phosphoacceptor receiver (REC) domain of hybrid sensor histidine kinases/response regulators similar to Arabidopsis thaliana CKI1 and Escherichia coli RcsC; This family is composed of hybrid sensor histidine kinases/response regulators that are sensor histidine kinases (HKs) fused with a REC domain, similar to the sensor histidine kinase CKI1 from Arabidopsis thaliana, which is involved in multi-step phosphorelay (MSP) signaling that mediates responses to a variety of important stimuli in plants. MSP involves a signal being transferred from HKs via histidine phosphotransfer proteins (AHP1-AHP5) to nuclear response regulators. The CKI1 REC domain specifically interacts with the downstream signaling protein AHP2, AHP3 and AHP5. The plant MSP system has evolved from the prokaryotic two-component system (TCS), which allows organisms to sense and respond to changes in environmental conditions. This family also includes bacterial hybrid sensor HKs such as Escherichia coli RcsC, which is a component of the Rcs signalling pathway that controls a variety of physiological functions like capsule synthesis, cell division, and motility. 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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   9 LIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLVTQadtlPDTVILLDLQMPDMNGFEFIDEFDQLSDGLRQkVR 88
Cdd:cd17546    3 VVDDNPVNRKVLKKLLEKLGYE--VDVAENGQEALELLKEE----PFDLVLMDLQMPVMDGLEATRRIRELEGGGRR-TP 75

                         90       100       110
                 ....*....|....*....|....*....|....*....
gi 506292086  89 IFMLSSTIDTRDIEKAKASqHIIDLLPKPLEIPFLKKKL 127
Cdd:cd17546   76 IIALTANALEEDREKCLEA-GMDDYLSKPVKLDQLKEVL 113

nitrogen regulation protein NR(I); Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   6 NFFLIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLVTQadtLPDtVILLDLQMPDMNGFEFIDEFdqlsdglrq 85
Cdd:PRK10923   5 IVWVVDDDSSIRWVLERALAGAGLT--CTTFENGNEVLEALASK---TPD-VLLSDIRMPGMDGLALLKQI--------- 69

                         90       100       110
                 ....*....|....*....|....*....|....*....
gi 506292086  86 KVRIFMLSSTIDT--RDIEKAKAS--QHIIDLLPKPLEI 120
Cdd:PRK10923  70 KQRHPMLPVIIMTahSDLDAAVSAyqQGAFDYLPKPFDI 108

Response regulator c-di-GMP phosphodiesterase, RpfG family, contains REC and HD-GYP domains [Signal transduction mechanisms];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   9 LIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQLSDGLRqkVR 88
Cdd:COG3437   11 IVDDDPENLELLRQLLRTLGYD--VVTAESGEEALELL---LEAPPD-LILLDVRMPGMDGFELLRLLRADPSTRD--IP 82

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|
gi 506292086  89 IFMLSSTIDTRDIEKAKASqHIIDLLPKPLEIPFLKKKLA 128
Cdd:COG3437   83 VIFLTALADPEDRERALEA-GADDYLTKPFDPEELLARVR 121

Two-component response regulator, PleD family, consists of two REC domains and a diguanylate cyclase (GGDEF) domain [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   9 LIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQLSDGlrQKVR 88
Cdd:COG3706    6 VVDDDPTNRKLLRRLLEAAGYE--VVEAADGEEALELL---QEHRPD-LILLDLEMPDMDGLELCRRLRADPRT--ADIP 77

                         90       100       110
                 ....*....|....*....|....*....|....*....
gi 506292086  89 IFMLSSTIDTRDIEKAKASQhIIDLLPKPLEIPFLKKKL 127
Cdd:COG3706   78 IIFLTALDDEEDRARALEAG-ADDYLTKPFDPEELLARV 115

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   9 LIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQLSdglrQKVR 88
Cdd:cd00156    2 IVDDDPAIRELLKSLLEREGYE--VDTAADGEEALELL---REERPD-LVLLDLMMPGMDGLELLRKLRELP----PDIP 71

                         90       100
                 ....*....|....*....|....*....
gi 506292086  89 IFMLSSTIDTRDIEKAKASqHIIDLLPKP 117
Cdd:cd00156   72 VIVLTAKADEEDAVRALEL-GADDYLVKP 99

DNA-binding transcriptional response regulator, NtrC family, contains REC, AAA-type ATPase, and a Fis-type DNA-binding domains [Signal transduction mechanisms];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   9 LIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQlsdgLRQKVR 88
Cdd:COG2204    7 VVDDDPDIRRLLKELLERAGYE--VETAASGEEALALL---REEPPD-LVLLDLRMPGMDGLELLRELRA----LDPDLP 76

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|
gi 506292086  89 IFMLSSTIDTRDIEKAKAsQHIIDLLPKPLEIPFLKKKLA 128
Cdd:COG2204   77 VILLTGYGDVETAVEAIK-AGAFDYLTKPFDLEELLAAVE 115

Response regulator receiver domain; This domain receives the signal from the sensor partner in bacterial two-component systems. It is usually found N-terminal to a DNA binding effector domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086    8 FLIDDSAFDLFIYEKLLIKSGItnSVKTFNSARDALKYLVTQAdtlPDtVILLDLQMPDMNGFEFIDEFDQLSDGlrqkV 87
Cdd:pfam00072   2 LIVDDDPLIRELLRQLLEKEGY--VVAEADDGKEALELLKEER---PD-LILLDINMPGMDGLELLKRIRRRDPT----T 71

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 506292086   88 RIFMLSSTIDTRDIEKAKaSQHIIDLLPKPLEIPFLKKKLA 128
Cdd:pfam00072  72 PVIILTAHGDEDDAVEAL-EAGADDFLSKPFDPDELLAAIR 111

Two-component response regulator, YesN/AraC family, consists of REC and AraC-type DNA-binding domains [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   6 NFFLIDDSAFDLFIYEKLLIKSGITNSVKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQLSdglrQ 85
Cdd:COG4753    1 KVLIVDDEPLIREGLKRILEWEAGFEVVGEAENGEEALELL---EEHKPD-LVITDINMPGMDGLELLEAIRELD----P 72

                         90       100       110
                 ....*....|....*....|....*....|..
gi 506292086  86 KVRIFMLSSTIDTRDIEKAKaSQHIIDLLPKP 117
Cdd:COG4753   73 DTKIIILSGYSDFEYAQEAI-KLGADDYLLKP 103

second phosphoacceptor receiver (REC) domain of Dictyostelium discoideum hybrid signal transduction histidine kinase D and similar domains; Dictyostelium discoideum hybrid signal transduction histidine kinase D (DhkD) is a large protein that contains two histidine kinase (HK) and two REC domains on the intracellular side of a single pass transmembrane domain, and extracellular PAS and PAC domains that likely are involved in ligand binding. This model represents the second REC domain and similar domains. DhkD activates the cAMP phosphodiesterase RegA to ensure proper prestalk and prespore patterning, tip formation, and the vertical elongation of the mound into a finger, in Dictyostelium discoideum. 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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086  33 VKTFNSARDALKYLVTQAdtlPDtVILLDLQMPDMNGFEFIDEFDQLSDGlrQKVRIFMLSSTIDTRDIEKAKASQ---H 109
Cdd:cd17580   25 VTTAHSGEEALEAAQRFR---PD-VILSDIGMPGMDGYELARRLRELPWL--ANTPAIALTGYGQPEDRERALEAGfdaH 98

                         90
                 ....*....|
gi 506292086 110 iidlLPKPLE 119
Cdd:cd17580   99 ----LVKPVD 104

phosphoacceptor receiver (REC) domain of C4-dicarboxylic acid transport protein D (DctD) and similar proteins; C4-dicarboxylic acid transport protein D (DctD) is part of the two-component regulatory system DctB/DctD, which regulates C4-dicarboxylate transport via regulation of expression of the dctPQM operon and dctA. It is an activator of sigma(54)-RNA polymerase holoenzyme that uses the energy released from ATP hydrolysis to stimulate the isomerization of a closed promoter complex to an open complex capable of initiating transcription. DctD is a member of the NtrC family, characterized by a domain architecture containing an N-terminal REC domain, followed by a central sigma-54 interaction/ATPase domain, and a C-terminal DNA binding domain. The ability of the central domain to hydrolyze ATP and thus to interact effectively with a complex of RNA polymerase, sigma54, and promoter, is controlled by the phosphorylation status of the REC domain. 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 506292086   8 FLIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKylvtQADTLPDTVILLDLQMPDMNGFEFIDEFDQLSDGL 83
Cdd:cd17549    2 LLVDDDADVREALQQTLELAGFR--VRAFADAEEALA----ALSPDFPGVVISDIRMPGMDGLELLAQIRELDPDL 71

nitrogen regulation protein NR(I); Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   6 NFFLIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLVTQadtLPDtVILLDLQMPDMNGFEFIDEFdqlsdglrq 85
Cdd:PRK10923   5 IVWVVDDDSSIRWVLERALAGAGLT--CTTFENGNEVLEALASK---TPD-VLLSDIRMPGMDGLALLKQI--------- 69

                         90       100       110
                 ....*....|....*....|....*....|....*....
gi 506292086  86 KVRIFMLSSTIDT--RDIEKAKAS--QHIIDLLPKPLEI 120
Cdd:PRK10923  70 KQRHPMLPVIIMTahSDLDAAVSAyqQGAFDYLPKPFDI 108

phosphoacceptor receiver (REC) domain of cyclic di-GMP phosphodiesterase PA4781 and similar domains; Pseudomonas aeruginosa cyclic di-GMP phosphodiesterase PA4781 contains an N-terminal REC domain and a C-terminal catalytic HD-GYP domain, characteristics of RpfG family response regulators. PA4781 is involved in cyclic di-3',5'-GMP (c-di-GMP) hydrolysis/degradation in a two-step reaction via the linear intermediate pGpG to produce GMP. Its unphosphorylated REC domain prevents accessibility of c-di-GMP to the active site. 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 506292086   8 FLIDDSAFDLFIYEKLLIKSGITnsVKTFNSARDALKYLVTQadtLPDtVILLDLQMPDMNGFE 71
Cdd:cd19920    2 LIVDDVPDNLRLLSELLRAAGYR--VLVATDGQQALQRAQAE---PPD-LILLDVMMPGMDGFE 59

DNA-binding response regulator, ActR/RegA family, consists of REC and Fis-type HTH domains [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   8 FLI--DDSAFdLFIYEKLLIKSGITnsVKTFNSARDALKYLVTQAdtlPDtVILLDLQMPDMNGFEFIDEFDQlsdgLRQ 85
Cdd:COG4567    7 LLLvdDDEAF-ARVLARALERRGFE--VTTAASVEEALALLEQAP---PD-YAVLDLRLGDGSGLDLIEALRE----RDP 75

                         90       100       110
                 ....*....|....*....|....*....|....*.
gi 506292086  86 KVRIFMLSstiDTRDIekAKASQHI----IDLLPKP 117
Cdd:COG4567   76 DARIVVLT---GYASI--ATAVEAIklgaDDYLAKP 106

phosphoacceptor receiver (REC) domain of plant ethylene receptors ETR1, ETR2, and EIN4, and similar proteins; Plant ethylene receptors contain N-terminal transmembrane domains that contain an ethylene binding site and also serve in localization of the receptor to the endoplasmic reticulum or the Golgi apparatus and a C-terminal histidine kinase (HK)-like domain. There are five ethylene receptors (ETR1, ERS1, ETR2, ERS2, and EIN4) in Arabidopsis thaliana. ETR1, ETR2, and EIN4 also contain REC domains C-terminal to the HK domain. ETR1 and ERS1 belong to subfamily 1, and have functional HK domains while ETR2, ERS2, and EIN4 belong to subfamily 2, and lack the necessary residues for HK activity and may function as serine/threonine kinases. The plant hormone ethylene plays an important role in plant growth and development. It regulates seed germination, seedling growth, leaf and petal abscission, fruit ripening, organ senescence, and pathogen responses. 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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   5 LNFFLIDDSAFDLFIYEKLLIKSGItnSVKTFNSARDALKYLvtQADTLPDTVILLDLQMPDMNGFEFIDEFDQLSdGLR 84
Cdd:cd19933    1 LKVLLVDDNAVNRMVTKGLLEKLGC--EVTTVSSGEECLNLL--ASAEHSFQLVLLDLCMPEMDGFEVALRIRKLF-GRR 75

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....
gi 506292086  85 QKVRIFMLssTIDTRDIEKAKASQHIID-LLPKPLEIPFLKKKL 127
Cdd:cd19933   76 ERPLIVAL--TANTDDSTREKCLSLGMNgVITKPVSLHALGDEL 117

phosphoacceptor receiver (REC) domain of DNA-binding transcriptional regulator NtrC; DNA-binding transcriptional regulator NtrC is also called nitrogen regulation protein NR(I) or nitrogen regulator I (NRI). It contains an N-terminal receiver (REC) domain, followed by a sigma-54 interaction domain, and a C-terminal helix-turn-helix DNA-binding domain. It is part of the two-component regulatory system NtrB/NtrC, which controls expression of the nitrogen-regulated (ntr) genes in response to nitrogen limitation. DNA-binding response regulator NtrC is phosphorylated by NtrB; phosphorylation of the N-terminal REC domain activates the central sigma-54 interaction domain and leads to the transcriptional activation from promoters that require sigma(54)-containing RNA polymerase. 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 506292086  11 DDSAFDlFIYEKLLIKSGItnSVKTFNSARDALKYLVTQAdtlPDtVILLDLQMPDMNGFEFIDEFDQ 78
Cdd:cd19919    8 DDSSIR-WVLERALAGAGL--TVTSFENAQEALAALASSQ---PD-VLISDIRMPGMDGLALLAQIKQ 68

phosphoacceptor receiver (REC) domain of nitrogen regulatory protein C 1 (NtrC1) from Aquifex aeolicus and similar NtrC family response regulators; NtrC family proteins are transcriptional regulators that have REC, AAA+ ATPase/sigma-54 interaction, and DNA-binding output domains. This subfamily of NtrC proteins include Aquifex aeolicus NtrC1 and Vibrio quorum-sensing signal integrator LuxO. The N-terminal REC domain of NtrC proteins regulate the activity of the protein and its phosphorylation controls the AAA+ domain oligomerization, while the central AAA+ domain participates in nucleotide binding, hydrolysis, oligomerization, and sigma54 interaction. 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 506292086   9 LIDDSAFDLFIYEKLLIKSGItnSVKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQ 78
Cdd:cd17572    3 LVEDSPSLAALYQEYLSDEGY--KVTHVETGKEALAFL---SDQPPD-VVLLDLKLPDMSGMEILKWIQE 66

phosphoacceptor receiver (REC) domain of chemotaxis response regulator protein-glutamate methylesterase CheB and similar chemotaxis proteins; Methylesterase CheB is a chemotaxis response regulator with an N-terminal REC domain and a C-terminal methylesterase domain. Chemotaxis is a behavior known in motile bacteria that directs their movement in response to chemical gradients. CheB is a phosphorylation-activated response regulator involved in the reversible modification of bacterial chemotaxis receptors. It catalyzes the demethylation of specific methylglutamate residues introduced into the chemoreceptors (methyl-accepting chemotaxis proteins) by CheR. The CheB REC domain packs against the active site of the C-terminal domain and inhibits methylesterase activity by directly restricting access to the active site. Also included in this family is chemotaxis response regulator CheY, which contains a stand-alone REC domain, and an uncharacterized subfamily composed of proteins containing an N-terminal REC domain and a C-terminal CheY-P phosphatase (CheC) domain. 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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086  10 IDDSAFdlfiYEKLLiKSGITNS-----VKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFEFIDEFDQlsdglR 84
Cdd:cd17541    6 VDDSAV----MRKLL-SRILESDpdievVGTARDGEEALEKI---KELKPD-VITLDIEMPVMDGLEALRRIMA-----E 71

                         90
                 ....*....|
gi 506292086  85 QKVRIFMLSS 94
Cdd:cd17541   72 RPTPVVMVSS 81

phosphoacceptor receiver (REC) domain of hydrogen uptake protein regulator (HupR) and similar domains; This family is composed of mostly uncharacterized response regulators with similarity to the REC domains of response regulator components of two-component systems that regulates hydrogenase activity, including HupR and HoxA. HupR is part of the HupT/HupR system that controls the synthesis of the membrane-bound [NiFe]hydrogenase, HupSL, of the photosynthetic bacterium Rhodobacter capsulatus. It contains an N-terminal REC domain, a central sigma-54 interaction domain that lacks ATPase activity, and a C-terminal DNA-binding domain. Members of this family contain a REC domain and various output domains including the cyclase homology domain (CHD) and the c-di-GMP phosphodiesterase domains, HD-GYP and EAL. 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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086  33 VKTFNSARDALKYLVTQadtlPDTVILLDLQMPDMNGFEFIDEfdqlsdgLRQK----VRIfMLSSTIDTRDIEKAKASQ 108
Cdd:cd17569   27 VLTATSGEEALEILKQE----PVDVVISDQRMPGMDGAELLKR-------VRERypdtVRI-LLTGYADLDAAIEAINEG 94

                         90
                 ....*....|....*....
gi 506292086 109 HIIDLLPKPLEIPFLKKKL 127
Cdd:cd17569   95 EIYRFLTKPWDDEELKETI 113

first (D1) phosphoacceptor receiver (REC) domain of response regulator PleD and similar domains; PleD contains a REC domain (D1) with the phosphorylatable aspartate, a REC-like adaptor domain (D2), and the enzymatic diguanylate cyclase (DGC) domain, also called the GGDEF domain according to a conserved sequence motif, as its output domain. The GGDEF-containing PleD response regulators are global regulators of cell metabolism in some important human pathogens. This model describes D1 of PleD and similar domains. 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 506292086   9 LIDDSAFDLFIYEKLLikSGITNSVKTFNSARDALKYLVTQadtLPDtVILLDLQMPDMNGFE 71
Cdd:cd17538    4 VVDDEPANRELLEALL--SAEGYEVLTADSGQEALALAEEE---LPD-LILLDVMMPGMDGFE 60

response regulator PleD; Reviewed

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 506292086  33 VKTFNSARDALKYLvtqADTLPDtVILLDLQMPDMNGFE 71
Cdd:PRK09581  29 VLTASSGAEAIAIC---EREQPD-IILLDVMMPGMDGFE 63

phosphoacceptor receiver (REC) domain of chemotaxis protein CheV and similar proteins; This subfamily includes the REC domains of Bacillus subtilis chemotaxis protein CheV, Myxococcus xanthus gliding motility regulatory protein FrzE, and similar proteins. CheV is a hybrid protein with an N-terminal CheW-like domain and a C-terminal CheY-like REC domain. The CheV pathway is one of three systems employed by B. subtilis for sensory adaptation that contribute to chemotaxis. It is involved in the transmission of sensory signals from chemoreceptors to flagellar motors. Together with CheW, it is involved in the coupling of methyl-accepting chemoreceptors to the central two-component histidine kinase CheA. FrzE is a hybrid sensor histidine kinase/response regulator that is part of the Frz pathway that controls cell reversal frequency to support directional motility during swarming and fruiting body formation. 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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 506292086   9 LIDDSAFDLFIYEKLLIKSGItnSVKTFNSARDALKYLVTQADTLPDT-----VILLDLQMPDMNGFEFIDEFDqlSDGL 83
Cdd:cd19924    3 VVDDSPTARKQLRDLLKNLGF--EIAEAVDGEEALNKLENLAKEGNDLskeldLIITDIEMPKMDGYELTFELR--DDPR 78

                         90       100
                 ....*....|....*....|..
gi 506292086  84 RQKVRIFMLSSTIDTRDIEKAK 105
Cdd:cd19924   79 LANIPVILNSSLSGEFSRARGK 100

phosphoacceptor receiver (REC) domain of chemotaxis response regulator CheY4 and similar CheY family proteins; CheY family chemotaxis response regulators (RRs) comprise about 17% of bacterial RRs and almost half of all RRs in archaea. This subfamily contains Vibrio cholerae CheY4 and similar CheY family RRs. CheY proteins control bacterial motility and participate in signaling phosphorelays and in protein-protein interactions. CheY RRs contain only the REC domain with no output/effector domain. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 506292086  57 VILLDLQMPDMNGFEFIDEFDQLSDglRQKVRIFMLssTIDTRDIEKAKA 106
Cdd:cd17562   47 LIITDQNMPNMDGIELIKELRKLPA--YKFTPILML--TTESSDEKKQEG 92

phosphoacceptor receiver (REC) domain of LytTR/AlgR family response regulators similar to AlgR; Members of the LytTR/AlgR family of response regulators contain a REC domain and a unique LytTR DNA-binding output domain that lacks the helix-turn-helix motif and consists mostly of beta-strands. Transcriptional regulators with the LytTR-type output domains are involved in biosynthesis of extracellular polysaccharides, fimbriation, expression of exoproteins, including toxins, and quorum sensing. Included in this AlgR-like group of LytTR/AlgR family response regulators are Streptococcus agalactiae sensory transduction protein LytR, Pseudomonas aeruginosa positive alginate biosynthesis regulatory protein AlgR, Bacillus subtilis sensory transduction protein LytT, and Escherichia coli transcriptional regulatory protein BtsR, which are members of two-component regulatory systems. LytR and LytT are components of regulatory systems that regulate genes involved in cell wall metabolism. AlgR positively regulates the algD gene, which codes for a GDP-mannose dehydrogenase, a key enzyme in the alginate biosynthesis pathway. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 506292086  33 VKTFNSARDALKYLVTQAdtlPDtVILLDLQMPDMNGFEFIDEFDQLS 80
Cdd:cd17532   27 VGEAENGEEALEAIEELK---PD-VVFLDIQMPGLDGLELAKKLSKLA 70