2. Academic Validation
  3. The E3 ligase RNF32 controls the IκB kinase complex and NF-κB signaling in intestinal stem cells

The E3 ligase RNF32 controls the IκB kinase complex and NF-κB signaling in intestinal stem cells

  • Mol Cell. 2025 Oct 29:S1097-2765(25)00822-6. doi: 10.1016/j.molcel.2025.10.005.
Angela Lauriola 1,  Juliana Haydeé Enriqué Steinberg 1,  Motoharu Sarubo 2,  Elena Maspero 3,  Fabiana Alejandra Rossi 4,  Yasuhiro Mouri 2,  Marco Pedretti 1,  Mohsen Hajisadeghian 1,  Vincenzo Taibi 3,  Andrea Vettori 1,  Nicola Vitulo 1,  Michael Assfalg 1,  Mariapina D'Onofrio 1,  Mario Rossi 4,  Akihiro Yasue 5,  Alessandra Astegno 1,  Simona Polo 3,  Spartaco Santi 6,  Yasusei Kudo 7,  Daniele Guardavaccaro 8
Affiliations

Affiliations

  • 1 Department of Biotechnology, University of Verona, 37134 Verona, Italy.
  • 2 Department of Oral Bioscience, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8504, Japan.
  • 3 IFOM ETS, The AIRC Institute of Molecular Oncology, 20139 Milan, Italy.
  • 4 Instituto de Investigaciones en Medicina Traslacional (IIMT), CONICET, Universidad Austral, B1629AHJ Pilar, Argentina; Facultad de Ciencias Biomédicas, Universidad Austral, B1629AHJ Pilar, Argentina.
  • 5 Nakano-Cho niconicoKamKam Dental and Orthodontics, 1-31 Nakano-cho, Tokushima 770-0932, Japan.
  • 6 Consiglio Nazionale delle Ricerche (CNR) Institute of Molecular Genetics "Luigi Luca Cavalli-Sforza", 40136 Bologna, Italy.
  • 7 Department of Oral Bioscience, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8504, Japan; Institute of Photonics and Human Health Frontier, Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8504, Japan. Electronic address: yasusei@tokushima-u.ac.jp.
  • 8 Department of Biotechnology, University of Verona, 37134 Verona, Italy. Electronic address: daniele.guardavaccaro@univr.it.
PMID: 41167191 DOI: 10.1016/j.molcel.2025.10.005
Abstract

Nuclear factor κB (NF-κB) signaling is a central pathway regulating a plethora of cellular functions. Here, we find that RNF32, a RING E3 ubiquitin Ligase whose expression is enriched in murine intestinal stem cells, regulates the activity of the IκB kinase (IKK) complex, the signal integration hub for NF-κB activation. The E3 Ligase activity of RNF32 depends on Calmodulin, the primary calcium sensor in eukaryotic cells. Increased levels of intracellular calcium ion (CA2+) induce RNF32 binding to Calmodulin, RNF32 activation, and autoubiquitylation. In turn, polyubiquitin chains conjugated to RNF32 recruit NEMO, the regulatory subunit of the IKK complex. Moreover, CA2+ rise triggers RNF32 phase separation, which is required for the formation of NEMO condensates and IKK activation. Finally, we show that RNF32 is required for NF-κB activation triggered by Bacterial lipopolysaccharides. Collectively, our findings uncover a mechanism controlling NF-κB signaling in the intestinal epithelium.

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