Fig. 7.

a Schematic of RNA recognition and antiviral signal activation by MDA5. b Electron micrograph and 2D-averaged image of the MDA5 filament formed on 512 and 112 bp dsRNA, respectively [146]. c Proposed model of dsRNA length-dependent signaling by MDA5. Filaments formed on short dsRNA disassemble rapidly during ATP hydrolysis, while filaments on longer dsRNA can undergo continuous cycles of filament assembly and disassembly, during which it activates the downstream antiviral signaling pathway through MAVS. d Summary of MDA5-stimulatory and suppressive features of RNA