Organ distribution in rats of two members of the low-density lipoprotein receptor gene family, gp330 and LRP/alpha 2MR, and the receptor-associated protein (RAP).
Organ distribution in rats of two members of the low-density lipoprotein receptor gene family, gp330 and LRP/alpha 2MR, and the receptor-associated protein (RAP).
复制标题
DOI：
10.1177/42.4.7510321
复制
发表时间：
1994-04
期刊：
影响因子：
--
通讯作者：
G. Zheng;D. Bachinsky;Ivan Stamenkovic;D. Strickland;Dennis Brown;Giuseppe Andres;R. T. McCluskey
中科院分区：
文献类型：
--
作者：
G. Zheng;D. Bachinsky;Ivan Stamenkovic;D. Strickland;Dennis Brown;Giuseppe Andres;R. T. McCluskey
我们用免疫组织化学方法研究了同源蛋白gp330、低密度脂蛋白受体相关蛋白（LRP/ α 2MR）和受体相关蛋白（RAP）在大鼠体内的分布，以及可溶性外源RAP结合的位点。我们在一组有限的上皮细胞中发现gp330，包括肾近端小管细胞、足细胞、II型肺细胞、甲状旁腺细胞、甲状腺、附睾、子宫内膜、室管膜、视网膜、纤毛体、卵黄囊和胎盘。在这些细胞中，除了甲状旁腺细胞和视网膜上皮细胞可见弥漫性细胞染色外，gp330主要在细胞表面检测到。LRP/alpha 2MR广泛分布于间质细胞，尤其是成纤维细胞和巨噬细胞，也存在于特定的上皮细胞或特化细胞中，包括肝细胞、肾上腺皮质细胞、卵巢滤泡细胞、脉络膜丛细胞、睫状体细胞、系膜细胞和一些神经元。在某些细胞中，特别是肝细胞和肾上腺皮质细胞，主要在表面检测到LRP/ α 2MR，但在其他细胞中，包括巨噬细胞、成纤维细胞、脉络膜丛和纤毛体的上皮细胞，整个细胞可见染色。唯一同时表达LRP/alpha 2MR和gp330的细胞是视网膜和睫状体上皮细胞。在所有表达gp330或LRP/alpha 2MR的细胞内囊泡中均发现RAP。细胞表面未明确检测到RAP。RAP的结合位点出现在具有表面gp330或LRP的细胞表面，并且在具有弥漫性细胞LRP/ α 2MR或gp330的细胞中遍布细胞质。由于gp330和LRP/alpha 2MR的位置不同，我们得出结论，尽管在体外观察到的配体结合特性相似，但gp330和LRP/alpha 2MR在体内具有不同的功能。由于RAP主要在细胞内发现，其主要生理功能可能与细胞内组装或与其结合的受体的运输有关。
We investigated immunohistochemically the distribution in rats of the homologous proteins gp330 and the LDL receptor-related protein (LRP/alpha 2MR), and a receptor-associated protein (RAP), and the sites to which soluble exogenous RAP binds. We found gp330 in a restricted group of epithelial cells, including renal proximal tubule cells, podocytes, Type II pneumocytes, cells of the parathyroid, thyroid, epididymis, lining of the uterus, ependyma, retina, ciliary body, yolk sac, and placenta. In these cells gp330 was detected mainly at the cell surface, except for parathyroid and retinal epithelial cells, where diffuse cell staining was found. LRP/alpha 2MR was widely distributed in interstitial cells, notably in fibroblasts and macrophages, and was also present in a selected group of epithelial or specialized cells, including hepatocytes, adrenal cortical cells, follicular cells of the ovary, cells of the choroid plexus, ciliary body, mesangial cells, and some neurons. In certain cells, notably hepatocytes and adrenal cortical cells, LRP/alpha 2MR was detected mainly on the surface, but in others, including macrophages, fibroblasts, and epithelial cells of the choroid plexus and ciliary body, staining throughout the cell was seen. The only cells that clearly expressed both LRP/alpha 2MR and gp330 were retinal and ciliary epithelial cells. RAP was found in intracellular vesicles in all cells that expressed gp330 or LRP/alpha 2MR. RAP was not definitely detected on the cell surface. Binding sites for RAP were found on the surface of those cells with surface gp330 or LRP, and also throughout the cytoplasm in cells with diffuse cellular LRP/alpha 2MR or gp330. Because of their different locations, we conclude that gp330 and LRP/alpha 2MR serve distinct functions in vivo, despite similarities in ligand-binding properties observed in vitro. Since RAP is found largely within cells, its major physiological function may be concerned with intracellular assembly or trafficking of the receptors to which it binds.