PKCβII augments NF-κB-dependent transcription at the CCL11 promoter via p300/CBP-associated factor recruitment and histone H4 acetylation

The transcription factor NF-kappa B plays a pivotal role in regulating inflammatory gene expression. Its effects are optimized by various coactivators, including histone acetyltransferases (HATs) such as CREB-binding protein/p300 and p300/CBP-associated factor (p/CAF). The molecular mechanisms regulating cofactor recruitment are poorly understood. In this study, we describe a novel role for protein kinase C (PKC) beta II in augmenting NF-kappa B-mediated TNF-alpha-induced transcription of the target gene CCL11 in human airway smooth muscle cells by phosphorylating the HAT p/CAF. Studies using reporters, overexpression strategies, kinase-dead and HAT-defective mutants, and chromatin immunoprecipitation showed that PKC beta II activation was not involved in NF-kappa B translocation, but facilitated NF-kappa B-mediated CCL11 transcription by colocalizing with and phosphorylating p/CAF, and thereby acetylating histone H4 and promoting p65 association with the CCL11 promoter. The effect was dependent on p/CAF's HAT activity. Furthermore, mouse embryonic fibroblasts from PKC beta knockout mice showed markedly reduced TNF-alpha-induced CCL11 expression and NF-kappa B reporter activity that was restored on PKC beta II overexpression, suggesting a critical role for this pathway. These data suggest a novel important biological role for PKC beta II in NF-kappa B-mediated CCL11 transcription by p/CAF activation and histone H4 acetylation.