Enhances NF-kappa-B transcriptional activity by regulating the nuclear localization of the NF-kappa-B subunit RELA and promoting the phosphorylation of RELA by PRKACA. Regulates the effect of the cAMP-dependent protein kinase signaling pathway on the NF-kappa-B activation cascade. Interacts with PRKACA and RELA. Locates to punctate spots. Expressed at high levels in adult heart and at lower levels in brain, testis, ovary and skeletal muscle. Up-regulated in some breast cancer cell lines. Isoform 1 and isoform 3 are expressed in fetal brain.