Identification of a 185-kDa band 3-related polypeptide in oxyntic cells.
Identification of a 185-kDa band 3-related polypeptide in oxyntic cells.
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泌酸细胞中 185 kDa 带 3 相关多肽的鉴定。
DOI：
10.1152/ajpcell.1989.257.3.c537
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Kopito,RR
中科院分区：
文献类型：
--
作者：
Thomas,HA;Machen,TE;Smolka,A;Baron,R;Kopito,RR
纯化的小鼠红细胞阴离子交换蛋白（带3）和保守的COOH-末端肽的小鼠带3（α-Ct）的多克隆抗体识别一个单一的主要185-kDa的多肽在免疫印迹法制备的膜组分从兔胃腺。竞争研究表明，兔胃185-kDa抗原和约100-kDa的小鼠红细胞带3蛋白之间共享的表位被限制在带3的COOH-末端结构域，这是已知的含有阴离子交换活性的催化位点。免疫荧光显微镜用于证明，这带3相关的多肽是与质膜在一个亚群的胃腺细胞组成的专门的泌酸细胞，判断与α-Ct和单克隆抗体的胃H+-K+-ATP酶的免疫荧光的重合。该α-Ct反应性抗原进一步定位于泌酸细胞的基底外侧膜的细胞质面，这与生理学确定的阴离子交换活性位点很好地相关。这些数据表明胃泌酸细胞中存在与红细胞阴离子交换相关的蛋白质家族的新成员。185-kDa多肽是阴离子交换剂的可能性进行了讨论。
Polyclonal antibodies to the purified mouse erythrocyte anion exchange protein (band 3) and to a conserved COOH-terminal peptide of mouse band 3 (alpha-Ct) recognized a single major 185-kDa polypeptide in immunoblots of a membrane fraction prepared from rabbit gastric glands. Competition studies revealed that the epitopes shared between the rabbit gastric 185-kDa antigen and the approximately 100-kDa mouse erythrocyte band 3 protein are restricted to the COOH-terminal domain of band 3, which is known to contain the catalytic site for anion exchange activity. Immunofluorescence microscopy was used to demonstrate that this band 3-related polypeptide is associated with the plasma membrane in a subpopulation of gastric gland cells composed exclusively of oxyntic cells, as judged by the coincidence of immunofluorescence with alpha-Ct and with a monoclonal antibody to the gastric H+-K+-ATPase. This alpha-Ct-reactive antigen was further localized to the cytoplasmic face of the basolateral membrane of oxyntic cells, which correlates well with the physiologically determined site of anion exchange activity. These data demonstrate the presence in gastric oxyntic cells of a novel member of the family of proteins related to the erythrocyte anion exchanger. The possibility that the 185-kDa polypeptide is an anion exchanger is discussed.