TY - JOUR
T1 - Binding and internalization of 125I-LDL in normal and mutant human fibroblasts. A quantitative autoradiographic study
AU - Carpentier, Jean Louis
AU - Gorden, Phillip
AU - Goldstein, Joseph L.
AU - Anderson, Richard G W
AU - Brown, Michael S.
AU - Orci, Lelio
N1 - Funding Information:
This work was performed while P. G. was a Visiting Professor at the Institute of Histology and Embryology, University of Geneva, Switzerland. This research was supported by grant no. 3.120.77 from the Swiss National Science Foundation and NIH Grant number PO-1-HL20948.
PY - 1979/6
Y1 - 1979/6
N2 - Using a quantitative EM autoradiographic technique, we have visualized the membrane binding and receptor-mediated uptake of low density lipoprotein (LDL) in human fibroblasts. The initial binding was restricted to the plasma membrane (2 h of incubation at 4 °C) and approx. 62% of the grains could be localized to coated pits in the plasma membrane. When the incubations were carried out at 37 °C, 125I radioactivity was found both on the membrane and within the cell and predominantly localized on or within lysosomes. In cells from the patient J. D., a familial hypercholesterolemic homozygote with an internalization defect, initial binding of 125I-LDL was restricted to the plasma membrane but not preferentially localized to coated segments of the plasma membrane. After incubation for 30 min at 37 °C, the membrane bound 125I-LDL in J. D. cells was not internalized. These data confirm results obtained with ferritin-labeled LDL and illustrate the complementary application of two different morphologic probes, each of which offers special advantages for special problems.
AB - Using a quantitative EM autoradiographic technique, we have visualized the membrane binding and receptor-mediated uptake of low density lipoprotein (LDL) in human fibroblasts. The initial binding was restricted to the plasma membrane (2 h of incubation at 4 °C) and approx. 62% of the grains could be localized to coated pits in the plasma membrane. When the incubations were carried out at 37 °C, 125I radioactivity was found both on the membrane and within the cell and predominantly localized on or within lysosomes. In cells from the patient J. D., a familial hypercholesterolemic homozygote with an internalization defect, initial binding of 125I-LDL was restricted to the plasma membrane but not preferentially localized to coated segments of the plasma membrane. After incubation for 30 min at 37 °C, the membrane bound 125I-LDL in J. D. cells was not internalized. These data confirm results obtained with ferritin-labeled LDL and illustrate the complementary application of two different morphologic probes, each of which offers special advantages for special problems.
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U2 - 10.1016/0014-4827(79)90453-1
DO - 10.1016/0014-4827(79)90453-1
M3 - Article
C2 - 221225
AN - SCOPUS:0018656891
SN - 0014-4827
VL - 121
SP - 135
EP - 142
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 1
ER -