Immunocytochemical localization of cathepsin B in rat kidney. II. Electron microscopic study using the protein A-gold technique.
Immunocytochemical localization of cathepsin B in rat kidney. II. Electron microscopic study using the protein A-gold technique.
复制标题
组织蛋白酶 B 在大鼠肾脏中的免疫细胞化学定位。
DOI：
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发表时间：
1986
影响因子：
3.2
通讯作者：
K. Kato
中科院分区：
文献类型：
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作者：
S. Yokota;H. Tsuji;K. Kato
Lowicryl K4M 包埋材料的薄片用蛋白 A-金复合物标记。代表组织蛋白酶 B 抗原位点的金颗粒仅局限于肾单位各节段的溶酶体中。最重的标记出现在近端肾小管 S1 段的溶酶体中。标记强度随个体溶酶体的不同而有很大差异。其他管段的溶酶体，例如近端小管、远端曲管和集合管的 S2 和 S3 段，均被金颗粒弱标记。标记密度的定量分析也证实，S1段中的溶酶体具有最高的标记密度，并且在除肾小球之外的整个肾段中大约65%的标记都在S1段中发现。这些结果表明，在大鼠肾脏中，S1段的溶酶体是组织蛋白酶B的主要场所。对S1段溶酶体的进一步精确观察发现，顶泡、肾小管和液泡中没有金颗粒，但当液泡中含有细小的纤维状物质时，在这些液泡中可以检测到金标记。随着溶酶体基质变得更致密，标记密度也增加。高尔基复合体周围的一些小囊泡也被标记。这些结果表明，包括顶泡、小管和液泡在内的内吞装置不含组织蛋白酶B。当液泡发育成吞噬体时，它们获得这种酶来消化吸收的蛋白质。
Thin sections of Lowicryl K4M-embedded materials were labeled with protein A-gold complex. Gold particles representing the antigen sites for cathepsin B were exclusively confined to lysosomes of each segment of the nephron. The heaviest labeling was noted in the lysosomes of the S1 segment of the proximal tubules. Labeling intensity varied considerably with the individual lysosomes. Lysosomes of the other tubular segments, such as the S2 and S3 segments of the proximal tubules, distal convoluted tubules, and collecting tubules were weakly labeled by gold particles. Quantitative analysis of labeling density also confirmed that lysosomes in the S1 segment have the highest labeling density and that approximately 65% of labeling in the whole renal segments, except for the glomerulus, was found in the S1 segment. These results indicate that in rat kidney the lysosomes of the S1 segment are a main location of cathepsin B. Further precise observations on lysosomes of the S1 segment revealed that apical vesicles, tubules, and vacuoles were devoid of gold particles, but when the vacuoles contained fine fibrillar materials, gold labeling was detectable in such vacuoles. As the lysosomal matrix becomes denser, the labeling density is increased. Some small vesicles around the Golgi complex were also labeled. These results indicate that the endocytotic apparatus including the apical vesicles, tubules, and vacuoles contains no cathepsin B. When the vacuoles develop into phagosomes, they acquire this enzyme to digest the absorbed proteins.