Binding of all-trans-retinoic acid to MLTC-1 proteins |
| |
Authors: | Erika Cione Paola Tucci Valentina Senatore Giuseppina Ioele Giuseppe Genchi |
| |
Institution: | (1) Dipartimento Farmaco-Biologico, Università della Calabria, Cosenza, 87100, Italia;(2) Dipartimento di Scienze Farmaceutiche, Edificio Polifunzionale, Università della Calabria, Italia |
| |
Abstract: | The covalent incorporation of 3H]all-trans-retinoic acid into proteins has been studied in tumoural Leydig (MLTC-1) cells. The maximum retinoylation activity of MLTC-1 cell proteins was 710 ± 29 mean ± SD) fmoles/8 × 104 cells at 37 °C. About 90% of 3H]retinoic acid was trichloroacetic acid-soluble after proteinase-K digestion and about 65–75% after hydrolysis with hydroxylamine. Thus, retinoic acid is most probably linked to proteins as a thiol ester. The retinoylation reaction was inhibited by 13-cis-retinoic acid and 9-cis-retinoic acid with IC50 values of 0.9 μM and 0.65 μM, respectively. Retinoylation was not inhibited by high concentrations of palmitic or myristic acids (250 μM); but there was an increase of the binding activity of about 25% and 130%, respectively. On the other hand, the retinoylation reaction was inhibited (about 40%) by 250 μM lauric acid. After pre-incubation of the cells with different concentrations of unlabeled RA, the retinoylation reaction with 100 nM 3H]RA involved first an increase at 100 nM RA and then a decrease of retinoylation activity between 200 and 600 nM RA. After cycloheximide treatment of the tumoural Leydig cells the binding activity of 3H]RA was about the same as that in the control, suggesting that the bond occurred on proteins in pre-existing cells. (Mol Cell Biochem 276: 55–60, 2005)This paper is dedicated to the memory of Prof. E. Quagliariello. |
| |
Keywords: | all-trans-retinoic acid cells MLTC-1 retinoylation protein |
本文献已被 PubMed SpringerLink 等数据库收录! |
|