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Updated: Nov 10, 2025

Use of Two Dimensional Semi-denaturing Detergent Agarose Gel Electrophoresis to Confirm Size Heterogeneity of Amyloid or Amyloid-like Fibers
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The structure of a minimum amyloid fibril core formed by necroptosis-mediating RHIM of human RIPK3

Xialian Wu1,2,3, Yeyang Ma2,4, Kun Zhao2,4

  • 1School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.

Proceedings of the National Academy of Sciences of the United States of America
|April 1, 2021
PubMed

Insights

Receptor-interacting protein kinases 3 (RIPK3) forms amyloid fibrils via its RHIM domain to trigger cell death. Structural analysis reveals a unique S-shaped fold and novel assembly, distinct from pathological fibrils.

Area of Science:

  • Biochemistry
  • Structural Biology
  • Cell Biology

Background:

  • Receptor-interacting protein kinases 3 (RIPK3) is crucial for necroptosis, a programmed cell death pathway.
  • RIPK3 activation involves polymerization into amyloid fibrils through its RIP homotypic interaction motif (RHIM).

Purpose of the Study:

  • To determine the atomic structure of RIPK3 amyloid fibrils formed by the RHIM-containing C-terminal domain (CTD).
  • To elucidate the assembly mechanism and structural features of physiological RIPK3 fibrils.

Main Methods:

  • Cryogenic electron microscopy (cryo-EM)
  • Solid-state nuclear magnetic resonance (ssNMR)

Main Results:

  • The structure reveals a single protofilament composed of the RHIM domain with a unique S-shaped fold.
  • The consensus tetrapeptide VQVG forms strand 2, facilitating heterozipper-like interfaces between β-strands.
  • RIPK3-CTD fibrils exhibit distinct assembly with a small core and dual-handed twisting, differing from pathological amyloid fibrils.

Conclusions:

  • The determined structure provides insights into the molecular mechanism of RIPK3-mediated necroptosis.
  • The unique fibril architecture may optimize the spatial arrangement of the RIPK3 kinase domain for efficient phosphorylation and signaling.
Keywords:
Cryo-EMamyloid fibrilnecroptosisssNMR

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