Role of FabT in Streptococcus virulence

The bacterial membrane bilayer coordinates its fatty acid (FA) composition in response to environmental changes. Regulation of FA synthesis (FASII) genes is crucial to this coordination. In streptococcaccae and enterococcaccae, FASII is feedback-controlled by the FabT repressor bound by an acyl-Acyl carrier protein. In Streptococcus pyogenes, FabT defects are associated with attenuated virulence in animal models. Paradoxically, fabT point mutations arise in vivo. We elucidate the nature of the link between FabT and virulence and propose a rationale for fabT mutant emergence in vivo.