Disease-associated KBTBD4 mutations in medulloblastoma elicit neomorphic ubiquitylation activity to promote CoREST degradationDisease-associated KBTBD4 mutations in medulloblastoma elicit neomorphic ubiquitylation activity to promote CoREST degradation

ABSTRACT: E3 ubiquitin ligases of the Cullin RING Ligase (CRL) family assemble into multiprotein complexes to diversify substrate adaptors and ensure selectivity in substrate engagement for degradation. Here we show a novel mechanism whereby mutations in substrate adaptors can drive neo-substrate degradation in cancer. KBTBD4 is a CRL3 substrate adaptor harbouring recurrent indel mutations in a subset of non-WNT/non-SHH medulloblastomas. We show that these mutations, arising in the substrate recognition domain of KBTBD4, promote the recruitment and ubiquitylation of the REST Corepressor (CoREST), which forms a complex to modulate chromatin accessibility and transcriptional programmes. We observe that this neomorphic activity of KBTBD4 mutants induces changes in epigenetic markers and significant alterations in transcription, diverting normal cellular programmes towards increased stemness. These results highlight mutation-driven neomorphic E3 ligase activity as a previously unrecognised mechanism in tumorigenesis, with implications for medulloblastoma pathogenesis and treatment.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture, Embryonic Stem Cell

DISEASE(S): Brain Cancer

SUBMITTER: iolanda Vendrell  

LAB HEAD: Vincenzo D'Angiolella

PROVIDER: PXD031683 | Pride | 2022-10-14

REPOSITORIES: Pride