The amyloid structure of mouse RIPK3 (receptor interacting protein kinase 3) in cell necroptosis

Xia-Lian Wu,Hua-Yi Wang,Jun-Xia Lu,Xing-Qi Dong,Charles D Schwieters,Hong Hu,Bing Li,Jing Liu,Jing Zhang,Guo-Xiang Wu,Jian Wang,Jing-Yu Lin

doi:10.1038/s41467-021-21881-2

Abstract

RIPK3 amyloid complex plays crucial roles during TNF-induced necroptosis and in response to immune defense in both human and mouse. Here, we have structurally characterized mouse RIPK3 homogeneous self-assembly using solid-state NMR, revealing a well-ordered N-shaped amyloid core structure featured with 3 parallel in-register β-sheets. This structure differs from previously published human RIPK1/RIPK3 hetero-amyloid complex structure, which adopted a serpentine fold. Functional studies indicate both RIPK1-RIPK3 binding and RIPK3 amyloid formation are essential but not sufficient for TNF-induced necroptosis. The structural integrity of RIPK3 fibril with three β-strands is necessary for signaling. Molecular dynamics simulations with a mouse RIPK1/RIPK3 model indicate that the hetero-amyloid is less stable when adopting the RIPK3 fibril conformation, suggesting a structural transformation of RIPK3 from RIPK1-RIPK3 binding to RIPK3 amyloid formation. This structural transformation would provide the missing link connecting RIPK1-RIPK3 binding to RIPK3 homo-oligomer formation in the signal transduction.

Highlights

RIPK3 amyloid complex plays crucial roles during tumor necrotic factor (TNF)-induced necroptosis and in response to immune defense in both human and mouse
Our results provide a picture of an amyloid structural transformation in the necroptosis signal transduction pathway from RIPK1–RIPK3 binding to RIPK3 self-assembly, explaining why RIPK1/RIPK3 hetero complex could not induce RIPK3 kinase activation directly
Our solid-state NMR (SSNMR) structure of mouse RIPK3 fibrils reveal an “N”shaped structure with three β-strands and a single copy of RIPK3 molecule in the fibril cross-β unit. It shows the β-arch conformation with a strand-turn-strand motif which is a common feature in fibril structures[24]

Summary

Introduction

RIPK3 amyloid complex plays crucial roles during TNF-induced necroptosis and in response to immune defense in both human and mouse. We have structurally characterized mouse RIPK3 homogeneous self-assembly using solid-state NMR, revealing a well-ordered N-shaped amyloid core structure featured with 3 parallel in-register β-sheets. This structure differs from previously published human RIPK1/RIPK3 hetero-amyloid complex structure, which adopted a serpentine fold. Functional studies indicate both RIPK1-RIPK3 binding and RIPK3 amyloid formation are essential but not sufficient for TNF-induced necroptosis. Molecular dynamics simulations with a mouse RIPK1/RIPK3 model indicate that the hetero-amyloid is less stable when adopting the RIPK3 fibril conformation, suggesting a structural transformation of RIPK3 from RIPK1-RIPK3 binding to RIPK3 amyloid formation This structural transformation would provide the missing link connecting RIPK1-RIPK3 binding to RIPK3 homo-oligomer formation in the signal transduction. We are still lacking detailed structural information on these different high-order

Methods

Results

Conclusion