Externalization of transferrin receptor in established human cell lines.
The externalization of transferrin receptors was found in established human tumor cell lines at the rate of 10-35 ng/hour/10(6) cells, when they were incubated with transferrin at 37 degrees C. This externalization is inhibited by lowering the incubation temperature to 4 degrees C or eliminating the ligand from the culture medium. Metabolic inhibitors such as sodium azide, colchicine, cytochalasin B and chloroquine also decreased the rate of externalization. Almost 95% of released transferrin receptors were precipitated by centrifugation at 100,000 x g for 30 min, suggesting that transferrin receptor is externalized into the medium as a vesicular form.
Department of Internal Medicine, Sapporo Medical College, Japan.
Y
Y
Kohgo
Y
Y
Niitsu
T
T
Nishisato
J
J
Kato
K
K
Sasaki
N
N
Tsushima
M
M
Hirayama
H
H
Kondo
I
I
Urushizaki
D014408:Biomarkers, Tumor / Q000097:blood*; D002461:Cell Line, Transformed; D006801:Humans; D011990:Receptors, Transferrin / Q000378:metabolism*
D014408:Biomarkers, Tumor; D011990:Receptors, Transferrin