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Stable variant of LM fibroblast defective in fluid‐phase but competent in receptor‐mediated endocytosis
Author(s) -
Ryser Hugues J.P.,
Li Wande,
Mandel Richard,
Shen WeiChiang
Publication year - 1988
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041370314
Subject(s) - endocytosis , receptor mediated endocytosis , receptor , microbiology and biotechnology , endosome , transferrin receptor , cell culture , biology , cell surface receptor , exocytosis , transferrin , endocytic cycle , biochemistry , membrane , genetics
The F‐40 cell line, a stable variant of LM fibroblasts selected for its resistance to polyethylene glycol (PEG)‐induced fusion (Roos and Davidson: Somatic Cell and Molecular Genetics 6:381‐‐391, 1980), has a decreased capacity to internalize fluid‐phase markers and nonspecifically surface‐bound macromolecules. It is not defective in exocytosis since, after a short sucrose pulse, it releases the same fraction of ingested sucrose into the medium as does the parental line. F40 cells have a normal capacity to carry out receptor‐mediated endocytosis, as tested with 125 I‐alpha‐2 macroglobulin (alpha‐2 MG) and 125 I‐transferrin (Tf), and to recycle Tf receptor to the cell surface. These data demonstrate that receptor‐mediated and non‐receptor mediated endocytosis are distinct processes that can be altered independently. Of the many membrane fusions occurring in the course of endocytosis, the only one that appears associated with the defect in cell fusion characteristic of F40 cells is the formation of primary endocytotic vesicles engaged in non‐receptor‐mediated internalizations.