<i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i>
<i>Cryptococcus neoformans</i> (<i>Cn</i>) is a pathogenic yeast that is the leading cause of fungal meningitis in immunocompromised patients. Various <i>Cn</i> virulence factors, such as the enzyme laccase and its product melanin, phospholipase, and capsular poly...
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MDPI AG
2022-10-01
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| Series: | Pathogens |
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| Online Access: | https://www.mdpi.com/2076-0817/11/11/1239 |
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| author | Emily S. Smith-Peavler Ronakkumar Patel Adejumoke Mary Onumajuru Bethany G. Bowring Joyce L. Miller Jean Michel Brunel Julianne T. Djordjevic Moses M. Prabu Erin E. McClelland |
| author_facet | Emily S. Smith-Peavler Ronakkumar Patel Adejumoke Mary Onumajuru Bethany G. Bowring Joyce L. Miller Jean Michel Brunel Julianne T. Djordjevic Moses M. Prabu Erin E. McClelland |
| author_sort | Emily S. Smith-Peavler |
| collection | DOAJ |
| description | <i>Cryptococcus neoformans</i> (<i>Cn</i>) is a pathogenic yeast that is the leading cause of fungal meningitis in immunocompromised patients. Various <i>Cn</i> virulence factors, such as the enzyme laccase and its product melanin, phospholipase, and capsular polysaccharide have been identified. During a screen of knockout mutants, the gene resistance to aminocholesterol 1 (<i>RTA1</i>) was identified, the function of which is currently unknown in <i>Cn</i>. Rta1 homologs in <i>S. cerevisiae</i> belong to a lipid-translocating exporter family of fungal proteins with transmembrane regions and confer resistance to the antimicrobial agent 7-aminocholesterol when overexpressed. To determine the role of <i>RTA1</i> in <i>Cn</i>, the knock-out (<i>rta1Δ</i>) and reconstituted (<i>rta1Δ+RTA1</i>) strains were created and phenotypically tested. <i>RTA1</i> was involved in resistance to 7-aminocholesterol, and also in exocyst complex component 3 (Sec6)-mediated secretion of urease, laccase, and the major capsule component, glucuronoxylomannan (GXM), which coincided with significantly smaller capsules in the <i>rta1Δ</i> and <i>rta1Δ+RTA1</i> strains compared to the wild-type H99 strain. Furthermore, <i>RTA1</i> expression was reduced in a secretory 14 mutant (<i>sec14Δ</i>) and increased in an RNAi Sec6 mutant. Transmission electron microscopy demonstrated vesicle accumulation inside the <i>rta1Δ</i> strain, predominantly near the cell membrane. Given that Rta1 is likely to be a transmembrane protein located at the plasma membrane, these data suggest that Rta1 may be involved in both secretion of various fungal virulence factors and resistance to 7-aminocholesterol in <i>Cn</i>. |
| first_indexed | 2024-03-09T18:46:20Z |
| format | Article |
| id | doaj.art-c19638ae11774cb8ad855ebd49f17efc |
| institution | Directory Open Access Journal |
| issn | 2076-0817 |
| language | English |
| last_indexed | 2024-03-09T18:46:20Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Pathogens |
| spelling | doaj.art-c19638ae11774cb8ad855ebd49f17efc2023-11-24T06:16:21ZengMDPI AGPathogens2076-08172022-10-011111123910.3390/pathogens11111239<i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i>Emily S. Smith-Peavler0Ronakkumar Patel1Adejumoke Mary Onumajuru2Bethany G. Bowring3Joyce L. Miller4Jean Michel Brunel5Julianne T. Djordjevic6Moses M. Prabu7Erin E. McClelland8Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USAOtsuka Pharmaceutical, 508 Carnegie Center Dr., Princeton, NJ 08540, USADepartment of Biology, Middle Tennessee State University, Murfreesboro, TN 37132, USACentre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW 2145, AustraliaMTSU Interdisciplinary Microanalysis and Imaging Center, Middle Tennessee State University, Murfreesboro, TN 37132, USAUMR_MD1 “Membranes et Cibles Thérapeutiques”, Faculté de Pharmacie, Aix Marseille Universite, INSERM, SSA, MCT, 13385 Marseille, FranceCentre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW 2145, AustraliaM&P Associates, Inc., Murfreesboro, TN 37129, USABiomedical Sciences Division, Marian University College of Osteopathic Medicine, Indianapolis, IN 46234, USA<i>Cryptococcus neoformans</i> (<i>Cn</i>) is a pathogenic yeast that is the leading cause of fungal meningitis in immunocompromised patients. Various <i>Cn</i> virulence factors, such as the enzyme laccase and its product melanin, phospholipase, and capsular polysaccharide have been identified. During a screen of knockout mutants, the gene resistance to aminocholesterol 1 (<i>RTA1</i>) was identified, the function of which is currently unknown in <i>Cn</i>. Rta1 homologs in <i>S. cerevisiae</i> belong to a lipid-translocating exporter family of fungal proteins with transmembrane regions and confer resistance to the antimicrobial agent 7-aminocholesterol when overexpressed. To determine the role of <i>RTA1</i> in <i>Cn</i>, the knock-out (<i>rta1Δ</i>) and reconstituted (<i>rta1Δ+RTA1</i>) strains were created and phenotypically tested. <i>RTA1</i> was involved in resistance to 7-aminocholesterol, and also in exocyst complex component 3 (Sec6)-mediated secretion of urease, laccase, and the major capsule component, glucuronoxylomannan (GXM), which coincided with significantly smaller capsules in the <i>rta1Δ</i> and <i>rta1Δ+RTA1</i> strains compared to the wild-type H99 strain. Furthermore, <i>RTA1</i> expression was reduced in a secretory 14 mutant (<i>sec14Δ</i>) and increased in an RNAi Sec6 mutant. Transmission electron microscopy demonstrated vesicle accumulation inside the <i>rta1Δ</i> strain, predominantly near the cell membrane. Given that Rta1 is likely to be a transmembrane protein located at the plasma membrane, these data suggest that Rta1 may be involved in both secretion of various fungal virulence factors and resistance to 7-aminocholesterol in <i>Cn</i>.https://www.mdpi.com/2076-0817/11/11/1239<i>Cryptococcus neoformans</i><i>RTA1</i>secretionextracellular vesicles |
| spellingShingle | Emily S. Smith-Peavler Ronakkumar Patel Adejumoke Mary Onumajuru Bethany G. Bowring Joyce L. Miller Jean Michel Brunel Julianne T. Djordjevic Moses M. Prabu Erin E. McClelland <i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i> Pathogens <i>Cryptococcus neoformans</i> <i>RTA1</i> secretion extracellular vesicles |
| title | <i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i> |
| title_full | <i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i> |
| title_fullStr | <i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i> |
| title_full_unstemmed | <i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i> |
| title_short | <i>RTA1</i> Is Involved in Resistance to 7-Aminocholesterol and Secretion of Fungal Proteins in <i>Cryptococcus neoformans</i> |
| title_sort | i rta1 i is involved in resistance to 7 aminocholesterol and secretion of fungal proteins in i cryptococcus neoformans i |
| topic | <i>Cryptococcus neoformans</i> <i>RTA1</i> secretion extracellular vesicles |
| url | https://www.mdpi.com/2076-0817/11/11/1239 |
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