title: Retinoylation reaction of proteins in Leydig (TM-3) cells.
abstract: The covalent incorporation of [(3)H]all-trans-retinoic acid into proteins has been studied in Leydig (TM-3) cells. The maximum retinoylation activity of Leydig cells proteins was 570+/- 27 fmoles/8 x 10(4) cells at 37( composite function)C. About 95% of [(3)H]retinoic acid was trichloroacetic acid-soluble after proteinase-K digestion or after hydrolysis with hydroxylamine. Thus, retinoic acid is most probably linked to proteins as a thiol ester. The retinoylation process was inhibited by 13-cis-retinoic acid and 9-cis-retinoic acid with IC(50) values of 0.6 and 1.2 microM respectively. Dibutyryl-cAMP and forskolin increased the retinoylation activity by 75 and 81% at 500 and 25 microM respectively. Also hCG increased the retinoylation binding activity of 110% at 250 ng/mL. After cycloheximide treatment of the Leydig cells the binding activity of [(3)H]RA was about the same that in the control, suggesting that the bond occurs on proteins in pre-existing cells. Retinoylation was not inhibited by high concentrations of palmitic or myristic acids (500 microM); on the contrary, there was an increase of the binding activity of about 60 and 50% respectively.
authors.affiliation: Dipartimento Farmaco-Biologico, Edificio Polifunzionale, Università della Calabria, 87036 Rende (Cosenza), Italy.
authors.forename: Erika
authors.initials: E
authors.lastname: Cione
authors.forename: Paola
authors.initials: P
authors.lastname: Tucci
authors.forename: Adele
authors.initials: A
authors.lastname: Chimento
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Pezzi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Genchi
mesh_terms: D000818:Animals; D002460:Cell Line; D007700:Kinetics; D007985:Leydig Cells / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D014212:Tretinoin / Q000378:metabolism*; D014316:Tritium
chemical_list: D011506:Proteins; D014316:Tritium; D014212:Tretinoin