Identifying the interactome of the RIG-I-like Receptor LGP2

Abstract

RIG-I-like receptors (RLRs) are DEAD box helicases and cytoplasmic pathogen recognition receptors that recognize and bind to nonself/viral RNA and trigger innate antiviral immunity. RLRs are essential for detection of RNA virus infection, and include RIG-I, MDA5, and LGP2. LGP2 has been implicated as RIG-I or MDA5 cofactor to regulate their activity. We conducted a yeast 2 hybrid (Y2H) screen (using LGP2 as bait) of a human hepatic cDNA library to identify protein binding partners of LGP2. Identified proteins were validated as LGP2 interactors through overexpression and co-immunoprecipitation assays of LGP2 binding. The validated proteins were then submitted to a cell-based interferon beta-promoter-luciferase assay model of Sendai virus (SenV) infection as well as a cell based NFkB-luciferase assay of the same system. Endogenous expression of the validated proteins was then assayed through the Huh7 human hepatoma cell line system with various stimuli including viral infection with SenV and Interferon-beta treatment. Through these studies we will define the LGP2 interactome and identify proteins that act as co-factors in RLR signaling.