GhoT is part of the GhoT-GhoS type V toxin-antitoxin (TA) system [1, 2]. OrtT is homologous to GhoT, but it is not part of a TA pair. In this case, it acts as an independent toxin to reduce growth during stress related to amino acid and DNA synthesis [3].

1: A new type V toxin-antitoxin system where mRNA for toxin GhoT is cleaved by antitoxin GhoS. Wang X, Lord DM, Cheng HY, Osbourne DO, Hong SH, Sanchez-Torres V, Quiroga C, Zheng K, Herrmann T, Peti W, Benedik MJ, Page R, Wood TK; Nat Chem Biol. 2012;8:855-861. PMID:22941047

2: Type II toxin/antitoxin MqsR/MqsA controls type V toxin/antitoxin GhoT/GhoS. Wang X, Lord DM, Hong SH, Peti W, Benedik MJ, Page R, Wood TK; Environ Microbiol. 2013;15:1734-1744. PMID:23289863

3: Orphan toxin OrtT (YdcX) of Escherichia coli reduces growth during the stringent response. Islam S, Benedik MJ, Wood TK; Toxins (Basel). 2015;7:299-321. PMID:25643179