Reviewed, UniProtKB/Swiss-Prot O95436 (NPT2B_HUMAN)

Names and origin

Protein names

Recommended name:
    Sodium-dependent phosphate transport protein 2B
      Short name=Sodium-phosphate transport protein 2B
Alternative name(s):
    Na(+)-dependent phosphate cotransporter 2B
    Sodium/phosphate cotransporter 2B
    Na(+)/Pi cotransporter 2B
      Short name=NaPi-2b
    NaPi3b
    Solute carrier family 34 member 2

Gene names

Name:

SLC34A2

Organism

Homo sapiens (Human)

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Primates › Haplorrhini › Catarrhini › Hominidae › Homo

Protein attributes

Sequence length	690 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	May be involved in actively transporting phosphate into cells via Na(+) cotransport. It may be the main phosphate transport protein in the intestinal brush border membrane. May have a role in the synthesis of surfactant in lungs' alveoli.
Subcellular location	Membrane; Multi-pass membrane protein.
Tissue specificity	Highly expressed in lung. Also detected in pancreas, kidney, small intestine, ovary, testis, prostate and mammary gland. In lung, it is found in alveolar type II cells but not in bronchiolar epithelium.
Induction	Down-regulated by EGF.
Involvement in disease	Defects in SLC34A2 are a cause of pulmonary alveolar microlithiasis [MIM:265100]. Pulmonary alveolar microlithiasis is a rare disease characterized by the deposition of calcium phosphate microliths throughout the lungs. Most patients are asymptomatic for several years or even for decades and generally, the diagnosis is incidental to clinical investigations unrelated to the disease. Cases with early onset or rapid progression are rare. A 'sandstorm-appearing' chest roentgenogram is a typical diagnostic finding. The onset of this potentially lethal disease varies from the neonatal period to old age and the disease follows a long-term, progressive course, resulting in a slow deterioration of lung functions. Pulmonary alveolar microlithiasis is a recessive monogenic disease with full penetrance.
Sequence similarities	Belongs to the SLC34A transporter family.
Biophysicochemical properties	pH dependence: Optimum pH is 6.6.

Ontologies

Keywords
Biological process	Ion transport Sodium transport Symport Transport
Cellular component	Membrane
Coding sequence diversity	Alternative splicing Polymorphism
Disease	Disease mutation
Domain	Transmembrane
Ligand	Sodium
PTM	Glycoprotein
Gene Ontology (GO)
Biological process	phosphate metabolic process Ref.1 Traceable author statement. Source: ProtInc phosphate transport Ref.1 Traceable author statement. Source: ProtInc
Cellular component	integral to plasma membrane Ref.1 Traceable author statement. Source: ProtInc membrane fraction Ref.1 Traceable author statement. Source: ProtInc
Molecular function	sodium-dependent phosphate transmembrane transporter activity Ref.1 Traceable author statement. Source: ProtInc
Complete GO annotation...

Alternative products

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

Isoform 1 (identifier: O95436-1)

Also known as: NaPi-3b;

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: O95436-2)

Also known as: NaPi-2b; NaPi-IIb;

The sequence of this isoform differs from the canonical sequence as follows:
     38-39: TD → N

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view
Molecule processing
	Chain	1 – 690	690	Sodium-dependent phosphate transport protein 2B
Regions
	Topological domain	1 – 100	100	Cytoplasmic Potential
	Transmembrane	101 – 121	21	M1 Potential
	Topological domain	122 – 135	14	Extracellular Potential
	Transmembrane	136 – 156	21	M2 Potential
	Topological domain	157 – 212	56	Cytoplasmic Potential
	Transmembrane	213 – 233	21	M3 Potential
	Topological domain	234 – 362	129	Extracellular Potential
	Transmembrane	363 – 383	21	M4 Potential
	Topological domain	384 – 407	24	Cytoplasmic Potential
	Transmembrane	408 – 428	21	M5 Potential
	Topological domain	429 – 485	57	Extracellular Potential
	Transmembrane	486 – 506	21	M6 Potential
	Topological domain	507 – 525	19	Cytoplasmic Potential
	Transmembrane	526 – 546	21	M7 Potential
	Topological domain	547 – 552	6	Extracellular Potential
	Transmembrane	553 – 573	21	M8 Potential
	Topological domain	574 – 689	116	Cytoplasmic Potential
	Compositional bias	464 – 467	4	Poly-Thr
	Compositional bias	612 – 644	33	Cys-rich
Amino acid modifications
	Glycosylation	295	1	N-linked (GlcNAc...) Potential
	Glycosylation	308	1	N-linked (GlcNAc...) Potential
	Glycosylation	313	1	N-linked (GlcNAc...) Potential
	Glycosylation	321	1	N-linked (GlcNAc...) Potential
	Glycosylation	340	1	N-linked (GlcNAc...) Potential
	Disulfide bond	303 ↔ 350		By similarity
Natural variations
	Alternative sequence	38 – 39	2	TD → N in isoform 2.
	Natural variant	45	1	V → A: dbSNP rs35426730.
	Natural variant	106	1	G → R in pulmonary alveolar microlithiasis.
	Natural variant	634	1	G → D: dbSNP rs6448389.
Experimental info
	Sequence conflict	228	1	V → L Ref.2 Ref.3
	Sequence conflict	330	1	T → V in BAC11354. Ref.4
	Sequence conflict	590 – 595	6	Missing Ref.4
	Sequence conflict	620	1	C → Y in AAC98695. Ref.1

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 (NaPi-3b) [UniParc]. Last modified December 20, 2005. Version 2. Checksum: 38D81923C992C035	FASTA	690	75,701
	10 20 30 40 50 60 MAPWPELGDA QPNPDKYLEG AAGQQPTAPD KSKETNKTDN TEAPVTKIEL LPSYSTATLI 70 80 90 100 110 120 DEPTEVDDPW NLPTLQDSGI KWSERDTKGK ILCFFQGIGR LILLLGFLYF FVCSLDILSS 130 140 150 160 170 180 AFQLVGGKMA GQFFSNSSIM SNPLLGLVIG VLVTVLVQSS STSTSIVVSM VSSSLLTVRA 190 200 210 220 230 240 AIPIIMGANI GTSITNTIVA LMQVGDRSEF RRAFAGATVH DFFNWLSVLV LLPVEVATHY 250 260 270 280 290 300 LEIITQLIVE SFHFKNGEDA PDLLKVITKP FTKLIVQLDK KVISQIAMND EKAKNKSLVK 310 320 330 340 350 360 IWCKTFTNKT QINVTVPSTA NCTSPSLCWT DGIQNWTMKN VTYKENIAKC QHIFVNFHLP 370 380 390 400 410 420 DLAVGTILLI LSLLVLCGCL IMIVKILGSV LKGQVATVIK KTINTDFPFP FAWLTGYLAI 430 440 450 460 470 480 LVGAGMTFIV QSSSVFTSAL TPLIGIGVIT IERAYPLTLG SNIGTTTTAI LAALASPGNA 490 500 510 520 530 540 LRSSLQIALC HFFFNISGIL LWYPIPFTRL PIRMAKGLGN ISAKYRWFAV FYLIIFFFLI 550 560 570 580 590 600 PLTVFGLSLA GWRVLVGVGV PVVFIIILVL CLRLLQSRCP RVLPKKLQNW NFLPLWMRSL 610 620 630 640 650 660 KPWDAVVSKF TGCFQMRCCC CCRVCCRACC LLCGCPKCCR CSKCCEDLEE AQEGQDVPVK 670 680 690 APETFDNITI SREAQGEVPA SDSKTECTAL
	Isoform 2 (NaPi-2b) (NaPi-IIb) [UniParc]. Checksum: BBD70076B2266490		689	75,599
	10 20 30 40 50 60 MAPWPELGDA QPNPDKYLEG AAGQQPTAPD KSKETNKNNT EAPVTKIELL PSYSTATLID 70 80 90 100 110 120 EPTEVDDPWN LPTLQDSGIK WSERDTKGKI LCFFQGIGRL ILLLGFLYFF VCSLDILSSA 130 140 150 160 170 180 FQLVGGKMAG QFFSNSSIMS NPLLGLVIGV LVTVLVQSSS TSTSIVVSMV SSSLLTVRAA 190 200 210 220 230 240 IPIIMGANIG TSITNTIVAL MQVGDRSEFR RAFAGATVHD FFNWLSVLVL LPVEVATHYL 250 260 270 280 290 300 EIITQLIVES FHFKNGEDAP DLLKVITKPF TKLIVQLDKK VISQIAMNDE KAKNKSLVKI 310 320 330 340 350 360 WCKTFTNKTQ INVTVPSTAN CTSPSLCWTD GIQNWTMKNV TYKENIAKCQ HIFVNFHLPD 370 380 390 400 410 420 LAVGTILLIL SLLVLCGCLI MIVKILGSVL KGQVATVIKK TINTDFPFPF AWLTGYLAIL 430 440 450 460 470 480 VGAGMTFIVQ SSSVFTSALT PLIGIGVITI ERAYPLTLGS NIGTTTTAIL AALASPGNAL 490 500 510 520 530 540 RSSLQIALCH FFFNISGILL WYPIPFTRLP IRMAKGLGNI SAKYRWFAVF YLIIFFFLIP 550 560 570 580 590 600 LTVFGLSLAG WRVLVGVGVP VVFIIILVLC LRLLQSRCPR VLPKKLQNWN FLPLWMRSLK 610 620 630 640 650 660 PWDAVVSKFT GCFQMRCCCC CRVCCRACCL LCGCPKCCRC SKCCEDLEEA QEGQDVPVKA 670 680 PETFDNITIS REAQGEVPAS DSKTECTAL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Cloning and functional characterization of a sodium-dependent phosphate transporter expressed in human lung and small intestine." Feild J.A., Zhang L., Brun K.A., Brooks D.P., Edwards R.M. Biochem. Biophys. Res. Commun. 258:578-582(1999) [PubMed: 10329428] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1), BIOPHYSICOCHEMICAL PROPERTIES, TISSUE SPECIFICITY. Tissue: Lung and Small intestine.
[2]	"Molecular cloning, functional characterization, tissue distribution, and chromosomal localization of a human, small intestinal sodium-phosphate (Na+-Pi) transporter (SLC34A2)." Xu H., Bai L., Collins J.F., Ghishan F.K. Genomics 62:281-284(1999) [PubMed: 10610722] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 2), TISSUE SPECIFICITY. Tissue: Small intestine.
[3]	"Regulation of the human sodium-phosphate cotransporter NaPi-IIb gene promoter by epidermal growth factor." Xu H., Collins J.F., Bai L., Kiela P.R., Ghishan F.K. Am. J. Physiol. 280:C628-C636(2001) [PubMed: 11171583] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-592 (ISOFORM 2), INDUCTION. Tissue: Intestine.
[4]	"Complete sequencing and characterization of 21,243 full-length human cDNAs." Ota T., Suzuki Y., Nishikawa T., Otsuki T., Sugiyama T., Irie R., Wakamatsu A., Hayashi K., Sato H., Nagai K., Kimura K., Makita H., Sekine M., Obayashi M., Nishi T., Shibahara T., Tanaka T., Ishii S. , Yamamoto J., Saito K., Kawai Y., Isono Y., Nakamura Y., Nagahari K., Murakami K., Yasuda T., Iwayanagi T., Wagatsuma M., Shiratori A., Sudo H., Hosoiri T., Kaku Y., Kodaira H., Kondo H., Sugawara M., Takahashi M., Kanda K., Yokoi T., Furuya T., Kikkawa E., Omura Y., Abe K., Kamihara K., Katsuta N., Sato K., Tanikawa M., Yamazaki M., Ninomiya K., Ishibashi T., Yamashita H., Murakawa K., Fujimori K., Tanai H., Kimata M., Watanabe M., Hiraoka S., Chiba Y., Ishida S., Ono Y., Takiguchi S., Watanabe S., Yosida M., Hotuta T., Kusano J., Kanehori K., Takahashi-Fujii A., Hara H., Tanase T.-O., Nomura Y., Togiya S., Komai F., Hara R., Takeuchi K., Arita M., Imose N., Musashino K., Yuuki H., Oshima A., Sasaki N., Aotsuka S., Yoshikawa Y., Matsunawa H., Ichihara T., Shiohata N., Sano S., Moriya S., Momiyama H., Satoh N., Takami S., Terashima Y., Suzuki O., Nakagawa S., Senoh A., Mizoguchi H., Goto Y., Shimizu F., Wakebe H., Hishigaki H., Watanabe T., Sugiyama A., Takemoto M., Kawakami B., Yamazaki M., Watanabe K., Kumagai A., Itakura S., Fukuzumi Y., Fujimori Y., Komiyama M., Tashiro H., Tanigami A., Fujiwara T., Ono T., Yamada K., Fujii Y., Ozaki K., Hirao M., Ohmori Y., Kawabata A., Hikiji T., Kobatake N., Inagaki H., Ikema Y., Okamoto S., Okitani R., Kawakami T., Noguchi S., Itoh T., Shigeta K., Senba T., Matsumura K., Nakajima Y., Mizuno T., Morinaga M., Sasaki M., Togashi T., Oyama M., Hata H., Watanabe M., Komatsu T., Mizushima-Sugano J., Satoh T., Shirai Y., Takahashi Y., Nakagawa K., Okumura K., Nagase T., Nomura N., Kikuchi H., Masuho Y., Yamashita R., Nakai K., Yada T., Nakamura Y., Ohara O., Isogai T., Sugano S. Nat. Genet. 36:40-45(2004) [PubMed: 14702039] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] OF 266-690. Tissue: Ovarian carcinoma.
[5]	"Mutations in SLC34A2 cause pulmonary alveolar microlithiasis and are possibly associated with testicular microlithiasis." Corut A., Senyigit A., Ugur S.A., Altin S., Ozcelik U., Calisir H., Yildirim Z., Gocmen A., Tolun A. Am. J. Hum. Genet. 79:650-656(2006) [PubMed: 16960801] [Abstract] Cited for: VARIANT PULMONARY ALVEOLAR MICROLITHIASIS ARG-106.
+	Additional computationally mapped references.

Web resources

GeneReviews

Cross-references

Sequence databases
EMBLGenBankDDBJ	AF111856 mRNA. Translation: AAC98695.1. AF146796 mRNA. Translation: AAF31328.1. AF234245 , AF234237, AF234238, AF234239, AF234242, AF234244, AF234243, AF234241 Genomic DNA. Translation: AAL55657.1. AK075015 mRNA. Translation: BAC11354.1. Different initiation.
RefSeq	NP_006415.2.
UniGene	Hs.479372
3D structure databases
ModBase	Search...
PTM databases
PhosphoSite	O95436.
Genome annotation databases
Ensembl	ENSG00000157765. Homo sapiens. [Contig view]
GeneID	10568.
KEGG	hsa:10568.
Organism-specific databases
HGNC	HGNC:11020. SLC34A2.
MIM	265100. phenotype. 604217. gene.
Orphanet	60025. Pulmonary alveolar microlithiasis.
PharmGKB	PA35888.
GenAtlas	Search...
GeneCards	Search...
Phylogenomic databases
HOGENOM	O95436.
HOVERGEN	O95436.
Gene expression databases
ArrayExpress	O95436.
CleanEx	HS_SLC34A2.
GermOnline	ENSG00000157765. Homo sapiens.
Family and domain databases
InterPro	IPR003841. Na/Pi_cotranspt. [Graphical view]
Pfam	PF02690. Na_Pi_cotrans. 2 hits. [Graphical view]
TIGRFAMs	TIGR01013. 2a58. 1 hit.
ProDom	O95436. [Graphical view] [Entries sharing at least one domain]
BLOCKS	Search...
Other Resources
SOURCE	Search...
ProtoNet	Search...

Entry information

Entry name

NPT2B_HUMAN

Accession

Primary (citable) accession number: O95436
Secondary accession number(s): Q8N2K2, Q8WYA9, Q9P0V7

Entry history

Integrated into UniProtKB/Swiss-Prot:	December 20, 2005
Last sequence update:	December 20, 2005
Last modified:	July 22, 2008
This is version 48 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HPI (Human Proteome Initiative)