Sulphate Transporter and Anti-Sigma factor antagonist domain of the "stressosome" complex proteins RsbS and RsbR, regulators of the bacterial stress activated alternative sigma factor sigma-B by phosphorylation
The STAS (Sulphate Transporter and Anti-Sigma factor antagonist) domain of proteins related to RsbS and RsbR which are part of the "stressosome" complex that plays an important role in the regulation of the bacterial stress activated alternative sigma factor sigma-B. During stress conditions RsbS and RsbR are phosphorylated which leads to the release of RsbT, an activator of of the RsbU phosphatase, which in turn activates RsbV which leads to the release and activation of sigma factor B. RsbS is a single domain protein (STAS domain), while RsbR-like proteins have a well-conserved C-terminal STATS domain and a variable N-terminal domain. The STAS domain is also found in the C- terminal region of sulphate transporters and anti-anti-sigma factors.