Chong S S, Kristjansson K, Zoghbi H Y, Hughes M R
Institute for Molecular Genetics, Baylor College of Medicine, Houston, Texas 77030.
Genomics. 1993 Nov;18(2):355-9. doi: 10.1006/geno.1993.1476.
Resorption of phosphate by the kidney is an important function in the maintenance of phosphate homeostasis in mammals, and a defect in renal phosphate uptake has been implicated in at least three human genetic disorders. We have isolated a cDNA encoding a human sodium-dependent phosphate transport protein (NPT1). This cDNA hybridizes to a single 2.5-kb RNA transcript from human kidney cortex, its nucleotide sequence shows 80.3% identity to the rabbit NaPi-1 sequence, and it encodes a polypeptide of 467 amino acids. Amino acid sequence comparisons indicate a 69.7% identity between human NPT1 and rabbit NaPi-1 polypeptides; the inclusion of conservative substitutions increases the homology between the two proteins to 81.5%. Alignment of both sequences also reveals several conserved potential N-glycosylation and protein kinase C phosphorylation sites. Polypeptide hydropathy analysis predicts several membrane-spanning domains. This cDNA maps the location of the gene encoding NPT1 to human chromosome 6q21.3-p23.
肾脏对磷酸盐的重吸收是维持哺乳动物磷酸盐稳态的一项重要功能，并且肾脏磷酸盐摄取缺陷与至少三种人类遗传疾病有关。我们分离出了一个编码人类钠依赖性磷酸盐转运蛋白（NPT1）的cDNA。该cDNA与来自人类肾皮质的一个单一2.5kb RNA转录本杂交，其核苷酸序列与兔NaPi-1序列具有80.3%的同一性，并且它编码一个467个氨基酸的多肽。氨基酸序列比较表明人类NPT1和兔NaPi-1多肽之间具有69.7%的同一性；包含保守性替换会使这两种蛋白质之间的同源性增加到81.5%。两条序列的比对还揭示了几个保守的潜在N-糖基化和蛋白激酶C磷酸化位点。多肽亲水性分析预测了几个跨膜结构域。这个cDNA将编码NPT1的基因定位到人类染色体6q21.3-p23。
