ID   HKT2_ORYSI              Reviewed;         530 AA.
AC   Q93XI5;
DT   20-DEC-2005, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2001, sequence version 1.
DT   22-JUL-2008, entry version 22.
DE   RecName: Full=Cation transporter HKT2;
DE            Short=OsHKT2;
DE   AltName: Full=Po-OsHKT2;
GN   Name=HKT2;
OS   Oryza sativa subsp. indica (Rice).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliophyta; Liliopsida; Poales; Poaceae; BEP clade;
OC   Ehrhartoideae; Oryzeae; Oryza.
OX   NCBI_TaxID=39946;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, AND INDUCTION.
RC   STRAIN=cv. Pokkali; TISSUE=Seedling root;
RX   PubMed=11489190;
RA   Horie T., Yoshida K., Nakayama H., Yamada K., Oiki S., Shinmyo A.;
RT   "Two types of HKT transporters with different properties of Na+ and K+
RT   transport in Oryza sativa.";
RL   Plant J. 27:129-138(2001).
RN   [2]
RP   FUNCTION, DOMAIN, AND MUTAGENESIS OF GLY-88.
RX   MEDLINE=21980570; PubMed=11959905; DOI=10.1073/pnas.082123799;
RA   Maeser P., Hosoo Y., Goshima S., Horie T., Eckelman B., Yamada K.,
RA   Yoshida K., Bakker E.P., Shinmyo A., Oiki S., Schroeder J.I.,
RA   Uozumi N.;
RT   "Glycine residues in potassium channel-like selectivity filters
RT   determine potassium selectivity in four-loop-per-subunit HKT
RT   transporters from plants.";
RL   Proc. Natl. Acad. Sci. U.S.A. 99:6428-6433(2002).
CC   -!- FUNCTION: Seems to be involved in regulation of K(+)/Na(+)
CC       homeostasis. Seems to act as a potassium-sodium cotransporter,
CC       which mediates increased potassium uptake under external sodium
CC       accumulation and contributes to salt-tolerance in cultivar indica
CC       Pokkali.
CC   -!- SUBCELLULAR LOCATION: Membrane; Multi-pass membrane protein
CC       (Probable).
CC   -!- INDUCTION: By potassium starvation in roots. Down-regulated by
CC       sodium.
CC   -!- DOMAIN: HKT transporters are proposed to contain 4 pore-forming
CC       regions enclosed by transmembrane segments with each containing a
CC       potassium channel-like selectivity filter motif.
CC   -!- SIMILARITY: Belongs to the trkH potassium transport family. HKT
CC       subfamily.
CC   -!- CAUTION: HKT2 is found in salt-tolerant cultivar indica Pokkali.
CC       It does not exist in cultivar indica 93-11 or japonica Nipponbare.
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DR   EMBL; AB061313; BAB61791.1; -; mRNA.
DR   Gramene; Q93XI5; -.
DR   InterPro; IPR003445; Cat_transpt.
DR   InterPro; IPR004773; Ktransp_euk.
DR   Pfam; PF02386; TrkH; 1.
DR   TIGRFAMs; TIGR00934; 2a38euk; 1.
PE   1: Evidence at protein level;
KW   Ion transport; Membrane; Potassium; Potassium transport; Sodium;
KW   Sodium transport; Transmembrane; Transport.
FT   CHAIN         1    530       Cation transporter HKT2.
FT                                /FTId=PRO_0000070467.
FT   TOPO_DOM      1     40       Cytoplasmic (Potential).
FT   TRANSMEM     41     61       1 (Potential).
FT   TRANSMEM    102    122       2 (Potential).
FT   TOPO_DOM    123    186       Cytoplasmic (Potential).
FT   TRANSMEM    187    207       3 (Potential).
FT   TRANSMEM    260    280       4 (Potential).
FT   TOPO_DOM    281    317       Cytoplasmic (Potential).
FT   TRANSMEM    318    338       5 (Potential).
FT   TRANSMEM    372    392       6 (Potential).
FT   TOPO_DOM    393    420       Cytoplasmic (Potential).
FT   TRANSMEM    421    441       7 (Potential).
FT   TRANSMEM    494    514       8 (Potential).
FT   TOPO_DOM    515    530       Cytoplasmic (Potential).
FT   MUTAGEN      88     88       G->S: Loss of selectivity for potassium
FT                                uptake.
SQ   SEQUENCE   530 AA;  59152 MW;  73087CF493AD3360 CRC64;
     MTSIYQEFIH TKCQSFRSIG RYVLHSIVLI YRFVSLHVHP FWIQLSYFLL ISILGSVLLM
     FLKPSSPEFK PGYIDMLFLS TSAMTVSGLS TIEMEVLSSS QIVVLTLLML VGGEVFVSFL
     GLMLRLKHKH NPEFSGDRVS SVPIELDTIE PTRTVMSSEE LQIEAAAPDV PSSTIKDLKR
     SKRLRWFLGF VVFSYFVVIH VVGFLLVLWY ISRVSSAKAP LKKKGINIAL FSFSVTVSSF
     ANGGLVPTNE NMAIFSKNPG LLLLFIGQIL AGNTLYPLFL RILIWFLGKV TKLKDLKLMI
     KNSDELQYDY LLPKLPTAFL ASTVIGLMAS LVTLFGSVDW NSSVFDGLSS YQKIINALFM
     AVNARHSGEN SIDCSLIAPA VLVLFIILMY LPPSTTFALS NGDEKTANKK AKRKLGLVVR
     NLAFSQLACN AVFVIVALIT ERSRLRNDPL NFSALNMIFE VISAYGNVGL TTGYSCSRLQ
     KLHPGSICQD KPYSLSGWWS DEGKLLLVSV MLYGRLKAFT KGTGEYWRLW
//