Structural studies of an antinecroptosis viral:human functional heteroamyloid M45:RIPK3 using SSNMR
Abstract
The formation of RIP-homotypic interaction motif (RHIM)-based heteromeric amyloid assemblies between effector proteins such as receptor-interacting protein kinases 1, Z-DNA Binding Protein 1, or TRIF and the kinase RIPK3 serves as regulating signals for the necroptosis process, a key element of innate immune defense. Murine cytomegalovirus expresses the M45-encoded viral inhibitor of RIP activation which inhibits necroptosis in a RHIM-dependent manner. A pivotal question is how viral M45 forms heteroamyloids with RIPK3 to effectively create an inhibitory assembly. We report a high-resolution structure of the M45:RIPK3 complex where M45 and RIPK3 alternately stack in an amyloid-state structure. Mutagenesis of the residues flanking the IQIG tetrad in M45 results in specific impacts on coassembly with RIPK3, indicating an extended interface in the heteromeric fibrils. Other key interactions support the formation of stable viral:host fibrils. The M45:RIPK3 heteroamyloid is likely to act as an antinecroptotic signal by competing with formation of other pronecroptotic species and introducing a barrier to RIPK3 autophosphorylation.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (17)
Chengming He
Department of Chemistry, Columbia University
Nikhil R. Varghese
School of Medical Sciences and Sydney Nano Institute, University of Sydney
Eric G. Keeler
Department of Chemistry, Columbia University
Chi L. L. Pham
School of Medical Sciences and Sydney Nano Institute, University of Sydney
Teng Xie
Institute of Quantitative Biology, Zhejiang University
Brayden Williams
School of Medical Sciences and Sydney Nano Institute, University of Sydney
Stephan Tetter
Laboratory of Organic Chemistry, ETH Zurich
Crystal Semaan
School of Medical Sciences and Sydney Nano Institute, University of Sydney
Karyn L. Wilde
National Deuteration Facility, Australian Nuclear Science and Technology Organization
Simon H. J. Brown
School of Chemistry and Molecular Bioscience, Molecular Horizons, and Australian Research Council Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong
James C. Bouwer
Australian Research Council Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong
Yann Gambin
Department of Molecular Medicine and European Molecular Biology Laboratory Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales
Emma Sierecki
Department of Molecular Medicine and European Molecular Biology Laboratory Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales
Megan Steain
School of Medical Sciences and Sydney Nano Institute, University of Sydney
Ruhong Zhou
Margaret Sunde
School of Medical Sciences and Sydney Nano Institute, University of Sydney
Ann E. McDermott
Department of Chemistry, Columbia University