An androgen signaling axis uses a writer and a reader of ADP-ribosylation to control protein complex assembly

Androgen signaling through the androgen receptor (AR) regulates multiple pathways in both normal and prostate cancer cells. Androgen regulates diverse aspects of the AR life cycle, including its post-translational modification, but understanding how specific modifications influence AR activity has been mostly elusive. Here, we show that androgen regulates AR through a pathway mediated by the mono-ADP ribosyltransferase, Parp7. We show that Parp7 ADP-ribosylates AR on multiple cysteines, and that a subset of these sites mediates agonist-specific recruitment of the E3 ligase Dtx3L/Parp9. Tandem macrodomains in Parp9 selectively recognize ADP ribosylated AR, and Dtx3L/Parp9 affects expression of a subset of AR-regulated genes. Parp7, ADP-ribosylation of AR, and AR-Dtx3L/Parp9 complex assembly are inhibited by 60 Olaparib, a compound used clinically to inhibit poly-ADP-ribosyltransferases Parp1/2. Our study reveals the components of a new androgen signaling axis that uses a writer and reader of ADP-ribosylation to modulate AR activity.