Molecular cloning, functional characterization, tissue distribution, and chromosomal localization of a human, small intestinal sodium-phosphate (Na+-Pi) transporter (SLC34A2).
Phosphate plays a crucial role in cellular metabolism, and its homeostatic regulation in intestinal and renal epithelia is critical. Apically expressed sodium-phosphate (Na(+)-P(i)) transporters play a critical role in this regulation. We have isolated a cDNA (HGMW-approved symbol SLC34A2) encoding a novel human small intestinal Na(+)-P(i) transporter. The cDNA is shown to be 4135 bp in length with an open reading frame that predicts a 689-amino-acid polypeptide. The putative protein has 76% homology to mouse intestinal type II Na(+)-P(i) transporter (Na/Pi-IIb) and lower homologies with renal type II Na(+)-P(i) transporters. Northern blots showed a singular transcript of 5.0 kb in human lung, small intestine, and kidney. Computer analysis suggests a protein with 11 transmembrane domains and several potential posttranslational modification sites. Functional characterization in Xenopus laevis oocytes showed that this cDNA encodes a functional Na(+)-P(i) transporter. Furthermore, the gene encoding this cDNA was mapped to human chromosome 4p15.1-p15.3 by the FISH method.
Xu
H
H
Department of Physiology, Steele Memorial Children's Research Center, Tucson, Arizona 85724, USA.
Bai
L
L
Collins
J F
JF
Ghishan
F K
FK
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D009928:Organ Specificity / Q000235:genetics; D010710:Phosphates / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D012964:Sodium / Q000378:metabolism; D050608:Sodium-Phosphate Cotransporter Proteins; D050610:Sodium-Phosphate Cotransporter Proteins, Type II; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb; D027981:Symporters; D014982:Xenopus laevis / Q000235:genetics
D002352:Carrier Proteins; D018076:DNA, Complementary; D010710:Phosphates; D012333:RNA, Messenger; C493557:SLC34A2 protein, human; C493558:Slc34a2 protein, mouse; D050608:Sodium-Phosphate Cotransporter Proteins; D050610:Sodium-Phosphate Cotransporter Proteins, Type II; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb; D027981:Symporters; D012964:Sodium