Regulation of nuclear factor-kB signalling by FK506 binding protein 52

DE LEO SA, CAMISAY MF, ERLEJMAN A, GALIGNIANA MD

Congreso; LXII Reunión Anual de SAIC; 2017

Nuclear Factor KappaB (NF-B) is key regulator of the transcription of genes involved in cell death, inflammation and invasion. Recently, we have demonstrated that FKBPs (FK506-binding proteins), especially FKBP51 and FKBP52, are able to modulate NF-B transcriptional activity. The aim of this work is to determine the participation of FKBP52 in different steps of NF-B signaling and the expression of NF-B target genes. Thus, we over expressed FKBP52, FKBP52 F130Y (a mutant lacking peptidylprolyl-isomerase activity (PPIase)), or empty vector (control group). Different hallmarks in NF-B (p65/p50) activation after PMA or TNF-α stimulation were evaluated: total and phosphorylated p65 protein levels and NF-B inhibitor´s phosphorylation (p-iB) by Western blot, p65 nuclear traslocation by immunofluorescence, and the expression of NF-B target genes by real time PCR. After PMA stimulation neither FKBP52 nor FKBP52 mutant transfection showed significant differences in iB phosphorylation kinetics compared to control, suggesting an iB independent mechanism. Also, p65 phosphorylation at Ser536 was not altered by overexpression of FKBP52 or FKBP52 F130Y, compared to control. However, basal p-p65 and total p65 were increased after overexpression of FKBP52 vs. control (p