Toxic component of a type V toxin-antitoxin (TA) system. Causes membrane damage when induced by MqsR, slowing cell growth and increasing the formation of dormant persister cells; involved with GhoS, its antitoxin, in reducing cell growth during antibacterial stress (PubMed:24373067). Overexpression causes cell lysis, forming ghost cells; both effects are neutralized by expression of GhoS. Overexpression in the presence of ampicillin increases persister cell formation (persister cells exhibit antibiotic tolerance without genetic change) (PubMed:22941047). Overexpression causes about 90-fold reduction in cellular ATP levels and dissipates the membrane potential (PubMed:24373067). Localizes to the cell pole. Expression controlled by its antitoxin GhoS, which digests ghoT transcripts in a sequence-specific manner (PubMed:22941047). Post-transcriptionally regulated by MqsR which acts on the ghoST transcript selectively, degrading the ghoS segment while leaving ghoT intact; conditions which induce MqsR (e.g. overexpression, nalidixic acid, azolocillin or H(2)O(2)) decrease ghoS expression and thus increase ghoT transcripts (PubMed:23289863). No visible effect in the absence of stress (PubMed:24373067). Reduces MqsR-mediated persistence (overexpression of MqsR increases persister cell formation). Decreased biofilm formation after 8 hours at 30 and 37 degrees Celsius, biofilm production has risen by 24 hours. Slight decrease in swimming motility (PubMed:22941047). Cells grown in 20 ug/ml ampicillin in the absence of ghoT and which overexpress MqsR elongate, suggesting MqsR inhibits cell elongation via ghoT (PubMed:23289863). When single mutant is grown in the presence of antibiotics carbenicillin or cefoxitin initial metabolism is significantly increased over that of wild-type, after 14 hours wild-type is slightly less active. In a double ghoS-ghoT mutant in presence of the 2 antibiotics metabolism is significantly increased over that of wild-type, but by 9 hours wild-type has caught up and eventually has slightly greater metabolic rates (PubMed:24373067). Belongs to the GhoT/OrtT toxin family.