Response regulator SaeR (SaeR)

Response regulator SaeR is a key DNA-binding protein within the SaeRS two-component regulatory system in *Staphylococcus aureus*. It belongs to the OmpR/PhoB family of response regulators and is composed of an N-terminal receiver (regulatory) domain and a C-terminal DNA-binding effector domain with a canonical winged helix-turn-helix motif. SaeR becomes activated by phosphorylation at a conserved aspartate residue (D51) in its receiver domain, enabling it to bind to target promoter regions with high affinity and cooperativity, and regulate the transcription of numerous genes encoding virulence factors, such as alpha-hemolysin, coagulase, and surface adhesins. The SaeRS system is essential for S. aureus pathogenicity, influencing infection severity and host inflammatory response. SaeR function is strain-dependent and extensively modulated by environmental cues and interaction with other regulatory systems. Structural characterization and biochemical studies reveal that phosphorylation induces major conformational changes, relieving autoinhibition and enabling sequence-specific DNA binding. While currently not directly targeted by clinical drugs, SaeR is an attractive target for anti-virulence therapy development.

Other names

SaeRResponse regulator SaeRStaphylococcus aureus SaeROmpR/PhoB family

Not applicable for drugs, since there are no direct SaeR inhibitors yet. - For natural function: phosphorylation by cognate sensor kinase SaeS activates SaeR, enabling DNA binding and transcriptional regulation