Cryo-EM reveals alternative modes of dimerization driving activation of IKK

Authors

Biswas, T., Shahabi, S., Zhong, X.-Y., Ko, M. S., Huxford, T., Ghosh, G.

Abstract

The inhibitor of {kappa}B kinase (IKK) complex integrates diverse cellular inflammatory responses, and induces transcription factor NF-{kappa}B. The molecular mechanism by which IKK becomes catalytically active in response to signaling remains unclear despite structural knowledge of the individual IKK1/, IKK2/{beta}, and NEMO/IKK{gamma} protein components within its hetero-oligomeric assembly. Cryo-EM of the IKK2/{beta} homodimer bound to an associating NEMO/IKK{gamma} protein fragment, reveals multiple conformers. Mutual exclusivity of dimeric conformers, canonical versus alternate, is reflected in and dependent upon order-to-disorder transition of the canonical 6-helical bundle dimerization interface. Correlation of this unusual structural plasticity of IKK2/{beta} with its biochemical and cellular activities suggests mechanistic possibilities for how association with its partner scaffold protein NEMO/IKK{gamma} and polyubiquitin chains might dictate catalytic activation of IKK through distinct IKK2/{beta} conformers.

Preprint server: bioRxiv
The authors list and abstract were imported from bioRxiv on 02 Jul 2026.

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