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J Biol Chem. 2014 Oct 10;289(41):28539-53. doi: 10.1074/jbc.M114.600031. Epub 2014 Aug 13.

Interaction with the Src homology (SH3-SH2) region of the Src-family kinase Hck structures the HIV-1 Nef dimer for kinase activation and effector recruitment.

Author information

1
From the Departments of Microbiology and Molecular Genetics and Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219 and.
2
From the Departments of Microbiology and Molecular Genetics and Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261.
3
Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219 and jiyeh@pitt.edu.
4
From the Departments of Microbiology and Molecular Genetics and tsmithga@pitt.edu.

Abstract

HIV-1 Nef supports high titer viral replication in vivo and is essential for AIDS progression. Nef function depends on interactions with multiple host cell effectors, including Hck and other Src-family kinases. Here we describe the x-ray crystal structure of Nef in complex with the Hck SH3-SH2 regulatory region to a resolution of 1.86 Å. The complex crystallized as a dimer of complexes, with the conserved Nef PXXPXR motif engaging the Hck SH3 domain. A new intercomplex contact was found between SH3 Glu-93, and Nef Arg-105. Mutagenesis of Hck SH3 Glu-93 interfered with Nef·Hck complex formation and kinase activation in cells. The Hck SH2 domains impinge on the N-terminal region of Nef to stabilize a dimer conformation that exposes Asp-123, a residue critical for Nef function. Our results suggest that in addition to serving as a kinase effector for Nef, Hck binding may reorganize the Nef dimer for functional interaction with other signaling partners.

KEYWORDS:

Hck Kinase; Human Immunodeficiency Virus (HIV); Src; Src Homology 2 Domain (SH2 Domain); Src Homology 3 Domain (SH3 Domain); X-ray Crystallography

PMID:
25122770
PMCID:
PMC4192505
DOI:
10.1074/jbc.M114.600031
[Indexed for MEDLINE]
Free PMC Article

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