Suppression of ADP-ribosylation reversal triggers cell vulnerability to alkylating agents.

The ADP-ribosyl hydrolases PARG and ARH3 counteract PARP enzymatic activity by removing ADP-ribosylation. PARG and ARH3 activities have a synthetic lethal effect; however, the specific molecular mechanisms underlying this response remain unknown. Here, we show that the PARG and ARH3 synthetic lethality is enhanced further in the presence of DNA alkylating agents, suggesting that the inability to revert ADP-ribosylation primarily affects the repair of alkylated DNA bases.

Targeting GOF p53 and c-MYC through LZK Inhibition or Degradation Suppresses Head and Neck Tumor Growth.

The worldwide frequency of head and neck squamous cell carcinoma (HNSCC) is approximately 800,000 new cases, with 430,000 deaths annually. We determined that LZK (encoded by ) is a therapeutic target in HNSCC and showed that inhibition with small molecule inhibitors decreases the viability of HNSCC cells with amplified . A drug-resistant mutant of LZK blocks decreases in cell viability due to LZK inhibition, indicating on-target activity by two separate small molecules.

Reversal of tyrosine-linked ADP-ribosylation by ARH3 and PARG.

ADP-ribosylation is an ancient posttranslational modification with exceptional versatility in terms of breadth of modification targets including at least seven different amino acid side chains, various moieties on nucleic acids, and a variety of small chemical compounds. The spatiotemporal signaling dynamic of the different modification variations is tightly regulated and depends on the writers, erases, and readers of each type. Among these, tyrosine ADP-ribosylation (Tyr-ADPr) has been consistently detected as a novel modification type, but systematic analysis of its potential physiological role, modification establishment, and reversal are still lacking.

Author Correction: PARP14 and PARP9/DTX3L regulate interferon-induced ADP-ribosylation.

[Image: see text]

Evolutionary and molecular basis of ADP-ribosylation reversal by zinc-dependent macrodomains.

Dynamic ADP-ribosylation signaling is a crucial pathway that controls fundamental cellular processes, in particular, the response to cellular stresses such as DNA damage, reactive oxygen species, and infection. In some pathogenic microbes, the response to oxidative stress is controlled by a SirTM/zinc-containing macrodomain (Zn-Macro) pair responsible for establishment and removal of the modification, respectively. Targeting this defence mechanism against the host's innate immune response may lead to novel approaches to support the fight against emerging antimicrobial resistance.