ID   MHK_ARATH               Reviewed;         443 AA.
AC   P43294; Q9C5D4; Q9SV67;
DT   01-NOV-1995, integrated into UniProtKB/Swiss-Prot.
DT   06-JUN-2002, sequence version 2.
DT   02-SEP-2026, entry version 173.
DE   RecName: Full=Serine/threonine-protein kinase MHK;
DE            EC=2.7.11.22;
GN   Name=MHK; OrderedLocusNames=At4g13020; ORFNames=F25G13.110;
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].
RC   STRAIN=cv. Columbia;
RX   PubMed=8218420; DOI=10.1016/0167-4781(93)90031-8;
RA   Moran T.V., Walker J.C.;
RT   "Molecular cloning of two novel protein kinase genes from Arabidopsis
RT   thaliana.";
RL   Biochim. Biophys. Acta 1216:9-14(1993).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=cv. Columbia;
RX   PubMed=10617198; DOI=10.1038/47134;
RA   Mayer K.F.X., Schueller C., Wambutt R., Murphy G., Volckaert G., Pohl T.,
RA   Duesterhoeft A., Stiekema W., Entian K.-D., Terryn N., Harris B.,
RA   Ansorge W., Brandt P., Grivell L.A., Rieger M., Weichselgartner M.,
RA   de Simone V., Obermaier B., Mache R., Mueller M., Kreis M., Delseny M.,
RA   Puigdomenech P., Watson M., Schmidtheini T., Reichert B., Portetelle D.,
RA   Perez-Alonso M., Boutry M., Bancroft I., Vos P., Hoheisel J.,
RA   Zimmermann W., Wedler H., Ridley P., Langham S.-A., McCullagh B.,
RA   Bilham L., Robben J., van der Schueren J., Grymonprez B., Chuang Y.-J.,
RA   Vandenbussche F., Braeken M., Weltjens I., Voet M., Bastiaens I., Aert R.,
RA   Defoor E., Weitzenegger T., Bothe G., Ramsperger U., Hilbert H., Braun M.,
RA   Holzer E., Brandt A., Peters S., van Staveren M., Dirkse W., Mooijman P.,
RA   Klein Lankhorst R., Rose M., Hauf J., Koetter P., Berneiser S., Hempel S.,
RA   Feldpausch M., Lamberth S., Van den Daele H., De Keyser A., Buysshaert C.,
RA   Gielen J., Villarroel R., De Clercq R., van Montagu M., Rogers J.,
RA   Cronin A., Quail M.A., Bray-Allen S., Clark L., Doggett J., Hall S.,
RA   Kay M., Lennard N., McLay K., Mayes R., Pettett A., Rajandream M.A.,
RA   Lyne M., Benes V., Rechmann S., Borkova D., Bloecker H., Scharfe M.,
RA   Grimm M., Loehnert T.-H., Dose S., de Haan M., Maarse A.C., Schaefer M.,
RA   Mueller-Auer S., Gabel C., Fuchs M., Fartmann B., Granderath K., Dauner D.,
RA   Herzl A., Neumann S., Argiriou A., Vitale D., Liguori R., Piravandi E.,
RA   Massenet O., Quigley F., Clabauld G., Muendlein A., Felber R., Schnabl S.,
RA   Hiller R., Schmidt W., Lecharny A., Aubourg S., Chefdor F., Cooke R.,
RA   Berger C., Monfort A., Casacuberta E., Gibbons T., Weber N., Vandenbol M.,
RA   Bargues M., Terol J., Torres A., Perez-Perez A., Purnelle B., Bent E.,
RA   Johnson S., Tacon D., Jesse T., Heijnen L., Schwarz S., Scholler P.,
RA   Heber S., Francs P., Bielke C., Frishman D., Haase D., Lemcke K.,
RA   Mewes H.-W., Stocker S., Zaccaria P., Bevan M., Wilson R.K.,
RA   de la Bastide M., Habermann K., Parnell L., Dedhia N., Gnoj L., Schutz K.,
RA   Huang E., Spiegel L., Sekhon M., Murray J., Sheet P., Cordes M.,
RA   Abu-Threideh J., Stoneking T., Kalicki J., Graves T., Harmon G.,
RA   Edwards J., Latreille P., Courtney L., Cloud J., Abbott A., Scott K.,
RA   Johnson D., Minx P., Bentley D., Fulton B., Miller N., Greco T., Kemp K.,
RA   Kramer J., Fulton L., Mardis E., Dante M., Pepin K., Hillier L.W.,
RA   Nelson J., Spieth J., Ryan E., Andrews S., Geisel C., Layman D., Du H.,
RA   Ali J., Berghoff A., Jones K., Drone K., Cotton M., Joshu C., Antonoiu B.,
RA   Zidanic M., Strong C., Sun H., Lamar B., Yordan C., Ma P., Zhong J.,
RA   Preston R., Vil D., Shekher M., Matero A., Shah R., Swaby I.K.,
RA   O'Shaughnessy A., Rodriguez M., Hoffman J., Till S., Granat S., Shohdy N.,
RA   Hasegawa A., Hameed A., Lodhi M., Johnson A., Chen E., Marra M.A.,
RA   Martienssen R., McCombie W.R.;
RT   "Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana.";
RL   Nature 402:769-777(1999).
RN   [3]
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   [4]
RP   GENOME REANNOTATION.
RC   STRAIN=cv. Columbia;
RG   The Arabidopsis Information Resource (TAIR);
RT   "Community-consensus reference genome of Arabidopsis thaliana Col-0.";
RL   Submitted (FEB-2026) to the EMBL/GenBank/DDBJ databases.
RN   [5]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA], AND ALTERNATIVE SPLICING.
RC   STRAIN=cv. Columbia;
RX   PubMed=14593172; DOI=10.1126/science.1088305;
RA   Yamada K., Lim J., Dale J.M., Chen H., Shinn P., Palm C.J., Southwick A.M.,
RA   Wu H.C., Kim C.J., Nguyen M., Pham P.K., Cheuk R.F., Karlin-Newmann G.,
RA   Liu S.X., Lam B., Sakano H., Wu T., Yu G., Miranda M., Quach H.L.,
RA   Tripp M., Chang C.H., Lee J.M., Toriumi M.J., Chan M.M., Tang C.C.,
RA   Onodera C.S., Deng J.M., Akiyama K., Ansari Y., Arakawa T., Banh J.,
RA   Banno F., Bowser L., Brooks S.Y., Carninci P., Chao Q., Choy N., Enju A.,
RA   Goldsmith A.D., Gurjal M., Hansen N.F., Hayashizaki Y., Johnson-Hopson C.,
RA   Hsuan V.W., Iida K., Karnes M., Khan S., Koesema E., Ishida J., Jiang P.X.,
RA   Jones T., Kawai J., Kamiya A., Meyers C., Nakajima M., Narusaka M.,
RA   Seki M., Sakurai T., Satou M., Tamse R., Vaysberg M., Wallender E.K.,
RA   Wong C., Yamamura Y., Yuan S., Shinozaki K., Davis R.W., Theologis A.,
RA   Ecker J.R.;
RT   "Empirical analysis of transcriptional activity in the Arabidopsis
RT   genome.";
RL   Science 302:842-846(2003).
CC   -!- FUNCTION: May play a role in the regulation of plant growth and
CC       development.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-seryl-[protein] + ATP = O-phospho-L-seryl-[protein] + ADP +
CC         H(+); Xref=Rhea:RHEA:17989, Rhea:RHEA-COMP:9863, Rhea:RHEA-
CC         COMP:11604, ChEBI:CHEBI:15378, ChEBI:CHEBI:29999, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:83421, ChEBI:CHEBI:456216; EC=2.7.11.22;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-threonyl-[protein] + ATP = O-phospho-L-threonyl-[protein] +
CC         ADP + H(+); Xref=Rhea:RHEA:46608, Rhea:RHEA-COMP:11060, Rhea:RHEA-
CC         COMP:11605, ChEBI:CHEBI:15378, ChEBI:CHEBI:30013, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:61977, ChEBI:CHEBI:456216; EC=2.7.11.22;
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=Long;
CC         IsoId=P43294-1; Sequence=Displayed;
CC       Name=Short;
CC         IsoId=P43294-2; Sequence=VSP_004861;
CC   -!- TISSUE SPECIFICITY: Roots, leaves and stems.
CC   -!- SIMILARITY: Belongs to the protein kinase superfamily. CMGC Ser/Thr
CC       protein kinase family. CDC2/CDKX subfamily. {ECO:0000305}.
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DR   EMBL; L07249; AAA18854.1; -; mRNA.
DR   EMBL; AL079349; CAB45501.1; -; Genomic_DNA.
DR   EMBL; AL161535; CAB78344.1; -; Genomic_DNA.
DR   EMBL; CP002687; AEE83214.1; -; Genomic_DNA.
DR   EMBL; CP002687; AEE83215.1; -; Genomic_DNA.
DR   EMBL; OZ408686; CAO7046948.1; -; Genomic_DNA.
DR   EMBL; OZ408686; CAO7046950.1; -; Genomic_DNA.
DR   EMBL; AF360324; AAK26034.1; -; mRNA.
DR   EMBL; AY056332; AAL07181.1; -; mRNA.
DR   PIR; C85140; C85140.
DR   PIR; S38327; S38327.
DR   RefSeq; NP_193038.1; NM_117371.1. [P43294-1]
DR   RefSeq; NP_849370.1; NM_179039.4. [P43294-2]
DR   AlphaFoldDB; P43294; -.
DR   SMR; P43294; -.
DR   BioGRID; 12212; 8.
DR   FunCoup; P43294; 751.
DR   IntAct; P43294; 9.
DR   STRING; 3702.P43294; -.
DR   iPTMnet; P43294; -.
DR   PaxDb; 3702-P43294; -.
DR   ProteomicsDB; 250930; -. [P43294-1]
DR   GeneID; 826915; -.
DR   KEGG; ath:AT4G13020; -.
DR   Araport; AT4G13020; -.
DR   TAIR; AT4G13020; MHK.
DR   eggNOG; KOG0661; Eukaryota.
DR   InParanoid; P43294; -.
DR   PhylomeDB; P43294; -.
DR   BRENDA; 2.7.11.22; 399.
DR   PRO; PR:P43294; -.
DR   Proteomes; UP000006548; Chromosome 4.
DR   ExpressionAtlas; P43294; baseline and differential.
DR   GO; GO:0005737; C:cytoplasm; ISM:TAIR.
DR   GO; GO:0005634; C:nucleus; ISM:TAIR.
DR   GO; GO:0005524; F:ATP binding; IEA:InterPro.
DR   GO; GO:0004693; F:cyclin-dependent protein serine/threonine kinase activity; IEA:UniProtKB-EC.
DR   GO; GO:0106310; F:protein serine kinase activity; IEA:RHEA.
DR   GO; GO:0035556; P:intracellular signal transduction; IBA:GO_Central.
DR   CDD; cd07830; STKc_MAK_like; 1.
DR   FunFam; 1.10.510.10:FF:000104; serine/threonine-protein kinase MAK isoform X1; 1.
DR   FunFam; 3.30.200.20:FF:000335; Serine/threonine-protein kinase MHK; 1.
DR   Gene3D; 3.30.200.20; Phosphorylase Kinase, domain 1; 1.
DR   Gene3D; 1.10.510.10; Transferase(Phosphotransferase) domain 1; 1.
DR   InterPro; IPR011009; Kinase-like_dom_sf.
DR   InterPro; IPR050117; MAPK.
DR   InterPro; IPR000719; Prot_kinase_dom.
DR   InterPro; IPR008271; Ser/Thr_kinase_AS.
DR   PANTHER; PTHR24055; MITOGEN-ACTIVATED PROTEIN KINASE; 1.
DR   Pfam; PF00069; Pkinase; 1.
DR   SMART; SM00220; S_TKc; 1.
DR   SUPFAM; SSF56112; Protein kinase-like (PK-like); 1.
DR   PROSITE; PS50011; PROTEIN_KINASE_DOM; 1.
DR   PROSITE; PS00108; PROTEIN_KINASE_ST; 1.
PE   2: Evidence at transcript level;
KW   Alternative splicing; ATP-binding; Kinase; Nucleotide-binding;
KW   Phosphoprotein; Reference proteome; Serine/threonine-protein kinase;
KW   Transferase.
FT   CHAIN           1..443
FT                   /note="Serine/threonine-protein kinase MHK"
FT                   /id="PRO_0000086325"
FT   DOMAIN          12..291
FT                   /note="Protein kinase"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00159"
FT   ACT_SITE        133
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00159,
FT                   ECO:0000255|PROSITE-ProRule:PRU10027"
FT   BINDING         18..26
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00159"
FT   BINDING         41
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00159"
FT   MOD_RES         164
FT                   /note="Phosphothreonine"
FT                   /evidence="ECO:0000250|UniProtKB:Q9C9M7"
FT   VAR_SEQ         1..10
FT                   /note="MMVFVVFVMC -> ME (in isoform Short)"
FT                   /evidence="ECO:0000305"
FT                   /id="VSP_004861"
FT   CONFLICT        66
FT                   /note="N -> K (in Ref. 1; AAA18854)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   443 AA;  50896 MW;  AF92A2233B673F0F CRC64;
     MMVFVVFVMC RYKILEELGD GTCGSVYKAV NLETYEVVAV KKMKRKFYYW EECVNLREVK
     ALRKLNHPHI IKLKEIVREH NELFFIFECM DHNLYHIMKE RERPFSEGEI RSFMSQMLQG
     LAHMHKNGYF HRDLKPENLL VTNNILKIAD FGLAREVASM PPYTEYVSTR WYRAPEVLLQ
     SSLYTPAVDM WAVGAILAEL YALTPLFPGE SEIDQLYKIC CVLGKPDWTT FPEAKSISRI
     MSISHTEFPQ TRIADLLPNA APEAIDLINR LCSWDPLKRP TADEALNHPF FSMATQASYP
     IHDLELRLDN MAALPNLELN LWDFNREPEE CFLGLTLAVK PSAPKLEMLR NVSQDMSENF
     LFCPGVNNDR EPSVFWSLLS PDENGLHAPV ESSPLSLSFS PMQQHTVGPP QSSGFTMTSS
     MQPNMLDRPW MAVSAPFQQS HYL
//