R, Kakimoto KI, Takegawa K, Higuchi Y. Involvement of AAA ATPase AipA in endocytosis of the arginine permease AoCan1 depending on AoAbp1 in Aspergillus oryzae. Fungal Biol 2021; 126:149-161. [DOI: 10.1016/j.funbio.2021.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 11/16/2021] [Accepted: 11/22/2021] [Indexed: 11/17/2022]
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Abstract
In a number of elongated cells, such as fungal hyphae, a vesicle cluster is observed at the growing tip. This cluster, called a Spitzenkörper, has been suggested to act as a vesicle supply center, yet analysis of its function is challenging, as a majority of components identified thus far are essential for growth. Here, we probe the function of the Spitzenkörper in the human fungal pathogen Candida albicans, using genetics and synthetic physical interactions (SPI). We show that the C. albicans Spitzenkörper is comprised principally of secretory vesicles. Mutant strains lacking the Spitzenkörper component myosin light chain 1 (Mlc1) or having a SPI between Mlc1 and either another Spitzenkörper component, the Rab GTPase Sec4, or prenylated green fluorescent protein (GFP), are viable and still exhibit a Spitzenkörper during filamentous growth. Strikingly, all of these mutants formed filaments with increased diameters and extension rates, indicating that Mlc1 negatively regulates myosin V, Myo2, activity. The results of our quantitative studies reveal a strong correlation between filament diameter and extension rate, which is consistent with the vesicle supply center model for fungal tip growth. Together, our results indicate that the Spitzenkörper protein Mlc1 is important for growth robustness and reveal a critical link between filament morphology and extension rate. IMPORTANCE Hyphal tip growth is critical in a range of fungal pathogens, in particular for invasion into animal and plant tissues. In Candida albicans, as in many filamentous fungi, a cluster of vesicles, called a Spitzenkörper, is observed at the tip of growing hyphae that is thought to function as a vesicle supply center. A central prediction of the vesicle supply center model is that the filament diameter is proportional to the extension rate. Here, we show that mutants lacking the Spitzenkörper component myosin light chain 1 (Mlc1) or having synthetic physical interactions between Mlc1 and either another Spitzenkörper component or prenylated GFP, are defective in filamentous growth regulation, exhibiting a range of growth rates and sizes, with a strong correlation between diameter and extension rate. These results suggest that the Spitzenkörper is important for growth robustness and reveal a critical link between filament morphology and extension rate.
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7
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Jin J, Iwama R, Takagi K, Horiuchi H. AP-2 complex contributes to hyphal-tip-localization of a chitin synthase in the filamentous fungus Aspergillus nidulans. Fungal Biol 2021; 125:806-814. [PMID: 34537176 DOI: 10.1016/j.funbio.2021.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/06/2021] [Accepted: 05/18/2021] [Indexed: 10/20/2022]
Abstract
Filamentous fungi maintain hyphal growth to continually internalize membrane proteins related to cell wall synthesis, transporting them to the hyphal tips. Endocytosis mediates protein internalization via target recognition by the adaptor protein 2 complex (AP-2 complex). The AP-2 complex specifically promotes the internalization of proteins important for hyphal growth, and loss of AP-2 complex function results in abnormal hyphal growth. In this study, deletion mutants of the genes encoding the subunits of the AP-2 complex (α, β2, μ2, or σ2) in the filamentous fungus Aspergillus nidulans resulted in the formation of conidiophores with abnormal morphology, fewer conidia, and activated the cell wall integrity pathway. We also investigated the localization of ChsB, which plays pivotal roles in hyphal growth in A. nidulans, in the Δμ2 strain. Quantitative analysis suggested that the AP-2 complex is involved in ChsB internalization at subapical collar regions. The absence of the AP-2 complex reduced ChsB localization at the hyphal tips. Our findings suggest that the AP-2 complex contributes to cell wall integrity by properly localizing ChsB to the hyphal tips.
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Affiliation(s)
- Jingyun Jin
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Ryo Iwama
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Keiko Takagi
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Hiroyuki Horiuchi
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan.
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8
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Pinar M, Peñalva MA. The fungal RABOME: RAB GTPases acting in the endocytic and exocytic pathways of Aspergillus nidulans (with excursions to other filamentous fungi). Mol Microbiol 2021; 116:53-70. [PMID: 33724562 DOI: 10.1111/mmi.14716] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/04/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022]
Abstract
RAB GTPases are major determinants of membrane identity that have been exploited as highly specific reporters to study intracellular traffic in vivo. A score of fungal papers have considered individual RABs, but systematic, integrated studies on the localization and physiological role of these regulators and their effectors have been performed only with Aspergillus nidulans. These studies have influenced the intracellular trafficking field beyond fungal specialists, leading to findings such as the maturation of trans-Golgi (TGN) cisternae into post-Golgi RAB11 secretory vesicles, the concept that these RAB11 secretory carriers are loaded with three molecular nanomotors, the understanding of the role of endocytic recycling mediated by RAB6 and RAB11 in determining the hyphal mode of life, the discovery that early endosome maturation and the ESCRT pathway are essential, the identification of specific adaptors of dynein-dynactin to RAB5 endosomes, the exquisite dependence that autophagy displays on RAB1 activity, the role of TRAPPII as a GEF for RAB11, or the conclusion that the RAB1-to-RAB11 transition is not mediated by TRAPP maturation. A remarkable finding was that the A. nidulans Spitzenkörper contains four RABs: RAB11, Sec4, RAB6, and RAB1. How these RABs cooperate during exocytosis represents an as yet outstanding question.
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Affiliation(s)
- Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain
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9
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Pinar M, Peñalva MA. En bloc TGN recruitment of Aspergillus TRAPPII reveals TRAPP maturation as unlikely to drive RAB1-to-RAB11 transition. J Cell Sci 2020; 133:jcs241141. [PMID: 32327558 DOI: 10.1242/jcs.241141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/06/2020] [Indexed: 08/31/2023] Open
Abstract
Transport protein particle (TRAPP) complexes regulate membrane traffic. TRAPPII and TRAPPIII share a core hetero-heptamer, also denoted TRAPPI. In fungi TRAPPIII and TRAPPII mediate GDP exchange on RAB1 and RAB11, respectively, regulating traffic across the Golgi, with TRAPPIII also activating RAB1 in autophagosomes. Our finding that Aspergillus nidulans TRAPPII can be assembled by addition of a TRAPPII-specific subcomplex onto core TRAPP prompted us to investigate the possibility that TRAPPI and/or TRAPPIII already residing in the Golgi matures into TRAPPII to determine a RAB1-to-RAB11 conversion as Golgi cisternae progress from early Golgi to TGN identity. By time-resolved microscopy, we determine that the TRAPPII reporter Trs120 (the homolog of metazoan TRAPPC9) is recruited to existing trans-Golgi network (TGN) cisternae slightly before RAB11 arrives, and resides for ∼45 s on them before cisternae tear off into RAB11 secretory carriers. Notably, the core TRAPP reporter Bet3 (the homolog of metazoan TRAPPC3) was not detectable in early Golgi cisternae, being instead recruited to TGN cisternae simultaneously with Trs120, indicating en bloc recruitment of TRAPPII to the Golgi and arguing strongly against the TRAPP maturation model.
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Affiliation(s)
- Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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10
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Dimou S, Martzoukou O, Dionysopoulou M, Bouris V, Amillis S, Diallinas G. Translocation of nutrient transporters to cell membrane via Golgi bypass in Aspergillus nidulans. EMBO Rep 2020; 21:e49929. [PMID: 32452614 DOI: 10.15252/embr.201949929] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/15/2020] [Accepted: 04/24/2020] [Indexed: 02/06/2023] Open
Abstract
Nutrient transporters, being polytopic membrane proteins, are believed, but not formally shown, to traffic from their site of synthesis, the ER, to the plasma membrane through Golgi-dependent vesicular trafficking. Here, we develop a novel genetic system to investigate the trafficking of a neosynthesized model transporter, the well-studied UapA purine transporter of Aspergillus nidulans. We show that sorting of neosynthesized UapA to the plasma membrane (PM) bypasses the Golgi and does not necessitate key Rab GTPases, AP adaptors, microtubules or endosomes. UapA PM localization is found to be dependent on functional COPII vesicles, actin polymerization, clathrin heavy chain and the PM t-SNARE SsoA. Actin polymerization proved to primarily affect COPII vesicle formation, whereas the essential role of ClaH seems indirect and less clear. We provide evidence that other evolutionary and functionally distinct transporters of A. nidulans also follow the herein identified Golgi-independent trafficking route of UapA. Importantly, our findings suggest that specific membrane cargoes drive the formation of distinct COPII subpopulations that bypass the Golgi to be sorted non-polarly to the PM, and thus serving house-keeping cell functions.
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Affiliation(s)
- Sofia Dimou
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Olga Martzoukou
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Vangelis Bouris
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Sotiris Amillis
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
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11
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Zhang J, Yun Y, Lou Y, Abubakar YS, Guo P, Wang S, Li C, Feng Y, Adnan M, Zhou J, Lu G, Zheng W. FgAP‐2 complex is essential for pathogenicity and polarised growth and regulates the apical localisation of membrane lipid flippases in
Fusarium graminearum. Cell Microbiol 2019; 21:e13041. [DOI: 10.1111/cmi.13041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/11/2019] [Accepted: 05/12/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Jing Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Yingzi Yun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Yi Lou
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life SciencesFujian Agriculture and Forestry University Fuzhou China
| | | | - Pusheng Guo
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Shumin Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Chunling Li
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Yuan Feng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Muhammad Adnan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Jie Zhou
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life SciencesFujian Agriculture and Forestry University Fuzhou China
| | - Guo‐dong Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
| | - Wenhui Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant ProtectionFujian Agriculture and Forestry University Fuzhou China
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12
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Hernández-González M, Bravo-Plaza I, de Los Ríos V, Pinar M, Pantazopoulou A, Peñalva MA. COPI localizes to the early Golgi in Aspergillus nidulans. Fungal Genet Biol 2018; 123:78-86. [PMID: 30550852 DOI: 10.1016/j.fgb.2018.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 01/21/2023]
Abstract
Coatomer-I (COPI) is a heteromeric protein coat that facilitates the budding of membranous carriers mediating Golgi-to-ER and intra-Golgi transport. While the structural features of COPI have been thoroughly investigated, its physiological role is insufficiently understood. Here we exploit the amenability of A. nidulans for studying intracellular traffic, taking up previous studies by Breakspear et al. (2007) with the α-COP/CopA subunit of COPI. Endogenously tagged α-COP/CopA largely localizes to SedVSed5 syntaxin-containing early Golgi cisterna, and acute inactivation of ER-to-Golgi traffic delocalizes COPI to a haze, consistent with the cisternal maturation model. In contrast, the Golgi localization of COPI is independent of the TGN regulators HypBSec7 and HypATrs120, implying that COPI budding predominates at the SedVSed5 early Golgi, with lesser contribution of the TGN. This finding agrees with the proposed role of COPI-mediated intra-Golgi retrograde traffic in driving cisternal maturation, which predicts that the capacity of the TGN to generate COPI carriers is low. The COPI early Golgi compartments intimately associates with Sec13-containing ER exit sites. Characterization of the heat-sensitive copA1ts (sodVIC1) mutation showed that it results in a single residue substitution in the ε-COP-binding Carboxyl-Terminal-Domain of α-COP that likely destabilizes its folding. However, we show that Golgi disorganization by copA1ts necessitates >150 min-long incubation at 42 °C. This weak subcellular phenotype makes it unsuitable for inactivating COPI traffic acutely for microscopy studies, and explains the aneuploidy-stabilizing role of the mutation at subrestrictive temperatures.
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Affiliation(s)
- Miguel Hernández-González
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain; Centre for Mechanochemical Cell Biology, Gibbet Hill Road, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK(1)
| | - Ignacio Bravo-Plaza
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Vivian de Los Ríos
- Proteomics and Genomics Facility, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain; Department of Molecular Genetics and Cell Biology, Biological Sciences Division, The University of Chicago, United States(1).
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain.
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13
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Hernández‐González M, Pantazopoulou A, Spanoudakis D, Seegers CL, Peñalva MA. Genetic dissection of the secretory route followed by a fungal extracellular glycosyl hydrolase. Mol Microbiol 2018; 109:781-800. [DOI: 10.1111/mmi.14073] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/15/2018] [Accepted: 07/02/2018] [Indexed: 01/16/2023]
Affiliation(s)
- Miguel Hernández‐González
- Department of Cellular and Molecular Biology and WhiteBiotech Interdepartmental Unit Centro de Investigaciones Biológicas CSIC Madrid Spain
| | - Areti Pantazopoulou
- Department of Cellular and Molecular Biology and WhiteBiotech Interdepartmental Unit Centro de Investigaciones Biológicas CSIC Madrid Spain
- Department of Molecular Genetics and Cell Biology The University of Chicago Chicago IL USA
| | - Dimitris Spanoudakis
- Department of Cellular and Molecular Biology and WhiteBiotech Interdepartmental Unit Centro de Investigaciones Biológicas CSIC Madrid Spain
| | - Christel L.C. Seegers
- Department of Cellular and Molecular Biology and WhiteBiotech Interdepartmental Unit Centro de Investigaciones Biológicas CSIC Madrid Spain
- Avebe UA Foxhol The Netherlands
| | - Miguel A. Peñalva
- Department of Cellular and Molecular Biology and WhiteBiotech Interdepartmental Unit Centro de Investigaciones Biológicas CSIC Madrid Spain
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14
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Secretory Vesicle Polar Sorting, Endosome Recycling and Cytoskeleton Organization Require the AP-1 Complex in Aspergillus nidulans. Genetics 2018; 209:1121-1138. [PMID: 29925567 DOI: 10.1534/genetics.118.301240] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/19/2018] [Indexed: 11/18/2022] Open
Abstract
The AP-1 complex is essential for membrane protein traffic via its role in the pinching-off and sorting of secretory vesicles (SVs) from the trans-Golgi and/or endosomes. While its essentiality is undisputed in metazoa, its role in simpler eukaryotes seems less clear. Here, we dissect the role of AP-1 in the filamentous fungus Aspergillus nidulans and show that it is absolutely essential for growth due to its role in clathrin-dependent maintenance of polar traffic of specific membrane cargoes toward the apex of growing hyphae. We provide evidence that AP-1 is involved in both anterograde sorting of RabERab11-labeled SVs and RabA/BRab5-dependent endosome recycling. Additionally, AP-1 is shown to be critical for microtubule and septin organization, further rationalizing its essentiality in cells that face the challenge of cytoskeleton-dependent polarized cargo traffic. This work also opens a novel issue on how nonpolar cargoes, such as transporters, are sorted to the eukaryotic plasma membrane.
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15
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Riquelme M, Aguirre J, Bartnicki-García S, Braus GH, Feldbrügge M, Fleig U, Hansberg W, Herrera-Estrella A, Kämper J, Kück U, Mouriño-Pérez RR, Takeshita N, Fischer R. Fungal Morphogenesis, from the Polarized Growth of Hyphae to Complex Reproduction and Infection Structures. Microbiol Mol Biol Rev 2018; 82:e00068-17. [PMID: 29643171 PMCID: PMC5968459 DOI: 10.1128/mmbr.00068-17] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Filamentous fungi constitute a large group of eukaryotic microorganisms that grow by forming simple tube-like hyphae that are capable of differentiating into more-complex morphological structures and distinct cell types. Hyphae form filamentous networks by extending at their tips while branching in subapical regions. Rapid tip elongation requires massive membrane insertion and extension of the rigid chitin-containing cell wall. This process is sustained by a continuous flow of secretory vesicles that depends on the coordinated action of the microtubule and actin cytoskeletons and the corresponding motors and associated proteins. Vesicles transport cell wall-synthesizing enzymes and accumulate in a special structure, the Spitzenkörper, before traveling further and fusing with the tip membrane. The place of vesicle fusion and growth direction are enabled and defined by the position of the Spitzenkörper, the so-called cell end markers, and other proteins involved in the exocytic process. Also important for tip extension is membrane recycling by endocytosis via early endosomes, which function as multipurpose transport vehicles for mRNA, septins, ribosomes, and peroxisomes. Cell integrity, hyphal branching, and morphogenesis are all processes that are largely dependent on vesicle and cytoskeleton dynamics. When hyphae differentiate structures for asexual or sexual reproduction or to mediate interspecies interactions, the hyphal basic cellular machinery may be reprogrammed through the synthesis of new proteins and/or the modification of protein activity. Although some transcriptional networks involved in such reprogramming of hyphae are well studied in several model filamentous fungi, clear connections between these networks and known determinants of hyphal morphogenesis are yet to be established.
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Affiliation(s)
- Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Jesús Aguirre
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Salomon Bartnicki-García
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany
| | - Michael Feldbrügge
- Institute for Microbiology, Heinrich Heine University Düsseldorf, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Ursula Fleig
- Institute for Functional Genomics of Microorganisms, Heinrich Heine University Düsseldorf, Cluster of Excellence on Plant Sciences, Düsseldorf, Germany
| | - Wilhelm Hansberg
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico
| | - Alfredo Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Mexico
| | - Jörg Kämper
- Karlsruhe Institute of Technology-South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
| | - Ulrich Kück
- Ruhr University Bochum, Lehrstuhl für Allgemeine und Molekulare Botanik, Bochum, Germany
| | - Rosa R Mouriño-Pérez
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Norio Takeshita
- University of Tsukuba, Faculty of Life and Environmental Sciences, Tsukuba, Japan
| | - Reinhard Fischer
- Karlsruhe Institute of Technology-South Campus, Institute for Applied Biosciences, Karlsruhe, Germany
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16
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Yang X, Ma N, Yang L, Zheng Y, Zhen Z, Li Q, Xie M, Li J, Zhang KQ, Yang J. Two Rab GTPases play different roles in conidiation, trap formation, stress resistance, and virulence in the nematode-trapping fungus Arthrobotrys oligospora. Appl Microbiol Biotechnol 2018; 102:4601-4613. [PMID: 29616315 DOI: 10.1007/s00253-018-8929-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/10/2018] [Accepted: 03/13/2018] [Indexed: 12/12/2022]
Abstract
Rab GTPases are the largest group of the small GTPases family, which play a pivotal role in the secretion of proteins. Arthrobotrys oligospora is a representative nematode-trapping fungus that can produce adhesive networks to capture nematodes. In this study, the roles of two Rab GTPases AoRab-7A and AoRab-2 were characterized by gene knockout in the fungus A. oligospora. The disruption of AoRab-7A hindered the mycelial growth in different media, the conidiation of ΔAoRab-7A transformants was almost abolished, and the transcription of four sporulation-related genes (AbaA, FluG, Hyp1, and VosA) was downregulated compared to the wild-type strain (WT). Furthermore, the tolerance of the ΔAoRab-7A mutants to sodium dodecyl sulfate (SDS) and H2O2 was also significantly reduced compared to the WT, and the transcription of several genes related to environmental resistance, such as genes for catalase and trehalose synthase, was downregulated. Similarly, the extracellular proteolytic activity was decreased. Importantly, the ΔAoRab-7A mutants were unable to produce traps and capture nematodes. However, the disruption of gene AoRab-2 only affected the conidiation slightly but non-significantly, while other phenotypic traits were unaffected. Moreover, the gene AoRab-7A was also involved in the autophagy induced by nitrogen deprivation in A. oligospora. Our results revealed for the first time that the Rab GTPases are involved in the regulation of mycelial growth, conidiation, trap formation, stress resistance, and pathogenicity in the nematode-trapping fungus A. oligospora.
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Affiliation(s)
- Xuewei Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Ni Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Le Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Yaqing Zheng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Zhengyi Zhen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Qing Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Meihua Xie
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Juan Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China. .,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China.
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, 650091, People's Republic of China. .,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China.
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17
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Hernández-González M, Bravo-Plaza I, Pinar M, de los Ríos V, Arst HN, Peñalva MA. Endocytic recycling via the TGN underlies the polarized hyphal mode of life. PLoS Genet 2018; 14:e1007291. [PMID: 29608571 PMCID: PMC5880334 DOI: 10.1371/journal.pgen.1007291] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/06/2018] [Indexed: 12/13/2022] Open
Abstract
Intracellular traffic in Aspergillus nidulans hyphae must cope with the challenges that the high rates of apical extension (1μm/min) and the long intracellular distances (>100 μm) impose. Understanding the ways in which the hyphal tip cell coordinates traffic to meet these challenges is of basic importance, but is also of considerable applied interest, as fungal invasiveness of animals and plants depends critically upon maintaining these high rates of growth. Rapid apical extension requires localization of cell-wall-modifying enzymes to hyphal tips. By combining genetic blocks in different trafficking steps with multidimensional epifluorescence microscopy and quantitative image analyses we demonstrate that polarization of the essential chitin-synthase ChsB occurs by indirect endocytic recycling, involving delivery/exocytosis to apices followed by internalization by the sub-apical endocytic collar of actin patches and subsequent trafficking to TGN cisternae, where it accumulates for ~1 min before being re-delivered to the apex by a RAB11/TRAPPII-dependent pathway. Accordingly, ChsB is stranded at the TGN by Sec7 inactivation but re-polarizes to the apical dome if the block is bypassed by a mutation in geaAgea1 that restores growth in the absence of Sec7. That polarization is independent of RAB5, that ChsB predominates at apex-proximal cisternae, and that upon dynein impairment ChsB is stalled at the tips in an aggregated endosome indicate that endocytosed ChsB traffics to the TGN via sorting endosomes functionally located upstream of the RAB5 domain and that this step requires dynein-mediated basipetal transport. It also requires RAB6 and its effector GARP (Vps51/Vps52/Vps53/Vps54), whose composition we determined by MS/MS following affinity chromatography purification. Ablation of any GARP component diverts ChsB to vacuoles and impairs growth and morphology markedly, emphasizing the important physiological role played by this pathway that, we propose, is central to the hyphal mode of growth. Filamentous fungi form long tubular cells, called hyphae, which grow rapidly by apical extension, enabling these sessile organisms to explore substrates and facilitating tissue invasion in the case of pathogenic species. Because the shape of the hyphae is determined by an external cell wall, hyphal growth requires that cell-wall sculpting enzymes polarize to the tips. Endocytosis is essential for hyphal growth, and it was suspected that this results from its participation in a recycling pathway that takes up cell-wall enzymes from the plasma membrane and re-delivers them to the apex. Here we track the trafficking of a chitin synthase (a cell-wall modifying enzyme) to demonstrate that it is polarized by endocytic recycling. This chitin synthase is delivered by exocytosis to the apex, but diffuses away until being captured by a subapical collar of actin patches (sites of endocytosis) from where it reaches a sorting endosome before undergoing transport to the nearest trans-Golgi cisternae and incorporating into secretory vesicles that re-deliver the enzyme to the apex. Because impairing transit across this pathway compromises apical extension markedly and results in severe morphological defects, the pathway could be manipulated to prevent fungal pathogenicity of plants and humans, an enormous burden on human welfare.
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Affiliation(s)
- Miguel Hernández-González
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Ignacio Bravo-Plaza
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Mario Pinar
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Vivian de los Ríos
- Proteomics Facility, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
| | - Herbert N. Arst
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, United Kingdom
| | - Miguel A. Peñalva
- Department of Cellular and Molecular Biology and Intradepartmental WhiteBiotech Unit, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
- * E-mail:
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18
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Etxebeste O, Espeso EA. Neurons show the path: tip-to-nucleus communication in filamentous fungal development and pathogenesis. FEMS Microbiol Rev 2017; 40:610-24. [PMID: 27587717 DOI: 10.1093/femsre/fuw021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 01/11/2023] Open
Abstract
Multiple fungal species penetrate substrates and accomplish host invasion through the fast, permanent and unidirectional extension of filamentous cells known as hyphae. Polar growth of hyphae results, however, in a significant increase in the distance between the polarity site, which also receives the earliest information about ambient conditions, and nuclei, where adaptive responses are executed. Recent studies demonstrate that these long distances are overcome by signal transduction pathways which convey sensory information from the polarity site to nuclei, controlling development and pathogenesis. The present review compares the striking connections of the mechanisms for long-distance communication in hyphae with those from neurons, and discusses the importance of their study in order to understand invasion and dissemination processes of filamentous fungi, and design strategies for developmental control in the future.
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Affiliation(s)
- Oier Etxebeste
- Biochemistry II laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country (UPV/EHU), 20018 San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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19
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Wakade R, Labbaoui H, Stalder D, Arkowitz RA, Bassilana M. Overexpression of YPT6 restores invasive filamentous growth and secretory vesicle clustering in a Candida albicans arl1 mutant. Small GTPases 2017; 11:204-210. [PMID: 28960163 DOI: 10.1080/21541248.2017.1378157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Virulence of the human fungal pathogen Candida albicans depends on the switch from budding to filamentous growth. Deletion of the Arf GTPase Arl1 results in hyphae that are shorter as well as reduced virulence. How Arl1 is regulated during hyphal growth, a process characteristic of filamentous fungi, yet absent in S. cerevisiae, is unknown. Here, we investigated the importance of the Rab6 homolog, Ypt6, in Arl1-dependent hyphal growth and determined that YPT6 overexpression specifically rescued the hyphal growth defect of an arl1 mutant, but not the converse. Furthermore, we show that deletion of ARL1 results in an alteration of the distribution of the Rab8 homolog, Sec4, in hyphal cells and that this defect is restored upon YPT6 overexpression.
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Affiliation(s)
- Rohan Wakade
- Université Côte d'Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, FRANCE
| | - Hayet Labbaoui
- Université Côte d'Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, FRANCE
| | - Danièle Stalder
- Université Côte d'Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, FRANCE
| | - Robert A Arkowitz
- Université Côte d'Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, FRANCE
| | - Martine Bassilana
- Université Côte d'Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, FRANCE
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20
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Pinar M, Peñalva MA. Aspergillus nidulansBapH is a RAB11 effector that connects membranes in the Spitzenkörper with basal autophagy. Mol Microbiol 2017; 106:452-468. [DOI: 10.1111/mmi.13777] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Mario Pinar
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas del CSIC, Ramiro de Maeztu 9; Madrid 28040 Spain
| | - Miguel A. Peñalva
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas del CSIC, Ramiro de Maeztu 9; Madrid 28040 Spain
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21
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Abstract
Filamentous fungi are a large and ancient clade of microorganisms that occupy a broad range of ecological niches. The success of filamentous fungi is largely due to their elongate hypha, a chain of cells, separated from each other by septa. Hyphae grow by polarized exocytosis at the apex, which allows the fungus to overcome long distances and invade many substrates, including soils and host tissues. Hyphal tip growth is initiated by establishment of a growth site and the subsequent maintenance of the growth axis, with transport of growth supplies, including membranes and proteins, delivered by motors along the cytoskeleton to the hyphal apex. Among the enzymes delivered are cell wall synthases that are exocytosed for local synthesis of the extracellular cell wall. Exocytosis is opposed by endocytic uptake of soluble and membrane-bound material into the cell. The first intracellular compartment in the endocytic pathway is the early endosomes, which emerge to perform essential additional functions as spatial organizers of the hyphal cell. Individual compartments within septated hyphae can communicate with each other via septal pores, which allow passage of cytoplasm or organelles to help differentiation within the mycelium. This article introduces the reader to more detailed aspects of hyphal growth in fungi.
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22
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Martzoukou O, Amillis S, Zervakou A, Christoforidis S, Diallinas G. The AP-2 complex has a specialized clathrin-independent role in apical endocytosis and polar growth in fungi. eLife 2017; 6. [PMID: 28220754 PMCID: PMC5338921 DOI: 10.7554/elife.20083] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 02/07/2017] [Indexed: 12/26/2022] Open
Abstract
Filamentous fungi provide excellent systems for investigating the role of the AP-2 complex in polar growth. Using Aspergillus nidulans, we show that AP-2 has a clathrin-independent essential role in polarity maintenance and growth. This is in line with a sequence analysis showing that the AP-2 β subunit (β2) of higher fungi lacks a clathrin-binding domain, and experiments showing that AP-2 does not co-localize with clathrin. We provide genetic and cellular evidence that AP-2 interacts with endocytic markers SlaBEnd4 and SagAEnd3 and the lipid flippases DnfA and DnfB in the sub-apical collar region of hyphae. The role of AP-2 in the maintenance of proper apical membrane lipid and cell wall composition is further supported by its functional interaction with BasA (sphingolipid biosynthesis) and StoA (apical sterol-rich membrane domains), and its essentiality in polar deposition of chitin. Our findings support that the AP-2 complex of dikarya has acquired, in the course of evolution, a specialized clathrin-independent function necessary for fungal polar growth. DOI:http://dx.doi.org/10.7554/eLife.20083.001
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Affiliation(s)
- Olga Martzoukou
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Sotiris Amillis
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Amalia Zervakou
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Savvas Christoforidis
- Institute of Molecular Biology and Biotechnology-Biomedical Research, Foundation for Research and Technology, Ioannina, Greece.,Laboratory of Biological Chemistry, Department of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
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23
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Pantazopoulou A. The Golgi apparatus: insights from filamentous fungi. Mycologia 2017; 108:603-22. [DOI: 10.3852/15-309] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/01/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
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24
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Abstract
Filamentous fungi have proven to be a better-suited model system than unicellular yeasts in analyses of cellular processes such as polarized growth, exocytosis, endocytosis, and cytoskeleton-based organelle traffic. For example, the filamentous fungus
Neurospora crassa develops a variety of cellular forms. Studying the molecular basis of these forms has led to a better, yet incipient, understanding of polarized growth. Polarity factors as well as Rho GTPases, septins, and a localized delivery of vesicles are the central elements described so far that participate in the shift from isotropic to polarized growth. The growth of the cell wall by apical biosynthesis and remodeling of polysaccharide components is a key process in hyphal morphogenesis. The coordinated action of motor proteins and Rab GTPases mediates the vesicular journey along the hyphae toward the apex, where the exocyst mediates vesicle fusion with the plasma membrane. Cytoplasmic microtubules and actin microfilaments serve as tracks for the transport of vesicular carriers as well as organelles in the tubular cell, contributing to polarization. In addition to exocytosis, endocytosis is required to set and maintain the apical polarity of the cell. Here, we summarize some of the most recent breakthroughs in hyphal morphogenesis and apical growth in
N. crassa and the emerging questions that we believe should be addressed.
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Affiliation(s)
- Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, Baja California, 22860, Mexico
| | - Leonora Martínez-Núñez
- Department of Microbiology, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, Baja California, 22860, Mexico
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25
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Schultzhaus Z, Johnson TB, Shaw BD. Clathrin localization and dynamics in Aspergillus nidulans. Mol Microbiol 2016; 103:299-318. [PMID: 27741567 DOI: 10.1111/mmi.13557] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2016] [Indexed: 12/15/2022]
Abstract
Cell growth necessitates extensive membrane remodeling events including vesicle fusion or fission, processes that are regulated by coat proteins. The hyphal cells of filamentous fungi concentrate both exocytosis and endocytosis at the apex. This investigation focuses on clathrin in Aspergillus nidulans, with the aim of understanding its role in membrane remodeling in growing hyphae. We examined clathrin heavy chain (ClaH-GFP) which localized to three distinct subcellular structures: late Golgi (trans-Golgi equivalents of filamentous fungi), which are concentrated just behind the hyphal tip but are intermittently present throughout all hyphal cells; the region of concentrated endocytosis just behind the hyphal apex (the "endocytic collar"); and small, rapidly moving puncta that were seen trafficking long distances in nearly all hyphal compartments. ClaH localized to distinct domains on late Golgi, and these clathrin "hubs" dispersed in synchrony after the late Golgi marker PHOSBP . Although clathrin was essential for growth, ClaH did not colocalize well with the endocytic patch marker fimbrin. Tests of FM4-64 internalization and repression of ClaH corroborated the observation that clathrin does not play an important role in endocytosis in A. nidulans. A minor portion of ClaH puncta exhibited bidirectional movement, likely along microtubules, but were generally distinct from early endosomes.
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Affiliation(s)
- Z Schultzhaus
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX, 77845, USA
| | - T B Johnson
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX, 77845, USA
| | - B D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, 2132 TAMU, College Station, TX, 77845, USA
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Schultzhaus Z, Quintanilla L, Hilton A, Shaw BD. Live Cell Imaging of Actin Dynamics in the Filamentous Fungus Aspergillus nidulans. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:264-274. [PMID: 26879694 DOI: 10.1017/s1431927616000131] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Hyphal cells of filamentous fungi grow at their tips in a method analogous to pollen tube and root hair elongation. This process, generally referred to as tip growth, requires precise regulation of the actin cytoskeleton, and characterizing the various actin structures in these cell types is currently an active area of research. Here, the actin marker Lifeact was used to document actin dynamics in the filamentous fungus Aspergillus nidulans. Contractile double rings were observed at septa, and annular clusters of puncta were seen subtending growing hyphal tips, corresponding to the well-characterized subapical endocytic collar. However, Lifeact also revealed two additional structures. One, an apical array, was dynamic on the face opposite the tip, while a subapical web was dynamic on the apical face and was located several microns behind the growth site. Each was observed turning into the other over time, implying that they could represent different localizations of the same structure, although hyphae with a subapical web grew faster than those exhibiting an apical array. The subapical web has not been documented in any filamentous fungus to date, and is separate from the networks of F-actin seen in other tip-growing organisms surrounding septa or stationary along the plasmalemma.
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Affiliation(s)
- Zachary Schultzhaus
- Department of Plant Pathology and Microbiology,Texas A&M University,College Station,TX 77843,USA
| | - Laura Quintanilla
- Department of Plant Pathology and Microbiology,Texas A&M University,College Station,TX 77843,USA
| | - Angelyn Hilton
- Department of Plant Pathology and Microbiology,Texas A&M University,College Station,TX 77843,USA
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology,Texas A&M University,College Station,TX 77843,USA
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Schultzhaus Z, Shaw BD. The flippase DnfB is cargo of fimbrin-associated endocytosis in Aspergillus nidulans, and likely recycles through the late Golgi. Commun Integr Biol 2016; 9:e1141843. [PMID: 27195062 PMCID: PMC4857784 DOI: 10.1080/19420889.2016.1141843] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 01/06/2016] [Accepted: 01/08/2016] [Indexed: 12/31/2022] Open
Affiliation(s)
- Zachary Schultzhaus
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station , TX, USA
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station , TX, USA
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Park J, Tefsen B, Heemskerk MJ, Lagendijk EL, van den Hondel CAMJJ, van Die I, Ram AFJ. Identification and functional analysis of two Golgi-localized UDP-galactofuranose transporters with overlapping functions in Aspergillus niger. BMC Microbiol 2015; 15:253. [PMID: 26526354 PMCID: PMC4630932 DOI: 10.1186/s12866-015-0541-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 09/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Galactofuranose (Galf)-containing glycoconjugates are present in numerous microbes, including filamentous fungi where they are important for morphology, virulence and maintaining cell wall integrity. The incorporation of Galf-residues into galactomannan, galactomannoproteins and glycolipids is carried out by Golgi-localized Galf transferases. The nucleotide sugar donor used by these transferases (UDP-Galf) is produced in the cytoplasm and has to be transported to the lumen of the Golgi by a dedicated nucleotide sugar transporter. METHODS Based on homology with recently identified UDP-Galf-transporters in A. fumigatus and A. nidulans, two putative UDP-Galf-transporters in A. niger were found. Their function and localization was determined by gene deletions and GFP-tagging studies, respectively. RESULTS The two putative UDP-Galf-transporters in A. niger are homologous to each other and are predicted to contain eleven transmembrane domains (UgtA) or ten transmembrane domains (UgtB) due to a reduced length of the C-terminal part of the UgtB protein. The presence of two putative UDP-Galf-transporters in the genome was not unique for A. niger. From the twenty Aspergillus species analysed, nine species contained two additional putative UDP-Galf-transporters. Three of the nine species were outside the Aspergillus section nigri, indication an early duplication of UDP-Galf-transporters and subsequent loss of the UgtB copy in several aspergilli. Deletion analysis of the single and double mutants in A. niger indicated that the two putative UDP-Galf-transporters (named UgtA and UgtB) have a redundant function in UDP-Galf-transport as only the double mutant displayed a Galf-negative phenotype. The Galf-negative phenotype of the double mutant could be complemented by expressing either CFP-UgtA or CFP-UgtB fusion proteins from their endogenous promoters, indicating that both CFP-tagged proteins are functional. Both Ugt proteins co-localize with each other as well as with the GDP-mannose nucleotide transporter, as was demonstrated by fluorescence microscopy, thereby confirming their predicted localization in the Golgi. CONCLUSION A. niger contains two genes encoding UDP-Galf-transporters. Deletion and localization studies indicate that UgtA and UgtB have redundant functions in the biosynthesis of Galf-containing glycoconjugates.
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Affiliation(s)
- Joohae Park
- Leiden University, Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
| | - Boris Tefsen
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, van den Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands. .,Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, 111 Ren Ai Road, Dushu Lake Higher Education Town, Suzhou Industrial Park, Suzhou, Jiangsu, 215123, China.
| | - Marc J Heemskerk
- Leiden University, Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
| | - Ellen L Lagendijk
- Leiden University, Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
| | - Cees A M J J van den Hondel
- Leiden University, Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
| | - Irma van Die
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, van den Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
| | - Arthur F J Ram
- Leiden University, Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
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López-Berges MS, Pinar M, Abenza JF, Arst HN, Peñalva MA. TheAspergillus nidulanssyntaxin PepAPep12is regulated by two Sec1/Munc-18 proteins to mediate fusion events at early endosomes, late endosomes and vacuoles. Mol Microbiol 2015; 99:199-216. [DOI: 10.1111/mmi.13226] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2015] [Indexed: 01/21/2023]
Affiliation(s)
- Manuel S. López-Berges
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Mario Pinar
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Juan F. Abenza
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Herbert N. Arst
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
- Section of Microbiology; Flowers Building; Imperial College; London SW7 2AZ UK
| | - Miguel A. Peñalva
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
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Bussink HJ, Bignell EM, Múnera-Huertas T, Lucena-Agell D, Scazzocchio C, Espeso EA, Bertuzzi M, Rudnicka J, Negrete-Urtasun S, Peñas-Parilla MM, Rainbow L, Peñalva MÁ, Arst HN, Tilburn J. Refining the pH response in Aspergillus nidulans: a modulatory triad involving PacX, a novel zinc binuclear cluster protein. Mol Microbiol 2015; 98:1051-72. [PMID: 26303777 PMCID: PMC4832277 DOI: 10.1111/mmi.13173] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2015] [Indexed: 01/18/2023]
Abstract
The Aspergillus nidulans PacC transcription factor mediates gene regulation in response to alkaline ambient pH which, signalled by the Pal pathway, results in the processing of PacC72 to PacC27 via PacC53. Here we investigate two levels at which the pH regulatory system is transcriptionally moderated by pH and identify and characterise a new component of the pH regulatory machinery, PacX. Transcript level analysis and overexpression studies demonstrate that repression of acid‐expressed palF, specifying the Pal pathway arrestin, probably by PacC27 and/or PacC53, prevents an escalating alkaline pH response. Transcript analyses using a reporter and constitutively expressed pacC
trans‐alleles show that pacC preferential alkaline‐expression results from derepression by depletion of the acid‐prevalent PacC72 form. We additionally show that pacC repression requires PacX. pacX mutations suppress PacC processing recalcitrant mutations, in part, through derepressed PacC levels resulting in traces of PacC27 formed by pH‐independent proteolysis. pacX was cloned by impala transposon mutagenesis. PacX, with homologues within the Leotiomyceta, has an unusual structure with an amino‐terminal coiled‐coil and a carboxy‐terminal zinc binuclear cluster. pacX mutations indicate the importance of these regions. One mutation, an unprecedented finding in A. nidulans genetics, resulted from an insertion of an endogenous Fot1‐like transposon.
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Affiliation(s)
- Henk-Jan Bussink
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Elaine M Bignell
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK.,Manchester Fungal Infection Group, Institute for Inflammation and Repair, University of Manchester, 46 Grafton Street, Manchester, M13 9NT, UK
| | - Tatiana Múnera-Huertas
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Daniel Lucena-Agell
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain
| | - Claudio Scazzocchio
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK.,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Orsay, France
| | - Eduardo A Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain
| | - Margherita Bertuzzi
- Manchester Fungal Infection Group, Institute for Inflammation and Repair, University of Manchester, 46 Grafton Street, Manchester, M13 9NT, UK
| | - Joanna Rudnicka
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Susana Negrete-Urtasun
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Maria M Peñas-Parilla
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Lynne Rainbow
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Miguel Á Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain
| | - Herbert N Arst
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
| | - Joan Tilburn
- Section of Microbiology, Imperial College London, Flowers Building, Armstrong Road, London, SW7 2AZ, UK
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Zheng H, Zheng W, Wu C, Yang J, Xi Y, Xie Q, Zhao X, Deng X, Lu G, Li G, Ebbole D, Zhou J, Wang Z. Rab GTPases are essential for membrane trafficking-dependent growth and pathogenicity in Fusarium graminearum. Environ Microbiol 2015; 17:4580-99. [PMID: 26177389 DOI: 10.1111/1462-2920.12982] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 12/12/2022]
Abstract
Rab GTPases represent the largest subfamily of Ras-related small GTPases and regulate membrane trafficking. Vesicular transport is a general mechanism that governs intracellular membrane trafficking along the endocytic and exocytic pathways in all eukaryotic cells. Fusarium graminearum is a filamentous fungus and causes the devastating and economically important head blight of wheat and related species. The mechanism of vesicular transport is not well understood, and little is known about Rab GTPases in F. graminearum. In this study, we systematically characterized all eleven FgRabs by live cell imaging and genetic analysis. We find that FgRab51 and FgRab52 are important for the endocytosis, FgRab7 localizes to the vacuolar membrane and regulates the fusion of vacuoles and autophagosomes, and FgRab8 and FgRab11 are important for polarized growth and/or exocytosis. Furthermore, both endocytic and exocytic FgRabs are required for vegetative growth, conidiogenesis, sexual reproduction, as well as pathogenesis and deoxynivalenol metabolism in F. graminearum. Thus, we conclude that Rab GTPases are essential for membrane trafficking-dependent growth and pathogenicity in F. graminearum.
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Affiliation(s)
- Huawei Zheng
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wenhui Zheng
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Congxian Wu
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jie Yang
- Institute of Forestry Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yang Xi
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qiurong Xie
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xu Zhao
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaolong Deng
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guodong Lu
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guangpu Li
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China.,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Daniel Ebbole
- Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China.,Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
| | - Jie Zhou
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zonghua Wang
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian-Taiwan Joint Center for Ecological Control of Crop Pests, Fujian Agriculture and Forestry University, Fuzhou, China
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Peñalva MA. A lipid-managing program maintains a stout Spitzenkörper. Mol Microbiol 2015; 97:1-6. [PMID: 25921726 DOI: 10.1111/mmi.13044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/27/2015] [Indexed: 01/09/2023]
Abstract
The Spitzenkörper (SPK) is an accumulation of vesicles interleaved with actin microfilaments present at the cytosolic side of the apical plasma membrane (PM) of hyphal tips of many species of filamentous fungi. The physiological role of the SPK has captivated fungal biologists over the years, but only very recently this 'organelle' is starting to be understood in the molecular terminology used for cell biological models. One aspect that has received little attention is the role of cellular membrane asymmetry in the organization of membrane traffic, in particular in the genetic and cell biological model Aspergillus nidulans. The paper by Schultzhaus et al. (2015) in this issue breaks the ice, providing original insight that may foster research in phospholipid composition in the context of intracellular traffic and the organization of the SPK. Notably, it shows that like the stout Neurospora crassa SPK, the much slimmer one of A. nidulans, appears to be formed by different strata, altogether suggesting that the SPK might be a mosaic of exocytic carriers with different functional specializations, and a major sorting hub for intracellular membranes.
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Affiliation(s)
- Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Ramiro de Maeztu 9, Madrid, 28040, Spain
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Schultzhaus Z, Yan H, Shaw BD. Aspergillus nidulansflippase DnfA is cargo of the endocytic collar and plays complementary roles in growth and phosphatidylserine asymmetry with another flippase, DnfB. Mol Microbiol 2015; 97:18-32. [DOI: 10.1111/mmi.13019] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Zachary Schultzhaus
- Department of Plant Pathology and Microbiology; Texas A&M University; College Station TX USA
| | - Huijuan Yan
- Department of Plant Protection; Fujian Agricultural and Forestry University; Fuzhou Fujian China
| | - Brian D. Shaw
- Department of Plant Pathology and Microbiology; Texas A&M University; College Station TX USA
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Aspergillus nidulans Ambient pH Signaling Does Not Require Endocytosis. EUKARYOTIC CELL 2015; 14:545-53. [PMID: 25841020 DOI: 10.1128/ec.00031-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 03/30/2015] [Indexed: 01/10/2023]
Abstract
Aspergillus nidulans (Pal) ambient pH signaling takes place in cortical structures containing components of the ESCRT pathway, which are hijacked by the alkaline pH-activated, ubiquitin-modified version of the arrestin-like protein PalF and taken to the plasma membrane. There, ESCRTs scaffold the assembly of dedicated Pal proteins acting downstream. The molecular details of this pathway, which results in the two-step proteolytic processing of the transcription factor PacC, have received considerable attention due to the key role that it plays in fungal pathogenicity. While current evidence strongly indicates that the pH signaling role of ESCRT complexes is limited to plasma membrane-associated structures where PacC proteolysis would take place, the localization of the PalB protease, which almost certainly catalyzes the first and only pH-regulated proteolytic step, had not been investigated. In view of ESCRT participation, this formally leaves open the possibility that PalB activation requires endocytic internalization. As endocytosis is essential for hyphal growth, nonlethal endocytic mutations are predicted to cause an incomplete block. We used a SynA internalization assay to measure the extent to which any given mutation prevents endocytosis. We show that none of the tested mutations impairing endocytosis to different degrees, including slaB1, conditionally causing a complete block, have any effect on the activation of the pathway. We further show that PalB, like PalA and PalC, localizes to cortical structures in an alkaline pH-dependent manner. Therefore, signaling through the Pal pathway does not involve endocytosis.
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TRAPPII regulates exocytic Golgi exit by mediating nucleotide exchange on the Ypt31 ortholog RabERAB11. Proc Natl Acad Sci U S A 2015; 112:4346-51. [PMID: 25831508 DOI: 10.1073/pnas.1419168112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The oligomeric complex transport protein particle I (TRAPPI) mediates nucleotide exchange on the RAB GTPase RAB1/Ypt1. TRAPPII is composed of TRAPPI plus three additional subunits, Trs120, Trs130, and Trs65. Unclear is whether TRAPPII mediates nucleotide exchange on RAB1/Ypt1, RAB11/Ypt31, or both. In Aspergillus nidulans, RabO(RAB1) resides in the Golgi, RabE(RAB11) localizes to exocytic post-Golgi carriers undergoing transport to the apex, and hypA encodes Trs120. RabE(RAB11), but not RabO(RAB1), immunoprecipitates contain Trs120/Trs130/Trs65, demonstrating specific association of TRAPPII with RabE(RAB11) in vivo. hypA1(ts) rapidly shifts RabE(RAB11), but not RabO(RAB1), to the cytosol, consistent with HypA(Trs120) being specifically required for RabE(RAB11) activation. Missense mutations rescuing hypA1(ts) at 42 °C mapped to rabE, affecting seven residues. Substitutions in six, of which four resulted in 7- to 36-fold accelerated GDP release, rescued lethality associated to TRAPPII deficiency, whereas equivalent substitutions in RabO(RAB1) did not, establishing that the essential role of TRAPPII is facilitating RabE(RAB11) nucleotide exchange. In vitro, TRAPPII purified with HypA(Trs120)-S-tag accelerates nucleotide exchange on RabE(RAB11) and, paradoxically, to a lesser yet substantial extent, on RabO(RAB1). Evidence obtained by exploiting hypA1-mediated destabilization of HypA(Trs120)/HypC(Trs130)/Trs65 assembly onto the TRAPPI core indicates that these subunits sculpt a second RAB binding site on TRAPP apparently independent from that for RabO(RAB1), which would explain TRAPPII in vitro activity on two RABs. Using A. nidulans in vivo microscopy, we show that HypA(Trs120) colocalizes with RabE(RAB11), arriving at late Golgi cisternae as they dissipate into exocytic carriers. Thus, TRAPPII marks, and possibly determines, the Golgi-to-post-Golgi transition.
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de Assis LJ, Ries LNA, Savoldi M, dos Reis TF, Brown NA, Goldman GH. Aspergillus nidulans protein kinase A plays an important role in cellulase production. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:213. [PMID: 26690721 PMCID: PMC4683954 DOI: 10.1186/s13068-015-0401-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/30/2015] [Indexed: 05/17/2023]
Abstract
BACKGROUND The production of bioethanol from lignocellulosic feedstocks is dependent on lignocellulosic biomass degradation by hydrolytic enzymes. The main component of lignocellulose is cellulose and different types of organisms are able to secrete cellulases. The filamentous fungus Aspergillus nidulans serves as a model organism to study cellulase production and the available tools allow exploring more in depth the mechanisms governing cellulase production and carbon catabolite repression. RESULTS In A. nidulans, microarray data identified the cAMP-dependent protein kinase A (PkaA) as being involved in the transcriptional modulation and the production of lignocellulolytic enzymes in the presence of cellulose. Deletion of pkaA resulted in increased hydrolytic enzyme secretion, but reduced growth in the presence of lignocellulosic components and various other carbon sources. Furthermore, genes involved in fungal development were increased in the ΔpkaA strain, probably leading to the increased hyphal branching as was observed in this strain. This would allow the secretion of higher amounts of proteins. In addition, the expression of SynA, encoding a V-SNARE synaptobrevin protein involved in secretion, was increased in the ΔpkaA mutant. Deletion of pkaA also resulted in the reduced nuclear localization of the carbon catabolite repressor CreA in the presence of glucose and in partial de-repression when grown on cellulose. PkaA is involved in the glucose signaling pathway as the absence of this protein resulted in reduced glucose uptake and lower hexokinase/glucokinase activity, directing the cell to starvation conditions. Genome-wide transcriptomics showed that the expression of genes encoding proteins involved in fatty acid metabolism, mitochondrial function and in the use of cell storages was increased. CONCLUSIONS This study shows that PkaA is involved in hydrolytic enzyme production in A. nidulans. It appears that this protein kinase blocks the glucose pathway, hence forcing the cell to change to starvation conditions, increasing hydrolytic enzyme secretion and inducing the usage of cellular storages. This work uncovered new regulatory avenues governing the tight interplay between the metabolic states of the cell, which are important for the production of hydrolytic enzymes targeting lignocellulosic biomass. Deletion of pkaA resulted in a strain with increased hydrolytic enzyme secretion and reduced biomass formation.
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Affiliation(s)
- Leandro José de Assis
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Laure Nicolas Annick Ries
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Marcela Savoldi
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Thaila Fernanda dos Reis
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Neil Andrew Brown
- />Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Gustavo Henrique Goldman
- />Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
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Hernández-González M, Peñalva MA, Pantazopoulou A. Conditional inactivation ofAspergillus nidulans sarASAR1uncovers the morphogenetic potential of regulating endoplasmic reticulum (ER) exit. Mol Microbiol 2014; 95:491-508. [DOI: 10.1111/mmi.12880] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2014] [Indexed: 12/17/2022]
Affiliation(s)
- Miguel Hernández-González
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Miguel A. Peñalva
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Areti Pantazopoulou
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
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Sánchez-León E, Bowman B, Seidel C, Fischer R, Novick P, Riquelme M. The Rab GTPase YPT-1 associates with Golgi cisternae and Spitzenkörper microvesicles inNeurospora crassa. Mol Microbiol 2014; 95:472-90. [DOI: 10.1111/mmi.12878] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 02/02/2023]
Affiliation(s)
- Eddy Sánchez-León
- Department of Microbiology; Center for Scientific Research and Higher Education of Ensenada (CICESE); Ensenada Baja California Mexico
| | - Barry Bowman
- Department of Molecular, Cell and Developmental Biology; University of California; Santa Cruz CA USA
| | - Constanze Seidel
- Department of Applied Microbiology; Karlsruhe Institute of Technology; Karlsruhe Germany
| | - Reinhard Fischer
- Department of Applied Microbiology; Karlsruhe Institute of Technology; Karlsruhe Germany
| | - Peter Novick
- Department of Cellular and Molecular Medicine; University of California; San Diego CA USA
| | - Meritxell Riquelme
- Department of Microbiology; Center for Scientific Research and Higher Education of Ensenada (CICESE); Ensenada Baja California Mexico
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Arst HN, Hernandez-Gonzalez M, Peñalva MA, Pantazopoulou A. GBF/Gea mutant with a single substitution sustains fungal growth in the absence of BIG/Sec7. FEBS Lett 2014; 588:4799-806. [PMID: 25451223 PMCID: PMC4266534 DOI: 10.1016/j.febslet.2014.11.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/07/2014] [Accepted: 11/10/2014] [Indexed: 12/11/2022]
Abstract
A. nidulans has a GBF/Gea and a BIG/Sec7 subfamily Golgi Arf1-GEFs, both essential. The late Golgi Arf1-GEF mutant hypB5 conditionally blocks secretion. Residue substitution in the early Golgi Arf1-GEF GeaA suppresses hypB5 and hypBΔ. The mutation alters a GBF/Gea amino acid motif and shifts GeaA localization. GeaA1 alone satisfies the eukaryotic requirement for two Golgi Arf1 GEFs.
Golgi Arf1-guanine nucleotide exchange factors (GEFs) belong to two subfamilies: GBF/Gea and BIG/Sec7. Both are conserved across eukaryotes, but the physiological role of each is not well understood. Aspergillus nidulans has a single member of the early Golgi GBF/Gea-subfamily, geaA, and the late Golgi BIG/Sec7-subfamily, hypB. Both geaA and hypB are essential. hypB5 conditionally blocks secretion. We sought extragenic hypB5 suppressors and obtained geaA1. geaA1 results in Tyr1022Cys within a conserved GBF/Gea-specific S(Y/W/F)(L/I) motif in GeaA. This mutation alters GeaA localization. Remarkably, geaA1 suppresses hypBΔ, indicating that a single mutant Golgi Arf1-GEF suffices for growth.
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Affiliation(s)
- Herbert N Arst
- Section of Microbiology, Department of Medicine, Imperial College London, London SW7 2AZ, United Kingdom; Centro de Investigaciones Biológicas, CSIC, Madrid 28040, Spain
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Riquelme M, Sánchez-León E. The Spitzenkörper: a choreographer of fungal growth and morphogenesis. Curr Opin Microbiol 2014; 20:27-33. [DOI: 10.1016/j.mib.2014.04.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 01/07/2023]
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Pantazopoulou A, Pinar M, Xiang X, Peñalva MA. Maturation of late Golgi cisternae into RabE(RAB11) exocytic post-Golgi carriers visualized in vivo. Mol Biol Cell 2014; 25:2428-43. [PMID: 24943841 PMCID: PMC4142615 DOI: 10.1091/mbc.e14-02-0710] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The mechanism(s) by which proteins traverse and exit the Golgi are incompletely understood. Using Aspergillus nidulans hyphae, we show that late Golgi cisternae undergo changes in composition to gradually lose Golgi identity while acquiring post-Golgi RabE(RAB11) identity. This behavior of late Golgi cisternae is consistent with the cisternal maturation model. Post-Golgi RabE(RAB11) carriers travel to, and accumulate at, the apex, indicating that fusion is rate limiting for exocytosis. These carriers, which are loaded with kinesin, dynein, and MyoE(MYO5), move on a microtubule-based bidirectional conveyor belt relaying them to actin, which ultimately focuses exocytosis at the apex. Dynein drags RabE(RAB11) carriers away if engagement of MyoE(MYO5) to actin cables fails. Microtubules seemingly cooperating with F-actin capture can sustain secretion if MyoE(MYO5) is absent. Thus, filamentous fungal secretion involving post-Golgi carriers is remarkably similar, mechanistically, to the transport of melanosomes in melanocyte dendrites, even though melanosome biogenesis involves lysosomes rather than Golgi.
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Affiliation(s)
- Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid 28040, Spain
| | - Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid 28040, Spain
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid 28040, Spain
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Bernardo SM, Rane HS, Chavez-Dozal A, Lee SA. Secretion and filamentation are mediated by the Candida albicans t-SNAREs Sso2p and Sec9p. FEMS Yeast Res 2014; 14:762-75. [PMID: 24911595 DOI: 10.1111/1567-1364.12165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/14/2014] [Accepted: 05/14/2014] [Indexed: 12/12/2022] Open
Abstract
To study the role of late secretion in Candida albicans pathogenesis, we created conditional mutant C. albicans strains in which the t-SNARE-encoding genes SSO2 or SEC9 were placed under the control of a tetracycline-regulated promoter. In repressing conditions, C. albicans tetR-SSO2 and tetR-SEC9 mutant strains were defective in cytokinesis and secretion of aspartyl proteases and lipases. The mutant strains also exhibited a defect in filamentation compared with controls, and thus, we followed the fate of the C. albicans Spitzenkörper, an assembly of secretory vesicles thought to act as a vesicle supply center for the growing hyphae. In the absence of Ca Sso2p, the Spitzenkörper dissipated within 5 h and thin-section electron microscopy revealed an accumulation of secretory vesicles. Moreover, the hyphal tip developed into a globular yeast-like structure rather than maintaining a typical narrow hyphae. These studies indicate that late secretory t-SNARE proteins in C. albicans are required for fundamental cellular processes and contribute to virulence-related attributes of C. albicans pathogenesis. Moreover, these results provide direct evidence for a key role of SNARE proteins in vesicle-mediated polarized hyphal growth of C. albicans.
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Affiliation(s)
- Stella M Bernardo
- Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, USA; University of New Mexico Health Science Center, Albuquerque, NM, USA
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Etxebeste O, Villarino M, Markina-Iñarrairaegui A, Araújo-Bazán L, Espeso EA. Cytoplasmic dynamics of the general nuclear import machinery in apically growing syncytial cells. PLoS One 2013; 8:e85076. [PMID: 24376868 PMCID: PMC3869923 DOI: 10.1371/journal.pone.0085076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/21/2013] [Indexed: 12/20/2022] Open
Abstract
Karyopherins are transporters involved in the bidirectional, selective and active transport of macromolecules through nuclear pores. Importin-β1 is the paradigm of karyopherins and, together with its cargo-adapter importin-α, mediates the general nuclear import pathway. Here we show the existence of different cellular pools of both importin-α and -β1 homologues, KapA and KapB, in the coenocytic ascomycete Aspergillus nidulans. Fluorescence analysis of haploid and diploid strains expressing KapB::GFP and/or KapA::mRFP showed patches of both karyopherins concurrently translocating long distances in apically-growing cells. Anterograde and retrograde movements allowed those patches to reach cell tips and distal regions with an average speed in the range of μm/s. This bidirectional traffic required microtubules as well as kinesin and dynein motors, since it is blocked by benomyl and also by the inactivation of the dynein/dynactin complex through nudA1 or nudK317 mutations. Deletion of Kinesin-3 motor UncA, required for the transport through detyrosinated microtubules, strongly inhibited KapA and KapB movement along hyphae. Overall, this is the first report describing the bidirectional dynamics of the main nuclear import system in coenocytic fungi. A functional link is proposed between two key cellular machines of the filamentous fungal cell: nuclear transport and the tip-growth apparatus.
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Affiliation(s)
- Oier Etxebeste
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country, San Sebastian, Spain
| | - María Villarino
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Ane Markina-Iñarrairaegui
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country, San Sebastian, Spain
| | - Lidia Araújo-Bazán
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Department of Molecular Microbiology and Infection Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Eduardo A. Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- * E-mail:
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Affiliation(s)
- Meritxell Riquelme
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, Baja California, Mexico 22860;
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The Aspergillus nidulans peripheral ER: disorganization by ER stress and persistence during mitosis. PLoS One 2013; 8:e67154. [PMID: 23826221 PMCID: PMC3691152 DOI: 10.1371/journal.pone.0067154] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/14/2013] [Indexed: 01/16/2023] Open
Abstract
The genetically amenable fungus Aspergillus nidulans is well suited for cell biology studies involving the secretory pathway and its relationship with hyphal tip growth by apical extension. We exploited live-cell epifluorescence microscopy of the ER labeled with the translocon component Sec63, endogenously tagged with GFP, to study the organization of ‘secretory’ ER domains. The Sec63 A. nidulans ER network includes brightly fluorescent peripheral strands and more faintly labeled nuclear envelopes. In hyphae, the most abundant peripheral ER structures correspond to plasma membrane-associated strands that are polarized, but do not invade the hyphal tip dome, at least in part because the subapical collar of endocytic actin patches constrict the cortical strands in this region. Thus the subapical endocytic ring might provide an attachment for ER strands, thereby ensuring that the growing tip remains ‘loaded’ with secretory ER. Acute disruption of secretory ER function by reductive stress-mediated induction of the unfolded protein response results in the reversible aggregation of ER strands, cessation of exocytosis and swelling of the hyphal tips. The secretory ER is insensitive to brefeldin A treatment and does not undergo changes during mitosis, in agreement with the reports that apical extension continues at normal rates during this period.
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Harris SD. Golgi organization and the apical extension of fungal hyphae: an essential relationship. Mol Microbiol 2013; 89:212-5. [DOI: 10.1111/mmi.12291] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Steven D. Harris
- Department of Plant Pathology and Center for Plant Science Innovation; University of Nebraska; Lincoln NE 68588-0660 USA
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Pinar M, Pantazopoulou A, Arst HN, Peñalva MA. Acute inactivation of theAspergillus nidulans Golgi membrane fusion machinery: correlation of apical extension arrest and tip swelling with cisternal disorganization. Mol Microbiol 2013; 89:228-48. [DOI: 10.1111/mmi.12280] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Mario Pinar
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Areti Pantazopoulou
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
| | - Herbert N. Arst
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
- Section of Microbiology; Department of Medicine; Imperial College; Armstrong Road London SW7 2AZ UK
| | - Miguel A. Peñalva
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas CSIC; Ramiro de Maeztu 9 Madrid 28040 Spain
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49
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Pinar M, Pantazopoulou A, Peñalva MA. Live-cell imaging of Aspergillus nidulans autophagy: RAB1 dependence, Golgi independence and ER involvement. Autophagy 2013; 9:1024-43. [PMID: 23722157 DOI: 10.4161/auto.24483] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We exploited the amenability of the fungus Aspergillus nidulans to genetics and live-cell microscopy to investigate autophagy. Upon nitrogen starvation, GFP-Atg8-containing pre-autophagosomal puncta give rise to cup-shaped phagophores and circular (0.9-μm diameter) autophagosomes that disappear in the vicinity of the vacuoles after their shape becomes irregular and their GFP-Atg8 fluorescence decays. This 'autophagosome cycle' gives rise to characteristic cone-shaped traces in kymographs. Autophagy does not require endosome maturation or ESCRTs, as autophagosomes fuse with vacuoles directly in a RabS (homolog of Saccharomyces cerevisiae Ypt7 and mammalian RAB7; written hereafter as RabS(RAB7))-HOPS-(homotypic fusion and vacuole protein sorting complex)-dependent manner. However, by removing RabS(RAB7) or Vps41 (a component of the HOPS complex), we show that autophagosomes may still fuse, albeit inefficiently, with the endovacuolar system in a process almost certainly mediated by RabA(RAB5)/RabB(RAB5) (yeast Vps21 homologs)-CORVET (class C core vacuole/endosome tethering complex), because acute inactivation of HbrA/Vps33, a key component of HOPS and CORVET, completely precludes access of GFP-Atg8 to vacuoles without affecting autophagosome biogenesis. Using a FYVE 2-GFP probe and endosomal PtdIns3P-depleted cells, we imaged PtdIns3P on autophagic membranes. PtdIns3P present on autophagosomes decays at late stages of the cycle, preceding fusion with the vacuole. Autophagy does not require Golgi traffic, but it is crucially dependent on RabO(RAB1). TRAPPIII-specific factor AN7311 (yeast Trs85) localizes to the phagophore assembly site (PAS) and RabO(RAB1) localizes to phagophores and autophagosomes. The Golgi and autophagy roles of RabO(RAB1) are dissociable by mutation: rabO(A136D) hyphae show relatively normal secretion at 28°C but are completely blocked in autophagy. This finding and the lack of Golgi traffic involvement pointed to the ER as one potential source of membranes for autophagy. In agreement, autophagosomes form in close association with ring-shaped omegasome-like ER structures resembling those described in mammalian cells.
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Affiliation(s)
- Mario Pinar
- Centro de Investigaciones Biológicas (CSIC); Madrid, Spain
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50
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Abenza JF, Galindo A, Pinar M, Pantazopoulou A, de los Ríos V, Peñalva MA. Endosomal maturation by Rab conversion in Aspergillus nidulans is coupled to dynein-mediated basipetal movement. Mol Biol Cell 2012; 23:1889-901. [PMID: 22456509 PMCID: PMC3350553 DOI: 10.1091/mbc.e11-11-0925] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Highly motile fungal early endosomes can be easily distinguished from more static late endosomes and vacuoles, a feature that is exploited to study endosomal maturation. RabA/RabB early endosomes mature into RabSRab7 late endosomes as they move away from the tip where endocytosis predominates, augmenting their size, with concomitant loss of motility. We exploit the ease with which highly motile early endosomes are distinguished from static late endosomes in order to study Aspergillus nidulans endosomal traffic. RabSRab7 mediates homotypic fusion of late endosomes/vacuoles in a homotypic fusion- and vacuole protein sorting/Vps41–dependent manner. Progression across the endocytic pathway involves endosomal maturation because the end products of the pathway in the absence of RabSRab7 are minivacuoles that are competent in multivesicular body sorting and cargo degradation but retain early endosomal features, such as the ability to undergo long-distance movement and propensity to accumulate in the tip region if dynein function is impaired. Without RabSRab7, early endosomal Rab5s—RabA and RabB—reach minivacuoles, in agreement with the view that Rab7 homologues facilitate the release of Rab5 homologues from endosomes. RabSRab7 is recruited to membranes already at the stage of late endosomes still lacking vacuolar morphology, but the transition between early and late endosomes is sharp, as only in a minor proportion of examples are RabA/RabB and RabSRab7 detectable in the same—frequently the less motile—structures. This early-to-late endosome/vacuole transition is coupled to dynein-dependent movement away from the tip, resembling the periphery-to-center traffic of endosomes accompanying mammalian cell endosomal maturation. Genetic studies establish that endosomal maturation is essential, whereas homotypic vacuolar fusion is not.
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Affiliation(s)
- Juan F Abenza
- Departamento de Medicina Molecular y Celular, Centro de Investigaciones Biológicas del Consejo Superior de Investigaciones Cientificas, 28040 Madrid, Spain
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