Structural constraints on human immunodeficiency virus type 1 Nef function |
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Authors: | Raney Alexa Shaw Alice Y Foster John L Garcia J Victor |
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Affiliation: | University of Texas Southwestern Medical Center at Dallas, TX 75390, USA. |
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Abstract: | HIV-1 Nef is a multifunctional protein that exerts its activities through interactions with multiple cellular partners. Nef uses different domains and mechanisms to exert its functions including cell surface down-modulation of CD4 and MHC-I receptors and activation of the serine/threonine kinase PAK-2. We inserted tags at the C-terminus and proximal to the N-terminus of Nef and the effects on Nef's structure/function relationships were examined. We discovered significant defects in MHC-I down-modulation with the insertion of HA/FLAG tags at either region. We also found impaired PAK-2 activation with a C-terminal fusion with GFP. Interestingly, Nef-GFP and Nef-GH(7) induced MHC-I down-modulation, suggesting that the negative charge of the HA/FLAG tag could contribute to the observed defect. Together, these observations highlight elements of Nef's functional complexity and demonstrate previously unsuspected structural requirements for PAK-2 activation and MHC-1 down-modulation in Nef's flexible N- and C-terminal regions. |
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Keywords: | HIV-1 Nef Structure-function Peptide tags GFP MHC-I down-modulation CD4 down-modulation PAK-2 activation |
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