ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
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°C, washed, and incubated in complete medium without ligand at 37°C for 5, 15, 30, and 120 minutes. At 5 minutes, the optimized sources/μm2 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 μm radius of the Golgi cisterns, 1.03 ± 0.31; Golgi cisterns, 〈 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.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041320303
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