Open AccessImmunocytochemical localization of P170 at the plasma membrane of multidrug-resistant human cells.
Author(s) -
Mark C. Willingham,
Nancy Richert,
Marilyn M. Cornwell,
T Tsuruo,
Hirotaka Hamada,
Michael M. Gottesman,
Ira Pastan
Publication year - 1987
Publication title -
journal of histochemistry and cytochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.971
H-Index - 124
eISSN - 1551-5044
pISSN - 0022-1554
DOI - 10.1177/35.12.2890686
Subject(s) - endoplasmic reticulum , golgi apparatus , biology , cell membrane , membrane , multiple drug resistance , immunofluorescence , microbiology and biotechnology , cell culture , membrane protein , antibody , membrane glycoproteins , monoclonal antibody , glycoprotein , biochemistry , immunology , genetics , antibiotics
P170 (P-glycoprotein) is a membrane protein found in high levels in multidrug-resistant cultured cell lines. We have localized this protein using monoclonal antibody MRK16 by immunofluorescence and electron microscopy in the multidrug-resistant human carcinoma cell line KB-C4. The P170 determinant recognized by antibody MRK16 was found on drug-resistant KB-C4 cells, but not on parental drug-sensitive KB-3-1 cells. The determinant was present on the external surface of the plasma membrane and on the luminal side of Golgi stack membranes. P170 was excluded from coated pits at the plasma membrane and absent from endocytic vesicles and lysosomes. This determinant was detected only in small amounts in the endoplasmic reticulum. The high protein concentration of P170 in the plasma membrane is consistent with a role of this protein as a drug efflux pump at the cell surface.
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