Mechanism of the phorbol ester-mediated redistribution of asialoglycoprotein receptor: Selective effects on receptor recycling pathways in Hep G2 cells

Robert Fallon, A. L. Schwartz

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

We have investigated the effect of phorbol dibutyrate on intracellular routing of the asialoglycoprotein receptor (ASGP-R) in a human hepatoma cell line, Hep G2. We have previously shown that this agent causes a net redistribution of 50% of cell surface receptors to the cell interior (Fallon, R.J., and A.L. Schwartz, J. Biol. Chem. 261:15081-15089 (1986)). To explore the mechanism of this effect, we measured the rate constants of receptor and ligand movement during internalization, ligand-receptor uncoupling, sorting of ligand to degradative sites or return to the extracellular medium, and return of receptor to the plasma membrane. The rate of internalization of bound asialoorosomucoid (ASOR) is identical in phorbol ester-treated and control cells, over a range of ASOR concentrations from 5 to 125 nM. The pathway of ligand recycling returns approximately 30% of internalized ASOR undegraded to the extracellular medium; phorbol esters do not modify the extent of this pathway in Hep G2 cells nor the kinetics of recovery of undegraded ASOR in the medium (t( 1/2 )=20 min). The rate of ligand-receptor uncoupling is similarly unaltered by phorbol esters, as measured by the amount of free ASOR that accumulates intracellularly and exits the cell after saponin permeabilization. In contrast, phorbol esters cause a rapid (

Original languageEnglish (US)
Pages (from-to)348-355
Number of pages8
JournalMolecular Pharmacology
Volume32
Issue number3
StatePublished - 1987
Externally publishedYes

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Asialoglycoprotein Receptor
Hep G2 Cells
Phorbol Esters
Ligands
Saponins
Recycling
Cell Surface Receptors
Hepatocellular Carcinoma
Cell Membrane
asialoorosomucoid

ASJC Scopus subject areas

  • Pharmacology

Cite this

Mechanism of the phorbol ester-mediated redistribution of asialoglycoprotein receptor : Selective effects on receptor recycling pathways in Hep G2 cells. / Fallon, Robert; Schwartz, A. L.

In: Molecular Pharmacology, Vol. 32, No. 3, 1987, p. 348-355.

Research output: Contribution to journalArticle

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