Dynamics of physical interaction between HIV-1 Nef and ASK1: identifying the interacting motif(s)

• Published in: PloS one 2013-06, Vol.8 (6), p.e67586
• Main Authors: Kumar, Balawant, Tripathi, Chakrapani, Kanchan, Ranjana K, Tripathi, Jitendra Kumar, Ghosh, Jimut K, Ramachandran, Ravishankar, Bhadauria, Smrati, Tripathi, Raj Kamal
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Apoptosis; Binding Sites; Binding, Competitive; Biology; CD4 antigen; Councils; Development and progression; Enzymatic activity; Enzymes; FasL protein; Health aspects; HEK293 Cells; HIV; HIV infections; HIV-1 - physiology; Host-Pathogen Interactions; Human immunodeficiency virus; Humans; Industrial research; Infection; Jurkat Cells; Kinases; Lymphocytes; Lymphocytes T; MAP kinase; MAP Kinase Kinase Kinase 5 - chemistry; MAP Kinase Kinase Kinase 5 - metabolism; nef Gene Products, Human Immunodeficiency Virus - chemistry; nef Gene Products, Human Immunodeficiency Virus - metabolism; Nef protein; Peptide Fragments - chemistry; Peptides; Phosphorylation; Physiological aspects; Protein Binding; Protein Interaction Domains and Motifs; Proteins; Site-directed mutagenesis; T cells; Toxicology; Two-Hybrid System Techniques; Viruses
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0067586

FasL mediated preferential apoptosis of bystander CTLs while protection of infected CD4(+)T cells remains one of the hallmarks of immune evasion during HIV infection. The property of infected host cells to evade cell-autonomous apoptosis emanates from ability of HIV-1Nef-protein to physically interact with ASK-1 and thereby inhibit its enzymatic activity. The specific domains of HIV-1Nef through which it may interact with ASK1 and thereby impair the ASK1 activity remain unidentified so far and represent a major challenge towards developing clear understanding about the dynamics of this interaction. Using mammalian two hybrid screen in association with site directed mutagenesis and competitive inhibitor peptides, we identified constituent minimal essential domain (152 DEVGEANN 159) through which HIV-1Nef interacts with ASK1 and inhibits its function. Furthermore our study also unravels a novel alternate mechanism underlying HIV-1 Nef mediated ASK1 functional modulation, wherein by potentiating the inhibitory ser(967) phosphorylation of ASK1, HIV-1Nef negatively modulated ASK1 function.