Regulation of the MAVS Signalosome by RNA and RNA-binding Proteins - PROJECT SUMMARY / ABSTRACT
Well controlled antiviral innate immunity is essential for restricting viral pathogens while preventing aberrant
inflammation. A key antiviral signaling pathway is initiated by RIG-I-like receptors (RLRs) which sense viral RNA
in the cytosol to induce the production of interferons through a higher order signaling platform centered on the
adaptor protein MAVS. Although the components of the MAVS signalosome are basally expressed, RLR
signaling only proceeds when they coalesce around MAVS at ER-mitochondrial contact sites. Many of the
protein-protein interactions and post-translational modifications required for the proper function of the MAVS
signalosome are known. While, functional interactions in protein complexes can be mediated by RNA molecules,
whether RNA molecules play a role in signaling through the MAVS signalosome remains unexplored. I have
found that 1) MAVS is associated with non-viral RNA, that 2) RNA promotes signaling through the MAVS
signalosome, and that 3) canonical RNA-binding proteins (RBPs) interact with MAVS. This proposal aims to
define the functional roles for RNA and RBPs in regulating antiviral signaling through the MAVS signalosome.
During the mentored phase, I will gain new training in the characterization of RNA-protein interactions through
biochemical, sequencing-based, and quantitative proteomic approaches, as well as the virological techniques
required to study RNA viruses and innate immunity. In Aim 1, I will define the RNA-dependent interactions
between components of the MAVS signalosome during the K99 phase, and identify novel proteins that associate
with RNA during RLR signaling at the R00 phase. Through Aim 2, I will pinpoint the sequences in MAVS required
for RNA-association, and identify a high-confidence set of MAVS-bound RNAs during the K99 phase. During the
R00 stage, I will functionally dissect the roles for these RNAs at the MAVS signalosome. In Aim 3, I will screen
a shortlist of MAVS-associated RBPs to identify those that influence MAVS signaling during the K99 stage, and
determine the molecular functions of three RBPs (STAU1, HNRNPL, and RBM10) in antiviral signaling at the
R00 stage. The overall outcome of these experiments will be to define new RNA-centric principles by which the
MAVS signalosome is organized. Understanding how RNA molecules influence antiviral signaling could unlock
new host-directed therapeutic strategies against viral diseases as well as autoimmune disorders. In addition to
my advisor Dr. Savan, I have assembled an Advisory Committee with expertise in the different facets of my
research. Together, this excellent training environment at the University of Washington will augment my research
during the mentored phase, and equip me with the skills required to transition to an independent academic
researcher studying the RNA regulation of innate immune processes.
