FBXO42 facilitates Notch signaling activation and global chromatin relaxation by promoting K63-linked polyubiquitination of RBPJ.

Jiang, Hua; Bian, Weixiang; Sui, Yue; Li, Huanle; Zhao, Han; Wang, Wenqi; Li, Xu · Sci Adv · 2022

basic_science · Level V

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Abstract

Dysregulation of the Notch-RBPJ (recombination signal-binding protein of immunoglobulin kappa J region) signaling pathway has been found associated with various human diseases including cancers; however, precisely how this key signaling pathway is fine-tuned via its interactors and modifications is still largely unknown. In this study, using a proteomic approach, we identified F-box only protein 42 (FBXO42) as a previously unidentified RBPJ interactor. FBXO42 promotes RBPJ polyubiquitination on lysine-175 via lysine-63 linkage, which enhances the association of RBPJ with chromatin remodeling complexes and induces a global chromatin relaxation. Genetically depleting <i>FBXO42</i> or pharmacologically targeting its E3 ligase activity attenuates the Notch signaling-related leukemia development in vivo. Together, our findings not only revealed FBXO42 as a critical regulator of the Notch pathway by modulating RBPJ-dependent global chromatin landscape changes but also provided insights into the therapeutic intervention of the Notch pathway for leukemia treatment.