NLRC5 competes with IPS-1 for binding to the CARD domain of RIG-I/MDA5. NLRC5 specifically recognize the CARD domains of RIG-I/MDA5 when the CARD domains become accessible after viral infection, leading to dampened activation of IRF3.
NLRX1 is a member of nucleotide-binding domain and leucine-rich repeat containing (NLR) protein family. NLRX1 competes with RIG-I for IPS-1 interaction and has been identified as a negative regulator of RLR signaling. NLRX1 resides at the outer mitochondrial membrane where IPS-1 is located and this interaction is mediated by the CARD region of IPS-1 and a putative nucleotide-binding domain (NBD) of NLRX1. This interaction between NLRX1 and IPS-1 prevents the association between RIG-1/MDA5 and IPS-1.
Upon binding viral dsRNA, Probable ATP-dependent RNA helicase DDX58 (DDX58, RIG-I, RIG-1) and Interferon-induced helicase C domain-containing protein 1 (IFIH1, MDA5) recruit the downstream signal transducer Mitochondrial antiviral-signaling protein (MAVS, IPS-1). This mitochondria-bound adaptor has an N-terminal CARD-like domain (CLD) which associates with the CARD regions of DDX58 and IFIH1 to mediate induction of interferons.