PKC signaling regulates drug resistance of the fungal pathogen Candida albicans via circuitry comprised of Mkc1, calcineurin, and Hsp90.

LaFayette, Shantelle L

Collins, Cathy

Zaas, Aimee K

Schell, Wiley A

Betancourt-Quiroz, Marisol

Gunatilaka, AA Leslie

Perfect, John R

Cowen, Leah E

Mitchell, Aaron P

United States

2011-06-21T17:32:23Z

2010-08-26

Fungal pathogens exploit diverse mechanisms to survive exposure to antifungal drugs. This poses concern given the limited number of clinically useful antifungals and the growing population of immunocompromised individuals vulnerable to life-threatening fungal infection. To identify molecules that abrogate resistance to the most widely deployed class of antifungals, the azoles, we conducted a screen of 1,280 pharmacologically active compounds. Three out of seven hits that abolished azole resistance of a resistant mutant of the model yeast Saccharomyces cerevisiae and a clinical isolate of the leading human fungal pathogen Candida albicans were inhibitors of protein kinase C (PKC), which regulates cell wall integrity during growth, morphogenesis, and response to cell wall stress. Pharmacological or genetic impairment of Pkc1 conferred hypersensitivity to multiple drugs that target synthesis of the key cell membrane sterol ergosterol, including azoles, allylamines, and morpholines. Pkc1 enabled survival of cell membrane stress at least in part via the mitogen activated protein kinase (MAPK) cascade in both species, though through distinct downstream effectors. Strikingly, inhibition of Pkc1 phenocopied inhibition of the molecular chaperone Hsp90 or its client protein calcineurin. PKC signaling was required for calcineurin activation in response to drug exposure in S. cerevisiae. In contrast, Pkc1 and calcineurin independently regulate drug resistance via a common target in C. albicans. We identified an additional level of regulatory control in the C. albicans circuitry linking PKC signaling, Hsp90, and calcineurin as genetic reduction of Hsp90 led to depletion of the terminal MAPK, Mkc1. Deletion of C. albicans PKC1 rendered fungistatic ergosterol biosynthesis inhibitors fungicidal and attenuated virulence in a murine model of systemic candidiasis. This work establishes a new role for PKC signaling in drug resistance, novel circuitry through which Hsp90 regulates drug resistance, and that targeting stress response signaling provides a promising strategy for treating life-threatening fungal infections.

Version of Record

http://www.ncbi.nlm.nih.gov/pubmed/20865172

1553-7374

https://hdl.handle.net/10161/4605

eng

en_US

Public Library of Science (PLoS)

PLoS Pathog

10.1371/journal.ppat.1001069

Plos Pathogens

Animals

Antifungal Agents

Calcineurin

Candida albicans

Drug Resistance, Fungal

Fungal Proteins

HSP90 Heat-Shock Proteins

Immunoblotting

Mice

Microbial Sensitivity Tests

Mitogen-Activated Protein Kinases

Protein Kinase C

Reverse Transcriptase Polymerase Chain Reaction

Saccharomyces cerevisiae

Signal Transduction

PKC signaling regulates drug resistance of the fungal pathogen Candida albicans via circuitry comprised of Mkc1, calcineurin, and Hsp90.

Journal article

Perfect, John R|0000-0002-6606-9460|0000-0003-3465-5518

2010-8-0

8

6

http://www.ncbi.nlm.nih.gov/pubmed/20865172

e1001069

8

Basic Science Departments

Clinical Science Departments

Duke

Medicine

Medicine, Infectious Diseases

Molecular Genetics and Microbiology

School of Medicine

Published online

6