Acyl-CoA esters antagonize the effects of ligands on peroxisome proliferator-activated receptor alpha conformation, DNA binding, and interaction withco-factors

Citation
R. Elholm et al., Acyl-CoA esters antagonize the effects of ligands on peroxisome proliferator-activated receptor alpha conformation, DNA binding, and interaction withco-factors, J BIOL CHEM, 276(24), 2001, pp. 21410-21416
Citations number
65
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
0021-9258 → ACNP
Volume
276
Issue
24
Year of publication
2001
Pages
21410 - 21416
Database
ISI
SICI code
0021-9258(20010615)276:24<21410:AEATEO>2.0.ZU;2-C
Abstract
The peroxisome proliferator-activated receptor alpha (PPAR alpha) is a liga nd-activated transcription factor and a key regulator of lipid homeostasis. Numerous fatty acids and eicosanoids serve as ligands and activators for P PAR. Here we demonstrate that S-hexadecyl-CoA, a nonhydrolyzable palmitoyl- CoA analog, antagonizes the effects of agonists on PPAR alpha conformation and function in vitro, In electrophoretic mobility shift assays, S-hexadecy l-CoA prevented agonist-induced binding of the PPAR alpha -retinoid X recep tor alpha heterodimer to the acyl-CoA oxidase peroxisome proliferator respo nse element. PPAR alpha bound specifically to immobilized palmitoyl-CoA and Wy14643, but not BRL49653, abolished binding. S-Hexadecyl-CoA increased in a dose-dependent and reversible manner the sensitivity of PPAR alpha to ch ymotrypsin digestion, and the S-hexadecyl-CoA-induced sensitivity required a functional PPAR alpha ligand-binding pocket. S-Hexadecyl-CoA prevented li gand-induced interaction between the co-activator SRC-1 and PPAR alpha but increased recruitment of the nuclear receptor corepressor NCoR, In cells, t he concentration of free acyl-CoA esters is kept in the low nanomolar range due to the buffering effect of high affinity acyl-CoA-binding proteins, es pecially the acyl-CoA-binding protein. By using PPAR alpha expressed in Sf2 1 cells for electrophoretic mobility shift assays, we demonstrate that S-he xadecyl-CoA was able to increase the mobility of the PPAR alpha -containing heterodimer even in the presence of a molar excess of acyl-CoA-binding pro tein, mimicking the conditions found in vivo.