ABC transporters are found in all known organisms. Overexpression of ABC multidrug transporters is a major cause of clinical resistance to antibiotics, antifungal and antitumor agents. We use the yeast Pdr5 multidrug efflux pump as a model to study an important subfamily of efflux pumps found only in fungi including the highly pathogenic Candida and Cryptocoocus species. In particular we are interested in learning how these complex, polytopic proteins hydrolyze ATP in the nucleotide-binding domains and then use the resulting chemical energy to transport drugs from the transmembrane domains located a good distance away. We used a combination of suppressor genetics, site-directed mutagenesis, and biochemical assays to begin to identify a transmission signal pathway of amino acid residues and will continue that work as described in this proposal to determine whether the pathway we identify by functional studies is similar to the one proposed by purely structural studies of more conventional transporters. If this is the case, such a result would suggest that this interface is conserved among even evolutionary distant drug transporters. Such an observation might lead to the design of agents that reduce pump activity during treatment.

Public Health Relevance

Broad spectrum drug resistance is a persistent problem in the treatment of infections with antibacterial and antifungal agents as well as the management of malignant tumors. The resistance is often due to genetic changes in protein detoxifying pumps known as ABC transporters which are found in all organisms. We use the yeast multidrug transporter Pdr5 to study the biochemical mechanism behind drug efflux. Pdr5 is the founding member of a subfamily of multidrug transporters that are responsible for the drug resistance of many pathogenic fungi that infect and kill immune compromised patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
2R15GM077211-03
Application #
8609939
Study Section
Biochemistry and Biophysics of Membranes Study Section (BBM)
Program Officer
Chin, Jean
Project Start
2006-04-01
Project End
2017-01-31
Budget Start
2014-02-01
Budget End
2017-01-31
Support Year
3
Fiscal Year
2014
Total Cost
$289,754
Indirect Cost
$61,754
Name
Catholic University of America
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
041962788
City
Washington
State
DC
Country
United States
Zip Code
20064
Ananthaswamy, Neeti; Rutledge, Robert; Sauna, Zuben E et al. (2010) The signaling interface of the yeast multidrug transporter Pdr5 adopts a cis conformation, and there are functional overlap and equivalence of the deviant and canonical Q-loop residues. Biochemistry 49:4440-9
Golin, John; Ambudkar, Suresh V; May, Leopold (2007) The yeast Pdr5p multidrug transporter: how does it recognize so many substrates? Biochem Biophys Res Commun 356:1-5