Q9C5U0 (AHK4_ARATH) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Histidine kinase 4
EC=2.7.13.3

Alternative name(s):
Arabidopsis histidine kinase 4
Short name=AtHK4
Cytokinin receptor CYTOKININ RESPONSE 1
Short name=AtCRE1
Short name=Cytokinin receptor CRE1
Phosphoprotein phosphatase AHK4
EC=3.1.3.16
Protein AUTHENTIC HIS-KINASE 4
Protein ROOT AS IN WOL 1
Protein WOODEN LEG

Gene names

Name:	AHK4
Synonyms:	CRE1, RAW1, WOL
Ordered Locus Names:	At2g01830
ORF Names:	T23K3.2

Organism

Arabidopsis thaliana (Mouse-ear cress) [Reference proteome]

Taxonomic identifier

3702 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Viridiplantae › Streptophyta › Streptophytina › Embryophyta › Tracheophyta › Euphyllophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › malvids › Brassicales › Brassicaceae › Camelineae › Arabidopsis

Protein attributes

Sequence length	1080 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Cytokinins (CK) receptor related to bacterial two-component regulators. Functions as a histidine kinase and transmits the stress signal to a downstream MAPK cascade. This protein undergoes an ATP-dependent autophosphorylation at a conserved histidine residue in the kinase core, and a phosphoryl group is then transferred to a conserved aspartate residue in the receiver domain. In the presence of cytokinin, feed phosphate to phosphorelay-integrating histidine phosphotransfer protein (HPt) and activates subsequent cascade. In the absence of cytokinin, removes phosphate from HPt proteins, decreasing the system phosphoload. Involved in meristems establishment in seedlings. Acts as a redundant negative regulator of drought and salt stress responses, and abscisic acid (ABA) signaling in a cytokinin-dependent manner. Required to set vascular asymmetric cell divisions that establish phloem and procambium cell lines. Redundant positive regulator of cytokinin signaling that regulates many development process including seed germination, cell division, seed size, chlorophyll retention during leaf senescence, root repression and shoot promotion. Can interact with isoprenoid-type cytokinins trans-zeatin (tZ and tZR), isopentenyladenine (iP), and isopentenyladenosine (iPR), the meta hydroxylated derivative of benzyladenine m-topolin, buta-2,3-dienyladenine (HA-8), penta-2,3-dienyladenine (HA-1), 4-methyl-penta-2,3-dienyladenine (HA-10), 4-hydroxy-2-butynyladenine (RM1), 2-butynyladenine (RM6), and to a lower extent, with cis-zeatin (cZ), zeatin riboside and dihydrozeatin (DZ). Together with AHK3, involved in the cytokinin-dependent responses to Pi starvation and sucrose stresses. Required for the formation of auxin-transporting vascular tissues in the hypocotyl, and primary and lateral roots, but not in adventitious roots, thus leading to auxin basipetal transport that regulates root development and branching. Involved in alkamides (e.g. N-isobutyl decanamide) and N-acylethanolamides (NAE) signaling that control meristematic activity and differentiation processes during plant development. Prevents the uptake of sulfate by mediating cytokinin-dependent down-regulation of high-affinity sulfate transporters (e.g. SULTR1;1 and SULTR1;2) expression in roots. Together with AHK2, required for growth and reproduction promotion stimulated by the endophytic fungus Piriformospora indica in a trans-zeatin-dependent manner. Required to trigger the phytotoxic effect of the snapdragon (Antirrhinum majus) flowers volatile organic compound (VOC) methyl benzoate (MB). Plays a role in the cytokinin-mediated repression of the iron uptake pathway. Ref.1 Ref.2 Ref.7 Ref.8 Ref.9 Ref.12 Ref.13 Ref.15 Ref.16 Ref.17 Ref.18 Ref.19 Ref.20 Ref.21 Ref.22 Ref.23 Ref.25 Ref.26 Ref.27 Ref.28 Ref.29 Ref.30 Ref.31 Ref.32 Ref.34 Ref.35 Ref.36 Ref.37
Catalytic activity	ATP + protein L-histidine = ADP + protein N-phospho-L-histidine. A phosphoprotein + H2O = a protein + phosphate.
Enzyme regulation	Activated by cytokinins to initiate phosphorelay signaling. This cytokinin-mediated activation is repressed by the trans-zeatin antagonists 6-(2-hydroxy-3-methylbenzylamino)purine (PI-55) and 6-(2,5-Dihydroxybenzylamino)purine (LGR-991). Ref.2 Ref.36 Ref.38
Subunit structure	Interacts with AHP1, AHP2, AHP3, AHP5, AHK3, AMPD, WNK5 and At4g15630. Ref.7 Ref.24 Ref.33
Subcellular location	Cell membrane; Multi-pass membrane protein By similarity.
Tissue specificity	Mostly expressed in roots, specifically in the vascular cylinder and pericycle, and, to a lower extent, in leaves and flowers. Present in seedlings. Ref.1 Ref.3 Ref.15 Ref.19
Developmental stage	Expressed specifically in the vasculature since the early stages of embryogenesis. At the globular stage of embryogenesis, detected in the four innermost cells, which are the precursors of the vascular tissue. During the heart, torpedo, and nearly mature stages, expressed in the procambium of the cotyledon shoulders, prospective hypocotyl, and embryonic root. In seedlings, mainly localized in meristematic tissues (e.g. shoot apical meristem SAM, root tips, and growing leaf and lateral root primordia), especially in vasculature. Present in all the vasculature and the shoot apical meristem (SAM) of the adult plant. In flowers, localized in carpels and developing ovules. In the root tips, expressed in the central cylinder. Ref.1 Ref.15 Ref.23
Induction	Rapidly induced by dehydration. Down-regulated by Pi starvation and induced by cytokinins. Ref.2 Ref.13 Ref.30 Ref.36 Ref.38
Post-translational modification	Autophosphorylated predominantly on His residues. Activation probably requires a transfer of a phosphate group between a His in the transmitter domain and an Asp of the receiver domain. Ref.23
Disruption phenotype	Reduced sensitivity to cytokinin (mostly in shoots). Narrow vascular cylinder composed mainly of protoxylem cell files, with no apparent metaxylem or phloem. Hypersensitivity to ABA. Strong drought and salinity tolerance only in the presence of CK. Reduced cytokinin repression of several Pi starvation-responsive genes and increased sucrose sensitivity. More rapid germination, reduced requirement for light, and decreased far-red light sensitivity. Reduced sensitivity to N-isobutyl decanamide. Impaired benzyladenine (6-BA)-mediated repression of the iron uptake pathway. Impaired meristematic development in seedlings. Ref.8 Ref.13 Ref.15 Ref.19 Ref.21 Ref.23 Ref.26 Ref.27 Ref.30 Ref.31 Ref.35 Ref.37
Sequence similarities	Contains 1 CHASE domain. Contains 1 histidine kinase domain. Contains 1 response regulatory domain.
Biophysicochemical properties	pH dependence: Optimum pH to bind cytokinin is about 7-8.5 at 0 degrees Celsius. Ref.20 Ref.25 Temperature dependence: Cytokinin-binding is more stable at 0 degrees Celsius than at 20 and 37 degrees Celsius.

Ontologies

Keywords
Biological process	Cytokinin signaling pathway
Cellular component	Cell membrane Membrane
Coding sequence diversity	Alternative splicing
Domain	Transmembrane Transmembrane helix
Molecular function	Developmental protein Hydrolase Kinase Protein phosphatase Transferase
PTM	Phosphoprotein
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	carbohydrate homeostasis Inferred from mutant phenotype PubMed 22422940. Source: TAIR cellular response to phosphate starvation Inferred from mutant phenotype Ref.21. Source: UniProtKB cellular response to sucrose stimulus Inferred from mutant phenotype Ref.21. Source: UniProtKB defense response to bacterium Inferred from direct assay PubMed 19129491. Source: TAIR embryonic root morphogenesis Inferred from mutant phenotype Ref.1. Source: TAIR intracellular signal transduction Inferred from electronic annotation. Source: GOC osmosensory signaling pathway Inferred from mutant phenotype PubMed 22422940. Source: TAIR phosphorelay signal transduction system Inferred from direct assay Ref.7. Source: UniProtKB regulation of meristem development Inferred from mutant phenotype Ref.37. Source: UniProtKB regulation of seed germination Inferred from mutant phenotype Ref.26. Source: TAIR regulation of shoot development Inferred from mutant phenotype Ref.26. Source: TAIR regulation of transcription, DNA-dependent Inferred from electronic annotation. Source: InterPro response to water deprivation Inferred from expression pattern Ref.30. Source: TAIR signal transduction by phosphorylation Inferred from electronic annotation. Source: GOC sulfate transport Inferred from mutant phenotype Ref.18. Source: UniProtKB
Cellular_component	endoplasmic reticulum Inferred from direct assay PubMed 22923678. Source: TAIR integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW plasma membrane Inferred from sequence or structural similarity. Source: UniProtKB
Molecular_function	ATP binding Inferred from electronic annotation. Source: InterPro cytokine binding Inferred from direct assay Ref.20. Source: TAIR osmosensor activity Inferred from genetic interaction Ref.30. Source: TAIR phosphoprotein phosphatase activity Inferred from direct assay Ref.23. Source: TAIR phosphorelay response regulator activity Inferred from electronic annotation. Source: InterPro phosphorelay sensor kinase activity Inferred from electronic annotation. Source: InterPro transmembrane histidine kinase cytokinin receptor activity Inferred from direct assay Ref.7. Source: UniProtKB
Complete GO annotation...

Binary interactions

With	Entry	#Exp.	IntAct	Notes
AHK3	Q9C5U1	2	EBI-1100775,EBI-1100653
AMPD	O80452	2	EBI-1100775,EBI-1807679
At1g03430	Q67XQ1	3	EBI-1100775,EBI-1100725
At4g15630	Q8L8Z1	2	EBI-1100775,EBI-1807704
WNK5	Q9SCU5	2	EBI-1100775,EBI-1807651

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]

Isoform 1 (identifier: Q9C5U0-1)

Also known as: CRE1b;

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Isoform 2 (identifier: Q9C5U0-2)

Also known as: CRE1a;

The sequence of this isoform differs from the canonical sequence as follows:
     1-23: Missing.

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 1080

1080

Histidine kinase 4

PRO_0000398589

Regions

Topological domain

1 – 124

124

Cytoplasmic Potential

Transmembrane

125 – 145

21

Helical; Potential

Topological domain

146 – 429

284

Extracellular Potential

Transmembrane

430 – 450

21

Helical; Potential

Topological domain

451 – 1080

630

Cytoplasmic Potential

Domain

198 – 411

214

CHASE

Domain

479 – 760

282

Histidine kinase

Domain

946 – 1071

126

Response regulatory

Compositional bias

823 – 826

4

Poly-Ala

Amino acid modifications

Modified residue

482

1

Phosphohistidine; by autocatalysis By similarity

Modified residue

996

1

4-aspartylphosphate By similarity

Natural variations

Alternative sequence

1 – 23

23

Missing in isoform 2.

VSP_039770

Natural variant

765

1

S → N in strain: cv. Se-0. Ref.6

Experimental info

Mutagenesis

301

1

T → I in wol-1; locked in the phosphoprotein phosphatase active form, retardation of the primary root growth with reduced cell number and exclusive xylem differentiation within the vascular tissue associated with abnormal vascular asymmetric cell divisions, impaired metaxylem and phloem differentiation, and reduced cytokinin-binding ability leading to impaired kinase activity and cyokinin-mediated activation. Ref.1 Ref.9 Ref.17 Ref.23 Ref.29

Mutagenesis

435

1

G → C: Constitutively activated independently of cytokinin. Ref.29

Mutagenesis

436

1

F → S: Constitutively activated independently of cytokinin. Ref.29

Mutagenesis

447

1

M → T: Constitutively activated independently of cytokinin. Ref.29

Mutagenesis

459

1

M → I in wol-3; retardation of the primary root growth, no production of lateral roots and enhanced formation of adventitious roots associated with impaired auxin basipetal transport. Ref.27

Mutagenesis

471

1

V → A: Constitutively activated independently of cytokinin. Ref.29

Mutagenesis

482

1

H → Q: Reduced phosphoprotein phosphatase activity. Ref.2 Ref.23

Mutagenesis

490

1

G → D in cre1-1; impaired histidine-kinase receptor activity and reduced responses to cytokinins, including rapid cell proliferation and shoot formation in tissue culture, repression of sulfate uptake, retardation of the primary root growth, no production of lateral roots and enhanced formation of adventitious roots associated with impaired auxin basipetal transport, as well as reduced cell number within the vascular tissues in roots. Ref.2 Ref.12 Ref.18 Ref.27

Mutagenesis

493

1

G → R in cre1-6; reduced sensitivity to cytokinin. Ref.13

Mutagenesis

494

1

M → L: Constitutively activated independently of cytokinin. Ref.29

Mutagenesis

529

1

L → F in wol-2/raw1; impaired metaxylem and phloem differentiation, and reduced sensitivity to cytokinins. Ref.17

Mutagenesis

529

1

L → F in wol-2; retardation of the primary root growth with reduced cell number and exclusive xylem differentiation within the vascular tissue associated with abnormal vascular asymmetric cell divisions, and impaired cytokinin-binding ability. Ref.17

Mutagenesis

708

1

F → L: No histidine kinase activity, but normal phosphoprotein phosphatase activity. Ref.23

Mutagenesis

996

1

D → N: Cytokinin-mediated autophosphorylation but impaired phosphotransfer to an HPt, abolished phosphoprotein phosphatase activity. Ref.2 Ref.23

Mutagenesis

1008

1

T → I in cre1-4; slightly reduced sensitivity to cytokinin, and impaired cytokinin repression of several Pi starvation-responses. Ref.13

Mutagenesis

1032

1

A → T in cre1-9; impaired cytokinin repression of several Pi starvation-responses. Ref.13

Sequence conflict

567

1

S → G in BAB33311. Ref.2

Sequence conflict

1018

1

T → A in BAB33311. Ref.2

Secondary structure

1

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

1080

Helix Strand Turn

Details...

Helix

151 – 193

43

Turn

194 – 196

3

Beta strand

197 – 199

3

Helix

204 – 213

10

Helix

215 – 217

3

Beta strand

221 – 228

8

Helix

232 – 234

3

Helix

235 – 242

8

Turn

249 – 251

3

Beta strand

259 – 261

3

Beta strand

263 – 267

5

Helix

269 – 274

6

Helix

279 – 281

3

Helix

283 – 295

13

Turn

307 – 309

3

Beta strand

312 – 321

10

Helix

331 – 336

6

Beta strand

338 – 346

9

Helix

348 – 357

10

Helix

362 – 364

3

Beta strand

365 – 371

7

Beta strand

379 – 382

4

Beta strand

385 – 387

3

Beta strand

395 – 399

5

Beta strand

408 – 414

7

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 (CRE1b) [UniParc]. Last modified June 1, 2001. Version 1. Checksum: 5950DB968B529401	FASTA	1,080	120,731
	10 20 30 40 50 60 MRRDFVYNNN AMFNPLTTHY SSDMNWALNN HQEEEEEPRR IEISDSESLE NLKSSDFYQL 70 80 90 100 110 120 GGGGALNSSE KPRKIDFWRS GLMGFAKMQQ QQQLQHSVAV KMNNNNNNDL MGNKKGSTFI 130 140 150 160 170 180 QEHRALLPKA LILWIIIVGF ISSGIYQWMD DANKIRREEV LVSMCDQRAR MLQDQFSVSV 190 200 210 220 230 240 NHVHALAILV STFHYHKNPS AIDQETFAEY TARTAFERPL LSGVAYAEKV VNFEREMFER 250 260 270 280 290 300 QHNWVIKTMD RGEPSPVRDE YAPVIFSQDS VSYLESLDMM SGEEDRENIL RARETGKAVL 310 320 330 340 350 360 TSPFRLLETH HLGVVLTFPV YKSSLPENPT VEERIAATAG YLGGAFDVES LVENLLGQLA 370 380 390 400 410 420 GNQAIVVHVY DITNASDPLV MYGNQDEEAD RSLSHESKLD FGDPFRKHKM ICRYHQKAPI 430 440 450 460 470 480 PLNVLTTVPL FFAIGFLVGY ILYGAAMHIV KVEDDFHEMQ ELKVRAEAAD VAKSQFLATV 490 500 510 520 530 540 SHEIRTPMNG ILGMLAMLLD TELSSTQRDY AQTAQVCGKA LIALINEVLD RAKIEAGKLE 550 560 570 580 590 600 LESVPFDIRS ILDDVLSLFS EESRNKSIEL AVFVSDKVPE IVKGDSGRFR QIIINLVGNS 610 620 630 640 650 660 VKFTEKGHIF VKVHLAEQSK DESEPKNALN GGVSEEMIVV SKQSSYNTLS GYEAADGRNS 670 680 690 700 710 720 WDSFKHLVSE EQSLSEFDIS SNVRLMVSIE DTGIGIPLVA QGRVFMPFMQ ADSSTSRNYG 730 740 750 760 770 780 GTGIGLSISK CLVELMRGQI NFISRPHIGS TFWFTAVLEK CDKCSAINHM KKPNVEHLPS 790 800 810 820 830 840 TFKGMKAIVV DAKPVRAAVT RYHMKRLGIN VDVVTSLKTA VVAAAAFERN GSPLPTKPQL 850 860 870 880 890 900 DMILVEKDSW ISTEDNDSEI RLLNSRTNGN VHHKSPKLAL FATNITNSEF DRAKSAGFAD 910 920 930 940 950 960 TVIMKPLRAS MIGACLQQVL ELRKTRQQHP EGSSPATLKS LLTGKKILVV DDNIVNRRVA 970 980 990 1000 1010 1020 AGALKKFGAE VVCAESGQVA LGLLQIPHTF DACFMDIQMP QMDGFEATRQ IRMMEKETKE 1030 1040 1050 1060 1070 1080 KTNLEWHLPI LAMTADVIHA TYEECLKSGM DGYVSKPFEE ENLYKSVAKS FKPNPISPSS
	Isoform 2 (CRE1a) [UniParc]. Checksum: E1381C8685F0D787	FASTA	1,057	117,955
	10 20 30 40 50 60 MNWALNNHQE EEEEPRRIEI SDSESLENLK SSDFYQLGGG GALNSSEKPR KIDFWRSGLM 70 80 90 100 110 120 GFAKMQQQQQ LQHSVAVKMN NNNNNDLMGN KKGSTFIQEH RALLPKALIL WIIIVGFISS 130 140 150 160 170 180 GIYQWMDDAN KIRREEVLVS MCDQRARMLQ DQFSVSVNHV HALAILVSTF HYHKNPSAID 190 200 210 220 230 240 QETFAEYTAR TAFERPLLSG VAYAEKVVNF EREMFERQHN WVIKTMDRGE PSPVRDEYAP 250 260 270 280 290 300 VIFSQDSVSY LESLDMMSGE EDRENILRAR ETGKAVLTSP FRLLETHHLG VVLTFPVYKS 310 320 330 340 350 360 SLPENPTVEE RIAATAGYLG GAFDVESLVE NLLGQLAGNQ AIVVHVYDIT NASDPLVMYG 370 380 390 400 410 420 NQDEEADRSL SHESKLDFGD PFRKHKMICR YHQKAPIPLN VLTTVPLFFA IGFLVGYILY 430 440 450 460 470 480 GAAMHIVKVE DDFHEMQELK VRAEAADVAK SQFLATVSHE IRTPMNGILG MLAMLLDTEL 490 500 510 520 530 540 SSTQRDYAQT AQVCGKALIA LINEVLDRAK IEAGKLELES VPFDIRSILD DVLSLFSEES 550 560 570 580 590 600 RNKSIELAVF VSDKVPEIVK GDSGRFRQII INLVGNSVKF TEKGHIFVKV HLAEQSKDES 610 620 630 640 650 660 EPKNALNGGV SEEMIVVSKQ SSYNTLSGYE AADGRNSWDS FKHLVSEEQS LSEFDISSNV 670 680 690 700 710 720 RLMVSIEDTG IGIPLVAQGR VFMPFMQADS STSRNYGGTG IGLSISKCLV ELMRGQINFI 730 740 750 760 770 780 SRPHIGSTFW FTAVLEKCDK CSAINHMKKP NVEHLPSTFK GMKAIVVDAK PVRAAVTRYH 790 800 810 820 830 840 MKRLGINVDV VTSLKTAVVA AAAFERNGSP LPTKPQLDMI LVEKDSWIST EDNDSEIRLL 850 860 870 880 890 900 NSRTNGNVHH KSPKLALFAT NITNSEFDRA KSAGFADTVI MKPLRASMIG ACLQQVLELR 910 920 930 940 950 960 KTRQQHPEGS SPATLKSLLT GKKILVVDDN IVNRRVAAGA LKKFGAEVVC AESGQVALGL 970 980 990 1000 1010 1020 LQIPHTFDAC FMDIQMPQMD GFEATRQIRM MEKETKEKTN LEWHLPILAM TADVIHATYE 1030 1040 1050 ECLKSGMDGY VSKPFEEENL YKSVAKSFKP NPISPSS

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"A novel two-component hybrid molecule regulates vascular morphogenesis of the Arabidopsis root." Maehoenen A.P., Bonke M., Kauppinen L., Riikonen M., Benfey P.N., Helariutta Y. Genes Dev. 14:2938-2943(2000) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2), TISSUE SPECIFICITY, DEVELOPMENTAL STAGE, FUNCTION, MUTAGENESIS OF THR-301. Strain: cv. Columbia. Tissue: Root.
[2]	"Identification of CRE1 as a cytokinin receptor from Arabidopsis." Inoue T., Higuchi M., Hashimoto Y., Seki M., Kobayashi M., Kato T., Tabata S., Shinozaki K., Kakimoto T. Nature 409:1060-1063(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2), FUNCTION, ENZYME REGULATION, MUTAGENESIS OF HIS-482; GLY-490 AND ASP-996. Strain: cv. Wassilewskija. Tissue: Seedling.
[3]	"Novel family of sensor histidine kinase genes in Arabidopsis thaliana." Ueguchi C., Koizumi H., Suzuki T., Mizuno T. Plant Cell Physiol. 42:231-235(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2), TISSUE SPECIFICITY.
[4]	"Sequence and analysis of chromosome 2 of the plant Arabidopsis thaliana." Lin X., Kaul S., Rounsley S.D., Shea T.P., Benito M.-I., Town C.D., Fujii C.Y., Mason T.M., Bowman C.L., Barnstead M.E., Feldblyum T.V., Buell C.R., Ketchum K.A., Lee J.J., Ronning C.M., Koo H.L., Moffat K.S., Cronin L.A. , Shen M., Pai G., Van Aken S., Umayam L., Tallon L.J., Gill J.E., Adams M.D., Carrera A.J., Creasy T.H., Goodman H.M., Somerville C.R., Copenhaver G.P., Preuss D., Nierman W.C., White O., Eisen J.A., Salzberg S.L., Fraser C.M., Venter J.C. Nature 402:761-768(1999) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Columbia.
[5]	The Arabidopsis Information Resource (TAIR) Submitted (APR-2011) to the EMBL/GenBank/DDBJ databases Cited for: GENOME REANNOTATION. Strain: cv. Columbia.
[6]	"The genetic architecture of shoot branching in Arabidopsis thaliana: a comparative assessment of candidate gene associations vs. quantitative trait locus mapping." Ehrenreich I.M., Stafford P.A., Purugganan M.D. Genetics 176:1223-1236(2007) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 722-983, VARIANT ASN-765. Strain: cv. Ag-0, cv. An-1, cv. Br-0, cv. C24, cv. Ct-1, cv. Cvi-1, cv. Edi-0, cv. Ga-0, cv. Kas-2, cv. Kin-0, cv. Landsberg erecta, cv. Ll-0, cv. Lz-0, cv. Ms-0, cv. Mt-0, cv. Nd-1, cv. Nok-3, cv. Oy-0, cv. Se-0, cv. Sorbo, cv. Tsu-1, cv. Van-0, cv. Wa-1 and cv. Wassilewskija.
[7]	"The Arabidopsis sensor His-kinase, AHk4, can respond to cytokinins." Suzuki T., Miwa K., Ishikawa K., Yamada H., Aiba H., Mizuno T. Plant Cell Physiol. 42:107-113(2001) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, INTERACTION WITH AHP1; AHP2; AHP3 AND AHP5.
[8]	"The AHK4 gene involved in the cytokinin-signaling pathway as a direct receptor molecule in Arabidopsis thaliana." Ueguchi C., Sato S., Kato T., Tabata S. Plant Cell Physiol. 42:751-755(2001) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[9]	"The Arabidopsis AHK4 histidine kinase is a cytokinin-binding receptor that transduces cytokinin signals across the membrane." Yamada H., Suzuki T., Terada K., Takei K., Ishikawa K., Miwa K., Yamashino T., Mizuno T. Plant Cell Physiol. 42:1017-1023(2001) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, ACTIVATION BY CYTOKININS, MUTAGENESIS OF THR-301.
[10]	"CREam of cytokinin signalling: receptor identified." Schmuelling T. Trends Plant Sci. 6:281-284(2001) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW.
[11]	"His-Asp phosphorelay signal transduction in higher plants: receptors and response regulators for cytokinin signaling in Arabidopsis thaliana." Oka A., Sakai H., Iwakoshi S. Genes Genet. Syst. 77:383-391(2002) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW.
[12]	"Characterization of the ARR15 and ARR16 response regulators with special reference to the cytokinin signaling pathway mediated by the AHK4 histidine kinase in roots of Arabidopsis thaliana." Kiba T., Yamada H., Mizuno T. Plant Cell Physiol. 43:1059-1066(2002) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, MUTAGENESIS OF GLY-490.
[13]	"Mutations at CRE1 impair cytokinin-induced repression of phosphate starvation responses in Arabidopsis." Franco-Zorrilla J.M., Martin A.C., Solano R., Rubio V., Leyva A., Paz-Ares J. Plant J. 32:353-360(2002) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE, INDUCTION, MUTAGENESIS OF GLY-493; THR-1008 AND ALA-1032.
[14]	"Two-component signal transduction pathways in Arabidopsis." Hwang I., Chen H.-C., Sheen J. Plant Physiol. 129:500-515(2002) [PubMed] [Europe PMC] [Abstract] Cited for: GENE FAMILY, NOMENCLATURE.
[15]	"Histidine kinase homologs that act as cytokinin receptors possess overlapping functions in the regulation of shoot and root growth in Arabidopsis." Nishimura C., Ohashi Y., Sato S., Kato T., Tabata S., Ueguchi C. Plant Cell 16:1365-1377(2004) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE, TISSUE SPECIFICITY, DEVELOPMENTAL STAGE.
[16]	"Two cytokinin receptors of Arabidopsis thaliana, CRE1/AHK4 and AHK3, differ in their ligand specificity in a bacterial assay." Spichal L., Rakova N.Y., Riefler M., Mizuno T., Romanov G.A., Strnad M., Schmuelling T. Plant Cell Physiol. 45:1299-1305(2004) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[17]	"Interallelic complementation at the Arabidopsis CRE1 locus uncovers independent pathways for the proliferation of vascular initials and canonical cytokinin signalling." de Leon B.G.-P., Zorrilla J.M.F., Rubio V., Dahiya P., Paz-Ares J., Leyva A. Plant J. 38:70-79(2004) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, MUTAGENESIS OF THR-301 AND LEU-529.
[18]	"A novel regulatory pathway of sulfate uptake in Arabidopsis roots: implication of CRE1/WOL/AHK4-mediated cytokinin-dependent regulation." Maruyama-Nakashita A., Nakamura Y., Yamaya T., Takahashi H. Plant J. 38:779-789(2004) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, MUTAGENESIS OF GLY-490.
[19]	"In planta functions of the Arabidopsis cytokinin receptor family." Higuchi M., Pischke M.S., Maehoenen A.P., Miyawaki K., Hashimoto Y., Seki M., Kobayashi M., Shinozaki K., Kato T., Tabata S., Helariutta Y., Sussman M.R., Kakimoto T. Proc. Natl. Acad. Sci. U.S.A. 101:8821-8826(2004) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, TISSUE SPECIFICITY, DISRUPTION PHENOTYPE.
[20]	"A live cell hormone-binding assay on transgenic bacteria expressing a eukaryotic receptor protein." Romanov G.A., Spichal L., Lomin S.N., Strnad M., Schmuelling T. Anal. Biochem. 347:129-134(2005) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, BIOPHYSICOCHEMICAL PROPERTIES.
[21]	"Interaction between phosphate-starvation, sugar, and cytokinin signaling in Arabidopsis and the roles of cytokinin receptors CRE1/AHK4 and AHK3." Franco-Zorrilla J.M., Martin A.C., Leyva A., Paz-Ares J. Plant Physiol. 138:847-857(2005) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[22]	"Topolins and hydroxylated thidiazuron derivatives are substrates of cytokinin O-glucosyltransferase with position specificity related to receptor recognition." Mok M.C., Martin R.C., Dobrev P.I., Vankova R., Ho P.S., Yonekura-Sakakibara K., Sakakibara H., Mok D.W. Plant Physiol. 137:1057-1066(2005) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[23]	"Cytokinins regulate a bidirectional phosphorelay network in Arabidopsis." Maehoenen A.P., Higuchi M., Toermaekangas K., Miyawaki K., Pischke M.S., Sussman M.R., Helariutta Y., Kakimoto T. Curr. Biol. 16:1116-1122(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, AUTOPHOSPHORYLATION AT HIS-482, MUTAGENESIS OF THR-301; HIS-482; PHE-708 AND ASP-996, DISRUPTION PHENOTYPE, DEVELOPMENTAL STAGE.
[24]	"Analysis of protein interactions within the cytokinin-signaling pathway of Arabidopsis thaliana." Dortay H., Mehnert N., Buerkle L., Schmuelling T., Heyl A. FEBS J. 273:4631-4644(2006) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH AHP1; AHP2; AHP3; AHP5 AND AHK3.
[25]	"Biochemical characteristics and ligand-binding properties of Arabidopsis cytokinin receptor AHK3 compared to CRE1/AHK4 as revealed by a direct binding assay." Romanov G.A., Lomin S.N., Schmuelling T. J. Exp. Bot. 57:4051-4058(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, BIOPHYSICOCHEMICAL PROPERTIES.
[26]	"Arabidopsis cytokinin receptor mutants reveal functions in shoot growth, leaf senescence, seed size, germination, root development, and cytokinin metabolism." Riefler M., Novak O., Strnad M., Schmuelling T. Plant Cell 18:40-54(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[27]	"Cytokinin receptors are required for normal development of auxin-transporting vascular tissues in the hypocotyl but not in adventitious roots." Kuroha T., Ueguchi C., Sakakibara H., Satoh S. Plant Cell Physiol. 47:234-243(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE, MUTAGENESIS OF MET-459 AND GLY-490.
[28]	"The floral volatile, methyl benzoate, from snapdragon (Antirrhinum majus) triggers phytotoxic effects in Arabidopsis thaliana." Horiuchi J., Badri D.V., Kimball B.A., Negre F., Dudareva N., Paschke M.W., Vivanco J.M. Planta 226:1-10(2007) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[29]	"Identification of amino acid substitutions that render the Arabidopsis cytokinin receptor histidine kinase AHK4 constitutively active." Miwa K., Ishikawa K., Terada K., Yamada H., Suzuki T., Yamashino T., Mizuno T. Plant Cell Physiol. 48:1809-1814(2007) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, MUTAGENESIS OF THR-301; GLY-435; PHE-436; MET-447; VAL-471 AND MET-494.
[30]	"Functional analysis of AHK1/ATHK1 and cytokinin receptor histidine kinases in response to abscisic acid, drought, and salt stress in Arabidopsis." Tran L.S., Urao T., Qin F., Maruyama K., Kakimoto T., Shinozaki K., Yamaguchi-Shinozaki K. Proc. Natl. Acad. Sci. U.S.A. 104:20623-20628(2007) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, INDUCTION, DISRUPTION PHENOTYPE.
[31]	"Cytokinin receptors are involved in alkamide regulation of root and shoot development in Arabidopsis." Lopez-Bucio J., Millan-Godinez M., Mendez-Bravo A., Morquecho-Contreras A., Ramirez-Chavez E., Molina-Torres J., Perez-Torres A., Higuchi M., Kakimoto T., Herrera-Estrella L. Plant Physiol. 145:1703-1713(2007) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[32]	"Mechanism-based inhibitors of cytokinin oxidase/dehydrogenase attack FAD cofactor." Kopecny D., Sebela M., Briozzo P., Spichal L., Houba-Herin N., Masek V., Joly N., Madzak C., Anzenbacher P., Laloue M. J. Mol. Biol. 380:886-899(2008) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[33]	"Toward an interaction map of the two-component signaling pathway of Arabidopsis thaliana." Dortay H., Gruhn N., Pfeifer A., Schwerdtner M., Schmuelling T., Heyl A. J. Proteome Res. 7:3649-3660(2008) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH AHP2; AMPD; WNK5 AND AT4G15630.
[34]	"The role of auxins and cytokinins in the mutualistic interaction between Arabidopsis and Piriformospora indica." Vadassery J., Ritter C., Venus Y., Camehl I., Varma A., Shahollari B., Novak O., Strnad M., Ludwig-Mueller J., Oelmueller R. Mol. Plant Microbe Interact. 21:1371-1383(2008) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[35]	"Cytokinins negatively regulate the root iron uptake machinery in Arabidopsis through a growth-dependent pathway." Seguela M., Briat J.-F., Vert G., Curie C. Plant J. 55:289-300(2008) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[36]	"The purine derivative PI-55 blocks cytokinin action via receptor inhibition." Spichal L., Werner T., Popa I., Riefler M., Schmuelling T., Strnad M. FEBS J. 276:244-253(2009) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, ENZYME REGULATION.
[37]	"STIMPY mediates cytokinin signaling during shoot meristem establishment in Arabidopsis seedlings." Skylar A., Hong F., Chory J., Weigel D., Wu X. Development 137:541-549(2010) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DISRUPTION PHENOTYPE.
[38]	"Cytokinin receptor antagonists derived from 6-benzylaminopurine." Nisler J., Zatloukal M., Popa I., Dolezal K., Strnad M., Spichal L. Phytochemistry 71:823-830(2010) [PubMed] [Europe PMC] [Abstract] Cited for: ENZYME REGULATION.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AJ278528 mRNA. Translation: CAC18521.1.
AJ278529 mRNA. Translation: CAC18522.1.
AJ278530 mRNA. Translation: CAC18523.1.
AB049934 mRNA. Translation: BAB33310.1.
AB049935 mRNA. Translation: BAB33311.1.
AB046871 mRNA. Translation: BAB40776.1.
AC007069 Genomic DNA. Translation: AAD21777.2.
CP002685 Genomic DNA. Translation: AEC05505.1.
CP002685 Genomic DNA. Translation: AEC05506.1.
CP002685 Genomic DNA. Translation: AEC05507.1.
EF598292 Genomic DNA. Translation: ABQ85264.1.
EF598293 Genomic DNA. Translation: ABQ85265.1.
EF598294 Genomic DNA. Translation: ABQ85266.1.
EF598295 Genomic DNA. Translation: ABQ85267.1.
EF598296 Genomic DNA. Translation: ABQ85268.1.
EF598297 Genomic DNA. Translation: ABQ85269.1.
EF598298 Genomic DNA. Translation: ABQ85270.1.
EF598299 Genomic DNA. Translation: ABQ85271.1.
EF598300 Genomic DNA. Translation: ABQ85272.1.
EF598301 Genomic DNA. Translation: ABQ85273.1.
EF598302 Genomic DNA. Translation: ABQ85274.1.
EF598303 Genomic DNA. Translation: ABQ85275.1.
EF598304 Genomic DNA. Translation: ABQ85276.1.
EF598305 Genomic DNA. Translation: ABQ85277.1.
EF598306 Genomic DNA. Translation: ABQ85278.1.
EF598307 Genomic DNA. Translation: ABQ85279.1.
EF598308 Genomic DNA. Translation: ABQ85280.1.
EF598309 Genomic DNA. Translation: ABQ85281.1.
EF598310 Genomic DNA. Translation: ABQ85282.1.
EF598311 Genomic DNA. Translation: ABQ85283.1.
EF598312 Genomic DNA. Translation: ABQ85284.1.
EF598313 Genomic DNA. Translation: ABQ85285.1.
EF598314 Genomic DNA. Translation: ABQ85286.1.
EF598315 Genomic DNA. Translation: ABQ85287.1.

IPI

IPI00521925.
IPI00548080.

PIR

F84429.

RefSeq

NP_565277.1. NM_126244.2.
NP_849925.1. NM_179594.1.
NP_973396.1. NM_201667.1.

UniGene

At.10485.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
3T4J	X-ray	1.65	A/B	149-418	[»]
3T4K	X-ray	1.77	A/B	149-418	[»]
3T4L	X-ray	1.53	A/B	149-418	[»]
3T4O	X-ray	1.75	A/B	149-418	[»]
3T4Q	X-ray	2.30	A/B	149-418	[»]
3T4S	X-ray	1.60	A/B	149-418	[»]
3T4T	X-ray	1.70	A/B	149-418	[»]

ProteinModelPortal

Q9C5U0.

SMR

Q9C5U0. Positions 150-416, 469-752, 941-1060.

ModBase

Search...

Protein-protein interaction databases

IntAct

Q9C5U0. 29 interactions.

STRING

3702.AT2G01830.2-P.

Proteomic databases

PaxDb

Q9C5U0.

PRIDE

Q9C5U0.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblPlants

AT2G01830.2; AT2G01830.2; AT2G01830.

GeneID

814714.

KEGG

ath:AT2G01830.

Organism-specific databases

TAIR

At2g01830.

Phylogenomic databases

eggNOG

COG0784.

InParanoid

Q9C5U0.

KO

K14489.

OMA

ADTVIMK.

PhylomeDB

Q9C5U0.

ProtClustDB

CLSN2687668.

Gene expression databases

Genevestigator

Q9C5U0.

Family and domain databases

Gene3D

1.10.287.130. 1 hit.
3.30.565.10. 2 hits.

InterPro

IPR006189. CHASE.
IPR011006. CheY-like_superfamily.
IPR003594. HATPase_ATP-bd.
IPR004358. Sig_transdc_His_kin-like_C.
IPR003661. Sig_transdc_His_kin_sub1_dim/P.
IPR005467. Sig_transdc_His_kinase_core.
IPR009082. Sig_transdc_His_kinase_dimeric.
IPR001789. Sig_transdc_resp-reg_receiver.
[Graphical view]

Pfam

PF03924. CHASE. 1 hit.
PF02518. HATPase_c. 1 hit.
PF00512. HisKA. 1 hit.
PF00072. Response_reg. 1 hit.
[Graphical view]

PRINTS

PR00344. BCTRLSENSOR.

SMART

SM01079. CHASE. 1 hit.
SM00387. HATPase_c. 1 hit.
SM00388. HisKA. 1 hit.
SM00448. REC. 1 hit.
[Graphical view]

SUPFAM

SSF55874. ATP_bd_ATPase. 1 hit.
SSF52172. CheY_like. 2 hits.
SSF47384. His_kin_homodim. 1 hit.

PROSITE

PS50839. CHASE. 1 hit.
PS50109. HIS_KIN. 1 hit.
PS50110. RESPONSE_REGULATORY. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

BindingDB

Q9C5U0.

ChEMBL

CHEMBL6124.

EvolutionaryTrace

Q9C5U0.

Entry information

Entry name

AHK4_ARATH

Accession

Primary (citable) accession number: Q9C5U0
Secondary accession number(s): A5YY60 , A5YY75, Q9C5T8, Q9C5T9, Q9FDZ3, Q9SIT0

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 5, 2010
Last sequence update:	June 1, 2001
Last modified:	May 1, 2013
This is version 81 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Plant Protein Annotation Program