Adipocyte-type fatty acid-binding protein as inter-compartmental shuttle for peroxisome proliferator activated receptor gamma agonists in cultured cell.
We and others showed earlier that liver-type, epidermal-type and adipocyte-type (A-) fatty acid-binding proteins (FABPs) mediate peroxisome proliferator activated receptor (PPAR) dependent gene expression by channelling their ligand (fatty acid or drug) to the nuclear receptors via direct protein/protein interaction. To clarify mechanistic details of this signaling path, we address here A-FABP import into the nucleus and its interaction with PPARgamma. Making use of COS cells transfected with wild-type or mutant A-FABPs, we exclude posttranslational modification of A-FABP as import signal and provide evidence for both, ligand-dependent and ligand-independent nuclear translocation. With the aid of in vitro pull down assay we demonstrate that specific interaction of A-FABP with PPARgamma isoforms does not require ligand. Moreover, A-FABP binds not only to the ligand-binding domain including hinge domain (domains DEF), but also to the DNA-binding domain including AB domains (domains ABC) of PPARgamma.
Department of Biochemistry, University of Münster, 48149 Münster, Germany.
Anne
A
Adida
Friedrich
F
Spener
D021581:Active Transport, Cell Nucleus; D000818:Animals; D001483:Base Sequence; D001693:Biological Transport, Active; D019556:COS Cells; D002451:Cell Compartmentation; D002522:Chlorocebus aethiops; D018076:DNA, Complementary / Q000235:genetics; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D066298:In Vitro Techniques; D008024:Ligands; D051379:Mice; D016297:Mutagenesis, Site-Directed; D047493:PPAR alpha / Q000378:metabolism; D047495:PPAR gamma / Q000819:agonists* / Q000737:chemistry / Q000378:metabolism; D048068:PPAR-beta / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; D050556:Fatty Acid-Binding Proteins; D008024:Ligands; D047493:PPAR alpha; D047495:PPAR gamma; D048068:PPAR-beta; D011994:Recombinant Proteins