A study reveals how two proteins cooperate in a key early step of antiviral detection, as reported by researchers at Science Tokyo. Using cryo-electron microscopy and high-speed atomic force microscopy, they found that LGP2 binds to viral RNA and recruits MDA5 molecules, as if threading beads on a string. This creates a scaffold that facilitates the formation of a large signaling complex, which ultimately triggers an innate immune response.