PJA2 ubiquitinates the HIV-1 Tat protein with atypical chain linkages to activate viral transcription.

ABSTRACT: Transcription complexes that assemble at the HIV-1 promoter efficiently initiate transcription but generate paused RNA polymerase II downstream from the start site. The virally encoded Tat protein hijacks positive transcription elongation factor b (P-TEFb) to phosphorylate and activate this paused polymerase. In addition, Tat undergoes a series of reversible post-translational modifications that regulate distinct steps of the transcription cycle. To identify additional functionally important Tat cofactors, we performed RNAi knockdowns of sixteen previously identified Tat interactors and found that a novel E3 ligase, PJA2, ubiquitinates Tat in a non-degradative manner and specifically regulates the step of HIV transcription elongation. Interestingly, several different lysine residues in Tat

SUBMITTER: Faust TB 

PROVIDER: S-EPMC5366948 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature