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Journal of Virology, March 2009, p. 2518-2530, Vol. 83, No. 6
0022-538X/09/$08.00+0     doi:10.1128/JVI.02227-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

A Basic Patch on -Adaptin Is Required for Binding of Human Immunodeficiency Virus Type 1 Nef and Cooperative Assembly of a CD4-Nef-AP-2 Complex ^,

Rittik Chaudhuri,^1,2 Rafael Mattera,¹ O. Wolf Lindwasser,¹ Margaret S. Robinson,² and Juan S. Bonifacino^1*

Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892,¹ Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0XY, United Kingdom²

Received 22 October 2008/ Accepted 26 December 2008

A critical function of the human immunodeficiency virus type 1 Nef protein is the downregulation of CD4 from the surfaces of infected cells. Nef is believed to act by linking the cytosolic tail of CD4 to the endocytic machinery, thereby increasing the rate of CD4 internalization. In support of this model, weak binary interactions between CD4, Nef, and the endocytic adaptor complex, AP-2, have been reported. In particular, dileucine and diacidic motifs in the C-terminal flexible loop of Nef have been shown to mediate binding to a combination of the and 2 subunits of AP-2. Here, we report the identification of a potential binding site for the Nef diacidic motif on -adaptin. This site comprises two basic residues, lysine-297 and arginine-340, on the -adaptin trunk domain. The mutation of these residues specifically inhibits the ability of Nef to bind AP-2 and downregulate CD4. We also present evidence that the diacidic motif on Nef and the basic patch on -adaptin are both required for the cooperative assembly of a CD4-Nef-AP-2 complex. This cooperativity explains how Nef is able to efficiently downregulate CD4 despite weak binary interactions between components of the tripartite complex.

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* Corresponding author. Mailing address: Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Building 18T, Room 101, National Institutes of Health, Bethesda, MD 20892. Phone: (301) 496-6368. Fax: (301) 402-0078. E-mail: juan{at}helix.nih.gov

Published ahead of print on 7 January 2009.

Supplemental material for this article may be found at http://jvi.asm.org/.

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Journal of Virology, March 2009, p. 2518-2530, Vol. 83, No. 6
0022-538X/09/$08.00+0     doi:10.1128/JVI.02227-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• daSilva, L. L. P., Sougrat, R., Burgos, P. V., Janvier, K., Mattera, R., Bonifacino, J. S. (2009). Human Immunodeficiency Virus Type 1 Nef Protein Targets CD4 to the Multivesicular Body Pathway. J. Virol. 83: 6578-6590 [Abstract] [Full Text]