3j6c
From Proteopedia
Cryo-EM structure of MAVS CARD filament
Structural highlights
Function[MAVS_HUMAN] Required for innate immune defense against viruses. Acts downstream of DDX58/RIG-I and IFIH1/MDA5, which detect intracellular dsRNA produced during viral replication, to coordinate pathways leading to the activation of NF-kappa-B, IRF3 and IRF7, and to the subsequent induction of antiviral cytokines such as IFN-beta and RANTES (CCL5). Peroxisomal and mitochondrial MAVS act sequentially to create an antiviral cellular state. Upon viral infection, peroxisomal MAVS induces the rapid interferon-independent expression of defense factors that provide short-term protection, whereas mitochondrial MAVS activates an interferon-dependent signaling pathway with delayed kinetics, which amplifies and stabilizes the antiviral response. May activate the same pathways following detection of extracellular dsRNA by TLR3. May protect cells from apoptosis.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedMitochondrial antiviral signaling (MAVS) protein is required for innate immune responses against RNA viruses. In virus-infected cells MAVS forms prion-like aggregates to activate antiviral signaling cascades, but the underlying structural mechanism is unknown. Here we report cryo-electron microscopic structures of the helical filaments formed by both the N-terminal caspase activation and recruitment domain (CARD) of MAVS and a truncated MAVS lacking part of the proline-rich region and the C-terminal transmembrane domain. Both structures are left-handed three-stranded helical filaments, revealing specific interfaces between individual CARD subunits that are dictated by electrostatic interactions between neighboring strands and hydrophobic interactions within each strand. Point mutations at multiple locations of these two interfaces impaired filament formation and antiviral signaling. Super-resolution imaging of virus-infected cells revealed rod-shaped MAVS clusters on mitochondria. These results elucidate the structural mechanism of MAVS polymerization, and explain how an alpha-helical domain uses distinct chemical interactions to form self-perpetuating filaments. DOI: http://dx.doi.org/10.7554/eLife.01489.001. Structural basis for the prion-like MAVS filaments in antiviral innate immunity.,Xu H, He X, Zheng H, Huang LJ, Hou F, Yu Z, de la Cruz MJ, Borkowski B, Zhang X, Chen ZJ, Jiang QX Elife. 2014 Jan 1;3:e01489. doi: 10.7554/eLife.01489. PMID:24569476[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Human | Large Structures | Borkowski, B | Chen, Z J | Cruz, M J.de la | He, X | Hou, F | Huang, L J | Jiang, Q X | Xu, H | Yu, Z | Zhang, X | Zheng, H | Helical filament | Innate immunity | Signaling protein
