ISSN:
0730-2312
Keywords:
retinoic acid
;
retinol
;
binding
;
transglutaminase
;
hepatic
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
When rat liver epithelial cells were exposed to retinoic acid or retinol for 24 hr, the levels of transforming growth factor-β (TGF-β) receptors were reduced in a dose-dependent way. The decrease appeared after 12 hr of incubation with the retinoids and binding levels remained low until 24 hr after the removal of the molecules. Retinoid treatment induced a fourfold enhancement of transglutaminase (TGase) activity in the cell membranes, and cystamine, an inhibitor of TGase, prevented the decrease of the receptors. Neutralization of TGF-β by a monoclonal antibody did not suppress the decrease of the binding levels, indicating that decreased TGF-β binding capacity was not due merely to the internalization of ligand-bound receptors promoted by a stimulation of TGF-β synthesis. Thus, retinoid treatment resulted in an intense disappearance of the functional receptors from the membranes that seemed to be mediated by increased TGase activity. This phenomenon can represent a strong signal attenuation for TGF-β following retinoid exposure. © 1996 Wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
