RNA degradation processes controlled by the RNA quality control and the RNA silencing pathways. RNA degradation processes targeted by the RNA quality control and the RNA silencing pathways and their interaction. The RQC pathway degrades aberrant RNAs such as decapped and/or deadenylated transcripts through exonuclease activities. Exogenous and a portion of endogenous RNAs enter to the RNA silencing pathway by the production of RDR6-dependent siRNAs. The siRNAs are loaded onto AGO1 and facilitate mRNA cleavage. The RQC pathway eliminates aberrant RNAs via mRNA deadenylation and decapping-dependent bidirectional degradation. The RQC pathway suppresses RNA silencing. When the RQC pathway does not operate properly, the accumulated RNAs are served as substrates for RDR6, which turns on RNA silencing. Meanwhile, RPT2a, a subunit of 26S proteasome complex, attenuates the RQC pathway, resulting enforced RNA silencing, which suggests that the two pathways might have more dynamic bidirectional antagonistic interaction depending on the situation.
