ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
In this study we have investigated whether cytokines, critical mediators of the immune response, might have a direct effect on the expression and/or function of the human hepatic asialoglycoprotein receptor (ASGPR). Binding and uptake of asialoglycoproteins by the human hepatoma cell line, HepG2, and by freshly isolated rat hepatocytes were inhibited by 50% after 3-6 hours and completely abolished following a 24 hour exposure to tumor necrosis factor (TNF) α, interferon (INF) α or γ, or interleukin-2 (IL-2). The loss of ASGPR binding activity mediated by IL-2 was reversible up to 4 hours of exposure and accompanied by the selective phosphorylatior, of the cell-surface receptor. Steady-state levels of total cellular ASGPR protein remained unchanged over the first 6 hours of IL-2 incubation but declined in a dose dependent manner thereafter. This down regulation of ASGPR expression was due to reduced synthesis as a result of reduced receptor transcript levels. No loss was detected, however, of cell surface-associated receptor protein even after 24 hours of IL-2 incubation, suggesting that cytokine induced phosphorvlation constitutes a mechanism to regulate receptor activity. © 1994 Wiley-Liss, Inc.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041580319
