title: Prokaryotic toxin-antitoxin systems: novel regulations of the toxins.
abstract: Toxin-antitoxin (TA) systems are widely conserved in prokaryotic plasmids and chromosomes and are linked to many roles in cell physiology, including plasmid maintenance, stress response, persistence and protection from phage infection. A TA system is composed of a stable toxin and a labile antitoxin that inhibits a harmful effect of the cognate toxin. When gene expression from the TA loci is repressed under certain conditions such as nutrient starvation, the toxin is freed from the rapidly degrading antitoxin and obstructs an essential cellular process, such as DNA replication, translation and peptidoglycan synthesis, which subsequently causes growth arrest. TA systems are classified into five types according to the nature and the function of antitoxins, and the activity of toxins is tightly regulated in a variety of ways. This short-review highlights several novel regulatory mechanisms for Escherichia coli toxins that we recently discovered.
authors.affiliation: Department of Microbiology, School of Medicine, Dokkyo Medical University, 880 Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi, 321-0293, Japan. otsukay@dokkyomed.ac.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Otsuka
mesh_terms: D000992:Antitoxins / Q000378:metabolism*; D017122:Bacteriophage T4; D004261:DNA Replication; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis
chemical_list: D000992:Antitoxins
keywords: Bacteriophage T4; Escherichia coli; MazE-MazF; RnlA-RnlB; Toxin–antitoxin system