MOLECULAR BASIS OF NA K ATPASE POLARITY--RP EPITHELIUM

Na-K-ATPase是一种重要的载体运输酶 NA穿过运输上皮细胞。在肾脏、消化道和 外分泌腺，Na-K-ATPase定位于基底外侧血浆 膜，而在视网膜色素上皮中，它存在于 顶端质膜。我们建议研究它的分子基础。 这种蛋白质和信使核糖核酸的差异组织定位 级别。大鼠肾脏、肠道和RPE Na-K-ATPase将 免疫荧光技术在半薄冰冻切片上的定位 抗α和β亚基的单特异性兔抗体。 同样的抗体将被用来比较阿尔法的流动性 和这些组织中的β亚基进行蛋白质印迹分析。 α和β亚基(包括脱糖基)的肽图 将比较三种组织中的β亚基)，以便 搜索特定组织的差异。最后，基因的mRNA 肾、肠和RPE中的α和β亚基将 Northern杂交分析和Sl作图技术的比较 编码大鼠脑内α和β亚基的cDNA。这是意料之中的 这些研究将提供重要信息，导致 关于分子信息的解释 上皮细胞顶端和基侧蛋白的分选。

Na K ATPase is an essential enzyme for the vectorial transport of Na across transporting epithelia. ln kidney, digestive tract and exocrine glands, Na K ATPase is localized in the basolateral plasma membrane, while in retinal pigmentary epithelium it is found in the apical plasmalemma. We propose to study the molecular basis of this differential tissue localization at the protein and mRNA levels. Rat kidney, intestinal and RPE Na K ATPase will be localized on semithin frozen sections by immunofluorescence using monospecific rabbit antibodies against alpha and beta subunits. The same antibodies will be used to compare the mobility of alpha and beta subunits from these tissues by Western blot analysis. Peptide maps of alpha and beta subunits (including deglycosylated beta subunit) from the three tissues will be compared in order to search for tissue-specific differences. Finally, the mRNAs for alpha and beta subunits in kidney, intestine and RPE will be compared by Northern blot analysis and Sl mapping techniques using cDNAs coding for rat brain alpha and beta subunits. It is expected that these studies will provide important information leading to the, elucidation of the molecular information responsible for the sorting of apical and basolateral proteins in epithelial cells.