Structural requirements for activity of Mind bomb1 in Notch signaling

Ruili Cao, Oren Gozlan, Alina Airich, Lena Tveriakhina, Haixia Zhou, Hanjie Jiang, Philip A. Cole, Jon C. Aster, Thomas Klein, David Sprinzak, Stephen C. Blacklow*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Mind bomb 1 (MIB1) is a RING E3 ligase that ubiquitinates Notch ligands, a necessary step for induction of Notch signaling. The structural basis for binding of the JAG1 ligand by the N-terminal region of MIB1 is known, yet how the ankyrin (ANK) and RING domains of MIB1 cooperate to catalyze ubiquitin transfer from E2∼Ub to Notch ligands remains unclear. Here, we show that the third RING domain and adjacent coiled coil region (ccRING3) drive MIB1 dimerization and that MIB1 ubiquitin transfer activity relies solely on ccRING3. We report X-ray crystal structures of a UbcH5B-ccRING3 complex and the ANK domain. Directly tethering the MIB1 N-terminal region to ccRING3 forms a minimal MIB1 protein sufficient to induce a Notch response in receiver cells and rescue mib knockout phenotypes in flies. Together, these studies define the functional elements of an E3 ligase needed for ligands to induce a Notch signaling response.

Original languageEnglish
Pages (from-to)1667-1676.e5
JournalStructure
Volume32
Issue number10
DOIs
StatePublished - 3 Oct 2024

Funding

FundersFunder number
Scorpion Therapeutics
Ayala Pharmaceuticals
Deutsche Forschungsgemeinschaft
United States-Israel Binational Science Foundation
Remix Therapeutics
Erasca, Inc.
Charles H. Revson Foundation
Odyssey Therapeutics
Droia Ventures
National Institutes of Health1R35 CA220340, R01 CA74305
Ludwig Center at Harvard2017245
Bloom's Syndrome FoundationKL 1028/13-1

    Keywords

    • Delta
    • Jagged
    • MIB1
    • Notch signaling
    • Notch1
    • X-ray crystallography
    • endocytosis

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