Characterization and functional study of CPAP-associated protein-1(CPAPAP-1) in NF-κB-mediated transcriptional activation (116.3)

Abstract

Abstract Nuclear factor-kappaB (NF-κB) is a Rel transcription factor that controls the gene expression involved in immune response, inflammation, apoptosis, and proliferation. Centrosomal P4.1-associated protein (CPAP) is an associating partner of the p65 subunit (RelA) of NF-κB. Molecular biology assays and cell biology experiments showed that the role of CPAP is a coactivator of NF-κB-mediated transcription. The C-terminal region of CPAP appears to contribute NF-κB-mediated transcriptional activation. However, knowledge about the factors that interact with the C-terminal region of CPAP is still little. In a yeast two-hybrid screen using the C-terminal region of CPAP as bait, we isolated a novel associating partner named CPAP-associated protein-1 (CPAPAP-1, GenBank: BC114945). CPAPAP-1 has the effector domain (cAMP) of the CAP family of transcription factors. We confirmed that CPAPAP-1 associates with C-terminal region of CPAP by using Glutathione S-transferase pull-down assays and co-immunoprecipitation experiments. After treatment with TNFα, a portion of CPAPAP-1 was observed to accumulate in the nucleus. We also confirmed that CPAPAP-1 controlled activation of TNFα-induced NF-κB by using NF-κB-dependent reporter gene expression assay and RNA interference technique. These results suggest that CPAPAP-1 functions as a coactivator of NF-κB-mediated transcription.