. Author manuscript; available in PMC: 2022 Apr 1.

Published in final edited form as: Nat Rev Mol Cell Biol. 2021 Nov 23;23(4):286–301. doi: 10.1038/s41580-021-00430-1

Table 1 |.

dsRNA length sensitivity of dsRNA sensors

dsRNA sensors		Preferred duplex length	Mechanism of dsRNA length discrimination
			At the receptor level	By downstream pathway
RLRs	RIG-I	~22–500 bp with peak activity for ~50–200-bp dsRNA	Filament formation (through ATP-driven translocation of the receptor)	RIPLET binding
RLRs	MDA5	~500–1,000 bp; activity progressively increases with dsRNA length	Filament formation (through ATP-independent cooperative binding)	TRIM65 binding
TLR3		40–50 bp; activity progressively increases with dsRNA length	Dimerization or multimerization Activity progressively increases with dsRNA length	ND
PKR		>~33 bp; activity progressively increases with dsRNA length	Proximity of at least two PKR dimers (interdimeric phosphorylation)	ND
OASes	OAS1	<20 bp	ND	ND
	OAS2	Unclear	ND	ND
	OAS3	>50 bp	Binding in an extended conformation (?)	ND
NLRP1		>500 bp	ND	ND

dsRNA, double-stranded RNA; ND, not determined; NLRP1, NOD-, LRR- and pyrin domain-containing 1; OAS, oligoadenylate synthase; PKR, protein kinase R; RIPLET, E3 ubiquitin-protein ligase RNF135; RLR, RIG-I-like receptor; TLR3, Toll-like receptor 3; TRIM65, tripartite motif-containing protein 65.