Short report

Refined study of the interaction between HIV-1 p6 late domain and ALIX

Carine Lazert^{* 1} , Nathalie Chazal^{* 2} , Laurence Briant² , Denis Gerlier¹ and Jean-Claude Cortay¹

¹Université Lyon 1, Centre National de la Recherche Scientifique (CNRS), VirPatH FRE 3011, Faculté de Médecine RTH Laennec, Lyon, France

²Université Montpellier 1, Université Montpellier 2, CNRS, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS), UMR 5236, F-34965 Montpellier, France

author email corresponding author email* Contributed equally

Retrovirology 2008, 5:39doi:10.1186/1742-4690-5-39

Published:	13 May 2008

Abstract

The interaction between the HIV-1 p6 late budding domain and ALIX, a class E vacuolar protein sorting factor, was explored by using the yeast two-hybrid approach. We refined the ALIX binding site of p6 as being the leucine triplet repeat sequence (Lxx)₄ (LYPLTSLRSLFG). Intriguingly, the deletion of the C-terminal proline-rich region of ALIX prevented detectable binding to p6. In contrast, a four-amino acid deletion in the central hinge region of p6 increased its association with ALIX as shown by its ability to bind to ALIX lacking the proline rich domain. Finally, by using a random screening approach, the minimal ALIX_391–510 fragment was found to specifically interact with this p6 deletion mutant. A parallel analysis of ALIX binding to the late domain p9 from EIAV revealed that p6 and p9, which exhibit distinct ALIX binding motives, likely bind differently to ALIX. Altogether, our data support a model where the C-terminal proline-rich domain of ALIX allows the access of its binding site to p6 by alleviating a conformational constraint resulting from the presence of the central p6 hinge.