Hepatocyte nuclear factor 4α (HNF4α) regulates liver type fatty acid binding protein (L-FABP) gene expression. Conversely as shown herein, L-FABP structurally and functionally also interacts with HNF4α. Fluorescence resonance energy transfer (FRET) between Cy3-HNF4α (donor) and Cy5-L-FABP (acceptor) as well as FRET microscopy detected L-FABP in close proximity (~80 Å) to HNF4α, binding with high affinity Kd ~250-300 nM. Circular dichroism (CD) determined that the HNF4α/L-FABP interaction altered protein secondary structure. Finally, L-FABP potentiated transactivation of HNF4α in COS7 cells. Taken together, these data suggest that L-FABP provides a signaling path to HNF4α activation in the nucleus.
Keywords: ACBP; CD; FRET; Fatty acid binding protein; HNF4α; Hepatocyte nuclear factor 4α; L-FABP; LCFA; LCFA-CoA; LSCM; Liver; PPARα; acyl CoA binding protein; circular dichroism; fluorescence resonance energy transfer; hepatocyte nuclear factor 4α; laser scanning confocal microscopy; liver type fatty acid binding protein; long chain fatty acid; long chain fatty acyl CoA; peroxisome proliferator activated receptor-α.
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