Prothymosin α interacts with the CREB-binding protein and potentiates transcription

Prothymosin α (ProTα) is a histone H1‐binding protein localized in sites of active transcription in the nucleus. We report here that ProTα physically interacts with the CREB‐binding protein (CBP), which is a versatile transcription co‐activator. Confocal laser scanning microscopy reveals that ProTα partially colocalizes with CBP in discrete subnuclear domains. Using transient transfections, we show that ProTα synergizes with CBP and stimulates AP1‐ and NF‐κB‐dependent transcription. Furthermore, overexpression of ProTα enhances the transactivation potential of CBP. These findings reveal a new function for ProTα in transcription activation, probably through CBP‐mediated recruitment to different promoters.