PARP9 and prostate cancer: Furthermore, androgen induces the association of AR with the DTX3L-PARP9 heterodimer, where PARP9, using its macrodomains (MD1 and MD2), binds to the ADP-ribose moieties on AR deposited by PARP7, thus modulating AR transcriptional activity both positively and negatively in prostate cancer cells (Yang et al, 2021).