Q93XI5 (HKT2_ORYSI) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Cation transporter HKT2
Short name=OsHKT2

Alternative name(s):
Po-OsHKT2

Gene names

Name:

HKT2

Organism

Oryza sativa subsp. indica (Rice)

Taxonomic identifier

39946 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Viridiplantae › Streptophyta › Streptophytina › Embryophyta › Tracheophyta › Euphyllophyta › Spermatophyta › Magnoliophyta › Liliopsida › commelinids › Poales › Poaceae › BEP clade › Ehrhartoideae › Oryzeae › Oryza › Oryza sativa

Protein attributes

Sequence length	530 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Seems to be involved in regulation of K+/Na+ homeostasis. Seems to act as a potassium-sodium cotransporter, which mediates increased potassium uptake under external sodium accumulation and contributes to salt-tolerance in cultivar indica Pokkali. Ref.1 Ref.2
Subcellular location	Membrane; Multi-pass membrane protein Probable.
Induction	By potassium starvation in roots. Down-regulated by sodium. Ref.1
Domain	HKT transporters are proposed to contain 4 pore-forming regions enclosed by transmembrane segments with each containing a potassium channel-like selectivity filter motif. Ref.2
Sequence similarities	Belongs to the TrkH potassium transport family. HKT (TC 2.A.38.3) subfamily. [View classification]
Caution	HKT2 is found in salt-tolerant cultivar indica Pokkali. It does not exist in cultivar indica 93-11 or japonica Nipponbare.

Ontologies

Keywords
Biological process	Ion transport Potassium transport Sodium transport Transport
Cellular component	Membrane
Domain	Transmembrane Transmembrane helix
Ligand	Potassium Sodium
Gene Ontology (GO)
Biological_process	potassium ion transport Inferred from electronic annotation. Source: UniProtKB-KW sodium ion transport Inferred from electronic annotation. Source: UniProtKB-KW
Cellular_component	integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular_function	cation transmembrane transporter activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 530	530	Cation transporter HKT2		PRO_0000070467
Regions
	Topological domain	1 – 40	40	Cytoplasmic Potential
	Transmembrane	41 – 61	21	Helical; Name=1; Potential
	Transmembrane	102 – 122	21	Helical; Name=2; Potential
	Topological domain	123 – 186	64	Cytoplasmic Potential
	Transmembrane	187 – 207	21	Helical; Name=3; Potential
	Transmembrane	260 – 280	21	Helical; Name=4; Potential
	Topological domain	281 – 317	37	Cytoplasmic Potential
	Transmembrane	318 – 338	21	Helical; Name=5; Potential
	Transmembrane	372 – 392	21	Helical; Name=6; Potential
	Topological domain	393 – 420	28	Cytoplasmic Potential
	Transmembrane	421 – 441	21	Helical; Name=7; Potential
	Transmembrane	494 – 514	21	Helical; Name=8; Potential
	Topological domain	515 – 530	16	Cytoplasmic Potential
Experimental info
	Mutagenesis	88	1	G → S: Loss of selectivity for potassium uptake. Ref.2

Sequences

	Sequence		Length	Mass (Da)
	Q93XI5 [UniParc]. Last modified December 1, 2001. Version 1. Checksum: 73087CF493AD3360	FASTA	530	59,152
	10 20 30 40 50 60 MTSIYQEFIH TKCQSFRSIG RYVLHSIVLI YRFVSLHVHP FWIQLSYFLL ISILGSVLLM 70 80 90 100 110 120 FLKPSSPEFK PGYIDMLFLS TSAMTVSGLS TIEMEVLSSS QIVVLTLLML VGGEVFVSFL 130 140 150 160 170 180 GLMLRLKHKH NPEFSGDRVS SVPIELDTIE PTRTVMSSEE LQIEAAAPDV PSSTIKDLKR 190 200 210 220 230 240 SKRLRWFLGF VVFSYFVVIH VVGFLLVLWY ISRVSSAKAP LKKKGINIAL FSFSVTVSSF 250 260 270 280 290 300 ANGGLVPTNE NMAIFSKNPG LLLLFIGQIL AGNTLYPLFL RILIWFLGKV TKLKDLKLMI 310 320 330 340 350 360 KNSDELQYDY LLPKLPTAFL ASTVIGLMAS LVTLFGSVDW NSSVFDGLSS YQKIINALFM 370 380 390 400 410 420 AVNARHSGEN SIDCSLIAPA VLVLFIILMY LPPSTTFALS NGDEKTANKK AKRKLGLVVR 430 440 450 460 470 480 NLAFSQLACN AVFVIVALIT ERSRLRNDPL NFSALNMIFE VISAYGNVGL TTGYSCSRLQ 490 500 510 520 530 KLHPGSICQD KPYSLSGWWS DEGKLLLVSV MLYGRLKAFT KGTGEYWRLW

References

[1]

"Two types of HKT transporters with different properties of Na+ and K+ transport in Oryza sativa." Horie T., Yoshida K., Nakayama H., Yamada K., Oiki S., Shinmyo A. Plant J. 27:129-138(2001) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, INDUCTION. Strain: cv. Pokkali. Tissue: Seedling root.

[2]

"Glycine residues in potassium channel-like selectivity filters determine potassium selectivity in four-loop-per-subunit HKT transporters from plants." Maeser P., Hosoo Y., Goshima S., Horie T., Eckelman B., Yamada K., Yoshida K., Bakker E.P., Shinmyo A., Oiki S., Schroeder J.I., Uozumi N. Proc. Natl. Acad. Sci. U.S.A. 99:6428-6433(2002) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DOMAIN, MUTAGENESIS OF GLY-88.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AB061313 mRNA. Translation: BAB61791.1.
3D structure databases
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Organism-specific databases
Gramene	Q93XI5.
Gene expression databases
ArrayExpress	Q93XI5.
Family and domain databases
InterPro	IPR003445. Cat_transpt. [Graphical view]
Pfam	PF02386. TrkH. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

HKT2_ORYSI

Accession

Primary (citable) accession number: Q93XI5

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 20, 2005
Last sequence update:	December 1, 2001
Last modified:	April 3, 2013
This is version 38 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Plant Protein Annotation Program