phosphoacceptor receiver (REC) domain of response regulators (RRs) and pseudo response regulators (PRRs); Two-component systems (TCSs) involving a sensor and a response regulator are used by bacteria to adapt to changing environments. Processes regulated by two-component systems in bacteria include sporulation, pathogenicity, virulence, chemotaxis, and membrane transport. Response regulators (RRs) share the common phosphoacceptor REC domain and different effector/output domains such as DNA, RNA, ligand-binding, protein-binding, or enzymatic domains. Response regulators regulate transcription, post-transcription or post-translation, or have functions such as methylesterases, adenylate or diguanylate cyclase, c-di-GMP-specific phosphodiesterases, histidine kinases, serine/threonine protein kinases, and protein phosphatases, depending on their output domains. The function of some output domains are still unknown. TCSs are found in all three domains of life - bacteria, archaea, and eukaryotes, however, the presence and abundance of particular RRs vary between the lineages. Archaea encode very few RRs with DNA-binding output domains; most are stand-alone REC domains. Among eukaryotes, TCSs are found primarily in protozoa, fungi, algae, and green plants. REC domains function as phosphorylation-mediated switches within RRs, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 489112050  59 YLAYALSRHlfsGTRTAVFQSVESALPSMQEPVIsQLVI-DIeslTLPYFDILERLRQLIKQRNDIQIfIMLSSRDED 135
Cdd:cd17574   12 LLSDYLEKE---GYEVDTAADGEEALELAREEQP-DLIIlDV---MLPGMDGFEVCRRLREKGSDIPI-IMLTAKDEE 81

phosphoacceptor receiver (REC) domain of OmpR family response regulators; OmpR-like proteins are one of the most widespread transcriptional regulators. OmpR family members contain REC and winged helix-turn-helix (wHTH) DNA-binding output effector domain. They are involved in the control of environmental stress tolerance (such as the oxidative, osmotic and acid stress response), motility, virulence, outer membrane biogenesis and other processes. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 489112050  59 YLAYALSRHlfsGTRTAVFQSVESALPSMQEPVIsQLVI-DIeslTLPYFDILERLRQLIKQRNDIQIfIMLSSRDED 135
Cdd:cd17574   12 LLSDYLEKE---GYEVDTAADGEEALELAREEQP-DLIIlDV---MLPGMDGFEVCRRLREKGSDIPI-IMLTAKDEE 81

phosphoacceptor receiver (REC) domain of OmpR family response regulators; OmpR-like proteins are one of the most widespread transcriptional regulators. OmpR family members contain REC and winged helix-turn-helix (wHTH) DNA-binding output effector domain. They are involved in the control of environmental stress tolerance (such as the oxidative, osmotic and acid stress response), motility, virulence, outer membrane biogenesis and other processes. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 489112050  59 YLAYALSRHlfsGTRTAVFQSVESALPSMQEPVIsQLVI-DIeslTLPYFDILERLRQLIKQRNDIQIfIMLSSRDED 135
Cdd:cd17574   12 LLSDYLEKE---GYEVDTAADGEEALELAREEQP-DLIIlDV---MLPGMDGFEVCRRLREKGSDIPI-IMLTAKDEE 81