ID AHK4_ARATH Reviewed; 1080 AA. AC Q9C5U0; A5YY60; A5YY75; Q9C5T8; Q9C5T9; Q9FDZ3; Q9SIT0; DT 05-OCT-2010, integrated into UniProtKB/Swiss-Prot. DT 01-JUN-2001, sequence version 1. DT 24-JAN-2024, entry version 154. DE RecName: Full=Histidine kinase 4; DE EC=2.7.13.3; DE AltName: Full=Arabidopsis histidine kinase 4; DE Short=AtHK4; DE AltName: Full=Cytokinin receptor CYTOKININ RESPONSE 1; DE Short=AtCRE1; DE Short=Cytokinin receptor CRE1; DE AltName: Full=Phosphoprotein phosphatase AHK4; DE EC=3.1.3.16; DE AltName: Full=Protein AUTHENTIC HIS-KINASE 4; DE AltName: Full=Protein ROOT AS IN WOL 1; DE AltName: Full=Protein WOODEN LEG; GN Name=AHK4; Synonyms=CRE1, RAW1, WOL; OrderedLocusNames=At2g01830; GN ORFNames=T23K3.2; OS Arabidopsis thaliana (Mouse-ear cress). OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae; OC rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis. OX NCBI_TaxID=3702; RN [1] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2), TISSUE SPECIFICITY, DEVELOPMENTAL RP STAGE, FUNCTION, AND MUTAGENESIS OF THR-301. RC STRAIN=cv. Columbia; TISSUE=Root; RX PubMed=11114883; DOI=10.1101/gad.189200; RA Maehoenen A.P., Bonke M., Kauppinen L., Riikonen M., Benfey P.N., RA Helariutta Y.; RT "A novel two-component hybrid molecule regulates vascular morphogenesis of RT the Arabidopsis root."; RL Genes Dev. 14:2938-2943(2000). RN [2] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2), FUNCTION, ACTIVITY RP REGULATION, AND MUTAGENESIS OF HIS-482; GLY-490 AND ASP-996. RC STRAIN=cv. Wassilewskija; TISSUE=Seedling; RX PubMed=11234017; DOI=10.1038/35059117; RA Inoue T., Higuchi M., Hashimoto Y., Seki M., Kobayashi M., Kato T., RA Tabata S., Shinozaki K., Kakimoto T.; RT "Identification of CRE1 as a cytokinin receptor from Arabidopsis."; RL Nature 409:1060-1063(2001). RN [3] RP NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2), AND TISSUE SPECIFICITY. RX PubMed=11230578; DOI=10.1093/pcp/pce015; RA Ueguchi C., Koizumi H., Suzuki T., Mizuno T.; RT "Novel family of sensor histidine kinase genes in Arabidopsis thaliana."; RL Plant Cell Physiol. 42:231-235(2001). RN [4] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=cv. Columbia; RX PubMed=10617197; DOI=10.1038/45471; RA Lin X., Kaul S., Rounsley S.D., Shea T.P., Benito M.-I., Town C.D., RA Fujii C.Y., Mason T.M., Bowman C.L., Barnstead M.E., Feldblyum T.V., RA Buell C.R., Ketchum K.A., Lee J.J., Ronning C.M., Koo H.L., Moffat K.S., RA Cronin L.A., Shen M., Pai G., Van Aken S., Umayam L., Tallon L.J., RA Gill J.E., Adams M.D., Carrera A.J., Creasy T.H., Goodman H.M., RA Somerville C.R., Copenhaver G.P., Preuss D., Nierman W.C., White O., RA Eisen J.A., Salzberg S.L., Fraser C.M., Venter J.C.; RT "Sequence and analysis of chromosome 2 of the plant Arabidopsis thaliana."; RL Nature 402:761-768(1999). RN [5] RP GENOME REANNOTATION. RC STRAIN=cv. Columbia; RX PubMed=27862469; DOI=10.1111/tpj.13415; RA Cheng C.Y., Krishnakumar V., Chan A.P., Thibaud-Nissen F., Schobel S., RA Town C.D.; RT "Araport11: a complete reannotation of the Arabidopsis thaliana reference RT genome."; RL Plant J. 89:789-804(2017). RN [6] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 722-983, AND VARIANT ASN-765. RC STRAIN=cv. Ag-0, cv. An-1, cv. Br-0, cv. C24, cv. Ct-1, cv. Cvi-1, cv. RC Edi-0, cv. Ga-0, cv. Kas-2, cv. Kin-0, cv. Landsberg erecta, cv. Ll-0, RC cv. Lz-0, cv. Ms-0, cv. Mt-0, cv. Nd-1, cv. Nok-3, cv. Oy-0, cv. Se-0, RC cv. Sorbo, cv. Tsu-1, cv. Van-0, cv. Wa-1, and cv. Wassilewskija; RX PubMed=17435248; DOI=10.1534/genetics.107.071928; RA Ehrenreich I.M., Stafford P.A., Purugganan M.D.; RT "The genetic architecture of shoot branching in Arabidopsis thaliana: a RT comparative assessment of candidate gene associations vs. quantitative RT trait locus mapping."; RL Genetics 176:1223-1236(2007). RN [7] RP FUNCTION, AND INTERACTION WITH AHP1; AHP2; AHP3 AND AHP5. RX PubMed=11230563; DOI=10.1093/pcp/pce037; RA Suzuki T., Miwa K., Ishikawa K., Yamada H., Aiba H., Mizuno T.; RT "The Arabidopsis sensor His-kinase, AHk4, can respond to cytokinins."; RL Plant Cell Physiol. 42:107-113(2001). RN [8] RP FUNCTION, AND DISRUPTION PHENOTYPE. RX PubMed=11479382; DOI=10.1093/pcp/pce094; RA Ueguchi C., Sato S., Kato T., Tabata S.; RT "The AHK4 gene involved in the cytokinin-signaling pathway as a direct RT receptor molecule in Arabidopsis thaliana."; RL Plant Cell Physiol. 42:751-755(2001). RN [9] RP FUNCTION, ACTIVATION BY CYTOKININS, AND MUTAGENESIS OF THR-301. RX PubMed=11577198; DOI=10.1093/pcp/pce127; RA Yamada H., Suzuki T., Terada K., Takei K., Ishikawa K., Miwa K., RA Yamashino T., Mizuno T.; RT "The Arabidopsis AHK4 histidine kinase is a cytokinin-binding receptor that RT transduces cytokinin signals across the membrane."; RL Plant Cell Physiol. 42:1017-1023(2001). RN [10] RP REVIEW. RX PubMed=11435149; DOI=10.1016/s1360-1385(01)02011-8; RA Schmuelling T.; RT "CREam of cytokinin signalling: receptor identified."; RL Trends Plant Sci. 6:281-284(2001). RN [11] RP REVIEW. RX PubMed=12589073; DOI=10.1266/ggs.77.383; RA Oka A., Sakai H., Iwakoshi S.; RT "His-Asp phosphorelay signal transduction in higher plants: receptors and RT response regulators for cytokinin signaling in Arabidopsis thaliana."; RL Genes Genet. Syst. 77:383-391(2002). RN [12] RP FUNCTION, AND MUTAGENESIS OF GLY-490. RX PubMed=12354925; DOI=10.1093/pcp/pcf121; RA Kiba T., Yamada H., Mizuno T.; RT "Characterization of the ARR15 and ARR16 response regulators with special RT reference to the cytokinin signaling pathway mediated by the AHK4 histidine RT kinase in roots of Arabidopsis thaliana."; RL Plant Cell Physiol. 43:1059-1066(2002). RN [13] RP FUNCTION, DISRUPTION PHENOTYPE, INDUCTION, AND MUTAGENESIS OF GLY-493; RP THR-1008 AND ALA-1032. RX PubMed=12410813; DOI=10.1046/j.1365-313x.2002.01431.x; RA Franco-Zorrilla J.M., Martin A.C., Solano R., Rubio V., Leyva A., RA Paz-Ares J.; RT "Mutations at CRE1 impair cytokinin-induced repression of phosphate RT starvation responses in Arabidopsis."; RL Plant J. 32:353-360(2002). RN [14] RP GENE FAMILY, AND NOMENCLATURE. RX PubMed=12068096; DOI=10.1104/pp.005504; RA Hwang I., Chen H.-C., Sheen J.; RT "Two-component signal transduction pathways in Arabidopsis."; RL Plant Physiol. 129:500-515(2002). RN [15] RP FUNCTION, DISRUPTION PHENOTYPE, TISSUE SPECIFICITY, AND DEVELOPMENTAL RP STAGE. RX PubMed=15155880; DOI=10.1105/tpc.021477; RA Nishimura C., Ohashi Y., Sato S., Kato T., Tabata S., Ueguchi C.; RT "Histidine kinase homologs that act as cytokinin receptors possess RT overlapping functions in the regulation of shoot and root growth in RT Arabidopsis."; RL Plant Cell 16:1365-1377(2004). RN [16] RP FUNCTION. RX PubMed=15509853; DOI=10.1093/pcp/pch132; RA Spichal L., Rakova N.Y., Riefler M., Mizuno T., Romanov G.A., Strnad M., RA Schmuelling T.; RT "Two cytokinin receptors of Arabidopsis thaliana, CRE1/AHK4 and AHK3, RT differ in their ligand specificity in a bacterial assay."; RL Plant Cell Physiol. 45:1299-1305(2004). RN [17] RP FUNCTION, AND MUTAGENESIS OF THR-301 AND LEU-529. RX PubMed=15053761; DOI=10.1111/j.1365-313x.2004.02023.x; RA de Leon B.G.-P., Zorrilla J.M.F., Rubio V., Dahiya P., Paz-Ares J., RA Leyva A.; RT "Interallelic complementation at the Arabidopsis CRE1 locus uncovers RT independent pathways for the proliferation of vascular initials and RT canonical cytokinin signalling."; RL Plant J. 38:70-79(2004). RN [18] RP FUNCTION, AND MUTAGENESIS OF GLY-490. RX PubMed=15144379; DOI=10.1111/j.1365-313x.2004.02079.x; RA Maruyama-Nakashita A., Nakamura Y., Yamaya T., Takahashi H.; RT "A novel regulatory pathway of sulfate uptake in Arabidopsis roots: RT implication of CRE1/WOL/AHK4-mediated cytokinin-dependent regulation."; RL Plant J. 38:779-789(2004). RN [19] RP FUNCTION, TISSUE SPECIFICITY, AND DISRUPTION PHENOTYPE. RX PubMed=15166290; DOI=10.1073/pnas.0402887101; RA Higuchi M., Pischke M.S., Maehoenen A.P., Miyawaki K., Hashimoto Y., RA Seki M., Kobayashi M., Shinozaki K., Kato T., Tabata S., Helariutta Y., RA Sussman M.R., Kakimoto T.; RT "In planta functions of the Arabidopsis cytokinin receptor family."; RL Proc. Natl. Acad. Sci. U.S.A. 101:8821-8826(2004). RN [20] RP FUNCTION, AND BIOPHYSICOCHEMICAL PROPERTIES. RX PubMed=16246292; DOI=10.1016/j.ab.2005.09.012; RA Romanov G.A., Spichal L., Lomin S.N., Strnad M., Schmuelling T.; RT "A live cell hormone-binding assay on transgenic bacteria expressing a RT eukaryotic receptor protein."; RL Anal. Biochem. 347:129-134(2005). RN [21] RP FUNCTION, AND DISRUPTION PHENOTYPE. RX PubMed=15923327; DOI=10.1104/pp.105.060517; RA Franco-Zorrilla J.M., Martin A.C., Leyva A., Paz-Ares J.; RT "Interaction between phosphate-starvation, sugar, and cytokinin signaling RT in Arabidopsis and the roles of cytokinin receptors CRE1/AHK4 and AHK3."; RL Plant Physiol. 138:847-857(2005). RN [22] RP FUNCTION. RX PubMed=15728338; DOI=10.1104/pp.104.057174; RA Mok M.C., Martin R.C., Dobrev P.I., Vankova R., Ho P.S., RA Yonekura-Sakakibara K., Sakakibara H., Mok D.W.; RT "Topolins and hydroxylated thidiazuron derivatives are substrates of RT cytokinin O-glucosyltransferase with position specificity related to RT receptor recognition."; RL Plant Physiol. 137:1057-1066(2005). RN [23] RP FUNCTION, PHOSPHORYLATION AT HIS-482, MUTAGENESIS OF THR-301; HIS-482; RP PHE-708 AND ASP-996, DISRUPTION PHENOTYPE, AND DEVELOPMENTAL STAGE. RX PubMed=16753566; DOI=10.1016/j.cub.2006.04.030; RA Maehoenen A.P., Higuchi M., Toermaekangas K., Miyawaki K., Pischke M.S., RA Sussman M.R., Helariutta Y., Kakimoto T.; RT "Cytokinins regulate a bidirectional phosphorelay network in Arabidopsis."; RL Curr. Biol. 16:1116-1122(2006). RN [24] RP INTERACTION WITH AHP1; AHP2; AHP3; AHP5 AND AHK3. RX PubMed=16965536; DOI=10.1111/j.1742-4658.2006.05467.x; RA Dortay H., Mehnert N., Buerkle L., Schmuelling T., Heyl A.; RT "Analysis of protein interactions within the cytokinin-signaling pathway of RT Arabidopsis thaliana."; RL FEBS J. 273:4631-4644(2006). RN [25] RP FUNCTION, AND BIOPHYSICOCHEMICAL PROPERTIES. RX PubMed=17075078; DOI=10.1093/jxb/erl179; RA Romanov G.A., Lomin S.N., Schmuelling T.; RT "Biochemical characteristics and ligand-binding properties of Arabidopsis RT cytokinin receptor AHK3 compared to CRE1/AHK4 as revealed by a direct RT binding assay."; RL J. Exp. Bot. 57:4051-4058(2006). RN [26] RP FUNCTION, AND DISRUPTION PHENOTYPE. RX PubMed=16361392; DOI=10.1105/tpc.105.037796; RA Riefler M., Novak O., Strnad M., Schmuelling T.; RT "Arabidopsis cytokinin receptor mutants reveal functions in shoot growth, RT leaf senescence, seed size, germination, root development, and cytokinin RT metabolism."; RL Plant Cell 18:40-54(2006). RN [27] RP FUNCTION, DISRUPTION PHENOTYPE, AND MUTAGENESIS OF MET-459 AND GLY-490. RX PubMed=16357038; DOI=10.1093/pcp/pci240; RA Kuroha T., Ueguchi C., Sakakibara H., Satoh S.; RT "Cytokinin receptors are required for normal development of auxin- RT transporting vascular tissues in the hypocotyl but not in adventitious RT roots."; RL Plant Cell Physiol. 47:234-243(2006). RN [28] RP FUNCTION. RX PubMed=17216481; DOI=10.1007/s00425-006-0464-0; RA Horiuchi J., Badri D.V., Kimball B.A., Negre F., Dudareva N., Paschke M.W., RA Vivanco J.M.; RT "The floral volatile, methyl benzoate, from snapdragon (Antirrhinum majus) RT triggers phytotoxic effects in Arabidopsis thaliana."; RL Planta 226:1-10(2007). RN [29] RP FUNCTION, AND MUTAGENESIS OF THR-301; GLY-435; PHE-436; MET-447; VAL-471 RP AND MET-494. RX PubMed=17956858; DOI=10.1093/pcp/pcm145; RA Miwa K., Ishikawa K., Terada K., Yamada H., Suzuki T., Yamashino T., RA Mizuno T.; RT "Identification of amino acid substitutions that render the Arabidopsis RT cytokinin receptor histidine kinase AHK4 constitutively active."; RL Plant Cell Physiol. 48:1809-1814(2007). RN [30] RP FUNCTION, INDUCTION, AND DISRUPTION PHENOTYPE. RX PubMed=18077346; DOI=10.1073/pnas.0706547105; RA Tran L.S., Urao T., Qin F., Maruyama K., Kakimoto T., Shinozaki K., RA Yamaguchi-Shinozaki K.; RT "Functional analysis of AHK1/ATHK1 and cytokinin receptor histidine kinases RT in response to abscisic acid, drought, and salt stress in Arabidopsis."; RL Proc. Natl. Acad. Sci. U.S.A. 104:20623-20628(2007). RN [31] RP FUNCTION, AND DISRUPTION PHENOTYPE. RX PubMed=17965178; DOI=10.1104/pp.107.107953; RA Lopez-Bucio J., Millan-Godinez M., Mendez-Bravo A., Morquecho-Contreras A., RA Ramirez-Chavez E., Molina-Torres J., Perez-Torres A., Higuchi M., RA Kakimoto T., Herrera-Estrella L.; RT "Cytokinin receptors are involved in alkamide regulation of root and shoot RT development in Arabidopsis."; RL Plant Physiol. 145:1703-1713(2007). RN [32] RP FUNCTION. RX PubMed=18571199; DOI=10.1016/j.jmb.2008.05.044; RA Kopecny D., Sebela M., Briozzo P., Spichal L., Houba-Herin N., Masek V., RA Joly N., Madzak C., Anzenbacher P., Laloue M.; RT "Mechanism-based inhibitors of cytokinin oxidase/dehydrogenase attack FAD RT cofactor."; RL J. Mol. Biol. 380:886-899(2008). RN [33] RP INTERACTION WITH AHP2; AMPD; WNK5 AND AT4G15630. RX PubMed=18642946; DOI=10.1021/pr0703831; RA Dortay H., Gruhn N., Pfeifer A., Schwerdtner M., Schmuelling T., Heyl A.; RT "Toward an interaction map of the two-component signaling pathway of RT Arabidopsis thaliana."; RL J. Proteome Res. 7:3649-3660(2008). RN [34] RP FUNCTION. RX PubMed=18785832; DOI=10.1094/mpmi-21-10-1371; RA Vadassery J., Ritter C., Venus Y., Camehl I., Varma A., Shahollari B., RA Novak O., Strnad M., Ludwig-Mueller J., Oelmueller R.; RT "The role of auxins and cytokinins in the mutualistic interaction between RT Arabidopsis and Piriformospora indica."; RL Mol. Plant Microbe Interact. 21:1371-1383(2008). RN [35] RP FUNCTION, AND DISRUPTION PHENOTYPE. RX PubMed=18397377; DOI=10.1111/j.1365-313x.2008.03502.x; RA Seguela M., Briat J.-F., Vert G., Curie C.; RT "Cytokinins negatively regulate the root iron uptake machinery in RT Arabidopsis through a growth-dependent pathway."; RL Plant J. 55:289-300(2008). RN [36] RP FUNCTION, AND ACTIVITY REGULATION. RX PubMed=19032596; DOI=10.1111/j.1742-4658.2008.06777.x; RA Spichal L., Werner T., Popa I., Riefler M., Schmuelling T., Strnad M.; RT "The purine derivative PI-55 blocks cytokinin action via receptor RT inhibition."; RL FEBS J. 276:244-253(2009). RN [37] RP FUNCTION, AND DISRUPTION PHENOTYPE. RX PubMed=20110319; DOI=10.1242/dev.041426; RA Skylar A., Hong F., Chory J., Weigel D., Wu X.; RT "STIMPY mediates cytokinin signaling during shoot meristem establishment in RT Arabidopsis seedlings."; RL Development 137:541-549(2010). RN [38] RP ACTIVITY REGULATION. RX PubMed=20189204; DOI=10.1016/j.phytochem.2010.01.018; RA Nisler J., Zatloukal M., Popa I., Dolezal K., Strnad M., Spichal L.; RT "Cytokinin receptor antagonists derived from 6-benzylaminopurine."; RL Phytochemistry 71:823-830(2010). RN [39] RP SUBCELLULAR LOCATION. RC STRAIN=cv. Columbia; RX PubMed=21709172; DOI=10.1104/pp.111.180539; RA Wulfetange K., Lomin S.N., Romanov G.A., Stolz A., Heyl A., Schmuelling T.; RT "The cytokinin receptors of Arabidopsis are located mainly to the RT endoplasmic reticulum."; RL Plant Physiol. 156:1808-1818(2011). RN [40] RP INTERACTION WITH FBR12 AND AHP1. RX PubMed=24163315; DOI=10.1105/tpc.113.116236; RA Ren B., Chen Q., Hong S., Zhao W., Feng J., Feng H., Zuo J.; RT "The Arabidopsis eukaryotic translation initiation factor eIF5A-2 regulates RT root protoxylem development by modulating cytokinin signaling."; RL Plant Cell 25:3841-3857(2013). RN [41] {ECO:0007744|PDB:3T4J, ECO:0007744|PDB:3T4K, ECO:0007744|PDB:3T4L, ECO:0007744|PDB:3T4O, ECO:0007744|PDB:3T4Q, ECO:0007744|PDB:3T4S, ECO:0007744|PDB:3T4T} RP X-RAY CRYSTALLOGRAPHY (1.53 ANGSTROMS) OF 149-418 IN COMPLEXES WITH THE RP CYTOKININS TRANS-ZEATIN; DIHYDROZEATIN; N(6)-DIMETHYLALLYLADENINE AND RP KINETIN OR THE HERBICIDE THIDIAZURON, SUBUNIT, AND MUTAGENESIS OF ALA-225; RP ALA-227; TYR-273; MET-279; ASP-285; THR-301; PRO-303; PHE-304; LEU-306; RP LEU-307; THR-317 AND GLY-343. RX PubMed=21964459; DOI=10.1038/nchembio.667; RA Hothorn M., Dabi T., Chory J.; RT "Structural basis for cytokinin recognition by Arabidopsis thaliana RT histidine kinase 4."; RL Nat. Chem. Biol. 7:766-768(2011). CC -!- FUNCTION: Cytokinins (CK) receptor related to bacterial two-component CC regulators. Binds also the synthetic urea-type cytokinin thidiazuron, a CC potent defoliant and herbicide. Functions as a histidine kinase and CC transmits the stress signal to a downstream MAPK cascade. This protein CC undergoes an ATP-dependent autophosphorylation at a conserved histidine CC residue in the kinase core, and a phosphoryl group is then transferred CC to a conserved aspartate residue in the receiver domain. In the CC presence of cytokinin, feeds phosphate to phosphorelay-integrating CC histidine phosphotransfer protein (HPt) and activates subsequent CC cascade. In the absence of cytokinin, removes phosphate from HPt CC proteins, decreasing the system phosphoload. Involved in meristems CC establishment in seedlings. Acts as a redundant negative regulator of CC drought and salt stress responses, and abscisic acid (ABA) signaling in CC a cytokinin-dependent manner. Required to set vascular asymmetric cell CC divisions that establish phloem and procambium cell lines. Redundant CC positive regulator of cytokinin signaling that regulates many CC developmental processes including seed germination, cell division, seed CC size, chlorophyll retention during leaf senescence, root repression and CC shoot promotion. Can interact with isoprenoid-type cytokinins trans- CC zeatin (tZ and tZR), isopentenyladenine (iP), and isopentenyladenosine CC (iPR), the meta hydroxylated derivative of benzyladenine m-topolin, CC buta-2,3-dienyladenine (HA-8), penta-2,3-dienyladenine (HA-1), 4- CC methyl-penta-2,3-dienyladenine (HA-10), 4-hydroxy-2-butynyladenine CC (RM1), 2-butynyladenine (RM6), and to a lower extent, with cis-zeatin CC (cZ), zeatin riboside and dihydrozeatin (DZ). Together with AHK3, CC involved in the cytokinin-dependent responses to Pi starvation and CC sucrose stresses. Required for the formation of auxin-transporting CC vascular tissues in the hypocotyl, and primary and lateral roots, but CC not in adventitious roots, thus leading to auxin basipetal transport CC that regulates root development and branching. Involved in alkamides CC (e.g. N-isobutyl decanamide) and N-acylethanolamides (NAE) signaling CC that control meristematic activity and differentiation processes during CC plant development. Prevents the uptake of sulfate by mediating CC cytokinin-dependent down-regulation of high-affinity sulfate CC transporters (e.g. SULTR1;1 and SULTR1;2) expression in roots. Together CC with AHK2, required for growth and reproduction promotion stimulated by CC the endophytic fungus Piriformospora indica in a trans-zeatin-dependent CC manner. Required to trigger the phytotoxic effect of the snapdragon CC (Antirrhinum majus) flowers volatile organic compound (VOC) methyl CC benzoate (MB). Plays a role in the cytokinin-mediated repression of the CC iron uptake pathway. {ECO:0000269|PubMed:11114883, CC ECO:0000269|PubMed:11230563, ECO:0000269|PubMed:11234017, CC ECO:0000269|PubMed:11479382, ECO:0000269|PubMed:11577198, CC ECO:0000269|PubMed:12354925, ECO:0000269|PubMed:12410813, CC ECO:0000269|PubMed:15053761, ECO:0000269|PubMed:15144379, CC ECO:0000269|PubMed:15155880, ECO:0000269|PubMed:15166290, CC ECO:0000269|PubMed:15509853, ECO:0000269|PubMed:15728338, CC ECO:0000269|PubMed:15923327, ECO:0000269|PubMed:16246292, CC ECO:0000269|PubMed:16357038, ECO:0000269|PubMed:16361392, CC ECO:0000269|PubMed:16753566, ECO:0000269|PubMed:17075078, CC ECO:0000269|PubMed:17216481, ECO:0000269|PubMed:17956858, CC ECO:0000269|PubMed:17965178, ECO:0000269|PubMed:18077346, CC ECO:0000269|PubMed:18397377, ECO:0000269|PubMed:18571199, CC ECO:0000269|PubMed:18785832, ECO:0000269|PubMed:19032596, CC ECO:0000269|PubMed:20110319}. CC -!- CATALYTIC ACTIVITY: CC Reaction=ATP + protein L-histidine = ADP + protein N-phospho-L- CC histidine.; EC=2.7.13.3; CC -!- CATALYTIC ACTIVITY: CC Reaction=H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + CC phosphate; Xref=Rhea:RHEA:20629, Rhea:RHEA-COMP:9863, Rhea:RHEA- CC COMP:11604, ChEBI:CHEBI:15377, ChEBI:CHEBI:29999, ChEBI:CHEBI:43474, CC ChEBI:CHEBI:83421; EC=3.1.3.16; CC -!- CATALYTIC ACTIVITY: CC Reaction=H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + CC phosphate; Xref=Rhea:RHEA:47004, Rhea:RHEA-COMP:11060, Rhea:RHEA- CC COMP:11605, ChEBI:CHEBI:15377, ChEBI:CHEBI:30013, ChEBI:CHEBI:43474, CC ChEBI:CHEBI:61977; EC=3.1.3.16; CC -!- ACTIVITY REGULATION: Activated by cytokinins to initiate phosphorelay CC signaling. This cytokinin-mediated activation is repressed by the CC trans-zeatin antagonists 6-(2-hydroxy-3-methylbenzylamino)purine (PI- CC 55) and 6-(2,5-dihydroxybenzylamino)purine (LGR-991). CC {ECO:0000269|PubMed:11234017, ECO:0000269|PubMed:19032596, CC ECO:0000269|PubMed:20189204}. CC -!- BIOPHYSICOCHEMICAL PROPERTIES: CC pH dependence: CC Optimum pH to bind cytokinin is about 7-8.5 at 0 degrees Celsius. CC {ECO:0000269|PubMed:16246292, ECO:0000269|PubMed:17075078}; CC Temperature dependence: CC Cytokinin-binding is more stable at 0 degrees Celsius than at 20 and CC 37 degrees Celsius. {ECO:0000269|PubMed:16246292, CC ECO:0000269|PubMed:17075078}; CC -!- SUBUNIT: Homodimer. Interacts with AHP1, AHP2, AHP3, AHP5, AHK3, AMPD, CC FBR12, WNK5 and At4g15630. {ECO:0000269|PubMed:11230563, CC ECO:0000269|PubMed:16965536, ECO:0000269|PubMed:18642946, CC ECO:0000269|PubMed:21964459, ECO:0000269|PubMed:24163315}. CC -!- INTERACTION: CC Q9C5U0; Q9C5U1: AHK3; NbExp=2; IntAct=EBI-1100775, EBI-1100653; CC Q9C5U0; O80452: AMPD; NbExp=2; IntAct=EBI-1100775, EBI-1807679; CC Q9C5U0; Q67XQ1: At1g03430; NbExp=3; IntAct=EBI-1100775, EBI-1100725; CC Q9C5U0; Q8L8Z1: At4g15630; NbExp=2; IntAct=EBI-1100775, EBI-1807704; CC Q9C5U0; Q9SCU5: WNK5; NbExp=2; IntAct=EBI-1100775, EBI-1807651; CC -!- SUBCELLULAR LOCATION: Endoplasmic reticulum membrane CC {ECO:0000269|PubMed:21709172}; Multi-pass membrane protein CC {ECO:0000269|PubMed:21709172}. CC -!- ALTERNATIVE PRODUCTS: CC Event=Alternative splicing; Named isoforms=2; CC Name=1; Synonyms=CRE1b; CC IsoId=Q9C5U0-1; Sequence=Displayed; CC Name=2; Synonyms=CRE1a; CC IsoId=Q9C5U0-2; Sequence=VSP_039770; CC -!- TISSUE SPECIFICITY: Mostly expressed in roots, specifically in the CC vascular cylinder and pericycle, and, to a lower extent, in leaves and CC flowers. Present in seedlings. {ECO:0000269|PubMed:11114883, CC ECO:0000269|PubMed:11230578, ECO:0000269|PubMed:15155880, CC ECO:0000269|PubMed:15166290}. CC -!- DEVELOPMENTAL STAGE: Expressed specifically in the vasculature since CC the early stages of embryogenesis. At the globular stage of CC embryogenesis, detected in the four innermost cells, which are the CC precursors of the vascular tissue. During the heart, torpedo, and CC nearly mature stages, expressed in the procambium of the cotyledon CC shoulders, prospective hypocotyl, and embryonic root. In seedlings, CC mainly localized in meristematic tissues (e.g. shoot apical meristem CC SAM, root tips, and growing leaf and lateral root primordia), CC especially in vasculature. Present in all the vasculature and the shoot CC apical meristem (SAM) of the adult plant. In flowers, localized in CC carpels and developing ovules. In the root tips, expressed in the CC central cylinder. {ECO:0000269|PubMed:11114883, CC ECO:0000269|PubMed:15155880, ECO:0000269|PubMed:16753566}. CC -!- INDUCTION: Rapidly induced by dehydration. Down-regulated by Pi CC starvation and induced by cytokinins. {ECO:0000269|PubMed:12410813, CC ECO:0000269|PubMed:18077346}. CC -!- PTM: Autophosphorylated predominantly on His residues. Activation CC probably requires a transfer of a phosphate group between a His in the CC transmitter domain and an Asp of the receiver domain. CC {ECO:0000269|PubMed:16753566}. CC -!- DISRUPTION PHENOTYPE: Reduced sensitivity to cytokinin (mostly in CC shoots). Narrow vascular cylinder composed mainly of protoxylem cell CC files, with no apparent metaxylem or phloem. Hypersensitivity to ABA. CC Strong drought and salinity tolerance only in the presence of CK. CC Reduced cytokinin repression of several Pi starvation-responsive genes CC and increased sucrose sensitivity. More rapid germination, reduced CC requirement for light, and decreased far-red light sensitivity. Reduced CC sensitivity to N-isobutyl decanamide. Impaired benzyladenine (6-BA)- CC mediated repression of the iron uptake pathway. Impaired meristematic CC development in seedlings. {ECO:0000269|PubMed:11479382, CC ECO:0000269|PubMed:12410813, ECO:0000269|PubMed:15155880, CC ECO:0000269|PubMed:15166290, ECO:0000269|PubMed:15923327, CC ECO:0000269|PubMed:16357038, ECO:0000269|PubMed:16361392, CC ECO:0000269|PubMed:16753566, ECO:0000269|PubMed:17965178, CC ECO:0000269|PubMed:18077346, ECO:0000269|PubMed:18397377, CC ECO:0000269|PubMed:20110319}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; AJ278528; CAC18521.1; -; mRNA. DR EMBL; AJ278529; CAC18522.1; -; mRNA. DR EMBL; AJ278530; CAC18523.1; -; mRNA. DR EMBL; AB049934; BAB33310.1; -; mRNA. DR EMBL; AB049935; BAB33311.1; -; mRNA. DR EMBL; AB046871; BAB40776.1; -; mRNA. DR EMBL; AC007069; AAD21777.2; -; Genomic_DNA. DR EMBL; CP002685; AEC05505.1; -; Genomic_DNA. DR EMBL; CP002685; AEC05506.1; -; Genomic_DNA. DR EMBL; CP002685; AEC05507.1; -; Genomic_DNA. DR EMBL; CP002685; ANM62256.1; -; Genomic_DNA. DR EMBL; CP002685; ANM62257.1; -; Genomic_DNA. DR EMBL; EF598292; ABQ85264.1; -; Genomic_DNA. DR EMBL; EF598293; ABQ85265.1; -; Genomic_DNA. DR EMBL; EF598294; ABQ85266.1; -; Genomic_DNA. DR EMBL; EF598295; ABQ85267.1; -; Genomic_DNA. DR EMBL; EF598296; ABQ85268.1; -; Genomic_DNA. DR EMBL; EF598297; ABQ85269.1; -; Genomic_DNA. DR EMBL; EF598298; ABQ85270.1; -; Genomic_DNA. DR EMBL; EF598299; ABQ85271.1; -; Genomic_DNA. DR EMBL; EF598300; ABQ85272.1; -; Genomic_DNA. DR EMBL; EF598301; ABQ85273.1; -; Genomic_DNA. DR EMBL; EF598302; ABQ85274.1; -; Genomic_DNA. DR EMBL; EF598303; ABQ85275.1; -; Genomic_DNA. DR EMBL; EF598304; ABQ85276.1; -; Genomic_DNA. DR EMBL; EF598305; ABQ85277.1; -; Genomic_DNA. DR EMBL; EF598306; ABQ85278.1; -; Genomic_DNA. DR EMBL; EF598307; ABQ85279.1; -; Genomic_DNA. DR EMBL; EF598308; ABQ85280.1; -; Genomic_DNA. DR EMBL; EF598309; ABQ85281.1; -; Genomic_DNA. DR EMBL; EF598310; ABQ85282.1; -; Genomic_DNA. DR EMBL; EF598311; ABQ85283.1; -; Genomic_DNA. DR EMBL; EF598312; ABQ85284.1; -; Genomic_DNA. DR EMBL; EF598313; ABQ85285.1; -; Genomic_DNA. DR EMBL; EF598314; ABQ85286.1; -; Genomic_DNA. DR EMBL; EF598315; ABQ85287.1; -; Genomic_DNA. DR PIR; F84429; F84429. DR RefSeq; NP_001324428.1; NM_001335080.1. [Q9C5U0-2] DR RefSeq; NP_001324429.1; NM_001335082.1. [Q9C5U0-2] DR RefSeq; NP_565277.1; NM_126244.3. [Q9C5U0-2] DR RefSeq; NP_849925.1; NM_179594.2. [Q9C5U0-1] DR RefSeq; NP_973396.1; NM_201667.1. [Q9C5U0-2] DR PDB; 3T4J; X-ray; 1.65 A; A/B=149-418. DR PDB; 3T4K; X-ray; 1.77 A; A/B=149-418. DR PDB; 3T4L; X-ray; 1.53 A; A/B=149-418. DR PDB; 3T4O; X-ray; 1.75 A; A/B=149-418. DR PDB; 3T4Q; X-ray; 2.30 A; A/B=149-418. DR PDB; 3T4S; X-ray; 1.60 A; A/B=149-418. DR PDB; 3T4T; X-ray; 1.70 A; A/B=149-418. DR PDB; 7P8C; X-ray; 2.15 A; A/B=941-1071. DR PDB; 7P8D; X-ray; 1.70 A; A/B=941-1080. DR PDBsum; 3T4J; -. DR PDBsum; 3T4K; -. DR PDBsum; 3T4L; -. DR PDBsum; 3T4O; -. DR PDBsum; 3T4Q; -. DR PDBsum; 3T4S; -. DR PDBsum; 3T4T; -. DR PDBsum; 7P8C; -. DR PDBsum; 7P8D; -. DR AlphaFoldDB; Q9C5U0; -. DR SMR; Q9C5U0; -. DR BioGRID; 117; 32. DR IntAct; Q9C5U0; 30. DR STRING; 3702.Q9C5U0; -. DR BindingDB; Q9C5U0; -. DR ChEMBL; CHEMBL6124; -. DR iPTMnet; Q9C5U0; -. DR PaxDb; 3702-AT2G01830-2; -. DR EnsemblPlants; AT2G01830.1; AT2G01830.1; AT2G01830. [Q9C5U0-2] DR EnsemblPlants; AT2G01830.2; AT2G01830.2; AT2G01830. [Q9C5U0-1] DR EnsemblPlants; AT2G01830.3; AT2G01830.3; AT2G01830. [Q9C5U0-2] DR EnsemblPlants; AT2G01830.4; AT2G01830.4; AT2G01830. [Q9C5U0-2] DR EnsemblPlants; AT2G01830.6; AT2G01830.6; AT2G01830. [Q9C5U0-2] DR GeneID; 814714; -. DR Gramene; AT2G01830.1; AT2G01830.1; AT2G01830. [Q9C5U0-2] DR Gramene; AT2G01830.2; AT2G01830.2; AT2G01830. [Q9C5U0-1] DR Gramene; AT2G01830.3; AT2G01830.3; AT2G01830. [Q9C5U0-2] DR Gramene; AT2G01830.4; AT2G01830.4; AT2G01830. [Q9C5U0-2] DR Gramene; AT2G01830.6; AT2G01830.6; AT2G01830. [Q9C5U0-2] DR KEGG; ath:AT2G01830; -. DR Araport; AT2G01830; -. DR TAIR; AT2G01830; WOL. DR eggNOG; KOG0519; Eukaryota. DR InParanoid; Q9C5U0; -. DR OrthoDB; 5476858at2759; -. DR PhylomeDB; Q9C5U0; -. DR EvolutionaryTrace; Q9C5U0; -. DR PRO; PR:Q9C5U0; -. DR Proteomes; UP000006548; Chromosome 2. DR ExpressionAtlas; Q9C5U0; baseline and differential. DR GO; GO:0005783; C:endoplasmic reticulum; HDA:TAIR. DR GO; GO:0005789; C:endoplasmic reticulum membrane; IEA:UniProtKB-SubCell. DR GO; GO:0005886; C:plasma membrane; ISS:UniProtKB. DR GO; GO:0009884; F:cytokinin receptor activity; IDA:TAIR. DR GO; GO:0019899; F:enzyme binding; IPI:UniProtKB. DR GO; GO:0017018; F:myosin phosphatase activity; IEA:UniProtKB-EC. DR GO; GO:0004721; F:phosphoprotein phosphatase activity; IDA:TAIR. DR GO; GO:0000155; F:phosphorelay sensor kinase activity; IEA:InterPro. DR GO; GO:0004673; F:protein histidine kinase activity; IDA:TAIR. DR GO; GO:0043424; F:protein histidine kinase binding; IPI:UniProtKB. DR GO; GO:0019901; F:protein kinase binding; IPI:UniProtKB. DR GO; GO:0009885; F:transmembrane histidine kinase cytokinin receptor activity; IDA:UniProtKB. DR GO; GO:0033500; P:carbohydrate homeostasis; IMP:TAIR. DR GO; GO:0016036; P:cellular response to phosphate starvation; IMP:UniProtKB. DR GO; GO:0071329; P:cellular response to sucrose stimulus; IMP:UniProtKB. DR GO; GO:0009736; P:cytokinin-activated signaling pathway; TAS:TAIR. DR GO; GO:0042742; P:defense response to bacterium; IDA:TAIR. DR GO; GO:0010086; P:embryonic root morphogenesis; IMP:TAIR. DR GO; GO:0007231; P:osmosensory signaling pathway; IMP:TAIR. DR GO; GO:0000160; P:phosphorelay signal transduction system; IDA:UniProtKB. DR GO; GO:0006468; P:protein phosphorylation; IGI:TAIR. DR GO; GO:0048509; P:regulation of meristem development; IMP:UniProtKB. DR GO; GO:0010029; P:regulation of seed germination; IMP:TAIR. DR GO; GO:0048831; P:regulation of shoot system development; IMP:TAIR. DR GO; GO:0009414; P:response to water deprivation; IEP:TAIR. DR GO; GO:0008272; P:sulfate transport; IMP:UniProtKB. DR CDD; cd16922; HATPase_EvgS-ArcB-TorS-like; 1. DR CDD; cd00082; HisKA; 1. DR CDD; cd06223; PRTases_typeI; 1. DR CDD; cd17546; REC_hyHK_CKI1_RcsC-like; 1. DR Gene3D; 1.10.287.130; -; 1. DR Gene3D; 3.40.50.2300; -; 1. DR Gene3D; 6.10.250.1190; -; 1. DR Gene3D; 3.30.450.350; CHASE domain; 1. DR Gene3D; 3.30.565.10; Histidine kinase-like ATPase, C-terminal domain; 1. DR InterPro; IPR006189; CHASE_dom. DR InterPro; IPR042240; CHASE_sf. DR InterPro; IPR011006; CheY-like_superfamily. DR InterPro; IPR003594; HATPase_C. DR InterPro; IPR036890; HATPase_C_sf. DR InterPro; IPR005467; His_kinase_dom. DR InterPro; IPR003661; HisK_dim/P. DR InterPro; IPR036097; HisK_dim/P_sf. DR InterPro; IPR000836; PRibTrfase_dom. DR InterPro; IPR004358; Sig_transdc_His_kin-like_C. DR InterPro; IPR001789; Sig_transdc_resp-reg_receiver. DR PANTHER; PTHR43719:SF51; HISTIDINE KINASE 4; 1. DR PANTHER; PTHR43719; TWO-COMPONENT HISTIDINE KINASE; 1. DR Pfam; PF03924; CHASE; 1. DR Pfam; PF02518; HATPase_c; 1. DR Pfam; PF00512; HisKA; 1. DR Pfam; PF00072; Response_reg; 1. DR PRINTS; PR00344; BCTRLSENSOR. DR SMART; SM01079; CHASE; 1. DR SMART; SM00387; HATPase_c; 1. DR SMART; SM00388; HisKA; 1. DR SMART; SM00448; REC; 1. DR SUPFAM; SSF55874; ATPase domain of HSP90 chaperone/DNA topoisomerase II/histidine kinase; 1. DR SUPFAM; SSF52172; CheY-like; 2. DR SUPFAM; SSF47384; Homodimeric domain of signal transducing histidine kinase; 1. DR PROSITE; PS50839; CHASE; 1. DR PROSITE; PS50109; HIS_KIN; 1. DR PROSITE; PS50110; RESPONSE_REGULATORY; 2. DR Genevisible; Q9C5U0; AT. PE 1: Evidence at protein level; KW 3D-structure; Alternative splicing; Cytokinin signaling pathway; KW Developmental protein; Endoplasmic reticulum; Hydrolase; Kinase; Membrane; KW Phosphoprotein; Protein phosphatase; Reference proteome; Transferase; KW Transmembrane; Transmembrane helix. FT CHAIN 1..1080 FT /note="Histidine kinase 4" FT /id="PRO_0000398589" FT TOPO_DOM 1..124 FT /note="Cytoplasmic" FT /evidence="ECO:0000255" FT TRANSMEM 125..145 FT /note="Helical" FT /evidence="ECO:0000255" FT TOPO_DOM 146..429 FT /note="Extracellular" FT /evidence="ECO:0000255" FT TRANSMEM 430..450 FT /note="Helical" FT /evidence="ECO:0000255" FT TOPO_DOM 451..1080 FT /note="Cytoplasmic" FT /evidence="ECO:0000255" FT DOMAIN 198..411 FT /note="CHASE" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00049" FT DOMAIN 479..760 FT /note="Histidine kinase" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00107" FT DOMAIN 786..920 FT /note="Response regulatory 1" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00169" FT DOMAIN 946..1071 FT /note="Response regulatory 2" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00169" FT BINDING 285 FT /ligand="dihydrozeatin" FT /ligand_id="ChEBI:CHEBI:17874" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4O" FT BINDING 285 FT /ligand="kinetin" FT /ligand_id="ChEBI:CHEBI:27407" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4S" FT BINDING 285 FT /ligand="N(6)-dimethylallyladenine" FT /ligand_id="ChEBI:CHEBI:17660" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4J" FT BINDING 285 FT /ligand="trans-zeatin" FT /ligand_id="ChEBI:CHEBI:16522" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4L, ECO:0007744|PDB:3T4Q" FT BINDING 307 FT /ligand="dihydrozeatin" FT /ligand_id="ChEBI:CHEBI:17874" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4O" FT BINDING 307 FT /ligand="kinetin" FT /ligand_id="ChEBI:CHEBI:27407" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4S" FT BINDING 307 FT /ligand="N(6)-dimethylallyladenine" FT /ligand_id="ChEBI:CHEBI:17660" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4J" FT BINDING 307 FT /ligand="trans-zeatin" FT /ligand_id="ChEBI:CHEBI:16522" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4L, ECO:0007744|PDB:3T4Q" FT BINDING 317 FT /ligand="dihydrozeatin" FT /ligand_id="ChEBI:CHEBI:17874" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4O" FT BINDING 317 FT /ligand="trans-zeatin" FT /ligand_id="ChEBI:CHEBI:16522" FT /evidence="ECO:0000269|PubMed:21964459, FT ECO:0007744|PDB:3T4L, ECO:0007744|PDB:3T4Q" FT MOD_RES 482 FT /note="Phosphohistidine; by autocatalysis" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00107, FT ECO:0000269|PubMed:16753566" FT MOD_RES 996 FT /note="4-aspartylphosphate" FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00169" FT VAR_SEQ 1..23 FT /note="Missing (in isoform 2)" FT /evidence="ECO:0000303|PubMed:11114883, FT ECO:0000303|PubMed:11230578, ECO:0000303|PubMed:11234017" FT /id="VSP_039770" FT VARIANT 765 FT /note="S -> N (in strain: cv. Se-0)" FT /evidence="ECO:0000269|PubMed:17435248" FT MUTAGEN 225 FT /note="A->L: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 227 FT /note="A->L: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 273 FT /note="Y->E: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 279 FT /note="M->A: No effect on activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 285 FT /note="D->A,E,R: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 301 FT /note="T->I: In wol-1; locked in the phosphoprotein FT phosphatase active form, retardation of the primary root FT growth with reduced cell number and exclusive xylem FT differentiation within the vascular tissue associated with FT abnormal vascular asymmetric cell divisions, impaired FT metaxylem and phloem differentiation, and reduced FT cytokinin-binding ability leading to impaired kinase FT activity and cytokinin-mediated activation." FT /evidence="ECO:0000269|PubMed:11114883, FT ECO:0000269|PubMed:11577198, ECO:0000269|PubMed:15053761, FT ECO:0000269|PubMed:16753566, ECO:0000269|PubMed:17956858, FT ECO:0000269|PubMed:21964459" FT MUTAGEN 303 FT /note="P->V: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 304 FT /note="F->A: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 306 FT /note="L->A: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 307 FT /note="L->A: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 317 FT /note="T->A: No effect on activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 343 FT /note="G->L: Loss of activity." FT /evidence="ECO:0000269|PubMed:21964459" FT MUTAGEN 435 FT /note="G->C: Constitutively activated independently of FT cytokinin." FT /evidence="ECO:0000269|PubMed:17956858" FT MUTAGEN 436 FT /note="F->S: Constitutively activated independently of FT cytokinin." FT /evidence="ECO:0000269|PubMed:17956858" FT MUTAGEN 447 FT /note="M->T: Constitutively activated independently of FT cytokinin." FT /evidence="ECO:0000269|PubMed:17956858" FT MUTAGEN 459 FT /note="M->I: In wol-3; retardation of the primary root FT growth, no production of lateral roots and enhanced FT formation of adventitious roots associated with impaired FT auxin basipetal transport." FT /evidence="ECO:0000269|PubMed:16357038" FT MUTAGEN 471 FT /note="V->A: Constitutively activated independently of FT cytokinin." FT /evidence="ECO:0000269|PubMed:17956858" FT MUTAGEN 482 FT /note="H->Q: Reduced phosphoprotein phosphatase activity." FT /evidence="ECO:0000269|PubMed:11234017, FT ECO:0000269|PubMed:16753566" FT MUTAGEN 490 FT /note="G->D: In cre1-1; impaired histidine-kinase receptor FT activity and reduced responses to cytokinins, including FT rapid cell proliferation and shoot formation in tissue FT culture, repression of sulfate uptake, retardation of the FT primary root growth, no production of lateral roots and FT enhanced formation of adventitious roots associated with FT impaired auxin basipetal transport, as well as reduced cell FT number within the vascular tissues in roots." FT /evidence="ECO:0000269|PubMed:11234017, FT ECO:0000269|PubMed:12354925, ECO:0000269|PubMed:15144379, FT ECO:0000269|PubMed:16357038" FT MUTAGEN 493 FT /note="G->R: In cre1-6; reduced sensitivity to cytokinin." FT /evidence="ECO:0000269|PubMed:12410813" FT MUTAGEN 494 FT /note="M->L: Constitutively activated independently of FT cytokinin." FT /evidence="ECO:0000269|PubMed:17956858" FT MUTAGEN 529 FT /note="L->F: In wol-2/raw1; impaired metaxylem and phloem FT differentiation, and reduced sensitivity to cytokinins." FT /evidence="ECO:0000269|PubMed:15053761" FT MUTAGEN 529 FT /note="L->F: In wol-2; retardation of the primary root FT growth with reduced cell number and exclusive xylem FT differentiation within the vascular tissue associated with FT abnormal vascular asymmetric cell divisions, and impaired FT cytokinin-binding ability." FT /evidence="ECO:0000269|PubMed:15053761" FT MUTAGEN 708 FT /note="F->L: No histidine kinase activity, but normal FT phosphoprotein phosphatase activity." FT /evidence="ECO:0000269|PubMed:16753566" FT MUTAGEN 996 FT /note="D->N: Cytokinin-mediated autophosphorylation but FT impaired phosphotransfer to an HPt, abolished FT phosphoprotein phosphatase activity." FT /evidence="ECO:0000269|PubMed:11234017, FT ECO:0000269|PubMed:16753566" FT MUTAGEN 1008 FT /note="T->I: In cre1-4; slightly reduced sensitivity to FT cytokinin, and impaired cytokinin repression of several Pi FT starvation-responses." FT /evidence="ECO:0000269|PubMed:12410813" FT MUTAGEN 1032 FT /note="A->T: In cre1-9; impaired cytokinin repression of FT several Pi starvation-responses." FT /evidence="ECO:0000269|PubMed:12410813" FT CONFLICT 567 FT /note="S -> G (in Ref. 2; BAB33311)" FT /evidence="ECO:0000305" FT CONFLICT 1018 FT /note="T -> A (in Ref. 2; BAB33311)" FT /evidence="ECO:0000305" FT HELIX 151..193 FT /evidence="ECO:0007829|PDB:3T4L" FT TURN 194..196 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 197..199 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 204..213 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 215..217 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 221..228 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 232..234 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 235..242 FT /evidence="ECO:0007829|PDB:3T4L" FT TURN 249..251 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 259..261 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 263..267 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 269..274 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 279..281 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 283..295 FT /evidence="ECO:0007829|PDB:3T4L" FT TURN 307..309 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 312..321 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 331..336 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 338..346 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 348..357 FT /evidence="ECO:0007829|PDB:3T4L" FT HELIX 362..364 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 365..371 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 379..382 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 385..387 FT /evidence="ECO:0007829|PDB:3T4T" FT STRAND 395..399 FT /evidence="ECO:0007829|PDB:3T4L" FT STRAND 408..414 FT /evidence="ECO:0007829|PDB:3T4L" FT TURN 941..944 FT /evidence="ECO:0007829|PDB:7P8D" FT STRAND 946..950 FT /evidence="ECO:0007829|PDB:7P8D" FT HELIX 954..966 FT /evidence="ECO:0007829|PDB:7P8D" FT STRAND 970..976 FT /evidence="ECO:0007829|PDB:7P8D" FT HELIX 977..983 FT /evidence="ECO:0007829|PDB:7P8D" FT STRAND 991..997 FT /evidence="ECO:0007829|PDB:7P8D" FT STRAND 1000..1002 FT /evidence="ECO:0007829|PDB:7P8D" FT HELIX 1004..1022 FT /evidence="ECO:0007829|PDB:7P8D" FT STRAND 1030..1033 FT /evidence="ECO:0007829|PDB:7P8D" FT HELIX 1035..1048 FT /evidence="ECO:0007829|PDB:7P8D" FT STRAND 1052..1056 FT /evidence="ECO:0007829|PDB:7P8D" FT HELIX 1063..1065 FT /evidence="ECO:0007829|PDB:7P8C" SQ SEQUENCE 1080 AA; 120731 MW; 5950DB968B529401 CRC64; MRRDFVYNNN AMFNPLTTHY SSDMNWALNN HQEEEEEPRR IEISDSESLE NLKSSDFYQL GGGGALNSSE KPRKIDFWRS GLMGFAKMQQ QQQLQHSVAV KMNNNNNNDL MGNKKGSTFI QEHRALLPKA LILWIIIVGF ISSGIYQWMD DANKIRREEV LVSMCDQRAR MLQDQFSVSV NHVHALAILV STFHYHKNPS AIDQETFAEY TARTAFERPL LSGVAYAEKV VNFEREMFER QHNWVIKTMD RGEPSPVRDE YAPVIFSQDS VSYLESLDMM SGEEDRENIL RARETGKAVL TSPFRLLETH HLGVVLTFPV YKSSLPENPT VEERIAATAG YLGGAFDVES LVENLLGQLA GNQAIVVHVY DITNASDPLV MYGNQDEEAD RSLSHESKLD FGDPFRKHKM ICRYHQKAPI PLNVLTTVPL FFAIGFLVGY ILYGAAMHIV KVEDDFHEMQ ELKVRAEAAD VAKSQFLATV SHEIRTPMNG ILGMLAMLLD TELSSTQRDY AQTAQVCGKA LIALINEVLD RAKIEAGKLE LESVPFDIRS ILDDVLSLFS EESRNKSIEL AVFVSDKVPE IVKGDSGRFR QIIINLVGNS VKFTEKGHIF VKVHLAEQSK DESEPKNALN GGVSEEMIVV SKQSSYNTLS GYEAADGRNS WDSFKHLVSE EQSLSEFDIS SNVRLMVSIE DTGIGIPLVA QGRVFMPFMQ ADSSTSRNYG GTGIGLSISK CLVELMRGQI NFISRPHIGS TFWFTAVLEK CDKCSAINHM KKPNVEHLPS TFKGMKAIVV DAKPVRAAVT RYHMKRLGIN VDVVTSLKTA VVAAAAFERN GSPLPTKPQL DMILVEKDSW ISTEDNDSEI RLLNSRTNGN VHHKSPKLAL FATNITNSEF DRAKSAGFAD TVIMKPLRAS MIGACLQQVL ELRKTRQQHP EGSSPATLKS LLTGKKILVV DDNIVNRRVA AGALKKFGAE VVCAESGQVA LGLLQIPHTF DACFMDIQMP QMDGFEATRQ IRMMEKETKE KTNLEWHLPI LAMTADVIHA TYEECLKSGM DGYVSKPFEE ENLYKSVAKS FKPNPISPSS //