1
|
Dai M, Liu X, Goldman GH, Lu L, Zhang S. The EH domain-containing protein, EdeA, is involved in endocytosis, cell wall integrity, and pathogenicity in Aspergillus fumigatus. mSphere 2024; 9:e0005724. [PMID: 38687129 PMCID: PMC11237632 DOI: 10.1128/msphere.00057-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 03/29/2024] [Indexed: 05/02/2024] Open
Abstract
Endocytosis has been extensively studied in yeasts, where it plays crucial roles in growth, signaling regulation, and cell-surface receptor internalization. However, the biological functions of endocytosis in pathogenic filamentous fungi remain largely unexplored. In this study, we aimed to functionally characterize the roles of EdeA, an ortholog of the Saccharomyces cerevisiae endocytic protein Ede1, in Aspergillus fumigatus. EdeA was observed to be distributed as patches on the plasma membrane and concentrated in the subapical collar of hyphae, a localization characteristic of endocytic proteins. Loss of edeA caused defective hyphal polarity, reduced conidial production, and fewer sites of endocytosis initiations than that of the parental wild type. Notably, the edeA null mutant exhibited increased sensitivity to cell wall-disrupting agents, indicating a role for EdeA in maintaining cell wall integrity in A. fumigatus. This observation was further supported by the evidence showing that the thickness of the cell wall in the ΔedeA mutant increased, accompanied by abnormal activation of MpkA, a key component in the cell wall integrity pathway. Additionally, the ΔedeA mutant displayed increased pathogenicity in the Galleria mellonella wax moth infection model, possibly due to alterations in cell wall morphology. Site-directed mutagenesis identified the conserved residue E348 within the third EH (Eps15 homology) domain of EdeA as crucial for its subcellular localization and functions. In conclusion, our results highlight the involvement of EdeA in endocytosis, hyphal polarity, cell wall integrity, and pathogenicity in A. fumigatus. IMPORTANCE Aspergillus fumigatus is a significant human pathogenic fungus known to cause invasive aspergillosis, a disease with a high mortality rate. Understanding the basic principles of A. fumigatus pathogenicity is crucial for developing effective strategies against this pathogen. Previous research has underscored the importance of endocytosis in the infection capacity of pathogenic yeasts; however, its biological function in pathogenic mold remains largely unexplored. Our characterization of EdeA in A. fumigatus sheds light on the role of endocytosis in the development, stress response, and pathogenicity of pathogenic molds. These findings suggest that the components of the endocytosis process may serve as potential targets for antifungal therapy.
Collapse
Affiliation(s)
- Mengyao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xintian Liu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Gustavo H Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shizhu Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| |
Collapse
|
2
|
Keita VM, Lee YQ, Lakshmanan M, Ow DSW, Staniland P, Staniland J, Savill I, Tee KL, Wong TS, Lee DY. Evaluating oleaginous yeasts for enhanced microbial lipid production using sweetwater as a sustainable feedstock. Microb Cell Fact 2024; 23:63. [PMID: 38402186 PMCID: PMC10893622 DOI: 10.1186/s12934-024-02336-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/14/2024] [Indexed: 02/26/2024] Open
Abstract
BACKGROUND Yeasts exhibit promising potential for the microbial conversion of crude glycerol, owing to their versatility in delivering a wide range of value-added products, particularly lipids. Sweetwater, a methanol-free by-product of the fat splitting process, has emerged as a promising alternative feedstock for the microbial utilization of crude glycerol. To further optimize sweetwater utilization, we compared the growth and lipid production capabilities of 21 oleaginous yeast strains under different conditions with various glycerol concentrations, sweetwater types and pH. RESULTS We found that nutrient limitation and the unique carbon composition of sweetwater boosted significant lipid accumulation in several strains, in particular Rhodosporidium toruloides NRRL Y-6987. Subsequently, to decipher the underlying mechanism, the transcriptomic changes of R. toruloides NRRL Y-6987 were further analyzed, indicating potential sugars and oligopeptides in sweetwater supporting growth and lipid accumulation as well as exogenous fatty acid uptake leading to the enhanced lipid accumulation. CONCLUSION Our comparative study successfully demonstrated sweetwater as a cost-effective feedstock while identifying R. toluroides NRRL Y-6987 as a highly promising microbial oil producer. Furthermore, we also suggested potential sweetwater type and strain engineering targets that could potentially enhance microbial lipid production.
Collapse
Affiliation(s)
- Valériane Malika Keita
- Department of Chemical & Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, Centros, Singapore, 138668, Singapore
| | - Yi Qing Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Meiyappan Lakshmanan
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, Centros, Singapore, 138668, Singapore
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Dave Siak-Wei Ow
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, Centros, Singapore, 138668, Singapore
| | - Paul Staniland
- Croda Europe Ltd., Oak Road, Clough Road, Hull, HU6 7PH, UK
| | | | - Ian Savill
- Croda Europe Ltd., Oak Road, Clough Road, Hull, HU6 7PH, UK
| | - Kang Lan Tee
- Department of Chemical & Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK
| | - Tuck Seng Wong
- Department of Chemical & Biological Engineering, University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, S1 3JD, UK.
- Evolutor Ltd, The Innovation Centre, 217 Portobello, Sheffield, S1 4DP, UK.
- National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Phahonyothin Road, Khlong Nueang, Khlong Luang, 12120, Pathum Thani, Thailand.
- School of Pharmacy, Bandung Institute of Technology, 10 Coblong, Bandung, West Java, 40132, Indonesia.
| | - Dong-Yup Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
| |
Collapse
|
3
|
Yu M, Ma D, Eszterhas S, Rollenhagen C, Lee SA. The Early Endocytosis Gene PAL1 Contributes to Stress Tolerance and Hyphal Formation in Candida albicans. J Fungi (Basel) 2023; 9:1097. [PMID: 37998902 PMCID: PMC10672141 DOI: 10.3390/jof9111097] [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: 08/31/2023] [Revised: 11/01/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023] Open
Abstract
The endocytic and secretory pathways of the fungal pathogen Candida albicans are fundamental to various key cellular processes such as cell growth, cell wall integrity, protein secretion, hyphal formation, and pathogenesis. Our previous studies focused on several candidate genes involved in early endocytosis, including ENT2 and END3, that play crucial roles in such processes. However, much remains to be discovered about other endocytosis-related genes and their contributions toward Candida albicans secretion and virulence. In this study, we examined the functions of the early endocytosis gene PAL1 using a reverse genetics approach based on CRISPR-Cas9-mediated gene deletion. Saccharomyces cerevisiae Pal1 is a protein in the early coat complex involved in clathrin-mediated endocytosis that is later internalized with the coat. The C. albicans pal1Δ/Δ null mutant demonstrated increased resistance to the antifungal agent caspofungin and the cell wall stressor Congo Red. In contrast, the null mutant was more sensitive to the antifungal drug fluconazole and low concentrations of SDS than the wild type (WT) and the re-integrant (KI). While pal1Δ/Δ can form hyphae and a biofilm, under some hyphal-inducing conditions, it was less able to demonstrate filamentous growth when compared to the WT and KI. The pal1Δ/Δ null mutant had no defect in clathrin-mediated endocytosis, and there were no changes in virulence-related processes compared to controls. Our results suggest that PAL1 has a role in susceptibility to antifungal agents, cell wall integrity, and membrane stability related to early endocytosis.
Collapse
Affiliation(s)
- Miranda Yu
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH 03755, USA;
- Medicine Service, White River Junction VA Medical Center, Hartford, VT 05009, USA; (D.M.); (S.E.)
| | - Dakota Ma
- Medicine Service, White River Junction VA Medical Center, Hartford, VT 05009, USA; (D.M.); (S.E.)
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Susan Eszterhas
- Medicine Service, White River Junction VA Medical Center, Hartford, VT 05009, USA; (D.M.); (S.E.)
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA;
| | - Christiane Rollenhagen
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA;
| | - Samuel A. Lee
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH 03755, USA;
| |
Collapse
|
4
|
Candida albicans END3 Mediates Endocytosis and Has Subsequent Roles in Cell Wall Integrity, Morphological Switching, and Tissue Invasion. Microbiol Spectr 2022; 10:e0188021. [PMID: 35234488 PMCID: PMC8941917 DOI: 10.1128/spectrum.01880-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of endocytosis in Candida albicans secretion, filamentation, and virulence remains poorly understood, despite its importance as a fundamental component of intracellular trafficking. Given that secretory mutants display defects in endocytosis, we have focused our attention on endocytic mutants to understand the interconnection between endocytosis and other secretory pathways. Using a reverse-genetic approach based upon CRISPR-Cas9 mediated gene deletion, we studied the functions of the gene END3, which plays a key role in clathrin-based endocytosis. In the end3Δ/Δ null mutant, clathrin-mediated endocytosis was substantially reduced. While in vitro growth, cell morphology, and vacuoles appeared normal, the mutant was impaired in actin patch formation, filamentous growth, biofilm formation, cell wall integrity, and extracellular protease secretion. In addition, susceptibility to various antifungal agents was altered. Consistent with the inability to form hyphae, in an in vitro keratinocyte infection model, the null mutant displayed reduced damage of mammalian adhesion zippers and host cell death. Thus, C. albicans END3 has a role in efficient endocytosis that is required for cell wall integrity, protein secretion, hyphal formation, and virulence-related processes. These findings suggest that impaired endocytosis subsequently affects other secretory pathways, providing evidence of the interconnection between these processes. IMPORTANCE Candida albicans is a fungal commensal organism that can cause serious opportunistic infections in immunocompromised patients leading to substantial complications and mortality. A better understanding of the microbe's biology to develop more effective therapeutic and diagnostic tools is required as invasive candidiasis is a problem of continued clinical importance. This study focuses on endocytosis, an important but incompletely understood cellular mechanism needed to uptake nutrients and communicate with a cell's environment. In this study, we have assessed the role of endocytosis in cell wall integrity, biofilm formation, and tissue invasion in C. albicans. These findings will improve our understanding of cellular mechanisms underlying endocytosis and will inform us of the interconnection with other intracellular transport processes.
Collapse
|
5
|
Candida albicans ENT2 Contributes to Efficient Endocytosis, Cell Wall Integrity, Filamentation, and Virulence. mSphere 2021; 6:e0070721. [PMID: 34585966 PMCID: PMC8550084 DOI: 10.1128/msphere.00707-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epsins play a pivotal role in the formation of endocytic vesicles and potentially provide a linkage between endocytic and other trafficking pathways. We identified a Candida albicans epsin, ENT2, that bears homology to the Saccharomyces cerevisiae early endocytosis genes ENT1 and ENT2 and studied its functions by a reverse genetic approach utilizing CRISPR-Cas9-mediated gene deletion. The C. albicans ent2Δ/Δ null mutant displayed cell wall defects and altered antifungal drug sensitivity. To define the role of C. albicans ENT2 in endocytosis, we performed assays with the lipophilic dye FM4-64 that revealed greatly reduced uptake in the ent2Δ/Δ mutant. Next, we showed that the C. albicans ent2Δ/Δ mutant was unable to form hyphae and biofilms. Assays for virulence properties in an in vitro keratinocyte infection model demonstrated reduced damage of mammalian adhesion zippers and host cell death from the ent2Δ/Δ mutant. We conclude that C. albicans ENT2 has a role in efficient endocytosis, a process that is required for maintaining cell wall integrity, hyphal formation, and virulence-defining traits. IMPORTANCE The opportunistic fungal pathogen Candida albicans is an important cause of invasive infections in hospitalized patients and a source of considerable morbidity and mortality. Despite its clinical importance, we still need to improve our ability to diagnose and treat this common pathogen. In order to support these advancements, a greater understanding of the biology of C. albicans is needed. In these studies, we are focused on the fundamental biological process of endocytosis, of which little is directly known in C. albicans. In addition to studying the function of a key gene in this process, we are examining the role of endocytosis in the virulence-related processes of filamentation, biofilm formation, and tissue invasion. These studies will provide greater insight into the role of endocytosis in causing invasive fungal infections.
Collapse
|
6
|
Chow EWL, Pang LM, Wang Y. From Jekyll to Hyde: The Yeast-Hyphal Transition of Candida albicans. Pathogens 2021; 10:pathogens10070859. [PMID: 34358008 PMCID: PMC8308684 DOI: 10.3390/pathogens10070859] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 06/30/2021] [Accepted: 07/05/2021] [Indexed: 12/22/2022] Open
Abstract
Candida albicans is a major fungal pathogen of humans, accounting for 15% of nosocomial infections with an estimated attributable mortality of 47%. C. albicans is usually a benign member of the human microbiome in healthy people. Under constant exposure to highly dynamic environmental cues in diverse host niches, C. albicans has successfully evolved to adapt to both commensal and pathogenic lifestyles. The ability of C. albicans to undergo a reversible morphological transition from yeast to filamentous forms is a well-established virulent trait. Over the past few decades, a significant amount of research has been carried out to understand the underlying regulatory mechanisms, signaling pathways, and transcription factors that govern the C. albicans yeast-to-hyphal transition. This review will summarize our current understanding of well-elucidated signal transduction pathways that activate C. albicans hyphal morphogenesis in response to various environmental cues and the cell cycle machinery involved in the subsequent regulation and maintenance of hyphal morphogenesis.
Collapse
Affiliation(s)
- Eve Wai Ling Chow
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore;
| | - Li Mei Pang
- National Dental Centre Singapore, National Dental Research Institute Singapore (NDRIS), 5 Second Hospital Ave, Singapore 168938, Singapore;
| | - Yue Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore;
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
- Correspondence:
| |
Collapse
|
7
|
Abstract
In the last decades, Candida albicans has served as the leading causal agent of life-threatening invasive infections with mortality rates approaching 40% despite treatment. Candida albicans (C. albicans) exists in three biological phases: yeast, pseudohyphae, and hyphae. Hyphae, which represent an important phase in the disease process, can cause tissue damage by invading mucosal epithelial cells then leading to blood infection. In this review, we summarized recent results from different fields of fungal cell biology that are instrumental in understanding hyphal growth. This includes research on the differences among C. albicans phases; the regulatory mechanism of hyphal growth, extension, and maintaining cutting-edge polarity; cross regulations of hyphal development and the virulence factors that cause serious infection. With a better understanding of the mechanism on mycelium formation, this review provides a theoretical basis for the identification of targets in candidiasis treatment. It also gives some reference to the study of antifungal drugs.
Collapse
Affiliation(s)
- Hui Chen
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Biao Ren
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China
| | - Lei Cheng
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.,Department of Operative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| |
Collapse
|
8
|
Athanasopoulos A, André B, Sophianopoulou V, Gournas C. Fungal plasma membrane domains. FEMS Microbiol Rev 2020; 43:642-673. [PMID: 31504467 DOI: 10.1093/femsre/fuz022] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/25/2019] [Indexed: 12/11/2022] Open
Abstract
The plasma membrane (PM) performs a plethora of physiological processes, the coordination of which requires spatial and temporal organization into specialized domains of different sizes, stability, protein/lipid composition and overall architecture. Compartmentalization of the PM has been particularly well studied in the yeast Saccharomyces cerevisiae, where five non-overlapping domains have been described: The Membrane Compartments containing the arginine permease Can1 (MCC), the H+-ATPase Pma1 (MCP), the TORC2 kinase (MCT), the sterol transporters Ltc3/4 (MCL), and the cell wall stress mechanosensor Wsc1 (MCW). Additional cortical foci at the fungal PM are the sites where clathrin-dependent endocytosis occurs, the sites where the external pH sensing complex PAL/Rim localizes, and sterol-rich domains found in apically grown regions of fungal membranes. In this review, we summarize knowledge from several fungal species regarding the organization of the lateral PM segregation. We discuss the mechanisms of formation of these domains, and the mechanisms of partitioning of proteins there. Finally, we discuss the physiological roles of the best-known membrane compartments, including the regulation of membrane and cell wall homeostasis, apical growth of fungal cells and the newly emerging role of MCCs as starvation-protective membrane domains.
Collapse
Affiliation(s)
- Alexandros Athanasopoulos
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Bruno André
- Molecular Physiology of the Cell laboratory, Université Libre de Bruxelles (ULB), Institut de Biologie et de Médecine Moléculaires, rue des Pr Jeener et Brachet 12, 6041, Gosselies, Belgium
| | - Vicky Sophianopoulou
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Christos Gournas
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| |
Collapse
|
9
|
The Role of Secretory Pathways in Candida albicans Pathogenesis. J Fungi (Basel) 2020; 6:jof6010026. [PMID: 32102426 PMCID: PMC7151058 DOI: 10.3390/jof6010026] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/19/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022] Open
Abstract
Candida albicans is a fungus that is a commensal organism and a member of the normal human microbiota. It has the ability to transition into an opportunistic invasive pathogen. Attributes that support pathogenesis include secretion of virulence-associated proteins, hyphal formation, and biofilm formation. These processes are supported by secretion, as defined in the broad context of membrane trafficking. In this review, we examine the role of secretory pathways in Candida virulence, with a focus on the model opportunistic fungal pathogen, Candida albicans.
Collapse
|
10
|
Abstract
Morphological changes are critical for the virulence of a range of plant and human fungal pathogens.
Candida albicans is a major human fungal pathogen whose ability to switch between different morphological states is associated with its adaptability and pathogenicity. In particular,
C. albicans can switch from an oval yeast form to a filamentous hyphal form, which is characteristic of filamentous fungi. What mechanisms underlie hyphal growth and how are they affected by environmental stimuli from the host or resident microbiota? These questions are the focus of intensive research, as understanding
C. albicans hyphal growth has broad implications for cell biological and medical research.
Collapse
Affiliation(s)
- Robert A Arkowitz
- Université Côte d'Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, Nice, France
| | - Martine Bassilana
- Université Côte d'Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, Nice, France
| |
Collapse
|
11
|
Weiner A, Orange F, Lacas‐Gervais S, Rechav K, Ghugtyal V, Bassilana M, Arkowitz RA. On‐site secretory vesicle delivery drives filamentous growth in the fungal pathogenCandida albicans. Cell Microbiol 2018; 21:e12963. [DOI: 10.1111/cmi.12963] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Allon Weiner
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| | | | | | - Katya Rechav
- Chemical Research SupportWeizmann Institute of Science Rehovot Israel
| | - Vikram Ghugtyal
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| | - Martine Bassilana
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| | - Robert A. Arkowitz
- Université Côte d'AzurCNRS, Inserm, Institute of Biology Valrose Parc Valrose Nice France
| |
Collapse
|
12
|
Bar-Yosef H, Gildor T, Ramírez-Zavala B, Schmauch C, Weissman Z, Pinsky M, Naddaf R, Morschhäuser J, Arkowitz RA, Kornitzer D. A Global Analysis of Kinase Function in Candida albicans Hyphal Morphogenesis Reveals a Role for the Endocytosis Regulator Akl1. Front Cell Infect Microbiol 2018; 8:17. [PMID: 29473018 PMCID: PMC5809406 DOI: 10.3389/fcimb.2018.00017] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/12/2018] [Indexed: 11/22/2022] Open
Abstract
The human pathogenic fungus Candida albicans can switch between yeast and hyphal morphologies as a function of environmental conditions and cellular physiology. The yeast-to-hyphae morphogenetic switch is activated by well-established, kinase-based signal transduction pathways that are induced by extracellular stimuli. In order to identify possible inhibitory pathways of the yeast-to-hyphae transition, we interrogated a collection of C. albicans protein kinases and phosphatases ectopically expressed under the regulation of the TETon promoter. Proportionately more phosphatases than kinases were identified that inhibited hyphal morphogenesis, consistent with the known role of protein phosphorylation in hyphal induction. Among the kinases, we identified AKL1 as a gene that significantly suppressed hyphal morphogenesis in serum. Akl1 specifically affected hyphal elongation rather than initiation: overexpression of AKL1 repressed hyphal growth, and deletion of AKL1 resulted in acceleration of the rate of hyphal elongation. Akl1 suppressed fluid-phase endocytosis, probably via Pan1, a putative clathrin-mediated endocytosis scaffolding protein. In the absence of Akl1, the Pan1 patches were delocalized from the sub-apical region, and fluid-phase endocytosis was intensified. These results underscore the requirement of an active endocytic pathway for hyphal morphogenesis. Furthermore, these results suggest that under standard conditions, endocytosis is rate-limiting for hyphal elongation.
Collapse
Affiliation(s)
- Hagit Bar-Yosef
- B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Tsvia Gildor
- B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | | | - Christian Schmauch
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institute Biology Valrose, Université Côte d'Azur, Nice, France
| | - Ziva Weissman
- B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Mariel Pinsky
- B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Rawi Naddaf
- B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| | - Joachim Morschhäuser
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Würzburg, Germany
| | - Robert A Arkowitz
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institute Biology Valrose, Université Côte d'Azur, Nice, France
| | - Daniel Kornitzer
- B. Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel
| |
Collapse
|
13
|
Qayyum S, Khan I, Bhatti ZA, Peng C. Cloning and characterization of F3PYC gene encoding pyruvate carboxylase in Aspergillus flavus strain (F3). 3 Biotech 2017; 7:245. [PMID: 28710744 DOI: 10.1007/s13205-017-0806-6] [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: 01/31/2017] [Accepted: 04/06/2017] [Indexed: 11/24/2022] Open
Abstract
Pyruvate carboxylase is a major enzyme for biosynthesis of organic acids like; citric acid, fumeric acid, and L-malic acid. These organic acids play very important role for biological remediation of heavy metals. In this study, gene walking method was used to clone and characterize pyruvate carboxylase gene (F3PYC) from heavy metal resistant indigenous fungal isolate Aspergillus flavus (F3). 3579 bp of an open reading frame which encodes 1193 amino acid protein (isoelectric point: 6.10) with a calculated molecular weight of 131.2008 kDa was characterized. Deduced protein showed 90-95% similarity to those deduced from PYC gene from different fungal strains including; Aspergillus parasiticus, Neosartorya fischeri, Aspergillus fumigatus, Aspergillus clavatus, and Aspergillus niger. Protein generated from the PYC gene was a homotetramer (α4) and having four potential N-linked glycosylation sites and had no signal peptide. Amongst most possible N-glycosylation sites were -N-S-S-I- at 36 amino acid, -N-G-T-V- at 237 amino acid, N-G-S-S- at 517 amino acid, and N-T-S-R- at 1111 amino acid, with several functions have been proposed for the carbohydrate moiety such as thermal stability, pH, and temperature optima for activity and stabilization of the three-dimensional structure. Hence, cloning of F3PYC gene from A. flavus has important biotechnological applications.
Collapse
Affiliation(s)
- Sadia Qayyum
- The Key Lab of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Department of Microbiology, Hazara University, Manshera, 21300, Pakistan
| | - Ibrar Khan
- Department of Microbiology, Hazara University, Manshera, 21300, Pakistan
| | - Zulfiqar Ahmad Bhatti
- Environmental Sciences Department, COMSATS Institute of Information Technology, Abbottabad, 22060, Pakistan
| | - Changsheng Peng
- The Key Lab of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| |
Collapse
|
14
|
Bar-Yosef H, Vivanco Gonzalez N, Ben-Aroya S, Kron SJ, Kornitzer D. Chemical inhibitors of Candida albicans hyphal morphogenesis target endocytosis. Sci Rep 2017; 7:5692. [PMID: 28720834 PMCID: PMC5515890 DOI: 10.1038/s41598-017-05741-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/01/2017] [Indexed: 01/12/2023] Open
Abstract
Candida albicans is an opportunistic pathogen, typically found as a benign commensal yeast living on skin and mucosa, but poised to invade injured tissue to cause local infections. In debilitated and immunocompromised individuals, C. albicans may spread to cause life-threatening systemic infections. Upon contact with serum and at body temperature, C. albicans performs a regulated switch to filamentous morphology, characterized by emergence of a germ tube from the yeast cell followed by mold-like growth of branching hyphae. The ability to switch between growth morphologies is an important virulence factor of C. albicans. To identify compounds able to inhibit hyphal morphogenesis, we screened libraries of existing drugs for inhibition of the hyphal switch under stringent conditions. Several compounds that specifically inhibited hyphal morphogenesis were identified. Chemogenomic analysis suggested an interaction with the endocytic pathway, which was confirmed by direct measurement of fluid-phase endocytosis in the presence of these compounds. These results suggest that the activity of the endocytic pathway, which is known to be particularly important for hyphal growth, represents an effective target for hyphae-inhibiting drugs.
Collapse
Affiliation(s)
- Hagit Bar-Yosef
- Department of Molecular Microbiology, B. Rappaport Faculty of Medicine, Technion - I.I.T. and the Rappaport Institute for Research in the Medical Sciences, Haifa, 31096, Israel
| | - Nora Vivanco Gonzalez
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Shay Ben-Aroya
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Stephen J Kron
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, 60637, USA.
| | - Daniel Kornitzer
- Department of Molecular Microbiology, B. Rappaport Faculty of Medicine, Technion - I.I.T. and the Rappaport Institute for Research in the Medical Sciences, Haifa, 31096, Israel.
| |
Collapse
|
15
|
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.
Collapse
|
16
|
Wang XY, Yu HZ, Geng L, Xu JP, Yu D, Zhang SZ, Ma Y, Fei DQ. Comparative Transcriptome Analysis of Bombyx mori (Lepidoptera) Larval Midgut Response to BmNPV in Susceptible and Near-Isogenic Resistant Strains. PLoS One 2016; 11:e0155341. [PMID: 27168061 PMCID: PMC4864234 DOI: 10.1371/journal.pone.0155341] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 04/27/2016] [Indexed: 01/04/2023] Open
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) is one of the primary pathogens causing severe economic losses in sericulture. However, the molecular mechanism of silkworm resistance to BmNPV remains largely unknown. Here, the recurrent parent P50 (susceptible strain) and the near-isogenic line BC9 (resistance strain) were used in a comparative transcriptome study examining the response to infection with BmNPV. A total of 14,300 unigenes were obtained from two different resistant strains; of these, 869 differentially expressed genes (DEGs) were identified after comparing the four transcriptomes. Many DEGs associated with protein metabolism, cytoskeleton, and apoptosis may be involved in the host response to BmNPV infection. Moreover, some immunity related genes were also altered following BmNPV infection. Specifically, after removing genetic background and individual immune stress response genes, 22 genes were found to be potentially involved in repressing BmNPV infection. These genes were related to transport, virus replication, intracellular innate immune, and apoptosis. Our study provided an overview of the molecular mechanism of silkworm resistance to BmNPV infection and laid a foundation for controlling BmNPV in the future.
Collapse
Affiliation(s)
- Xue-Yang Wang
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Hai-Zhong Yu
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Lei Geng
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Jia-Ping Xu
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
- * E-mail:
| | - Dong Yu
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Shang-Zhi Zhang
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Yan Ma
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| | - Dong-Qiong Fei
- School of Life Sciences, Anhui Agricultural University, Hefei, People’s Republic of China
| |
Collapse
|
17
|
Role of Candida albicans Tem1 in mitotic exit and cytokinesis. Fungal Genet Biol 2014; 69:84-95. [PMID: 24973462 DOI: 10.1016/j.fgb.2014.06.007] [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: 02/13/2014] [Revised: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 11/20/2022]
Abstract
Candida albicans demonstrates three main growth morphologies: yeast, pseudohyphal and true hyphal forms. Cell separation is distinct in these morphological forms and the process of separation is closely linked to the completion of mitosis and cytokinesis. In Saccharomyces cerevisiae the small GTPase Tem1 is known to initiate the mitotic exit network, a signalling pathway involved in signalling the end of mitosis and initiating cytokinesis and cell separation. Here we have characterised the role of Tem1 in C. albicans, and demonstrate that it is essential for mitotic exit and cytokinesis, and that this essential function is signalled through the kinase Cdc15. Cells depleted of Tem1 displayed highly polarised growth but ultimately failed to both complete cytokinesis and re-enter the cell cycle following nuclear division. Consistent with its role in activating the mitotic exit network Tem1 localises to spindle pole bodies in a cell cycle-dependent manner. Ultimately, the mitotic exit network in C. albicans appears to co-ordinate the sequential processes of mitotic exit, cytokinesis and cell separation.
Collapse
|
18
|
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.
Collapse
Affiliation(s)
- Gero Steinberg
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
| |
Collapse
|
19
|
Miramón P, Dunker C, Kasper L, Jacobsen ID, Barz D, Kurzai O, Hube B. A family of glutathione peroxidases contributes to oxidative stress resistance in Candida albicans. Med Mycol 2014; 52:223-39. [PMID: 24625675 DOI: 10.1093/mmy/myt021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Candida albicans is a well-adapted human commensal but is also a facultative pathogen that can cause superficial and systemic infections. Its remarkable capacity to thrive within the human host relies on its ability to adapt and respond to the local environment of different niches. C. albicans is able to cope with oxidative stress in a coordinated fashion via upregulation of different protective mechanisms. Here, we unravel the role of a family of glutathione peroxidase (GPx), designated Gpx31, Gpx32, and Gpx33, in oxidative stress resistance. We show that GPx activity in C. albicans is induced upon exposure to peroxides and that this enzymatic activity is required for full resistance to oxidative stress. The GPx activity relies on the presence of GPX31, with no apparent contribution from GPX32 and GPX33 during in vitro short-term (3 h) exposure to peroxides. However, a triple gpx31-33Δ/Δ mutant exhibited a more pronounced sensitivity than a single gpx31Δ/Δ mutant on solid media in the presence of oxidants, suggesting that GPX32 and GPX33 may be involved in long-term adaptation to oxidative stress. Interestingly, reintegration of a single allele of GPX31 was sufficient to restore the wild-type phenotype in both the single and triple mutants. We found that mutants lacking GPX31-33 were more susceptible to killing by phagocytic cells, suggesting that GPxs are required for full resistance to innate immune effector cells. Despite the sensitivity to oxidative stress and phagocytes, these mutants were not affected in their virulence in the chicken embryo model of candidiasis.
Collapse
Affiliation(s)
- Pedro Miramón
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology
| | | | | | | | | | | | | |
Collapse
|
20
|
Caballero-Lima D, Kaneva IN, Watton SP, Sudbery PE, Craven CJ. The spatial distribution of the exocyst and actin cortical patches is sufficient to organize hyphal tip growth. EUKARYOTIC CELL 2013; 12:998-1008. [PMID: 23666623 PMCID: PMC3697460 DOI: 10.1128/ec.00085-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/07/2013] [Indexed: 11/20/2022]
Abstract
In the hyphal tip of Candida albicans we have made detailed quantitative measurements of (i) exocyst components, (ii) Rho1, the regulatory subunit of (1,3)-β-glucan synthase, (iii) Rom2, the specialized guanine-nucleotide exchange factor (GEF) of Rho1, and (iv) actin cortical patches, the sites of endocytosis. We use the resulting data to construct and test a quantitative 3-dimensional model of fungal hyphal growth based on the proposition that vesicles fuse with the hyphal tip at a rate determined by the local density of exocyst components. Enzymes such as (1,3)-β-glucan synthase thus embedded in the plasma membrane continue to synthesize the cell wall until they are removed by endocytosis. The model successfully predicts the shape and dimensions of the hyphae, provided that endocytosis acts to remove cell wall-synthesizing enzymes at the subapical bands of actin patches. Moreover, a key prediction of the model is that the distribution of the synthase is substantially broader than the area occupied by the exocyst. This prediction is borne out by our quantitative measurements. Thus, although the model highlights detailed issues that require further investigation, in general terms the pattern of tip growth of fungal hyphae can be satisfactorily explained by a simple but quantitative model rooted within the known molecular processes of polarized growth. Moreover, the methodology can be readily adapted to model other forms of polarized growth, such as that which occurs in plant pollen tubes.
Collapse
Affiliation(s)
- David Caballero-Lima
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | | | | | | | | |
Collapse
|
21
|
|
22
|
Wang P, Shen G. The endocytic adaptor proteins of pathogenic fungi: charting new and familiar pathways. Med Mycol 2011; 49:449-57. [PMID: 21254965 DOI: 10.3109/13693786.2011.553246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Intracellular transport is an essential biological process that is highly conserved throughout the eukaryotic organisms. In fungi, adaptor proteins implicated in the endocytic cycle of endocytosis and exocytosis were found to be important for growth, differentiation, and/or virulence. For example, Saccharomyces cerevisiae Pan1 is an endocytic protein that regulates membrane trafficking, the actin cytoskeleton, and signaling. In Cryptococcus neoformans, a multi-modular endocytic protein, Cin1, was recently found to have pleiotropic functions in morphogenesis, endocytosis, exocytosis, and virulence. Interestingly, Cin1 is homologous to human intersectin ITSN1, but homologs of Cin1/ITSN1 were not found in ascomycetous S. cerevisiae and Candida albicans, or zygomycetous fungi. Moreover, an Eps15 protein homologous to S. cerevisiae Pan1/Ede1 and additional relevant protein homologs were identified in C. neoformans, suggesting the existence of either a distinct endocytic pathway mediated by Cin1 or pathways by either Cin1 or/and Pan1/Ede1 homologs. Whether and how the Cin1-mediated endocytic pathway represents a unique role in pathogenesis or reflects a redundancy of a transport apparatus remains an open and challenging question. This review discusses recent findings of endocytic adaptor proteins from pathogenic fungi and provides a perspective for novel endocytic machinery operating in C. neoformans. An understanding of intracellular trafficking mechanisms as they relate to pathogenesis will likely reveal the identity of novel antifungal targets.
Collapse
Affiliation(s)
- Ping Wang
- The Research Institute for Children, New Orleans, Louisiana, USA.
| | | |
Collapse
|
23
|
Bernardo SM, Lee SA. Candida albicans SUR7 contributes to secretion, biofilm formation, and macrophage killing. BMC Microbiol 2010; 10:133. [PMID: 20433738 PMCID: PMC2887802 DOI: 10.1186/1471-2180-10-133] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 04/30/2010] [Indexed: 12/13/2022] Open
Abstract
Background Candida albicans SUR7 has been shown to be required for plasma membrane organization and cell wall synthesis, but its role in virulence is not known. Using a bioinformatics strategy, we previously identified several novel putative secretion pathway proteins potentially involved in virulence, including the C. albicans homolog of the Saccharomyces cerevisiae endocytosis-related protein Sur7p. We therefore generated a C. albicans sur7Δ null mutant and examined its contribution to key virulence attributes. Results Structurally, the C. albicans sur7Δ mutant was impaired in response to filamentation-inducing conditions, and formed aberrant hyphae with extensive accumulation of plasma membrane-derived structures within the cell. Absence of SUR7 resulted in a temperature-sensitive growth defect at high temperatures (42°C), which was partially rescued by addition of NaCl. We next examined the role of the SUR7 paralog C. albicans FMP45 in this temperature-sensitive phenotype. Analysis of C. albicans Fmp45p-GFP demonstrated co-localization of Fmp45p with Sur7p and increased fluorescence in the plasma membrane in the presence of high salt. We next focused on key virulence-related phenotypes. The C. albicans sur7Δ null mutant exhibited secretory defects: reduced lipase secretion, and increased levels of secreted Sap2p. The null mutant was hyper-susceptible to sub-inhibitory concentrations of caspofungin, but not amphotericin B and 5-fluorocytosine. Functionally, the sur7Δ mutant demonstrated increased adhesion to polystyrene and of note, was markedly defective in biofilm formation. In an in vitro macrophage model of virulence, the sur7Δ mutant was impaired in macrophage killing. Conclusions Plasma membrane and cell wall organization are important for cell morphology, and alterations of these structures contributed to impairment of several key virulence-associated phenotypes in the C. albicans sur7Δ mutant.
Collapse
Affiliation(s)
- Stella M Bernardo
- Section of Infectious Diseases, New Mexico Veterans Healthcare System, Albuquerque, NM, USA
| | | |
Collapse
|
24
|
Reijnst P, Jorde S, Wendland J. Candida albicans SH3-domain proteins involved in hyphal growth, cytokinesis, and vacuolar morphology. Curr Genet 2010; 56:309-19. [PMID: 20383711 DOI: 10.1007/s00294-010-0301-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/22/2010] [Accepted: 03/29/2010] [Indexed: 12/13/2022]
Abstract
This report describes the analyses of three Candida albicans genes that encode Src Homology 3 (SH3)-domain proteins. Homologs in Saccharomyces cerevisiae are encoded by the SLA1, NBP2, and CYK3 genes. Deletion of CYK3 in C. albicans was not feasible, suggesting it is essential. Promoter shutdown experiments of CaCYK3 revealed cytokinesis defects, which are in line with the localization of GFP-tagged Cyk3 at septal sites. Deletion of SLA1 resulted in strains with decreased ability to form hyphal filaments. The number of cortical actin patches was strongly reduced in Deltasla1 strains during all growth stages. Sla1-GFP localizes in patches that are found concentrated at the hyphal tip. Deletion of the first two SH3-domains of Sla1 still resulted in cortical localization of the truncated protein. However, the actin cytoskeleton in this strain was aberrant like in the Deltasla1 deletion mutant indicating a function of these SH3 domains to recruit actin nucleation to sites of endocytosis. Deletion of NBP2 resulted in a defect in vacuolar fusion in hyphae. Germ cells of Deltanbp2 strains lacked a large vacuole but initiated several germ tubes. The mutant phenotypes of Deltanbp2 and Deltasla1 could be corrected by reintegration of the wild-type genes.
Collapse
Affiliation(s)
- Patrick Reijnst
- Carlsberg Laboratory, Yeast Biology, Valby, Copenhagen, Denmark
| | | | | |
Collapse
|
25
|
Reijnst P, Walther A, Wendland J. Functional analysis of Candida albicans genes encoding SH3-domain-containing proteins. FEMS Yeast Res 2010; 10:452-61. [DOI: 10.1111/j.1567-1364.2010.00624.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
|
26
|
|
27
|
Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|