Proteomic characterization of HIV-1 Tat interactome

The HIV-1 regulatory protein, Tat (86aa), displays pleiotropic activities, ultimately, contributing to HIV-1 pathogenesis. Sequence analysis reveals a unique arrangement of five distinct functional domains. Additionally, Tat has been described as a natively unfolded protein with fast dynamics. Collectively these findings suggest that Tat is a protein suited for multiple protein interactions and highlight how Tat can elicit multifaceted activities. To achieve the unprecedented comprehensive interaction map of Tat, we have designed and performed high-throughput affinity chromatography coupled with MS/MS.

We successfully identified a total of 270 proteins with size ranging from 15 kD to 400 kD, the majority of which have not been previously identified as Tat partners. The entire dataset was organised according to distinct cellular processes, which remarkably resulted in the wide functional distribution of the proteins over 15 categories. We then assigned each individual protein to their respective complexes and obtained functional interaction maps.

Our study clearly reveals that Tat is involved in supercomplexes encompassing a multitude of biochemical entities and particularly emphasises the scope of combinatorial control involved in the coordination of mRNA biogenesis and maturation, and DNA replication and repair by HIV-1 Tat.