This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The abundant molecular chaperone Hsp90 is critical for the folding and regulation of a specific set of diverse client proteins involved in cell division and differentiation. In the last few years Hsp90 has emerged as a viable anti-cancer drug target since many oncogenic proteins require Hsp90 for function. As proof of concept, Hsp90 inhibitors slow tumor growth and are currently in Phase II clinical trials. In addition to playing a critical role in the growth of certain tumors, Hsp90 is also required for the development of drug-resistant pathogenic yeast infections caused by Candida albicans, since Hsp90 inhibitors slowed or prevented drug resistance. Thus it seems likely that Hsp90 is required for the function of key proteins involved in C. albicans pathogenicity and the adaptation to drug treatment. The overall goals of this proposal are to determine how Hsp90 function differs depending on the life stage of C. albicans. The driving hypothesis is that during the switch to the pathogenic growth phase or during development of drug resistance, activities of Hsp90 will be focused on client proteins essential for these specialized functions.
Specific Aim 1. Characterize the cellular events that lead to cleavage of Candida albicans Hsp90. Patients that survive systemic infections of C. albicans have circulating antibodies against a fragment of Hsp90. Additional studies indicate that antibodies against C. ablicans Hsp90 are protective in treating candidiasis. Another laboratory established that when expressed in S. cerevisiae, C. albicans undergoes cleavage to generate the immunogenic fragments. We will use a genetic approach in yeast to identify conditions that alter production of the immunogenic fragments with the goal of making directed mutations in C. ablicans to determine the effect of altered proteolytic cleavage on infection and immunogenicity in mouse models.
Specific Aim 2. Characterize the interaction of Hsp90 with Hbt1, a protein required for polarized morphogenesis in Saccharomyces cerevisiae. During the hyphal transition, C. albicans undergoes polarized morphogeneis and reorganization of the cell wall. We identified an interaction between Hbt1 and Hsp90 containing mutations that cause slow, temperature sensitive growth accompanied by altered morphology. Our hypothesis is that Hsp90 interacts with Hbt1 in cells under limiting growth conditions or in cells undergoing morphological changes. These studies will provide novel information about the functions of Hsp90 and Hbt1 in cellular signaling pathways.
Specific Aim 3. Understanding the similarities and differences in how Hsp90 interacts with diverse client proteins. In conjunction with co-chaperone proteins, Hsp90 interacts with hundreds of diverse proteins. We will determine whether the activity of diverse Hsp90 client proteins is similarly affected by mutations in Hsp90 and co-chaperones.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Exploratory Grants (P20)
Project #
5P20RR015587-10
Application #
7959725
Study Section
Special Emphasis Panel (ZRR1-RI-8 (01))
Project Start
2009-06-01
Project End
2010-05-31
Budget Start
2009-06-01
Budget End
2010-05-31
Support Year
10
Fiscal Year
2009
Total Cost
$145,703
Indirect Cost
Name
University of Idaho
Department
Microbiology/Immun/Virology
Type
Schools of Earth Sciences/Natur
DUNS #
075746271
City
Moscow
State
ID
Country
United States
Zip Code
83844
Kuan, Man I; O'Dowd, John M; Fortunato, Elizabeth A (2016) The absence of p53 during Human Cytomegalovirus infection leads to decreased UL53 expression, disrupting UL50 localization to the inner nuclear membrane, and thereby inhibiting capsid nuclear egress. Virology 497:262-278
Zavala, Anamaria G; O'Dowd, John M; Fortunato, Elizabeth A (2016) Infection of a Single Cell Line with Distinct Strains of Human Cytomegalovirus Can Result in Large Variations in Virion Production and Facilitate Efficient Screening of Virus Protein Function. J Virol 90:2523-35
Kuan, Man I; O'Dowd, John M; Chughtai, Kamila et al. (2016) Human Cytomegalovirus nuclear egress and secondary envelopment are negatively affected in the absence of cellular p53. Virology 497:279-293
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Kashyap, Bhavani; Pegorsch, Laurel; Frey, Ruth A et al. (2014) Eye-specific gene expression following embryonic ethanol exposure in zebrafish: roles for heat shock factor 1. Reprod Toxicol 43:111-24
Kulkarni, Amit S; Fortunato, Elizabeth A (2014) Modulation of homology-directed repair in T98G glioblastoma cells due to interactions between wildtype p53, Rad51 and HCMV IE1-72. Viruses 6:968-85
Duan, Ying-Liang; Ye, Han-Qing; Zavala, Anamaria G et al. (2014) Maintenance of large numbers of virus genomes in human cytomegalovirus-infected T98G glioblastoma cells. J Virol 88:3861-73

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