Azole resistance in a <i>Candida albicans</i> mutant lacking the ABC transporter <i>CDR6/ROA1</i> depends on TOR signaling.
Details
Serval ID
serval:BIB_383820A83AF7
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Azole resistance in a <i>Candida albicans</i> mutant lacking the ABC transporter <i>CDR6/ROA1</i> depends on TOR signaling.
Journal
The Journal of biological chemistry
ISSN
1083-351X (Electronic)
ISSN-L
0021-9258
Publication state
Published
Issued date
12/01/2018
Peer-reviewed
Oui
Volume
293
Number
2
Pages
412-432
Language
english
Notes
Publication types: Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Publication Status: ppublish
Abstract
ATP-binding cassette (ABC) transporters help export various substrates across the cell membrane and significantly contribute to drug resistance. However, a recent study reported an unusual case in which the loss of an ABC transporter in <i>Candida albicans</i> , orf19.4531 (previously named ROA1), increases resistance against antifungal azoles, which was attributed to an altered membrane potential in the mutant strain. To obtain further mechanistic insights into this phenomenon, here we confirmed that the plasma membrane-localized transporter (renamed <i>CDR6/ROA1</i> for consistency with <i>C. albicans</i> nomenclature) could efflux xenobiotics such as berberine, rhodamine 123, and paraquat. Moreover, a <i>CDR6/ROA1</i> null mutant, NKKY101, displayed increased susceptibility to these xenobiotics. Interestingly, fluorescence recovery after photobleaching (FRAP) results indicated that NKKY101 mutant cells exhibited increased plasma membrane rigidity, resulting in reduced azole accumulation and contributing to azole resistance. Transcriptional profiling revealed that ribosome biogenesis genes were significantly up-regulated in the NKKY101 mutant. As ribosome biogenesis is a well-known downstream phenomenon of target of rapamycin (TOR1) signaling, we suspected a link between ribosome biogenesis and TOR1 signaling in NKKY101. Therefore, we grew NKKY101 cells on rapamycin and observed TOR1 hyperactivation, which leads to Hsp90-dependent calcineurin stabilization and thereby increased azole resistance. This <i>in vitro</i> finding was supported by <i>in vivo</i> data from a mouse model of systemic infection in which NKKY101 cells led to higher fungal load after fluconazole challenge than wild-type cells. Taken together, our study uncovers a mechanism of azole resistance in <i>C. albicans</i> , involving increased membrane rigidity and TOR signaling.
Keywords
ATP-Binding Cassette Transporters/genetics, ATP-Binding Cassette Transporters/metabolism, Antifungal Agents/pharmacology, Azoles/pharmacology, Biological Transport/drug effects, Biological Transport/genetics, Candida albicans/drug effects, Candida albicans/genetics, Candida albicans/metabolism, Drug Resistance, Fungal/drug effects, Drug Resistance, Fungal/genetics, Fluconazole/pharmacology, Fluorescence Recovery After Photobleaching, Fungal Proteins/genetics, Fungal Proteins/metabolism, Membrane Transport Proteins/genetics, Membrane Transport Proteins/metabolism, Microbial Sensitivity Tests, TOR Serine-Threonine Kinases/genetics, TOR Serine-Threonine Kinases/metabolism, ABC transporter, Azole resistance, CDR6, TOR signaling, mTOR complex (mTORC), membrane transport, multidrug transporter, yeast
Pubmed
Web of science
Create date
23/11/2017 19:08
Last modification date
20/08/2019 13:27