Bacterial RNA Degradosomes: Molecular Machines under Tight Control

Bacterial RNA degradosomes are multienzyme molecular machines that act as hubs for post-transcriptional regulation of gene expression. The ribonuclease activities of these complexes require tight regulation, as they are usually essential for cell survival while potentially destructive. Recent studies have unveiled a wide variety of regulatory mechanisms including autoregulation, post-translational modifications, and protein compartmentalization. Recently, the subcellular organization of bacterial RNA degradosomes was found to present similarities with eukaryotic messenger ribonucleoprotein (mRNP) granules, membraneless compartments that are also involved in mRNA and protein storage and/or mRNA degradation. In this review, we present the current knowledge on the composition and targets of RNA degradosomes, the most recent developments regarding the regulation of these machineries, and their similarities with the eukaryotic mRNP granules. RNA degradosomes, molecular machines composed of at least one RNase and one RNA helicase, are major players in post-transcriptional regulation of gene expression in bacteria.RNA degradosomes are diverse in composition and are tightly regulated by a wealth of mechanisms, including autoregulation, post-translational modifications, protein localization, or interaction with different partners.Some RNA degradosomes seem to be compartmentalized at the membrane, which could affect their activity.Some bacterial RNA degradosomes show similarities with eukaryotic mRNP granules at the level of their physicochemical properties.