Localization of the extracellular Ca2+ polyvalent cation-sensing protein in rat kidney
Localization of the extracellular Ca2+ polyvalent cation-sensing protein in rat kidney
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DOI：
10.1152/ajprenal.1998.274.3.f611
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发表时间：
1998-03-01
影响因子：
4.2
通讯作者：
Hebert, SC
中科院分区：
文献类型：
--
作者：
Riccardi, D;Hall, AE;Hebert, SC
我们先前在大鼠肾脏中鉴定了编码G蛋白偶联的细胞外钙/多价阳离子敏感受体RaKCaR的转录本（D. Riccardi，J. Park，W.- S.李，G. Gamba，E. M. Brown和S. C.赫伯特Proc. Natl. Acad. Sci.第92章：一个女人131-135，1994），其被提出提供响应于细胞外Ca（2+）的变化而调节多种肾功能的机制（E. M.布朗《生理学手册》（Handbook of Physiology）Bethesda，MD：Am.生理学部分，1992，sect. 8，vol. 2，chapt. 39，p. 1841-1916;和S. C.赫伯特50：2129-2139，1996）。在这里，我们检查细胞和区域分布的受体蛋白的免疫荧光显微镜使用多克隆抗体提出了对22个氨基酸的区域的NH（2）末端的受体。在皮质厚的升肢细胞的基底外侧边缘处观察到最强的荧光。在髓质粗的升支中也检测到受体的基底外侧染色，在致密斑细胞中通过与脑一氧化氮合酶（NOS-B1）的抗体共染色来鉴定，在远曲小管细胞中通过顶端噻嗪敏感性Na（+）-Cl（-）共转运蛋白共染色来区分。在近端小管刷状缘的基部检测到顶端抗RaKCaR染色，从S1到S3段强度逐渐降低。在皮质集合管中，抗RaKCaR染色在一些（但不是全部）A型嵌入细胞中检测到，通过抗H（+）-ATP酶和抗AE 1 Cl（-）/HCO（3）（-）交换抗体共染色鉴定。目前的研究表明，RaKCaR蛋白表达在许多不同的肾单位节段和受体表达的极性随细胞类型沿着肾单位。这些结果表明细胞外Ca（2+）/多价阳离子敏感受体在响应二价矿物质和潜在的其他多价阳离子（例如，氨基糖苷类抗生素）来调节肾单位功能。
We previously identified transcripts encoding a G protein-coupled, extracellular calcium/polyvalent cation-sensing receptor, RaKCaR, in rat kidney (D. Riccardi, J. Park, W.-S. Lee, G. Gamba, E. M. Brown, and S. C. Hebert. Proc. Natl. Acad. Sci. USA 92: 131-135, 1994), which was proposed to provide the mechanism for modulating a variety of renal functions in response to changes in extracellular Ca(2+) (E. M. Brown. In: Handbook of Physiology. Bethesda, MD: Am. Physiol. Sec., 1992, sect. 8, vol. 2, chapt. 39, p. 1841-1916; and S. C. Hebert. Kidney Int. 50: 2129-2139, 1996). Here, we examine the cellular and regional distribution of receptor protein by immunofluorescence microscopy using a polyclonal antibody raised against a 22 amino acid region of the NH(2) terminus of the receptor. The most intense fluorescence was seen at the basolateral border of cortical thick ascending limb cells. Basolateral staining for the receptor was also detected in medullary thick ascending limbs, in macula densa cells identified by costaining with antibody to brain nitric oxide synthase, NOS-B1, and in distal convoluted tubule cells distinguished by costaining for the apical thiazide-sensitive Na(+)-Cl(-) cotransporter. Apical anti-RaKCaR staining was detected at the base of the brush border of proximal tubules with decreasing intensity from S1 to S3 segments. In cortical collecting ducts, anti-RaKCaR staining was detected in some, but not all, type A intercalated cells identified by costaining with anti-H(+)-ATPase and anti-AE1 Cl(-)/HCO(3)(-) exchanger antibodies. The present study demonstrates that RaKCaR protein is expressed in many different nephron segments and that the polarity of receptor expression varies with cell type along the nephron. These results suggest potential roles for the extracellular Ca(2+)/polyvalent cation-sensing receptor in responding to both circulating and urinary concentrations of divalent minerals and potentially other polyvalent cations (e.g., aminoglycoside antibiotics) to modulate nephron function.