Receptor-mediated endocytosis by the asialoglycoprotein receptor: Effect of ethanol administration on endosomal distribution of receptor and ligand

Shana R. Dalton, Robert L. Wiegert, Carol A Casey

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Using the asialoglycoprotein receptor (ASGP-R) and a representative ligand, asialoorosomucoid (ASOR), we have previously shown ethanol-induced impairment of endosomal acidification, receptor recycling and ligand binding, internalization, and degradation. In the current study, we further investigated ethanol-induced alterations in receptor/ligand trafficking by labeling endosomes in vivo with either Texas-Red-ASOR or 125I-ASOR, and then assessing the receptor/ligand content of endosomes. We assessed two fractions after both 5 and 25 min of labeling: 'early endosomes' (EEs; endosomes from the cell periphery) and 'late endosomes' (LEs; endosomes farther into the cell interior). At both time points, significantly more ligand was found in EE fractions isolated from chow- and pair-fed controls (3:1, EE to LE, respectively). However, endosomes isolated from ethanol-fed animals showed a shift over time toward a more equal ligand distribution between endosome fractions (P≤0.05). Analysis of the ASGP-R content revealed a distribution pattern between the endosome fractions similar to that observed for ligand distribution. Impairment of receptor-ligand dissociation was assessed in endosome fractions by determining bound/free ligand ratios. Analysis showed that most of the ligand present in both endosome fractions was free (56-99%), although more was bound to receptor in EE vs LE of both control and ethanol animals (P≤0.05). At 5 min, more ligand remained bound in endosomes from ethanol-fed animals compared with control endosomes (P≤0.05), and the same pattern was observed at the latter time point. These results suggest that delayed dissociation may cause the receptor-ligand complexes to travel farther into the cell interior, which may impair proper trafficking of the ligand to lysosomes and alter the receptor recycling.

Original languageEnglish (US)
Pages (from-to)484-491
Number of pages8
JournalLiver International
Volume23
Issue number6
DOIs
StatePublished - Dec 2003

Fingerprint

Asialoglycoprotein Receptor
Endosomes
Endocytosis
Ethanol
Ligands
Lysosomes

Keywords

  • Asialoglycoprotein receptor
  • Endosomes
  • Ethanol
  • Ligand trafficking
  • Receptor trafficking
  • Receptor-mediated endocytosis

ASJC Scopus subject areas

  • Hepatology

Cite this

Receptor-mediated endocytosis by the asialoglycoprotein receptor : Effect of ethanol administration on endosomal distribution of receptor and ligand. / Dalton, Shana R.; Wiegert, Robert L.; Casey, Carol A.

In: Liver International, Vol. 23, No. 6, 12.2003, p. 484-491.

Research output: Contribution to journalArticle

@article{4cd16347cd64455a820b57a7a72284a5,
title = "Receptor-mediated endocytosis by the asialoglycoprotein receptor: Effect of ethanol administration on endosomal distribution of receptor and ligand",
abstract = "Using the asialoglycoprotein receptor (ASGP-R) and a representative ligand, asialoorosomucoid (ASOR), we have previously shown ethanol-induced impairment of endosomal acidification, receptor recycling and ligand binding, internalization, and degradation. In the current study, we further investigated ethanol-induced alterations in receptor/ligand trafficking by labeling endosomes in vivo with either Texas-Red-ASOR or 125I-ASOR, and then assessing the receptor/ligand content of endosomes. We assessed two fractions after both 5 and 25 min of labeling: 'early endosomes' (EEs; endosomes from the cell periphery) and 'late endosomes' (LEs; endosomes farther into the cell interior). At both time points, significantly more ligand was found in EE fractions isolated from chow- and pair-fed controls (3:1, EE to LE, respectively). However, endosomes isolated from ethanol-fed animals showed a shift over time toward a more equal ligand distribution between endosome fractions (P≤0.05). Analysis of the ASGP-R content revealed a distribution pattern between the endosome fractions similar to that observed for ligand distribution. Impairment of receptor-ligand dissociation was assessed in endosome fractions by determining bound/free ligand ratios. Analysis showed that most of the ligand present in both endosome fractions was free (56-99{\%}), although more was bound to receptor in EE vs LE of both control and ethanol animals (P≤0.05). At 5 min, more ligand remained bound in endosomes from ethanol-fed animals compared with control endosomes (P≤0.05), and the same pattern was observed at the latter time point. These results suggest that delayed dissociation may cause the receptor-ligand complexes to travel farther into the cell interior, which may impair proper trafficking of the ligand to lysosomes and alter the receptor recycling.",
keywords = "Asialoglycoprotein receptor, Endosomes, Ethanol, Ligand trafficking, Receptor trafficking, Receptor-mediated endocytosis",
author = "Dalton, {Shana R.} and Wiegert, {Robert L.} and Casey, {Carol A}",
year = "2003",
month = "12",
doi = "10.1111/j.1478-3231.2003.00874.x",
language = "English (US)",
volume = "23",
pages = "484--491",
journal = "Liver International",
issn = "1478-3223",
publisher = "Wiley-Blackwell",
number = "6",

}

TY - JOUR

T1 - Receptor-mediated endocytosis by the asialoglycoprotein receptor

T2 - Effect of ethanol administration on endosomal distribution of receptor and ligand

AU - Dalton, Shana R.

AU - Wiegert, Robert L.

AU - Casey, Carol A

PY - 2003/12

Y1 - 2003/12

N2 - Using the asialoglycoprotein receptor (ASGP-R) and a representative ligand, asialoorosomucoid (ASOR), we have previously shown ethanol-induced impairment of endosomal acidification, receptor recycling and ligand binding, internalization, and degradation. In the current study, we further investigated ethanol-induced alterations in receptor/ligand trafficking by labeling endosomes in vivo with either Texas-Red-ASOR or 125I-ASOR, and then assessing the receptor/ligand content of endosomes. We assessed two fractions after both 5 and 25 min of labeling: 'early endosomes' (EEs; endosomes from the cell periphery) and 'late endosomes' (LEs; endosomes farther into the cell interior). At both time points, significantly more ligand was found in EE fractions isolated from chow- and pair-fed controls (3:1, EE to LE, respectively). However, endosomes isolated from ethanol-fed animals showed a shift over time toward a more equal ligand distribution between endosome fractions (P≤0.05). Analysis of the ASGP-R content revealed a distribution pattern between the endosome fractions similar to that observed for ligand distribution. Impairment of receptor-ligand dissociation was assessed in endosome fractions by determining bound/free ligand ratios. Analysis showed that most of the ligand present in both endosome fractions was free (56-99%), although more was bound to receptor in EE vs LE of both control and ethanol animals (P≤0.05). At 5 min, more ligand remained bound in endosomes from ethanol-fed animals compared with control endosomes (P≤0.05), and the same pattern was observed at the latter time point. These results suggest that delayed dissociation may cause the receptor-ligand complexes to travel farther into the cell interior, which may impair proper trafficking of the ligand to lysosomes and alter the receptor recycling.

AB - Using the asialoglycoprotein receptor (ASGP-R) and a representative ligand, asialoorosomucoid (ASOR), we have previously shown ethanol-induced impairment of endosomal acidification, receptor recycling and ligand binding, internalization, and degradation. In the current study, we further investigated ethanol-induced alterations in receptor/ligand trafficking by labeling endosomes in vivo with either Texas-Red-ASOR or 125I-ASOR, and then assessing the receptor/ligand content of endosomes. We assessed two fractions after both 5 and 25 min of labeling: 'early endosomes' (EEs; endosomes from the cell periphery) and 'late endosomes' (LEs; endosomes farther into the cell interior). At both time points, significantly more ligand was found in EE fractions isolated from chow- and pair-fed controls (3:1, EE to LE, respectively). However, endosomes isolated from ethanol-fed animals showed a shift over time toward a more equal ligand distribution between endosome fractions (P≤0.05). Analysis of the ASGP-R content revealed a distribution pattern between the endosome fractions similar to that observed for ligand distribution. Impairment of receptor-ligand dissociation was assessed in endosome fractions by determining bound/free ligand ratios. Analysis showed that most of the ligand present in both endosome fractions was free (56-99%), although more was bound to receptor in EE vs LE of both control and ethanol animals (P≤0.05). At 5 min, more ligand remained bound in endosomes from ethanol-fed animals compared with control endosomes (P≤0.05), and the same pattern was observed at the latter time point. These results suggest that delayed dissociation may cause the receptor-ligand complexes to travel farther into the cell interior, which may impair proper trafficking of the ligand to lysosomes and alter the receptor recycling.

KW - Asialoglycoprotein receptor

KW - Endosomes

KW - Ethanol

KW - Ligand trafficking

KW - Receptor trafficking

KW - Receptor-mediated endocytosis

UR - http://www.scopus.com/inward/record.url?scp=0347382501&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0347382501&partnerID=8YFLogxK

U2 - 10.1111/j.1478-3231.2003.00874.x

DO - 10.1111/j.1478-3231.2003.00874.x

M3 - Article

C2 - 14986823

AN - SCOPUS:0347382501

VL - 23

SP - 484

EP - 491

JO - Liver International

JF - Liver International

SN - 1478-3223

IS - 6

ER -