Localization of PEPT1 and PEPT2 proton-coupled oligopeptide transporter mRNA and protein in rat kidney
Localization of PEPT1 and PEPT2 proton-coupled oligopeptide transporter mRNA and protein in rat kidney
复制标题
DOI：
10.1152/ajprenal.1999.276.5.f658
复制
发表时间：
1999-05-01
影响因子：
4.2
通讯作者：
Brosius, FC
中科院分区：
文献类型：
--
作者：
Shen, H;Smith, DE;Brosius, FC
为了确定寡肽转运蛋白在肾脏的定位，采用Northern印迹杂交技术，制备了针对两个克隆的大鼠H+/多肽转运蛋白PEPT1和PEPT2的多克隆抗血清。在高强度条件下，大鼠PEPT1的3.0kb的mRNA转录本主要在皮质浅层表达，而PEPT2的3.5kb的mRNA转录本主要在皮质深层/外延髓的外条表达。PEPT1抗血清在肾和肠刷状缘小泡免疫印迹上检测到一条明显迁移率接近90 kDa的条带。PEPT2抗血清在肾BBMV中检测到一条与85 kDa相似的特异条带，而在肠道BBMV中未检测到。PEPT1免疫定位实验显示，在近端小管的S1段和所有小肠段的绒毛刷缘均检测到刷状边缘抗原。相反，PEPT2免疫定位主要局限于近端小管S3段的刷状边缘。其他大鼠肾单位节段PEPT1和PEPT2染色均为阴性。总体而言，我们的结果最终证明，尽管PEPT1在近曲小管的早期区域(卷曲部)表达，但PEPT2在近端小管的后期区域(直肠部)特异表达。
To determine the renal localization of oligopeptide transporters, Northern blot analyses were performed and polyclonal antisera were generated against PEPT1 and PEPT2, the two cloned rat H+/peptide transporters. Under high-stringency conditions, a 3.0-kb mRNA transcript of rat PEPT1 was expressed primarily in superficial cortex, whereas a 3.5-kb mRNA transcript of PEPT2 was expressed primarily in deep cortex/outer stripe of outer medulla. PEPT1 antisera detected a specific band on immunoblots of renal and intestinal brush-border membrane vesicles (BBMV) with an apparent mobility of similar to 90 kDa. PEPT2 antisera detected a specific broad band of similar to 85 kDa in renal but not in intestinal BBMV. PEPT1 immunolocalization experiments showed detection of a brush border antigen in S1 segments of the proximal tubule and in the brush border of villi from all segments of the small intestine. In contrast, PEPT2 immunolocalization was primarily confined to the brush border of S3 segments of the proximal tubule. AU other nephron segments in rat were negative for PEPT1 and PEPT2 staining. Overall, our results conclusively demonstrate that although PEPT1 is expressed in early regions of the proximal tubule (pars convoluta), PEPT2 is specific for the latter regions of proximal tubule (pars recta).