Dual pathways for the uptake of rat asialotransferrin by rat hepatocytes

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Dual pathways for the uptake of rat asialotransferrin by rat hepatocytes. / Young, S P; Bomford, A; Williams, R.

In: Journal of Biological Chemistry, Vol. 258, No. 8, 25.04.1983, p. 4972-6.

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@article{d46f0812c2c74dbdba19d9e04d4cc256,
title = "Dual pathways for the uptake of rat asialotransferrin by rat hepatocytes",
abstract = "Studies of the interaction of rat asialotransferrin with rat hepatocytes at 4 degrees C showed that the protein binds to two types of receptor on these cells--to 31,000 transferrin receptors with a Ka of 1.9 x 10(7) liters . mol-1 and to 110,000 asialoglycoprotein receptors with a Ka of 1.4 x 10(6) liters . mol-1. The uptake of the protein by the cells at 37 degrees C is mediated by both receptors simultaneously. Binding to the asialoglycoprotein receptor was abolished by the addition of excess asialoorosomucoid and, under these conditions asialotransferrin, taken into the cells via the transferrin receptor, was subsequently released from the cells undegraded, an event also observed when the uptake of holotransferrin was examined in similar studies. Addition of excess unlabeled transferrin prevented uptake of asialotransferrin via the transferrin receptor and internalization was then mediated solely by the asialoglycoprotein receptor. Ligand subsequently released from the cells after endocytosis via this receptor was found to be degraded, with 80% soluble in trichloroacetic acid, a proportion similar to that observed during release of asialoorosomucoid from the cells. These results indicate that rat asialotransferrin is processed by the asialoglycoprotein uptake pathway in the same way as observed with other ligands. Release from the cells of undegraded asialotransferrin occurred only after endocytosis via the transferrin receptor.",
keywords = "Asialoglycoproteins, Animals, Humans, Receptors, Transferrin, Biological Transport, Receptors, Cell Surface, Rats, Rats, Inbred Strains, Transferrin, Asialoglycoprotein Receptor, Liver, Reticulocytes, Time Factors, Male",
author = "Young, {S P} and A Bomford and R Williams",
year = "1983",
month = apr,
day = "25",
language = "English",
volume = "258",
pages = "4972--6",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology",
number = "8",

}

RIS

TY - JOUR

T1 - Dual pathways for the uptake of rat asialotransferrin by rat hepatocytes

AU - Young, S P

AU - Bomford, A

AU - Williams, R

PY - 1983/4/25

Y1 - 1983/4/25

N2 - Studies of the interaction of rat asialotransferrin with rat hepatocytes at 4 degrees C showed that the protein binds to two types of receptor on these cells--to 31,000 transferrin receptors with a Ka of 1.9 x 10(7) liters . mol-1 and to 110,000 asialoglycoprotein receptors with a Ka of 1.4 x 10(6) liters . mol-1. The uptake of the protein by the cells at 37 degrees C is mediated by both receptors simultaneously. Binding to the asialoglycoprotein receptor was abolished by the addition of excess asialoorosomucoid and, under these conditions asialotransferrin, taken into the cells via the transferrin receptor, was subsequently released from the cells undegraded, an event also observed when the uptake of holotransferrin was examined in similar studies. Addition of excess unlabeled transferrin prevented uptake of asialotransferrin via the transferrin receptor and internalization was then mediated solely by the asialoglycoprotein receptor. Ligand subsequently released from the cells after endocytosis via this receptor was found to be degraded, with 80% soluble in trichloroacetic acid, a proportion similar to that observed during release of asialoorosomucoid from the cells. These results indicate that rat asialotransferrin is processed by the asialoglycoprotein uptake pathway in the same way as observed with other ligands. Release from the cells of undegraded asialotransferrin occurred only after endocytosis via the transferrin receptor.

AB - Studies of the interaction of rat asialotransferrin with rat hepatocytes at 4 degrees C showed that the protein binds to two types of receptor on these cells--to 31,000 transferrin receptors with a Ka of 1.9 x 10(7) liters . mol-1 and to 110,000 asialoglycoprotein receptors with a Ka of 1.4 x 10(6) liters . mol-1. The uptake of the protein by the cells at 37 degrees C is mediated by both receptors simultaneously. Binding to the asialoglycoprotein receptor was abolished by the addition of excess asialoorosomucoid and, under these conditions asialotransferrin, taken into the cells via the transferrin receptor, was subsequently released from the cells undegraded, an event also observed when the uptake of holotransferrin was examined in similar studies. Addition of excess unlabeled transferrin prevented uptake of asialotransferrin via the transferrin receptor and internalization was then mediated solely by the asialoglycoprotein receptor. Ligand subsequently released from the cells after endocytosis via this receptor was found to be degraded, with 80% soluble in trichloroacetic acid, a proportion similar to that observed during release of asialoorosomucoid from the cells. These results indicate that rat asialotransferrin is processed by the asialoglycoprotein uptake pathway in the same way as observed with other ligands. Release from the cells of undegraded asialotransferrin occurred only after endocytosis via the transferrin receptor.

KW - Asialoglycoproteins

KW - Animals

KW - Humans

KW - Receptors, Transferrin

KW - Biological Transport

KW - Receptors, Cell Surface

KW - Rats

KW - Rats, Inbred Strains

KW - Transferrin

KW - Asialoglycoprotein Receptor

KW - Liver

KW - Reticulocytes

KW - Time Factors

KW - Male

M3 - Article

C2 - 6300107

VL - 258

SP - 4972

EP - 4976

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 8

ER -