Despite great advances in AIDS diagnosis and treatment, the continuing devastation of the AIDS epidemic demands continuing efforts to understand all aspects of HIV replication, and to develop new methods for its inhibition. In pursuit of these goals, we have sought to define the activities of the HIV-1 structural (Gag) proteins so as to design antivirals that interfere with these functions. The Gag proteins are attractive targets since they perform multiple roles during the life cycle. The proteins initially are synthesized as N-terminally myristylated precursor (PrGag) proteins that employ their N-terminal matrix (MA) domains to target delivery to plasma membrane (PM) virus assembly sites. Evidence indicates that MA preferentially binds to the signaling phospholipid phosphatidylinositol 4,5 bisphosphate (PI[4,5]P2), and that HIV-1 virus membranes are enriched for lipid raft constituents such as cholesterol, sphingomyelin, and ceramide. MA also has been shown to mediate the incorporation of the HIV-1 envelope (Env) glycoprotein complex into virus particles, and interacts with the cytoplasmic tail (CT) of the transmembrane (TM, gp41) portion of Env. Retrovirus matrix proteins also have been known to bind nucleic acids, and we recently discovered that the RNA and PI(4,5)P2 binding sites on MA overlap, supporting a new model in which RNA binding protects MA from association with inappropriate cellular membranes prior to PrGag delivery to the PM. Using our previous studies and preliminary results as a foundation, we propose novel approaches to dissect the mechanisms of matrix protein membrane, nucleic acid, and envelope protein binding, and to characterize methods for their inhibition. Our results will help elucidate how the HIV assembly machinery operates;and will lead to the development of Gag-targeted antivirals, and an understanding of how they work. To achieve these ends, our specific aims are as follows: 1. Characterization of the nucleic acid binding activity of the HIV-1 matrix protein. 2. Determination of membrane binding properties of HIV-1 MA. 3. Elucidation of HIV-1 matrix-envelope protein interactions.

Public Health Relevance

Our investigations focus on an analysis of the activities of the HIV-1 precursor Gag (PrGag) protein, the structural protein of HIV. We propose to characterize the functions of the matrix (MA) Gag protein and how they may be inhibited. These studies are of direct public health relevance in that they will lead to the development of new Gag- targeted anti-HIV therapeutics and an understanding of how they work.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM060170-14
Application #
8456996
Study Section
AIDS Discovery and Development of Therapeutics Study Section (ADDT)
Program Officer
Sakalian, Michael
Project Start
1999-09-01
Project End
2016-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
14
Fiscal Year
2013
Total Cost
$308,781
Indirect Cost
$108,274
Name
Oregon Health and Science University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
096997515
City
Portland
State
OR
Country
United States
Zip Code
97239
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Alfadhli, Ayna; McNett, Henry; Eccles, Jacob et al. (2013) Analysis of small molecule ligands targeting the HIV-1 matrix protein-RNA binding site. J Biol Chem 288:666-76
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Alfadhli, Ayna; McNett, Henry; Tsagli, Seyram et al. (2011) HIV-1 matrix protein binding to RNA. J Mol Biol 410:653-66
Still, Amelia; Huseby, Douglas; Barklis, Eric (2011) Analysis of the N-terminal region of the murine leukemia virus nucleocapsid protein. Virus Res 155:181-8
Dikeakos, Jimmy D; Atkins, Katelyn M; Thomas, Laurel et al. (2010) Small molecule inhibition of HIV-1-induced MHC-I down-regulation identifies a temporally regulated switch in Nef action. Mol Biol Cell 21:3279-92
Alfadhli, Ayna; Barklis, Robin Lid; Barklis, Eric (2009) HIV-1 matrix organizes as a hexamer of trimers on membranes containing phosphatidylinositol-(4,5)-bisphosphate. Virology 387:466-72
Barklis, Eric; Alfadhli, Ayna; McQuaw, Carolyn et al. (2009) Characterization of the in vitro HIV-1 capsid assembly pathway. J Mol Biol 387:376-89

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