Hsp90 is an essential eukaryotic chaperone that helps to produce and maintain the active state of a select set of substrates or clients that are disproportionately linked to signaling processes including many that promote cancer and the emergence of drug resistance in fungi. For these reasons, inhibitor strategies to manipulate the Hsp90 chaperone system promise many potential therapeutic benefits. Inhibitors targeting the ATPase site of Hsp90 effectively limit the emergence of drug resistance in fungi and show promise as anti-cancer agents. However, ATPase inhibitors block all known functions of Hsp90, leading to undesirable side effects. In this proposal, we will determine how thousands of specific perturbations to the Hsp90 chaperone system impact the emergence of drug resistance in fungi and the maturation of three specific clients in order to systematically identify regions of Hsp90 o co-chaperones that could be targeted for the development of client selective inhibitors. To accomplish these goals, we will use the EMPIRIC approach that we developed to determine the effects of all possible point mutations in Hsp90 on yeast growth in the presence and absence of an anti-fungal drug and in combination with knockouts and/or hypomorphic alleles of co-chaperones. We will augment these fitness studies that integrate over the effects of Hsp90 mutants on the function of many clients with analyses of specific clients using yeast reporter strategies. These analyses of environmental and genetic epistasis will provide important mechanistic insights into the network properties of the Hsp90 chaperone system that underlies signaling processes in eukaryotes. In addition, our studies will delineate client and co-chaperone binding sites as well as allosteric sites on Hsp90 that are critical for the maturation o specific clients and for the emergence of drug resistance in fungi.

Public Health Relevance

Drug resistance of fungal infections is an increasing challenge to human health. In order to combat drug resistance it is important to understand resistance mechanism. In fungal infections, the emergence of drug resistance is often critically dependent on the Hsp90 chaperone system that is composed of Hsp90 and multiple co-chaperones. In this proposal we will determine how interactions between Hsp90, co-chaperones, and substrates that are critical for drug resistance function as a cohesive network to enable drug resistance in fungi. We anticipate that this research will reveal new strategies to combat drug resistance in fungi.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM112844-03
Application #
9205518
Study Section
Genomics, Computational Biology and Technology Study Section (GCAT)
Program Officer
Krasnewich, Donna M
Project Start
2015-02-01
Project End
2019-01-31
Budget Start
2017-02-01
Budget End
2018-01-31
Support Year
3
Fiscal Year
2017
Total Cost
$290,194
Indirect Cost
$116,943
Name
University of Massachusetts Medical School Worcester
Department
Biochemistry
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code
01655
Mishra, Parul; Flynn, Julia M; Starr, Tyler N et al. (2016) Systematic Mutant Analyses Elucidate General and Client-Specific Aspects of Hsp90 Function. Cell Rep 15:588-98
Mavor, David; Barlow, Kyle; Thompson, Samuel et al. (2016) Determination of ubiquitin fitness landscapes under different chemical stresses in a classroom setting. Elife 5:
Flynn, Julia M; Mishra, Parul; Bolon, Daniel N A (2015) Mechanistic Asymmetry in Hsp90 Dimers. J Mol Biol 427:2904-11