Uncovering the honeycomb network formed by RIPK1 amyloid fibrils

What is it about?

Inside our cells, the protein RIPK1 acts as a critical molecular switch, governing cell fate decisions between survival and death. To exert its function, RIPK1 can assemble into long, thread-like amyloid fibrils—a process tightly regulated in healthy cells but prone to dysregulation in disease states. For a long time, scientists believed that RIPK1 fibrils existed solely as isolated, individual filaments. In this study, we report an unexpected discovery: under specific conditions, these discrete fibrils can further assemble into ordered, higher-order networks. Using a suite of advanced imaging and structural biology techniques—including solid-state NMR, cryo-electron tomography, and atomic force microscopy—we reveal that these networks adopt striking quadrilateral and hexagonal architectures, reminiscent of a microscopic honeycomb or chicken wire.

Featured Image

Photo by Ante Hamersmit on Unsplash

Photo by Ante Hamersmit on Unsplash

Why is it important?

Our atomic-level structural analysis demonstrates that this network assembly is not random. Distinct surface regions on each fibril—especially flexible residues—function like molecular Velcro, enabling neighboring fibrils to interact at precise interfaces. We validate the functional importance of these key residues by showing that their mutation completely disrupts network formation. This work provides atomic-resolution insight into how amyloid fibrils self-organize into complex, functional assemblies.

Perspectives