Argonaute-2–containing RNA-induced silencing complex (AGO2-RISC) (AGO2-RISC)

The Argonaute-2–containing RNA-induced silencing complex (AGO2-RISC) is a multi-protein ribonucleoprotein complex that serves as the central effector of the RNA interference (RNAi) pathway (Meister, G., 2013, Nature Reviews Genetics). At its core is Argonaute-2 (AGO2), a specialized endonuclease that binds small regulatory RNAs, such as microRNAs (miRNAs) or small interfering RNAs (siRNAs) (UniProt P98170). The guide strand of the RNA molecule directs the complex to complementary messenger RNA (mRNA) sequences, where AGO2 facilitates sequence-specific gene silencing through mRNA cleavage or translational inhibition (Pratt & MacRae, 2009, Nature Structural & Molecular Biology). In modern medicine, AGO2-RISC is the primary therapeutic machinery utilized by siRNA-based drugs, which are designed to harness this natural system to 'knock down' disease-causing proteins (Setten et al., 2019, Nature Reviews Drug Discovery). This mechanism is highly potent and catalytic, allowing a single RISC to process multiple mRNA targets over an extended period. Therapeutic applications currently span a wide range of conditions, including hereditary transthyretin-mediated amyloidosis (Patisiran) and hypercholesterolemia (Inclisiran) (FDA, 2018, 2021). However, challenges remain regarding the potential for off-target effects and the efficient delivery of RNA triggers to specific tissues.

Other names

RNA-induced silencing complexRISCArgonaute-2 complexAGO2 complexsiRISCmiRISCEukaryotic translation initiation factor 2C 2 complex

The complex incorporates a single-stranded siRNA or miRNA guide, which directs the Argonaute-2 protein to a complementary mRNA target. Argonaute-2 then acts as an endonuclease to cleave the target mRNA (slicing) or recruits additional factors to induce translational repression and decay (Meister, G., 2013, Nature Reviews Genetics; Pratt & MacRae, 2009, Nature Structural & Molecular Biology).