Globally modulates RNA abundance by binding to RNase E (Rne) and regulating its endonucleolytic activity. Can modulate Rne action in a substrate-dependent manner by altering the composition of the degradosome. Modulates RNA-binding and helicase activities of the degradosome. Homotrimer. Forms a ring-like structure with a central cavity. Binds to both RNA-binding sites in the C-terminal region of Rne and to RhlB. Induced upon entry into stationary phase, in a RpoS-dependent manner. Stability of the rraA transcript is Rne dependent, suggesting the existence of a feedback mechanism in the regulation of RraA level. RraA and RraB interact with Rne at separate sites within the Rne and exert distinct effects on the composition of the degradosome, affecting distinct sets of RNA transcripts. Belongs to the RraA family. Although it was initially thought to be a methyltransferase of the menaquinone pathway, PubMed:13678585 showed that it has no SAM-dependent methyltransferase activity and is not involved in the menaquinone pathway.