Feild J A, Zhang L, Brun K A, Brooks D P, Edwards R M
Department of Molecular Biology, Department of Renal Pharmacology, Smithkline Beecham Pharmaceuticals, 709 Swedeland Road, King of Prussia, Pennsylvania, 19406, USA.
Biochem Biophys Res Commun. 1999 May 19;258(3):578-82. doi: 10.1006/bbrc.1999.0666.
A cDNA clone with 53% amino acid identity to the human type II sodium-dependent phosphate transporter (NaPi-3) was isolated from human small intestine and lung. Functional characterization in Xenopus laevis oocytes showed this cDNA to encode a sodium-dependent phosphate transporter. The electrogenic response is similar to that found in other type II transporters but an inverse pH dependence was observed. By Northern blot, a 4.2-kb transcript was found to be abundantly expressed in lung and, to a lesser degree, in several other tissues of epithelial origin including small intestine, pancreas, prostate, and kidney. This transcript encompasses a 2.073-kb open reading frame which is most closely related (78% amino acid identity) to the mouse sodium-dependent phosphate transporter IIb isoform. This novel transporter, designated human NaPi-3b (Genbank AF111856), appears to be an isoform of the mammalian renal type II co-transporter family.
从人小肠和肺中分离出一个与人类Ⅱ型钠依赖性磷酸盐转运体（NaPi-3）氨基酸同一性为53%的cDNA克隆。非洲爪蟾卵母细胞中的功能特性表明，该cDNA编码一种钠依赖性磷酸盐转运体。电生性反应与其他Ⅱ型转运体中的反应相似，但观察到了相反的pH依赖性。通过Northern印迹法发现，一个4.2kb的转录本在肺中大量表达，在包括小肠、胰腺、前列腺和肾脏在内的其他几种上皮来源组织中表达程度较低。该转录本包含一个2.073kb的开放阅读框，与小鼠钠依赖性磷酸盐转运体IIb亚型关系最为密切（氨基酸同一性为78%）。这种新型转运体被命名为人NaPi-3b（Genbank AF111856），似乎是哺乳动物肾Ⅱ型共转运体家族的一个亚型。
