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Desmarini D, Liu G, Jessen H, Bowring B, Connolly A, Crossett B, Djordjevic JT. Arg1 from Cryptococcus neoformans lacks PI3 kinase activity and conveys virulence roles via its IP 3-4 kinase activity. mBio 2024; 15:e0060824. [PMID: 38742909 DOI: 10.1128/mbio.00608-24] [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: 02/26/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024] Open
Abstract
Inositol tris/tetrakis phosphate kinases (IP3-4K) in the human fungal priority pathogens, Cryptococcus neoformans (CnArg1) and Candida albicans (CaIpk2), convey numerous virulence functions, yet it is not known whether the IP3-4K catalytic activity or a scaffolding role is responsible. We therefore generated a C. neoformans strain with a non-functional kinase, referred to as the dead-kinase (dk) CnArg1 strain (dkArg1). We verified that, although dkARG1 cDNA cloned from this strain produced a protein with the expected molecular weight, dkArg1 was catalytically inactive with no IP3-4K activity. Using recombinant CnArg1 and CaIpk2, we confirmed that, unlike the IP3-4K homologs in humans and Saccharomyces cerevisiae, CnArg1 and CaIpk2 do not phosphorylate the lipid-based substrate, phosphatidylinositol 4,5-bisphosphate, and therefore do not function as class I PI3Ks. Inositol polyphosphate profiling using capillary electrophoresis-electrospray ionization-mass spectrometry revealed that IP3 conversion is blocked in the dkArg1 and ARG1 deletion (Cnarg1Δ) strains and that 1-IP7 and a recently discovered isomer (4/6-IP7) are made by wild-type C. neoformans. Importantly, the dkArg1 and Cnarg1Δ strains had similar virulence defects, including suppressed growth at 37°C, melanization, capsule production, and phosphate starvation response, and were avirulent in an insect model, confirming that virulence is dependent on IP3-4K catalytic activity. Our data also implicate the dkArg1 scaffold in transcriptional regulation of arginine metabolism but via a different mechanism to S. cerevisiae since CnArg1 is dispensable for growth on different nitrogen sources. IP3-4K catalytic activity therefore plays a dominant role in fungal virulence, and IPK pathway function has diverged in fungal pathogens.IMPORTANCEThe World Health Organization has emphasized the urgent need for global action in tackling the high morbidity and mortality rates stemming from invasive fungal infections, which are exacerbated by the limited variety and compromised effectiveness of available drug classes. Fungal IP3-4K is a promising target for new therapy, as it is critical for promoting virulence of the human fungal priority pathogens, Cryptococcus neoformans and Candida albicans, and impacts numerous functions, including cell wall integrity. This contrasts to current therapies, which only target a single function. IP3-4K enzymes exert their effect through their inositol polyphosphate products or via the protein scaffold. Here, we confirm that the IP3-4K catalytic activity of CnArg1 promotes all virulence traits in C. neoformans that are attenuated by ARG1 deletion, reinforcing our ongoing efforts to find inositol polyphosphate effector proteins and to create inhibitors targeting the IP3-4K catalytic site, as a new antifungal drug class.
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Affiliation(s)
- Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, Australia
- Faculty of Medicine and Health, Sydney Institute for Infectious Diseases, University of Sydney, Sydney, Australia
| | - Guizhen Liu
- Institute of Organic Chemistry, University of Freiburg, Freiburg im Breisgau, Germany
- Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Henning Jessen
- Institute of Organic Chemistry, University of Freiburg, Freiburg im Breisgau, Germany
- Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Bethany Bowring
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, Australia
- Faculty of Medicine and Health, Sydney Institute for Infectious Diseases, University of Sydney, Sydney, Australia
| | - Angela Connolly
- Sydney Mass Spectrometry, University of Sydney, Sydney, Australia
| | - Ben Crossett
- Sydney Mass Spectrometry, University of Sydney, Sydney, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, Australia
- Faculty of Medicine and Health, Sydney Institute for Infectious Diseases, University of Sydney, Sydney, Australia
- Westmead Hospital, Western Sydney Local Health District, Sydney, Australia
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TNP Analogues Inhibit the Virulence Promoting IP3-4 Kinase Arg1 in the Fungal Pathogen Cryptococcus neoformans. Biomolecules 2022; 12:biom12101526. [PMID: 36291735 PMCID: PMC9599641 DOI: 10.3390/biom12101526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/29/2022] Open
Abstract
New antifungals with unique modes of action are urgently needed to treat the increasing global burden of invasive fungal infections. The fungal inositol polyphosphate kinase (IPK) pathway, comprised of IPKs that convert IP3 to IP8, provides a promising new target due to its impact on multiple, critical cellular functions and, unlike in mammalian cells, its lack of redundancy. Nearly all IPKs in the fungal pathway are essential for virulence, with IP3-4 kinase (IP3-4K) the most critical. The dibenzylaminopurine compound, N2-(m-trifluorobenzylamino)-N6-(p-nitrobenzylamino)purine (TNP), is a commercially available inhibitor of mammalian IPKs. The ability of TNP to be adapted as an inhibitor of fungal IP3-4K has not been investigated. We purified IP3-4K from the human pathogens, Cryptococcus neoformans and Candida albicans, and optimised enzyme and surface plasmon resonance (SPR) assays to determine the half inhibitory concentration (IC50) and binding affinity (KD), respectively, of TNP and 38 analogues. A novel chemical route was developed to efficiently prepare TNP analogues. TNP and its analogues demonstrated inhibition of recombinant IP3-4K from C. neoformans (CnArg1) at low µM IC50s, but not IP3-4K from C. albicans (CaIpk2) and many analogues exhibited selectivity for CnArg1 over the human equivalent, HsIPMK. Our results provide a foundation for improving potency and selectivity of the TNP series for fungal IP3-4K.
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Squizani ED, Reuwsaat JC, Motta H, Tavanti A, Kmetzsch L. Calcium: a central player in Cryptococcus biology. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lev S, Bowring B, Desmarini D, Djordjevic JT. Inositol polyphosphate-protein interactions: Implications for microbial pathogenicity. Cell Microbiol 2021; 23:e13325. [PMID: 33721399 PMCID: PMC9286782 DOI: 10.1111/cmi.13325] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/03/2021] [Accepted: 03/07/2021] [Indexed: 11/29/2022]
Abstract
Inositol polyphosphates (IPs) and inositol pyrophosphates (PP-IPs) regulate diverse cellular processes in eukaryotic cells. IPs and PP-IPs are highly negatively charged and exert their biological effects by interacting with specific protein targets. Studies performed predominantly in mammalian cells and model yeasts have shown that IPs and PP-IPs modulate target function through allosteric regulation, by promoting intra- and intermolecular stabilization and, in the case of PP-IPs, by donating a phosphate from their pyrophosphate (PP) group to the target protein. Technological advances in genetics have extended studies of IP function to microbial pathogens and demonstrated that disrupting PP-IP biosynthesis and PP-IP-protein interaction has a profound impact on pathogenicity. This review summarises the complexity of IP-mediated regulation in eukaryotes, including microbial pathogens. It also highlights examples of poor conservation of IP-protein interaction outcome despite the presence of conserved IP-binding domains in eukaryotic proteomes.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Bethany Bowring
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
| | - Julianne Teresa Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, New South Wales, Australia.,Sydney Medical School-Westmead, University of Sydney, Sydney, New South Wales, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, New South Wales, Australia
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Abstract
In the human-pathogenic fungus Cryptococcus neoformans, the inositol polyphosphate signaling pathway is critical for virulence. We recently demonstrated the key role of the inositol pyrophosphate IP7 (isomer 5-PP-IP5) in driving fungal virulence; however, the mechanism of action remains elusive. Using genetic and biochemical approaches, and mouse infection models, we show that IP7 synthesized by Kcs1 regulates fungal virulence by binding to a conserved lysine surface cluster in the SPX domain of Pho81. Pho81 is the cyclin-dependent kinase (CDK) inhibitor of the phosphate signaling (PHO) pathway. We also provide novel mechanistic insight into the role of IP7 in PHO pathway regulation by demonstrating that IP7 functions as an intermolecular "glue" to stabilize Pho81 association with Pho85/Pho80 and, hence, promote PHO pathway activation and phosphate acquisition. Blocking IP7-Pho81 interaction using site-directed mutagenesis led to a dramatic loss of fungal virulence in a mouse infection model, and the effect was similar to that observed following PHO81 gene deletion, highlighting the key importance of Pho81 in fungal virulence. Furthermore, our findings provide additional evidence of evolutionary divergence in PHO pathway regulation in fungi by demonstrating that IP7 isomers have evolved different roles in PHO pathway control in C. neoformans and nonpathogenic yeast.IMPORTANCE Invasive fungal diseases pose a serious threat to human health globally with >1.5 million deaths occurring annually, 180,000 of which are attributable to the AIDS-related pathogen, Cryptococcus neoformans Here, we demonstrate that interaction of the inositol pyrophosphate, IP7, with the CDK inhibitor protein, Pho81, is instrumental in promoting fungal virulence. IP7-Pho81 interaction stabilizes Pho81 association with other CDK complex components to promote PHO pathway activation and phosphate acquisition. Our data demonstrating that blocking IP7-Pho81 interaction or preventing Pho81 production leads to a dramatic loss in fungal virulence, coupled with Pho81 having no homologue in humans, highlights Pho81 function as a potential target for the development of urgently needed antifungal drugs.
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Zhu H, Zhu N, Peng L, Zhang B, Yu Q, Li M. The inositol polyphosphate kinase Ipk1 transcriptionally regulates mitochondrial functions in Candida albicans. FEMS Yeast Res 2020; 20:5896454. [DOI: 10.1093/femsyr/foaa050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/21/2020] [Indexed: 12/22/2022] Open
Abstract
ABSTRACT
Inositol polyphosphates (IPs) is an important family of signaling molecules that regulate multiple cellular processes, such as chromatin remodeling, transcription and mRNA export. Inositol polyphosphate kinases, as the critical enzymes for production and transformation of IPs, directly determine the intracellular levels of IPs and therefore are involved in many cellular processes. However, its roles in Candida albicans, the leading fungal pathogen in human beings, remain to be investigated. In this study, we identified the inositol polyphosphate kinase Ipk1 in C. albicans and found that it localizes in the nucleus. Moreover, in the ipk1Δ/Δ mutant, the activity of mitochondrial respiratory chain complexes and the mitochondrial function was severely impaired, which were associated with down-regulation of mitochondrial function-related genes revealed by transcription profiling analysis. The ipk1Δ/Δ mutant also displayed hypersensitivity to a series of environmental stresses, such as antifungal drugs, oxidants, cell wall perturbing agents and macrophage attacks, followed by attenuation of virulence in a mouse systematic infection model. These findings firstly reported the importance of inositol polyphosphate kinase Ipk1 in C. albicans, especially its role in mitochondrial function maintenance and pathogenicity.
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Affiliation(s)
- Hangqi Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, No. 94, Weijin Road, Tianjin 300071, P. R. China
| | - Nali Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, No. 94, Weijin Road, Tianjin 300071, P. R. China
| | - Liping Peng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, No. 94, Weijin Road, Tianjin 300071, P. R. China
| | - Bing Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, No. 94, Weijin Road, Tianjin 300071, P. R. China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, No. 94, Weijin Road, Tianjin 300071, P. R. China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Science, Nankai University, No. 94, Weijin Road, Tianjin 300071, P. R. China
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Wang J, Liu Y, Zhao G, Gao J, Liu J, Wu X, Xu C, Li Y. Integrated proteomic and metabolomic analysis to study the effects of spaceflight on Candida albicans. BMC Genomics 2020; 21:57. [PMID: 31952470 PMCID: PMC6969454 DOI: 10.1186/s12864-020-6476-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/09/2020] [Indexed: 11/23/2022] Open
Abstract
Background Candida albicans is an opportunistic pathogenic yeast, which could become pathogenic in various stressful environmental factors including the spaceflight environment. In this study, we aim to explore the phenotypic changes and possible mechanisms of C. albicans after exposure to spaceflight conditions. Results The effect of C. albicans after carried on the “SJ-10” satellite for 12 days was evaluated by proliferation, morphology, environmental resistance and virulence experiment. The result showed that the proliferation rate, biofilm formation, antioxidant capacity, cytotoxicity and filamentous morphology of C. albicans were increased in the spaceflight group compared to the control group. Proteomics and metabolomics technologies were used to analyze the profiles of proteins and metabolites in C. albicans under spaceflight conditions. Proteomic analysis identified 548 up-regulated proteins involved in the ribosome, DNA replication, base excision repair and sulfur metabolism in the spaceflight group. Moreover, 332 down-regulated proteins related to metabolic processes were observed. The metabolomic analysis found five differentially expressed metabolites. The combined analysis of proteomic and metabolomic revealed the accumulation of cysteine and methionine in C. albicans after spaceflight. Conclusions Mechanisms that could explain the results in the phenotypic experiment of C. albicans were found through proteomic and metabolomic analysis. And our data provide an important basis for the assessment of the risk that C. albicans could cause under spaceflight environment.
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Affiliation(s)
- Jiaping Wang
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Yu Liu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Guangxian Zhao
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Jianyi Gao
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Junlian Liu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xiaorui Wu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Chong Xu
- China Astronaut Research and Training Center, Beijing, 100094, China
| | - Yongzhi Li
- China Astronaut Research and Training Center, Beijing, 100094, China.
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Lev S, Li C, Desmarini D, Sorrell TC, Saiardi A, Djordjevic JT. Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities. Front Cell Infect Microbiol 2019; 9:248. [PMID: 31380293 PMCID: PMC6660261 DOI: 10.3389/fcimb.2019.00248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Cecilia Li
- Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology-Public Health, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
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Hameed S, Hans S, Singh S, Fatima Z. Harnessing Metal Homeostasis Offers Novel and Promising Targets Against Candida albicans. Curr Drug Discov Technol 2019; 17:415-429. [PMID: 30827249 DOI: 10.2174/1570163816666190227231437] [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: 08/03/2018] [Revised: 01/08/2019] [Accepted: 01/30/2019] [Indexed: 11/22/2022]
Abstract
Fungal infections, particularly of Candida species, which are the commensal organisms of human, are one of the major debilitating diseases in immunocompromised patients. The limited number of antifungal drugs available to treat Candida infections, with the concomitant increasing incidence of multidrug-resistant (MDR) strains, further worsens the therapeutic options. Thus, there is an urgent need for the better understanding of MDR mechanisms, and their reversal, by employing new strategies to increase the efficacy and safety profiles of currently used therapies against the most prevalent human fungal pathogen, Candida albicans. Micronutrient availability during C. albicans infection is regarded as a critical factor that influences the progression and magnitude of the disease. Intracellular pathogens colonize a variety of anatomical locations that are likely to be scarce in micronutrients, as a defense strategy adopted by the host, known as nutritional immunity. Indispensable critical micronutrients are required both by the host and by C. albicans, especially as a cofactor in important metabolic functions. Since these micronutrients are not freely available, C. albicans need to exploit host reservoirs to adapt within the host for survival. The ability of pathogenic organisms, including C. albicans, to sense and adapt to limited micronutrients in the hostile environment is essential for survival and confers the basis of its success as a pathogen. This review describes that micronutrients availability to C. albicans is a key attribute that may be exploited when one considers designing strategies aimed at disrupting MDR in this pathogenic fungi. Here, we discuss recent advances that have been made in our understanding of fungal micronutrient acquisition and explore the probable pathways that may be utilized as targets.
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Affiliation(s)
- Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
| | - Sandeep Hans
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
| | - Shweta Singh
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
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Effects of Disruption of PMC1 in the tfp1∆/∆ Mutant on Calcium Homeostasis, Oxidative and Osmotic Stress Resistance in Candida albicans. Mycopathologia 2017; 183:315-327. [PMID: 29086141 DOI: 10.1007/s11046-017-0216-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/17/2017] [Indexed: 10/18/2022]
Abstract
The vacuolar-type H+-ATPase (V-ATPase) is essential for many cell processes. Our previous study has demonstrated that Tfp1 is a putative subunit of V-ATPase, loss of which causes disorders in calcium homeostasis and decreased resistance to oxidative stress. In this study, we found that further deletion of PMC1, a vacuolar calcium pump, in tfp1∆/∆ mutant led to more severe dysregulation of calcium homeostasis. Besides, the tfp1∆/∆pmc1∆/∆ mutant was more sensitive to H2O2 and had a higher ROS level. As is known, V-ATPase mutants are sensitive to NaCl, and PMC1 mutant is resistant against NaCl. However, the tfp1∆/∆pmc1∆/∆ mutant exhibited sensitivity to NaCl. Mechanism study demonstrated that their sensitivity was associated with reduced osmotic resistance caused by relatively low expression of GPD1. In addition, we first found that NaCl addition significantly declined ROS levels in tfp1∆/∆ and tfp1∆/∆pmc1∆/∆ mutants. In tfp1∆/∆ mutant, decreased ROS levels were relevant to enhanced antioxidant activities. However, in tfp1∆/∆pmc1∆/∆ mutant, reduced ROS resulted from decreased total calcium content, revealing that NaCl affected ROS levels in the two mutants through different mechanisms. Taken together, our data indicated that loss of both TFP1 and PMC1 further affected calcium homeostasis and other cellular processes in Candida albicans and provides a potential antifungal target.
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