A novel molecular glue degrader, M12, induces degradation of the RNA helicase DDX18 by recruiting it to the CRL4DCAF11 ubiquitin ligase complex, but only after M12 is activated by cellular glutathionylation to form GSH-M12.

GST enzymes catalyze M12 glutathionylation in cells, and in vitro studies show GSH-M12 promotes the DCAF11–DDX18 interaction and subsequent ubiquitination by CRL4DCAF11.

Mutations that disrupt GSH–DCAF11 interactions or a knockout of DCAF11 abolish M12-induced DDX18 degradation, underscoring the dependency on DCAF11 and the glutathionylation-activation mechanism.

The research introduces a high-throughput, unbiased workflow that multiplexes E3 ligases, small molecules, and cell lysates to discover molecular glue degraders and identify new ligases like DCAF11 capable of neo-substrate degradation.

Overall, the findings reveal a new mechanism of targeted protein degradation where a prodrug is activated by cellular glutathionylation to function as a molecular glue degrader, expanding therapeutic targets among E3 ligases.

GSH-M12 serves as a flexible prodrug warhead for DCAF11-directed PROTACs; conjugates of M12 with ligands such as JQ1, SMARCA2, or BRD9 inhibitors drive degradation of BRD4, SMARCA2, BRD9, and several kinases, showing broad applicability.

Cryo-EM and biochemical data reveal that GSH-M12 binds in the WD40 propeller pocket of DCAF11, remodeling its surface to recruit DDX18, with a distinct GSH-binding site conserved through evolution.

The study highlights the evolutionary conservation of DCAF11’s GSH-binding site and suggests DCAF11 may bind other glutathionylated species, implying broader physiological roles beyond M12 activation.

M12 is identified as a novel molecular glue degrader that triggers degradation of DDX18 by recruiting it to the CRL4DCAF11 complex.

Structural insights show the GSH moiety positions M12 at DCAF11’s central pocket, with the M12 fragment buried at the DCAF11–DDX18 interface; GSH modification is essential for productive ternary complex formation.