Translational machinery and protein folding: evidence of conformational variants of the estrogen receptor alpha.
As an approach to understand how translation may affect protein folding, we analyzed structural and functional properties of the human estrogen receptor alpha synthesized by different eukaryotic translation systems. A minimum of three conformations of the receptor were detected using limited proteolysis and a sterol ligand-binding assay. The receptor in vitro translated in rabbit reticulocyte lysate was rapidly degraded by protease, produced major bands of about 34kDa and showed a high affinity for estradiol. In a wheat germ translation system, the receptor was more slowly digested. Two soluble co-existing conformations were evident by different degradation patterns and estradiol binding. Our data show that differences in the translation machinery may result in alternative conformations of the receptor with distinct sterol binding properties. These studies suggest that components of the cellular translation machinery itself might influence the protein folding pathways and the relative abundance of different receptor conformers.
Horjales
Sofía
S
Sección Bioquímica, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay.
Cota
Germán
G
Señorale-Pose
Mario
M
Rovira
Carlos
C
Román
Estela
E
Artagaveytia
Nora
N
Ehrlich
Ricardo
R
Marín
Mónica
M
D001665:Binding Sites; D047628:Estrogen Receptor alpha / Q000737:chemistry* / Q000648:ultrastructure*; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D020033:Protein Isoforms / Q000737:chemistry; D046188:Protein Modification, Translational
D047628:Estrogen Receptor alpha; D020033:Protein Isoforms