Mezitis S G, Stieber A, Gonatas N K
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6079.
J Cell Physiol. 1987 Sep;132(3):401-14. doi: 10.1002/jcp.1041320303.
Several ligands undergo endocytosis into the Golgi apparatus. We have examined with a quantitative ultrastructural, autoradiographic method the sequential endocytosis of tritiated wheat germ agglutinin (3H-WGA) by cultured murine neuroblastoma cells. Cells were incubated with 3H-WGA for 1 hour at 4 degrees C, washed, and incubated in complete medium without ligand at 37 degrees C for 5, 15, 30, and 120 minutes. At 5 minutes, the optimized sources/micron 2 of neuroblastoma cell area, which represented the grain density of each compartment, were as follows: smooth vesicles and tubules, 1.03 +/- 0.88; Golgi-associated vesicles, i.e., clusters of vesicles within a 1 micron radius of the Golgi cisterns, 1.03 +/- 0.31; Golgi cisterns, less than 0.01; and lysosomes, 0.26 +/- 0.16. At 15 minutes grain densities were: smooth vesicles and tubules, 0.9 +/- 0.34; Golgi-associated vesicles, 1.41 +/- 0.28; Golgi cisterns, 0.73 +/- 0.41; and lysosomes, 0.1 +/- 0.09. At 30 minutes grain densities were: smooth vesicles and tubules, 0.46 +/- 0.46; Golgi-associated vesicles, 1.78 +/- 0.34; Golgi cisterns, 0.89 +/- 0.78; and lysosomes, 0.39 +/- 0.14. At 2 hours, smooth vesicles, tubules, and Golgi cisterns were not labeled, Golgi-associated vesicles were still labeled (0.71 +/- 0.1), and lysosomes were heavily labeled (2.17 +/- 0.22). These results are consistent with the hypotheses that either the Golgi complex (cisterns and associated vesicles) is an early and intermediate step of the endocytosis of 3H-WGA into lysosomes or that it constitutes part of a separate and quantitatively significant pathway of endocytosis of this ligand.
几种配体通过胞吞作用进入高尔基体。我们用一种定量超微结构放射自显影方法研究了培养的小鼠神经母细胞瘤细胞对氚标记的小麦胚凝集素（3H-WGA）的连续胞吞作用。将细胞在4℃下与3H-WGA孵育1小时，洗涤后，在不含配体的完全培养基中于37℃孵育5、15、30和120分钟。5分钟时，代表每个区室颗粒密度的神经母细胞瘤细胞面积的优化源/微米2如下：光滑囊泡和小管，1.03±0.88；高尔基体相关囊泡，即高尔基体潴泡半径1微米内的囊泡簇，1.03±0.31；高尔基体潴泡，小于0.01；溶酶体，0.26±0.16。15分钟时颗粒密度为：光滑囊泡和小管，0.9±0.34；高尔基体相关囊泡，1.41±0.28；高尔基体潴泡，0.73±0.41；溶酶体，0.1±0.09。30分钟时颗粒密度为：光滑囊泡和小管，0.46±0.46；高尔基体相关囊泡，1.78±0.34；高尔基体潴泡，0.89±0.78；溶酶体，0.39±0.14。2小时时，光滑囊泡、小管和高尔基体潴泡未被标记，高尔基体相关囊泡仍被标记（0.71±0.1），溶酶体被大量标记（2.17±0.22）。这些结果与以下假设一致：要么高尔基体复合体（潴泡和相关囊泡）是3H-WGA胞吞进入溶酶体的早期和中间步骤，要么它构成了该配体胞吞的一个独立且数量上显著的途径的一部分。
