Plays a role in RNA-mediated gene silencing by micro-RNAs (miRNAs). Required for miRNA-dependent translational repression of complementary mRNAs by argonaute family proteins. As scaffoldng protein associates with argonaute proteins bound to partially complementary mRNAs and simultaneously can recruit CCR4-NOT and PAN deadenylase complexes. Interacts with one or more of the argonaute family proteins AGO1, AGO2, AGO3 and AGO4. Interacts with PABPC1 and EIF4G1. Interacts with CNOT1; the interaction is direct and mediates the association with the CCR4-NOT complex. Interacts with PAN3; the interaction mediates the association with the PAN complex. The silencing domain, also known as C-terminal effector domain (CED), can act in autonomous repression, including both translational inhibition and mRNA degradation. Belongs to the GW182 family. Extended N-terminus. Truncated N-terminus.