| Type: | Family | Name: | Signal transduction response regulator, PEP-CTERM system, putative |
| Description: | Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions []. Some bacteria can contain up to as many as 200 two-component systems that need tight regulation to prevent unwanted cross-talk []. These pathways have been adapted to response to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, and more []. Two-component systems are comprised of a sensor histidine kinase (HK) and its cognate response regulator (RR) []. The HK catalyses its own auto-phosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, which can then effect changes in cellular physiology, often by regulating gene expression. Some HK are bifunctional, catalysing both the phosphorylation and dephosphorylation of their cognate RR. The input stimuli can regulate either the kinase or phosphatase activity of the bifunctional HK.A variant of the two-component system is the phospho-relay system. Here a hybrid HK auto-phosphorylates and then transfers the phosphoryl group to an internal receiver domain, rather than to a separate RR protein. The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response [, ].This entry represents a protein family that shares full-length homology with (but do not include) the acetoacetate metabolism regulatory protein AtoC (see ). These proteins have a Fis family DNA binding sequence, a response regulator receiver domain, and sigma-54 interaction domain. They are found strictly within a subset of Gram-negative bacterial species with the proposed PEP-CTERM/exosortase system, analogous to the LPXTG/sortase system [] common in Gram-positive bacteria, where members of and also occur. | Short Name: | Sig_transdc_resp-reg_PEP-CTERM |
