Photoaffinity labeling of the uncoupling protein UCP1 with retinoic acid: ubiquinone favors binding.
Retinoic acid is a potent activator of the uncoupling protein-1 (UCP1) both at the gene and mitochondrial level. Irradiation with ultraviolet light can be used to directly photolabel proteins with retinoic acid. The procedure has been applied to investigate its interaction with UCP1 isolated from brown adipose tissue mitochondria. All-trans-retinoic acid binds to UCP1 with high affinity and the labeling is only partially protected by guanosine diphosphate. Ubiquinone (UQ) has been described to be an obligatory cofactor for uncoupling protein function and we demonstrate that it greatly increases the affinity of UCP1 for retinoic acid. Data support the notion of a direct interaction between UQ and retinoic acid.
Centro de Investigaciones Biológicas, CSIC, Velázquez 144, 28006 Madrid, Spain.
Paula
P
Tomás
Amalia
A
Ledesma
Eduardo
E
Rial
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000345:Affinity Labels; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D006224:Cricetinae; D006153:Guanosine Diphosphate / Q000378:metabolism; D007473:Ion Channels; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D024101:Mitochondrial Proteins; D019308:Palmitic Acid / Q000378:metabolism; D014212:Tretinoin / Q000378:metabolism*; D014451:Ubiquinone / Q000378:metabolism*; D000071256:Uncoupling Protein 1
D000345:Affinity Labels; D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D000071256:Uncoupling Protein 1; D014451:Ubiquinone; D006153:Guanosine Diphosphate; D019308:Palmitic Acid; D014212:Tretinoin