Fusion accessibility of endocytic compartments along the recycling and lysosomal endocytic pathways in intact cells. J Cell Biol 1989 Nov;109(5):2097-104
Date
11/01/1989Pubmed ID
2681226Pubmed Central ID
PMC2115866DOI
10.1083/jcb.109.5.2097Scopus ID
2-s2.0-0024454465 (requires institutional sign-in at Scopus site) 100 CitationsAbstract
A fluorescence assay developed for the quantitation of intracellular fusion of sequentially formed endocytic compartments (Salzman, N. H., and F. R. Maxfield. 1988 J. Cell Biol. 106:1083-1091) has been used to measure the time course of endosome fusion accessibility along the recycling and degradative endocytic pathways. Transferrin (Tf) was used to label the recycling pathway, and alpha2-macroglobulin (alpha 2 M) was used to label the lysosomal degradative pathway. Along the degradative pathway, accessibility of vesicles containing alpha 2M to fusion with subsequently formed endocytic vesicles decreased with apparent first order kinetics. The t12 for the loss of fusion accessibility was approximately 8 min. The behavior of Tf is more complex. Initially the fusion accessibility of Tf decayed rapidly (t1/2 less than 3 min), but a constant level of fusion accessibility was then observed for 10 min. This suggests that Tf moves through one fusion accessible endosome rapidly and then enters a second fusion accessible compartment on the recycling pathway. At 18 degrees C, fusion of antifluorescein antibodies (AFA) containing vesicles with F-alpha 2M was observed when the interval between additions was 10 min. However, if the interval was increased to 1 h, no fusion with incoming vesicles was observed. These results identify the site of F-alpha 2M accumulation at 18 degrees C as a prelysosomal late endosome that no longer fuses with newly formed endosomes since no delivery to lysosomes is observed at this temperature.
Author List
Salzman NH, Maxfield FRAuthor
Nita H. Salzman MD, PhD Director, Professor in the Pediatrics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCell Line
Endocytosis
Fluoresceins
Fluorescent Antibody Technique
Humans
Lysosomes
Models, Biological
Mutation
Receptors, Transferrin
Spectrometry, Fluorescence
Transfection
Transferrin
