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Qiu R, Zhang J, McDaniel D, Peñalva MA, Xiang X. Live-Cell Imaging of Dynein-Mediated Cargo Transport in Aspergillus nidulans. Methods Mol Biol 2023; 2623:3-23. [PMID: 36602676 DOI: 10.1007/978-1-0716-2958-1_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Filamentous fungi have been used for studying long-distance transport of cargoes driven by cytoplasmic dynein. Aspergillus nidulans is a well-established genetic model organism used for studying dynein function and regulation in vivo. Here, we describe how we grow A. nidulans strains for live-cell imaging and how we observe the dynein-mediated distribution of early endosomes and secretory vesicles. Using an on-stage incubator and culture chambers for inverted microscopes, we can image fungal hyphae that naturally attach to the bottom of the chambers, using wide-field epifluorescence microscopes or the new Zeiss LSM 980 (with Airyscan 2) microscope. In addition to methods for preparing cells for imaging, a procedure for A. nidulans transformation is also described.
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Affiliation(s)
- Rongde Qiu
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Jun Zhang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Dennis McDaniel
- Department of Microbiology and Immunology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, MD, USA
| | - Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas, CSIC, Madrid, Spain.
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences- F. Edward Hébert School of Medicine, Bethesda, MD, USA.
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2
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A Kinesin Vdkin2 Required for Vacuole Formation, Mycelium Growth, and Penetration Structure Formation of Verticillium dahliae. J Fungi (Basel) 2022; 8:jof8040391. [PMID: 35448622 PMCID: PMC9030024 DOI: 10.3390/jof8040391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/06/2022] [Accepted: 04/08/2022] [Indexed: 12/18/2022] Open
Abstract
The soil-borne vascular fungus Verticillium dahliae infects hundreds of dicotyledonous plants, causing severe wilt diseases. During the initial colonization, V. dahliae develops a penetration peg to enable infection of cotton roots. In some phytopathogenic fungi, vacuoles play a critical role in normal formation of the infection structure. Kinesin 2 protein is associated with vacuole formation in Ustilago maydis. To identify the function of vacuoles in the V. dahliae infection structure, we identified VdKin2, an ortholog of kinesin 2, in V. dahliae and investigated its function through gene knockout. VdKin2 mutants showed severe defects in virulence and were suppressed during initial infection and root colonization based on observation of green fluorescent protein-labeled V. dahliae. We also found that deletion of VdKin2 compromised penetration peg formation and the derived septin neck. Disruption strains were viable and showed normal microsclerotia formation, whereas mycelium growth and conidial production were reduced, with shorter and more branched hyphae. Furthermore, the VdKin2 mutant, unlike wild-type V. dahliae, lacked a large basal vacuole, accompanied by a failure to generate concentrated lipid droplets. Taken together, VdKin2 regulates vacuole formation by V. dahliae, which is required for conidiation, mycelium growth, and penetration structure formation during initial plant root infection.
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Raudaskoski M. Kinesin Motors in the Filamentous Basidiomycetes in Light of the Schizophyllum commune Genome. J Fungi (Basel) 2022; 8:jof8030294. [PMID: 35330296 PMCID: PMC8950801 DOI: 10.3390/jof8030294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 12/10/2022] Open
Abstract
Kinesins are essential motor molecules of the microtubule cytoskeleton. All eukaryotic organisms have several genes encoding kinesin proteins, which are necessary for various cell biological functions. During the vegetative growth of filamentous basidiomycetes, the apical cells of long leading hyphae have microtubules extending toward the tip. The reciprocal exchange and migration of nuclei between haploid hyphae at mating is also dependent on cytoskeletal structures, including the microtubules and their motor molecules. In dikaryotic hyphae, resulting from a compatible mating, the nuclear location, synchronous nuclear division, and extensive nuclear separation at telophase are microtubule-dependent processes that involve unidentified molecular motors. The genome of Schizophyllum commune is analyzed as an example of a species belonging to the Basidiomycota subclass, Agaricomycetes. In this subclass, the investigation of cell biology is restricted to a few species. Instead, the whole genome sequences of several species are now available. The analyses of the mating type genes and the genes necessary for fruiting body formation or wood degrading enzymes in several genomes of Agaricomycetes have shown that they are controlled by comparable systems. This supports the idea that the genes regulating the cell biological process in a model fungus, such as the genes encoding kinesin motor molecules, are also functional in other filamentous Agaricomycetes.
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Affiliation(s)
- Marjatta Raudaskoski
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
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Moreno-Velásquez SD, Pérez JC. Imaging and Quantification of mRNA Molecules at Single-Cell Resolution in the Human Fungal Pathogen Candida albicans. mSphere 2021; 6:e0041121. [PMID: 34232078 PMCID: PMC8386430 DOI: 10.1128/msphere.00411-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/24/2021] [Indexed: 11/20/2022] Open
Abstract
The study of gene expression in fungi has typically relied on measuring transcripts in populations of cells. A major disadvantage of this approach is that the transcripts' spatial distribution and stochastic variation among individual cells within a clonal population is lost. Traditional fluorescence in situ hybridization techniques have been of limited use in fungi due to poor specificity and high background signal. Here, we report that in situ hybridization chain reaction (HCR), a method that employs split-initiator probes to trigger signal amplification upon mRNA-probe hybridization, is ideally suited for the imaging and quantification of low-abundance transcripts at single-cell resolution in the fungus Candida albicans. We show that HCR allows the absolute quantification of transcripts within a cell by microscopy as well as their relative quantification by flow cytometry. mRNA imaging also revealed the subcellular localization of specific transcripts. Furthermore, we establish that HCR is amenable to multiplexing by visualizing different transcripts in the same cell. Finally, we combine HCR with immunostaining to image specific mRNAs and proteins simultaneously within a single C. albicans cell. The fungus is a major pathogen in humans where it can colonize and invade mucosal surfaces and most internal organs. The technical development that we introduce, therefore, paves the way to study the patterns of expression of pathogenesis-associated C. albicans genes in infected organs at single-cell resolution. IMPORTANCE Tools to visualize and quantify transcripts at single-cell resolution have enabled the dissection of spatiotemporal patterns of gene expression in animal cells and tissues. Yet the accurate quantification of transcripts at single-cell resolution remains challenging for the much smaller microbial cells. Widespread phenomena such as stochastic variation in transcript levels among cells-even within a clonal population-seem to play important roles in the biology of many microorganisms. Investigating this process requires microbial cell-optimized procedures to image and measure mRNAs at single-molecule resolution. In this report, we adapt and expand in situ hybridization chain reaction (HCR) combined with split-initiator probes to visualize transcripts in the human-pathogenic fungus Candida albicans at high resolution.
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Affiliation(s)
- Sergio D. Moreno-Velásquez
- Interdisciplinary Center for Clinical Research, University Hospital Würzburg, Würzburg, Germany
- Institute for Molecular Infection Biology, University Würzburg, Würzburg, Germany
| | - J. Christian Pérez
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas, USA
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5
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Higuchi Y. Membrane traffic related to endosome dynamics and protein secretion in filamentous fungi. Biosci Biotechnol Biochem 2021; 85:1038-1045. [PMID: 33686391 DOI: 10.1093/bbb/zbab004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/29/2020] [Indexed: 12/27/2022]
Abstract
In eukaryotic cells, membrane-surrounded organelles are orchestrally organized spatiotemporally under environmental situations. Among such organelles, vesicular transports and membrane contacts occur to communicate each other, so-called membrane traffic. Filamentous fungal cells are highly polarized and thus membrane traffic is developed to have versatile functions. Early endosome (EE) is an endocytic organelle that dynamically exhibits constant long-range motility through the hyphal cell, which is proven to have physiological roles, such as other organelle distribution and signal transduction. Since filamentous fungal cells are also considered as cell factories, to produce valuable proteins extracellularly, molecular mechanisms of secretory pathway including protein glycosylation have been well investigated. In this review, molecular and physiological aspects of membrane traffic especially related to EE dynamics and protein secretion in filamentous fungi are summarized, and perspectives for application are also described.
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Affiliation(s)
- Yujiro Higuchi
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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Kijpornyongpan T, Aime MC. Comparative transcriptomics reveal different mechanisms for hyphal growth across four plant-associated dimorphic fungi. Fungal Genet Biol 2021; 152:103565. [PMID: 33991665 DOI: 10.1016/j.fgb.2021.103565] [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: 09/24/2020] [Revised: 03/07/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022]
Abstract
Fungal dimorphism is a phenomenon by which a fungus can grow both as a yeast form and a hyphal form. It is frequently related to pathogenicity as different growth forms are more suitable for different functions during a life cycle. Among dimorphic plant pathogens, the corn smut fungus Ustilago maydis serves as a model organism to understand fungal dimorphism and its effect on pathogenicity. However, there is a lack of data on whether mechanisms elucidated from model species are broadly applicable to other fungi. In this study, two non-model plant-associated species in the smut fungus subphylum (Ustilaginomycotina), Tilletiopsis washingtonensis and Meira miltonrushii, were selected to compare dimorphic mechanisms in these to those in U. maydis. We sequenced transcriptomic profiles during both yeast and hyphal growth in these two species using Tween40, a lipid mimic, as a trigger for hyphal growth. We then compared our data with previously published data from U. maydis and a fourth but unrelated dimorphic phytopathogen, Ophiostoma novo-ulmi. Comparative transcriptomics was performed to identify common genes upregulated during hyphal growth in all four dimorphic species. Intriguingly, T. washingtonensis shares the least similarities of transcriptomic alteration (hyphal growth versus yeast growth) with the others, although it is closely related to M. miltonrushii and U. maydis. This suggests that phylogenetic relatedness is not correlated with transcriptomic similarity under the same biological phenomenon. Among commonly expressed genes in the four species, genes in cell energy production and conversion, amino acid transport and metabolism and cytoskeleton are significantly enriched. Considering dimorphism genes characterized in U. maydis, as well as hyphal tip-associated genes from the literature, we found only genes encoding the cell end marker Tea4/TeaC and the kinesin motor protein Kin3 concordantly expressed in all four species. This suggests a divergence in species-specific mechanisms for dimorphic transition and hyphal growth.
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Affiliation(s)
- Teeratas Kijpornyongpan
- Department of Botany and Plant Pathology, Purdue University, 915 W State St, West Lafayette, IN 47907-2054, USA
| | - M Catherine Aime
- Department of Botany and Plant Pathology, Purdue University, 915 W State St, West Lafayette, IN 47907-2054, USA.
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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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Qiu R, Zhang J, Xiang X. LIS1 regulates cargo-adapter-mediated activation of dynein by overcoming its autoinhibition in vivo. J Cell Biol 2019; 218:3630-3646. [PMID: 31562232 PMCID: PMC6829669 DOI: 10.1083/jcb.201905178] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/08/2019] [Accepted: 08/29/2019] [Indexed: 02/08/2023] Open
Abstract
Deficiency of the LIS1 protein causes lissencephaly, a brain developmental disorder. Although LIS1 binds the microtubule motor cytoplasmic dynein and has been linked to dynein function in many experimental systems, its mechanism of action remains unclear. Here, we revealed its function in cargo-adapter-mediated dynein activation in the model organism Aspergillus nidulans Specifically, we found that overexpressed cargo adapter HookA (Hook in A. nidulans) missing its cargo-binding domain (ΔC-HookA) causes dynein and its regulator dynactin to relocate from the microtubule plus ends to the minus ends, and this relocation requires LIS1 and its binding protein, NudE. Astonishingly, the requirement for LIS1 or NudE can be bypassed to a significant extent by mutations that prohibit dynein from forming an autoinhibited conformation in which the motor domains of the dynein dimer are held close together. Our results suggest a novel mechanism of LIS1 action that promotes the switch of dynein from the autoinhibited state to an open state to facilitate dynein activation.
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Affiliation(s)
- Rongde Qiu
- Department of Biochemistry and Molecular Biology, the Uniformed Services University F. Edward Hébert School of Medicine, Bethesda, MD
| | - Jun Zhang
- Department of Biochemistry and Molecular Biology, the Uniformed Services University F. Edward Hébert School of Medicine, Bethesda, MD
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, the Uniformed Services University F. Edward Hébert School of Medicine, Bethesda, MD
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Cano-Domínguez N, Bowman B, Peraza-Reyes L, Aguirre J. Neurospora crassa NADPH Oxidase NOX-1 Is Localized in the Vacuolar System and the Plasma Membrane. Front Microbiol 2019; 10:1825. [PMID: 31474947 PMCID: PMC6702951 DOI: 10.3389/fmicb.2019.01825] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/24/2019] [Indexed: 12/13/2022] Open
Abstract
The NADPH oxidases (NOX) catalyze the production of superoxide by transferring electrons from NADPH to O2, in a regulated manner. In Neurospora crassa NOX-1 is required for normal growth of hyphae, development of aerial mycelium and asexual spores, and it is essential for sexual differentiation and cell-cell fusion. Determining the subcellular localization of NOX-1 is a critical step in understanding the mechanisms by which this enzyme can regulate all these different processes. Using fully functional versions of NOX-1 tagged with mCherry, we show that in growing hyphae NOX-1 shows only a minor association with the endoplasmic reticulum (ER) markers Ca2+-ATPase NCA-1 and an ER lumen-targeted GFP. Likewise, NOX-1 shows minor co-localization with early endosomes labeled with YPT-52, a GTPase of the Rab5 family. In contrast, NOX-1 shows extensive co-localization with two independent markers of the entire vacuolar system; the vacuolar ATPase subunit VMA-1 and the fluorescent molecule carboxy-DFFDA. In addition, part of NOX-1 was detected at the plasma membrane. The NOX-1 regulatory subunit NOR-1 displays a very different pattern of localization, showing a fine granular distribution along the entire hypha and some accumulation at the hyphal tip. In older hyphal regions, germinating conidia, and conidiophores it forms larger and discrete puncta some of which appear localized at the plasma membrane and septa. Notably, co-localization of NOX-1 and NOR-1 was mainly observed under conidial cell-cell fusion conditions in discrete vesicular structures. NOX functions in fungi have been evaluated mainly in mutants that completely lacked this protein, also eliminating interactions between hyphal growth regulatory proteins NOR-1, the GTPase RAC-1 and the scaffold protein BEM-1. To dissect NOX-1 roles as scaffold and as ROS-producing enzyme, we analyzed the function of NOX-1::mCherry proteins carrying proline 382 by histidine (P382H) or cysteine 524 by arginine (C524R) substitutions, predicted to only affect NADPH-binding. Without notably affecting NOX-1 localization or protein levels, each of these substitutions resulted in lack of function phenotypes, indicating that NOX-1 multiple functions are all dependent on its oxidase activity. Our results open new interpretations to possible NOX functions, as components of the fungal vacuolar system and the plasma membrane, as well as to new vacuolar functions.
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Affiliation(s)
- Nallely Cano-Domínguez
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Barry Bowman
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Leonardo Peraza-Reyes
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Jesús Aguirre
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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10
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Kinesin-1 Proteins KIF5A, -5B, and -5C Promote Anterograde Transport of Herpes Simplex Virus Enveloped Virions in Axons. J Virol 2018; 92:JVI.01269-18. [PMID: 30068641 DOI: 10.1128/jvi.01269-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 01/09/2023] Open
Abstract
Herpes simplex virus (HSV) and other alphaherpesviruses must spread from sites of viral latency in sensory ganglia to peripheral tissues, where the viruses can replicate to higher titers before spreading to other hosts. These viruses move in neuronal axons from ganglia to the periphery propelled by kinesin motors moving along microtubules. Two forms of HSV particles undergo this anterograde transport in axons: (i) unenveloped capsids that become enveloped after reaching axon tips and (ii) enveloped virions that are transported within membrane vesicles in axons. Fundamental to understanding this axonal transport is the question of which of many different axonal kinesins convey HSV particles. Knowing which kinesins promote axonal transport would provide clues to the identity of HSV proteins that tether onto kinesins. Prominent among axonal kinesins are the kinesin-1 (KIF5A, -5B, and -5C) and kinesin-3 (e.g., KIF1A and -1B) families. We characterized fluorescent forms of cellular cargo molecules to determine if enveloped HSV particles were present in the vesicles containing these cargos. Kinesin-1 cargo proteins were present in vesicles containing HSV particles, but not kinesin-3 cargos. Fluorescent kinesin-1 protein KIF5C extensively colocalized with HSV particles, while fluorescent kinesin-1 KIF1A did not. Silencing of kinesin-1 proteins KIF5A, -5B, and -5C or light chains KLC1 and KLC2 inhibited the majority of HSV anterograde transport, while silencing of KIF1A had little effect on HSV transport in axons. We concluded that kinesin-1 proteins are important in the anterograde transport of the majority of HSV enveloped virions in neuronal axons and kinesin-3 proteins are less important.IMPORTANCE Herpes simplex virus (HSV) and other alphaherpesviruses, such as varicella-zoster virus, depend upon the capacity to navigate in neuronal axons. To do this, virus particles tether onto dyneins and kinesins that motor along microtubules from axon tips to neuronal cell bodies (retrograde) or from cell bodies to axon tips (anterograde). Following reactivation from latency, alphaherpesviruses absolutely depend upon anterograde transport of virus particles in axons in order to reinfect peripheral tissues and spread to other hosts. Which of the many axonal kinesins transport HSV in axons is not clear. We characterized fluorescent cellular cargo molecules and kinesins to provide evidence that HSV enveloped particles are ferried by kinesin-1 proteins KIF5A, -5B, and -5C and their light chains, KLC1 and KLC2, in axons. Moreover, we obtained evidence that kinesin-1 proteins are functionally important in anterograde transport of HSV virions by silencing these proteins.
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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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12
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Kreitzer G, Myat MM. Microtubule Motors in Establishment of Epithelial Cell Polarity. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a027896. [PMID: 28264820 DOI: 10.1101/cshperspect.a027896] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epithelial cells play a key role in insuring physiological homeostasis by acting as a barrier between the outside environment and internal organs. They are also responsible for the vectorial transport of ions and fluid essential to the function of many organs. To accomplish these tasks, epithelial cells must generate an asymmetrically organized plasma membrane comprised of structurally and functionally distinct apical and basolateral membranes. Adherent and occluding junctions, respectively, anchor cells within a layer and prevent lateral diffusion of proteins in the outer leaflet of the plasma membrane and restrict passage of proteins and solutes through intercellular spaces. At a fundamental level, the establishment and maintenance of epithelial polarity requires that signals initiated at cell-substratum and cell-cell adhesions are transmitted appropriately and dynamically to the cytoskeleton, to the membrane-trafficking machinery, and to the regulation of occluding and adherent junctions. Rigorous descriptive and mechanistic studies published over the last 50 years have provided great detail to our understanding of epithelial polarization. Yet still, critical early steps in morphogenesis are not yet fully appreciated. In this review, we discuss how cytoskeletal motor proteins, primarily kinesins, contribute to coordinated modification of microtubule and actin arrays, formation and remodeling of cell adhesions to targeted membrane trafficking, and to initiating the formation and expansion of an apical lumen.
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Affiliation(s)
- Geri Kreitzer
- Department of Pathobiology, Sophie Davis School of Biomedical Education, City College of New York, The City University of New York School of Medicine, New York, New York 10031
| | - Monn Monn Myat
- Department of Biology, Medgar Evers College, Brooklyn, New York 11225.,The Graduate Center, The City University of New York, New York, New York 10016
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13
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Early endosome motility mediates α-amylase production and cell differentiation in Aspergillus oryzae. Sci Rep 2017; 7:15757. [PMID: 29150640 PMCID: PMC5693997 DOI: 10.1038/s41598-017-16163-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/08/2017] [Indexed: 01/09/2023] Open
Abstract
Recent research in filamentous fungi has revealed that the motility of an endocytic organelle early endosome (EE) has a versatile role in many physiological functions. Here, to further examine the motility of EEs in the industrially important fungus Aspergillus oryzae, we visualized these organelles via the Rab5 homolog AoRab5 and identified AoHok1, a putative linker protein between an EE and a motor protein. The Aohok1 disruptant showed retarded mycelial growth and no EE motility, in addition to an apical accumulation of EEs and peroxisomes. We further demonstrated that the Aohok1 disruptant exhibited less sensitivity to osmotic and cell wall stresses. Analyses on the protein secretory pathway in ΔAohok1 cells showed that, although distribution of the endoplasmic reticulum and Golgi was not affected, formation of the apical secretory vesicle cluster Spitzenkörper was impaired, probably resulting in the observed reduction of the A. oryzae major secretory protein α-amylase. Moreover, we revealed that the transcript level of α-amylase-encoding gene amyB was significantly reduced in the Aohok1 disruptant. Furthermore, we observed perturbed conidial and sclerotial formations, indicating a defect in cell differentiation, in the Aohok1 disruptant. Collectively, our results suggest that EE motility is crucial for α-amylase production and cell differentiation in A. oryzae.
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Siddiqui N, Straube A. Intracellular Cargo Transport by Kinesin-3 Motors. BIOCHEMISTRY (MOSCOW) 2017; 82:803-815. [PMID: 28918744 DOI: 10.1134/s0006297917070057] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Intracellular transport along microtubules enables cellular cargoes to efficiently reach the extremities of large, eukaryotic cells. While it would take more than 200 years for a small vesicle to diffuse from the cell body to the growing tip of a one-meter long axon, transport by a kinesin allows delivery in one week. It is clear from this example that the evolution of intracellular transport was tightly linked to the development of complex and macroscopic life forms. The human genome encodes 45 kinesins, 8 of those belonging to the family of kinesin-3 organelle transporters that are known to transport a variety of cargoes towards the plus end of microtubules. However, their mode of action, their tertiary structure, and regulation are controversial. In this review, we summarize the latest developments in our understanding of these fascinating molecular motors.
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Affiliation(s)
- N Siddiqui
- Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, CV4 7AL, UK.
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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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Peñalva MA, Zhang J, Xiang X, Pantazopoulou A. Transport of fungal RAB11 secretory vesicles involves myosin-5, dynein/dynactin/p25, and kinesin-1 and is independent of kinesin-3. Mol Biol Cell 2017; 28:947-961. [PMID: 28209731 PMCID: PMC5385943 DOI: 10.1091/mbc.e16-08-0566] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 01/31/2017] [Accepted: 02/07/2017] [Indexed: 12/02/2022] Open
Abstract
In Aspergillus nidulans, the distribution of exocytic carriers involves interplay between kinesin-1, myosin-5, and dynein. Engagement of the dynein complex to these carriers requires dynactin p25, but, unlike that of early endosomes, it does not require the Hook complex. Hyphal tip cells of the fungus Aspergillus nidulans are useful for studying long-range intracellular traffic. Post-Golgi secretory vesicles (SVs) containing the RAB11 orthologue RabE engage myosin-5 as well as plus end– and minus end–directed microtubule motors, providing an experimental system with which to investigate the interplay between microtubule and actin motors acting on the same cargo. By exploiting the fact that depolymerization of F-actin unleashes SVs focused at the apex by myosin-5 to microtubule-dependent motors, we establish that the minus end–directed transport of SVs requires the dynein/dynactin supercomplex. This minus end–directed transport is largely unaffected by genetic ablation of the Hook complex adapting early endosomes (EEs) to dynein but absolutely requires p25 in dynactin. Thus dynein recruitment to two different membranous cargoes, namely EEs and SVs, requires p25, highlighting the importance of the dynactin pointed-end complex to scaffold cargoes. Finally, by studying the behavior of SVs and EEs in null and rigor mutants of kinesin-3 and kinesin-1 (UncA and KinA, respectively), we demonstrate that KinA is the major kinesin mediating the anterograde transport of SVs. Therefore SVs arrive at the apex of A. nidulans by anterograde transport involving cooperation of kinesin-1 with myosin-5 and can move away from the apex powered by dynein.
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Affiliation(s)
- Miguel A Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid 28040, Spain
| | - Jun Zhang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | - Areti Pantazopoulou
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid 28040, Spain
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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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Abstract
Filamentous fungi are extremely polarized organisms, exhibiting continuous growth at their hyphal tips. The hyphal form is related to their pathogenicity in animals and plants, and their high secretion ability for biotechnology. Polarized growth requires a sequential supply of proteins and lipids to the hyphal tip. This transport is managed by vesicle trafficking via the actin and microtubule cytoskeleton. Therefore, the arrangement of the cytoskeleton is a crucial step to establish and maintain the cell polarity. This review summarizes recent findings unraveling the mechanism of polarized growth with special emphasis on the role of actin and microtubule cytoskeleton and polarity marker proteins. Rapid insertions of membranes via highly active exocytosis at hyphal tips could quickly dilute the accumulated polarity marker proteins. Recent findings by a super-resolution microscopy indicate that filamentous fungal cells maintain their polarity at the tips by repeating transient assembly and disassembly of polarity sites.
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Affiliation(s)
- Norio Takeshita
- a Department of Microbiology , Institute for Applied Bioscience, Karlsruhe Institute of Technology (KIT) , Karlsruhe , Germany.,b Faculty of Life and Environmental Sciences , University of Tsukuba , Tsukuba , Japan
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Mouriño-Pérez RR, Riquelme M, Callejas-Negrete OA, Galván-Mendoza JI. Microtubules and associated molecular motors in Neurospora crassa. Mycologia 2016; 108:515-27. [PMID: 26951369 DOI: 10.3852/15-323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/02/2016] [Indexed: 11/10/2022]
Abstract
The cytoskeleton provides structure, shape and movement to various cells. Microtubules (MTs) are tubular structures made of α and β-tubulin heterodimers organized in 13 protofilaments, forming a hollow cylinder. A vast group of MT-associated proteins determines the function, behavior and interaction of the MTs with other cellular components. Among these proteins, molecular motors such as the dynein-dynactin complex and kinesin superfamily play roles in MT organization and organelle transport. This article focuses on the MT cytoskeleton and associated molecular motors in the filamentous fungus Neurospora crassa In addition to reviewing current available information for this fungus and contrasting it with knowledge of other fungal species, we present new experimental results that support the role of dynein, dynactin and conventional kinesin in MT organization, dynamics and transport of subcellular structures (nuclei and secretory vesicles). In wild type hyphae of N. crassa, cytoplasmic MTs are arranged longitudinally along hyphae and display a helical curvature. They interlace with one another to form a network throughout the cytoplasm. N. crassa dynein and dynactin mutants have a scant and disorganized MT cytoskeleton, an erratic and reduced Spitzenkörper (Spk) and distorted hyphal morphology. In contrast, hyphae of mutants with defective conventional kinesin exhibit only minor disruptions in MT and Spk organization. Although nuclear positioning is affected in all mutants, the MT-associated motor proteins are not major contributors to nuclear movement during hyphal growth. Cytoplasmic bulk flow is the vehicle for nuclear displacement in growing hyphal regions of N. crassa Motors are involved in nuclei saltatory movements in both retrograde or anterograde direction. In the dynein and kinesin mutants, micro and macrovesicles can reach the Spk, although growth is slightly impaired and the Spk displays an erratic path. Hyphal growth requires MTs, and their associated motors are required for their organization and dynamics and Spk integrity.
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Affiliation(s)
- Rosa Reyna Mouriño-Pérez
- Departamento de Microbiología. Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE, Ensenada B.C. 22860 Mexico
| | - Meritxell Riquelme
- Departamento de Microbiología. Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE, Ensenada B.C. 22860 Mexico
| | - Olga Alicia Callejas-Negrete
- Departamento de Microbiología. Centro de Investigación Científica y de Educación Superior de Ensenada, CICESE, Ensenada B.C. 22860 Mexico
| | - José Iván Galván-Mendoza
- Unidad de Microscopia Confocal y Multifotónica, CINVESTAV-Zacatenco. San Pedro Zacatenco, 07360 Ciudad de México DF, Mexico
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Kilaru S, Schuster M, Latz M, Guo M, Steinberg G. Fluorescent markers of the endocytic pathway in Zymoseptoria tritici. Fungal Genet Biol 2016; 79:150-7. [PMID: 26092801 PMCID: PMC4502447 DOI: 10.1016/j.fgb.2015.03.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/12/2015] [Accepted: 03/17/2015] [Indexed: 12/28/2022]
Abstract
We establish Z. tritici fimbrin (ZtFim1) and small GTPases (ZtRab5, ZtRab7) as endocytic markers. All markers localize correctly, proven by live cell imaging and co-staining and pharmaceutical studies. We provide 3 carboxin-resistance conveying vectors for integration of all markers into the sdi1 locus. We provide 3 hygromycin B-resistance conveying vectors for random integration of all markers.
Hyphal growth in filamentous fungi is supported by the uptake (endocytosis) and recycling of membranes and associated proteins at the growing tip. An increasing body of published evidence in various fungi demonstrates that this process is of essential importance for fungal growth and pathogenicity. Here, we introduce fluorescent markers to visualize the endocytic pathway in the wheat pathogen Zymoseptoria tritici. We fused enhanced green-fluorescent protein (eGFP) to the actin-binding protein fimbrin (ZtFim1), which is located in actin patches that are formed at the plasma membrane and are participating in endocytic uptake at the cell surface. In addition, we tagged early endosomes by eGFP-labelling a Rab5-homologue (ZtRab5) and late endosomes and vacuoles by expressing eGFP-Rab7 homologue (ZtRab7). Using fluorescent dyes and live cell imaging we confirmed the dynamic behavior and localization of these markers. This set of molecular tools enables an in-depth phenotypic analysis of Z. tritici mutant strains thereby supporting new strategies towards the goal of controlling wheat against Z. tritici.
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Affiliation(s)
- S Kilaru
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - M Schuster
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - M Latz
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - M Guo
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - G Steinberg
- Biosciences, University of Exeter, Exeter EX4 4QD, UK.
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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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Characterization of a Novel Prevacuolar Compartment in Neurospora crassa. EUKARYOTIC CELL 2015; 14:1253-63. [PMID: 26453652 DOI: 10.1128/ec.00128-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/03/2015] [Indexed: 12/22/2022]
Abstract
Using confocal microscopy, we observed ring-like organelles, similar in size to nuclei, in the hyphal tip of the filamentous fungus Neurospora crassa. These organelles contained a subset of vacuolar proteins. We hypothesize that they are novel prevacuolar compartments (PVCs). We examined the locations of several vacuolar enzymes and of fluorescent compounds that target the vacuole. Vacuolar membrane proteins, such as the vacuolar ATPase (VMA-1) and the polyphosphate polymerase (VTC-4), were observed in the PVCs. A pigment produced by adenine auxotrophs, used to visualize vacuoles, also accumulated in PVCs. Soluble enzymes of the vacuolar lumen, alkaline phosphatase and carboxypeptidase Y, were not observed in PVCs. The fluorescent molecule Oregon Green 488 carboxylic acid diacetate, succinimidyl ester (carboxy-DFFDA) accumulated in vacuoles and in a subset of PVCs, suggesting maturation of PVCs from the tip to distal regions. Three of the nine Rab GTPases in N. crassa, RAB-2, RAB-4, and RAB-7, localized to the PVCs. RAB-2 and RAB-4, which have similar amino acid sequences, are present in filamentous fungi but not in yeasts, and no function has previously been reported for these Rab GTPases in fungi. PVCs are highly pleomorphic, producing tubular projections that subsequently become detached. Dynein and dynactin formed globular clusters enclosed inside the lumen of PVCs. The size, structure, dynamic behavior, and protein composition of the PVCs appear to be significantly different from those of the well-studied prevacuolar compartment of yeasts.
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23
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Xiang X, Qiu R, Yao X, Arst HN, Peñalva MA, Zhang J. Cytoplasmic dynein and early endosome transport. Cell Mol Life Sci 2015; 72:3267-80. [PMID: 26001903 DOI: 10.1007/s00018-015-1926-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 11/25/2022]
Abstract
Microtubule-based distribution of organelles/vesicles is crucial for the function of many types of eukaryotic cells and the molecular motor cytoplasmic dynein is required for transporting a variety of cellular cargos toward the microtubule minus ends. Early endosomes represent a major cargo of dynein in filamentous fungi, and dynein regulators such as LIS1 and the dynactin complex are both required for early endosome movement. In fungal hyphae, kinesin-3 and dynein drive bi-directional movements of early endosomes. Dynein accumulates at microtubule plus ends; this accumulation depends on kinesin-1 and dynactin, and it is important for early endosome movements towards the microtubule minus ends. The physical interaction between dynein and early endosome requires the dynactin complex, and in particular, its p25 component. The FTS-Hook-FHIP (FHF) complex links dynein-dynactin to early endosomes, and within the FHF complex, Hook interacts with dynein-dynactin, and Hook-early endosome interaction depends on FHIP and FTS.
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Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, F. Edward Hébert School of Medicine, The Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA,
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24
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Higuchi Y, Steinberg G. Early endosomes motility in filamentous fungi: How and why they move. FUNGAL BIOL REV 2015. [DOI: 10.1016/j.fbr.2015.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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25
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Schuster M, Kilaru S, Latz M, Steinberg G. Fluorescent markers of the microtubule cytoskeleton in Zymoseptoria tritici. Fungal Genet Biol 2015; 79:141-9. [PMID: 25857261 PMCID: PMC4502552 DOI: 10.1016/j.fgb.2015.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 03/12/2015] [Accepted: 03/17/2015] [Indexed: 11/28/2022]
Abstract
The microtubule cytoskeleton supports vital processes in fungal cells, including hyphal growth and mitosis. Consequently, it is a target for fungicides, such as benomyl. The use of fluorescent fusion proteins to illuminate microtubules and microtubule-associated proteins has led to a break-through in our understanding of their dynamics and function in fungal cells. Here, we introduce fluorescent markers to visualize microtubules and accessory proteins in the wheat pathogen Zymoseptoria tritici. We fused enhanced green-fluorescent protein to α-tubulin (ZtTub2), to ZtPeb1, a homologue of the mammalian plus-end binding protein EB1, and to ZtGrc1, a component of the minus-end located γ-tubulin ring complex, involved in the nucleation of microtubules. In vivo observation confirms the localization and dynamic behaviour of all three markers. These marker proteins are useful tools for understanding the organization and importance of the microtubule cytoskeleton in Z. tritici.
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Affiliation(s)
- M Schuster
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - S Kilaru
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - M Latz
- Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - G Steinberg
- Biosciences, University of Exeter, Exeter EX4 4QD, UK.
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Steinberg G. Kinesin-3 in the basidiomycete Ustilago maydis transports organelles along the entire microtubule array. Fungal Genet Biol 2015; 74:59-61. [DOI: 10.1016/j.fgb.2014.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 10/08/2014] [Accepted: 10/11/2014] [Indexed: 11/16/2022]
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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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Long-distance endosome trafficking drives fungal effector production during plant infection. Nat Commun 2014; 5:5097. [PMID: 25283249 PMCID: PMC4205857 DOI: 10.1038/ncomms6097] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/28/2014] [Indexed: 01/29/2023] Open
Abstract
To cause plant disease, pathogenic fungi can secrete effector proteins into plant cells to suppress plant immunity and facilitate fungal infection. Most fungal pathogens infect plants using very long strand-like cells, called hyphae, that secrete effectors from their tips into host tissue. How fungi undergo long-distance cell signalling to regulate effector production during infection is not known. Here we show that long-distance retrograde motility of early endosomes (EEs) is necessary to trigger transcription of effector-encoding genes during plant infection by the pathogenic fungus Ustilago maydis. We demonstrate that motor-dependent retrograde EE motility is necessary for regulation of effector production and secretion during host cell invasion. We further show that retrograde signalling involves the mitogen-activated kinase Crk1 that travels on EEs and participates in control of effector production. Fungal pathogens therefore undergo long-range signalling to orchestrate host invasion. It is unclear how the nuclei of very long fungal cells (hyphae) receive information from the hyphal tips during the invasion of plant tissues. Here, the authors show that retrograde movement of early endosomes, from the hyphal tip to the nucleus, is required for this signalling process.
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F-box protein RcyA controls turnover of the kinesin-7 motor KipA in Aspergillus nidulans. EUKARYOTIC CELL 2014; 13:1085-94. [PMID: 24951440 DOI: 10.1128/ec.00042-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fungal filamentous growth depends on continuous membrane insertion at the tip, the delivery of membrane-bound positional markers, and the secretion of enzymes for cell wall biosynthesis. This is achieved through exocytosis. At the same time, polarized growth requires membrane and protein recycling through endocytosis. Endocytic vesicles are thought to enter the protein degradation pathway or recycle their content to the cell surface. In Saccharomyces cerevisiae, the Rcy1 F-box protein is involved in the recycling process of a v-SNARE protein. We identified a Rcy1 orthologue, RcyA, in the filamentous fungus Aspergillus nidulans as a protein interacting with the KipA kinesin-7 motor protein in a yeast two-hybrid screen. The interaction was confirmed through bimolecular fluorescence complementation. RcyA possesses an F-box domain at the N terminus and a prenylation (CaaX) motif at the C terminus. RcyA shows also similarity to Sec10, a component of the exocyst complex. The RcyA protein localized to the hyphal tip and forming septa, likely through transportation on secretory vesicles and partially on early endosomes, but independently of KipA. Deletion of rcyA did not cause severe morphological changes but caused partial defects in the recycling of the SynA v-SNARE protein and the positioning of the cell end markers TeaA and TeaR. In addition, deletion of rcyA led to increased concentrations of the KipA protein, whereas the transcript concentration was unaffected. These results suggest that RcyA probably labels KipA for degradation and thereby controls the protein amount of KipA.
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Yao X, Wang X, Xiang X. FHIP and FTS proteins are critical for dynein-mediated transport of early endosomes in Aspergillus. Mol Biol Cell 2014; 25:2181-9. [PMID: 24870033 PMCID: PMC4091831 DOI: 10.1091/mbc.e14-04-0873] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The minus end-directed microtubule motor cytoplasmic dynein transports various cellular cargoes, including early endosomes, but how dynein binds to its cargo remains unclear. Recently fungal Hook homologues were found to link dynein to early endosomes for their transport. Here we identified FhipA in Aspergillus nidulans as a key player for HookA (A. nidulans Hook) function via a genome-wide screen for mutants defective in early-endosome distribution. The human homologue of FhipA, FHIP, is a protein in the previously discovered FTS/Hook/FHIP (FHF) complex, which contains, besides FHIP and Hook proteins, Fused Toes (FTS). Although this complex was not previously shown to be involved in dynein-mediated transport, we show here that loss of either FhipA or FtsA (A. nidulans FTS homologue) disrupts HookA-early endosome association and inhibits early endosome movement. Both FhipA and FtsA associate with early endosomes, and interestingly, while FtsA-early endosome association requires FhipA and HookA, FhipA-early endosome association is independent of HookA and FtsA. Thus FhipA is more directly linked to early endosomes than HookA and FtsA. However, in the absence of HookA or FtsA, FhipA protein level is significantly reduced. Our results indicate that all three proteins in the FtsA/HookA/FhipA complex are important for dynein-mediated early endosome movement.
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Affiliation(s)
- Xuanli Yao
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814
| | - Xiangfeng Wang
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814
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Takeshita N, Manck R, Grün N, de Vega SH, Fischer R. Interdependence of the actin and the microtubule cytoskeleton during fungal growth. Curr Opin Microbiol 2014; 20:34-41. [PMID: 24879477 DOI: 10.1016/j.mib.2014.04.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/28/2014] [Accepted: 04/29/2014] [Indexed: 02/04/2023]
Abstract
Cell polarization is a theme in biology conserved from bacteria to man. One of the most extremely polarized cells in nature is the hyphae of filamentous fungi. A continuous flow of secretion vesicles from the hyphal cell body to the tip is essential for cell wall and membrane extension. Microtubules (MTs) and actin, along with their corresponding motor proteins, are involved in the secretion process. Therefore, the arrangement of the cytoskeleton is a crucial step to establish and maintain polarity. Here we review recent findings unraveling the mechanism of polarized growth with special emphasis on the role of the actin and MT cytoskeletons and cell end markers linking the two cytoskeletons. We will mainly focus on Neurospora crassa and Aspergillus nidulans as model organisms.
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Affiliation(s)
- Norio Takeshita
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Hertzstrasse 16, D-76187 Karlsruhe, Germany; University of Tsukuba, Faculty of Life and Environmental Sciences, Tsukuba, Ibaraki 305-8572, Japan.
| | - Raphael Manck
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Hertzstrasse 16, D-76187 Karlsruhe, Germany
| | - Nathalie Grün
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Hertzstrasse 16, D-76187 Karlsruhe, Germany
| | - Satur Herrero de Vega
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Hertzstrasse 16, D-76187 Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Department of Microbiology, Hertzstrasse 16, D-76187 Karlsruhe, Germany.
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Steinberg G. Endocytosis and early endosome motility in filamentous fungi. Curr Opin Microbiol 2014; 20:10-8. [PMID: 24835422 PMCID: PMC4148197 DOI: 10.1016/j.mib.2014.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 04/21/2014] [Indexed: 10/25/2022]
Abstract
Hyphal growth of filamentous fungi requires microtubule-based long-distance motility of early endosomes. Since the discovery of this process in Ustilago maydis, our understanding of its molecular basis and biological function has greatly advanced. Studies in U. maydis and Aspergillus nidulans reveal a complex interplay of the motor proteins kinesin-3 and dynein, which co-operate to support bi-directional motion of early endosomes. Genetic screening has shed light on the molecular mechanisms underpinning motor regulation, revealing Hook protein as general motor adapters on early endosomes. Recently, fascinating insight into unexpected roles for endosome motility has emerged. This includes septin filament formation and cellular distribution of the machinery for protein translation.
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Affiliation(s)
- Gero Steinberg
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
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Tan K, Roberts AJ, Chonofsky M, Egan MJ, Reck-Peterson SL. A microscopy-based screen employing multiplex genome sequencing identifies cargo-specific requirements for dynein velocity. Mol Biol Cell 2014; 25:669-78. [PMID: 24403603 PMCID: PMC3937092 DOI: 10.1091/mbc.e13-09-0557] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The timely delivery of membranous organelles and macromolecules to specific locations within the majority of eukaryotic cells depends on microtubule-based transport. Here we describe a screening method to identify mutations that have a critical effect on intracellular transport and its regulation using mutagenesis, multicolor-fluorescence microscopy, and multiplex genome sequencing. This screen exploits the filamentous fungus Aspergillus nidulans, which has many of the advantages of yeast molecular genetics but uses long-range microtubule-based transport in a manner more similar to metazoan cells. Using this method, we identified seven mutants that represent novel alleles of components of the intracellular transport machinery: specifically, kinesin-1, cytoplasmic dynein, and the dynein regulators Lis1 and dynactin. The two dynein mutations identified in our screen map to dynein's AAA+ catalytic core. Single-molecule studies reveal that both mutations reduce dynein's velocity in vitro. In vivo these mutants severely impair the distribution and velocity of endosomes, a known dynein cargo. In contrast, another dynein cargo, the nucleus, is positioned normally in these mutants. These results reveal that different dynein functions have distinct stringencies for motor performance.
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Affiliation(s)
- Kaeling Tan
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115 Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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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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