Ethan Garvin
Ph.D. Student in Genetics, admitted Autumn 2023
All Publications
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The molecular basis for nuclear pore destruction by a proximity-inducing molecular glue.
Cell chemical biology
2026
Abstract
Molecular glues that induce new protein interactions can be potent therapeutics. We and others recently discovered that the small molecule PRLX-93936 (PRLX), which was originally developed as an erastin derivative with antitumor activity, is a molecular glue that alters the substrate specificity of the TRIM21 ubiquitin ligase. PRLX causes TRIM21 to bind the nuclear pore protein NUP98, triggering nuclear pore complex (NPC) degradation. We present here the structural and biochemical basis of NUP98 recognition, finding that ternary complex assembly depends on the creation of a composite TRIM21-small molecule surface competent for NUP98 binding. A scarcity of direct small molecule-NUP98 contacts likely explains how multiple structurally diverse TRIM21 ligands can induce NPC degradation. We also report the discovery of an enhanced molecular glue, MAN-021, and describe its structure. Our findings provide a basis for rational development of next-generation small molecules with enhanced or differentiated activities.
View details for DOI 10.1016/j.chembiol.2026.04.016
View details for PubMedID 42202785
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Mutational scanning reveals substrate-assisted autoregulation of the WNT destruction complex.
bioRxiv : the preprint server for biology
2025
Abstract
The β-catenin destruction complex (BDC) is a central node in WNT/β-catenin signaling, governing embryonic development and adult tissue homeostasis. Although recognized as a prime therapeutic target in colorectal cancer (CRC) for three decades, its dynamic architecture and biochemical complexity have hindered mechanistic understanding. Here, we systematically mapped the sequence-function landscape of the BDC using tiled base editor screens across four endogenous components-CTNNB1, AXIN1, APC, and GSK3B. Validation studies identified ~150 previously unreported mutations across these genes that affected WNT/β-catenin signaling. In addition to known cancer-associated mutations, we discovered rare gain-of-function and separation-of-function alleles of AXIN1 and CTNNB1 that provide mechanistic insights into complex assembly and regulation. We describe a region in β-catenin that regulates its binding to TCF/LEF transcription factors and demonstrate that the AXIN1-β-catenin interface is critical for controlling signaling flux through the oncogenic BDC. Mechanistic studies revealed that assembly of the oncogenic BDC is scaffolded by its own substrate β-catenin, establishing an autoregulatory mechanism that represents an unexploited vulnerability in cancers harboring common APC truncations. Our comprehensive mutational resource provides a foundation for understanding WNT/β-catenin signaling mechanisms in health and disease, while revealing strategies for therapeutic intervention in WNT-driven cancers.
View details for DOI 10.1101/2025.10.17.683169
View details for PubMedID 41278994
View details for PubMedCentralID PMC12633535
https://orcid.org/0000-0003-3609-6457