Keller T C, Gordon P V
Department of Biological Science, Florida State University, Tallahassee 32312-3050.
Cell Motil Cytoskeleton. 1991;19(3):169-79. doi: 10.1002/cm.970190305.
Two isozymes of creatine kinase have been purified differentially from mitochondrial and cytoplasmic subfractions of intestinal epithelial cells. These intestinal epithelial cell creatine kinases were indistinguishable from the cytoplasmic (B-CK) and mitochondrial (Mi-CK) creatine kinase isozymes of brain when compared by SDS-PAGE, cellulose polyacetate electrophoresis, and peptide mapping. In intestinal epithelial cells, immunolocalization of the Mi-CK isozyme indicates that it is associated with long, thin mitochondria, which are excluded from the brush border at the apical end of each cell. In contrast, immunolocalization of the B-CK isozyme indicates that it is concentrated distinctly in the brush border terminal web domain. Although absent from the microvilli, B-CK also is distributed diffusely throughout the cytoplasm. Terminal web localization of B-CK was maintained in glycerol-permeabilized cells and in isolated brush borders, indicating that B-CK binds to the brush border structure. The abundance and localization of the mitochondrial and cytoplasmic creatine kinase isozymes suggest that they are part of a system that temporally and/or spatially buffers dynamic energy requirements of intestinal epithelial cells.
已从肠上皮细胞的线粒体和细胞质亚组分中分别纯化出两种肌酸激酶同工酶。通过SDS - PAGE、纤维素醋酸酯电泳和肽图谱分析比较，这些肠上皮细胞肌酸激酶与脑细胞质（B - CK）和线粒体（Mi - CK）肌酸激酶同工酶无法区分。在肠上皮细胞中，Mi - CK同工酶的免疫定位表明它与长而细的线粒体相关，这些线粒体在每个细胞顶端的刷状缘区域不存在。相比之下，B - CK同工酶的免疫定位表明它明显集中在刷状缘终末网区域。虽然微绒毛中不存在B - CK，但它也分散分布于整个细胞质中。B - CK在甘油透化细胞和分离的刷状缘中保持终末网定位，表明B - CK与刷状缘结构结合。线粒体和细胞质肌酸激酶同工酶的丰度和定位表明它们是一个在时间和/或空间上缓冲肠上皮细胞动态能量需求的系统的一部分。
