title: Toxin-antitoxin systems as multilevel interaction systems.
abstract: Toxin-antitoxin (TA) systems are small genetic modules usually composed of a toxin and an antitoxin counteracting the activity of the toxic protein. These systems are widely spread in bacterial and archaeal genomes. TA systems have been assigned many functions, ranging from persistence to DNA stabilization or protection against mobile genetic elements. They are classified in five types, depending on the nature and mode of action of the antitoxin. In type I and III, antitoxins are RNAs that either inhibit the synthesis of the toxin or sequester it. In type II, IV and V, antitoxins are proteins that either sequester, counterbalance toxin activity or inhibit toxin synthesis. In addition to these interactions between the antitoxin and toxin components (RNA-RNA, protein-protein, RNA-protein), TA systems interact with a variety of cellular factors, e.g., toxins target essential cellular components, antitoxins are degraded by RNAses or ATP-dependent proteases. Hence, TA systems have the capacity to interact with each other at different levels. In this review, we will discuss the different interactions in which TA systems are involved and their implications in TA system functions and evolution.
authors.affiliation: Laboratoire de Génétique et Physiologie Bactérienne, IBMM, Faculté des Sciences, Université Libre de Bruxelles (ULB), 12 rue des Professeurs Jeener et Brachet, Gosselies B-6041, Belgium. ngoeders@ulb.ac.be.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Goeders
authors.affiliation: Laboratoire de Génétique et Physiologie Bactérienne, IBMM, Faculté des Sciences, Université Libre de Bruxelles (ULB), 12 rue des Professeurs Jeener et Brachet, Gosselies B-6041, Belgium. lvmelder@ulb.ac.be.
authors.forename: Laurence
authors.initials: L
authors.lastname: Van Melderen
mesh_terms: D000992:Antitoxins / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D054730:Protein Interaction Domains and Motifs; D014118:Toxins, Biological / Q000494:pharmacology*; D015533:Transcriptional Activation
chemical_list: D000992:Antitoxins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D014118:Toxins, Biological