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TGF‐β receptors are diminished after retinoid exposure in rat liver epithelial cells
Author(s) -
Mercier Thierry,
GaillardSanchez Isabelle,
Martel Paule,
Heberden Christine
Publication year - 1996
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19960501)61:2<230::aid-jcb6>3.0.co;2-v
Subject(s) - retinoid , receptor , internalization , endocrinology , retinoic acid , transforming growth factor , medicine , stimulation , cystamine , chemistry , biology , biochemistry , gene
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.