IgaA
IgaA is a conserved bacterial membrane protein involved in the negative regulation of the Rcs phosphorelay system, a signaling pathway that controls envelope stress responses in many Gram-negative bacteria. The protein is essential for bacterial viability in several species, including Salmonella enterica, and plays a key role in modulating growth and virulence.
Function
IgaA is a multi-pass inner membrane protein that suppresses activation of the RcsCDB phosphorelay system under non-stress conditions. When functioning properly, IgaA prevents unnecessary activation of envelope stress responses, helping maintain homeostasis and prevent toxic overexpression of capsular polysaccharides and other surface components.Loss-of-function mutations in igaA lead to constitutive activation of Rcs signaling, resulting in defects in cell division, envelope structure, and motility, and in some cases a reduction in virulence.