Cyclin-dependent kinase 11^p58 interacts with HBO1 and enhances its histone acetyltransferase activity

CDK11^p58, a 58 kDa protein of the PITSLRE kinase family, plays an important role in cell cycle progression, and is closely related to cell apoptosis. To gain further insight into the function of CDK11^p58, we screened a human fetal liver cDNA library for its interacting proteins using the yeast two-hybrid system. Here we report that histone acetyltransferase (HAT) HBO1, a MYST family protein, interacts with CDK11^p58 in vitro and in vivo. CDK11^p58 and HBO1 colocalize in the cell nucleus. Recombinant CDK11^p58 enhances the HAT activity of HBO1 significantly in vitro. Meanwhile, overexpression of CDK11^p58 in mammalian cells leads to the enhanced HAT activity of HBO1 towards free histones. Thus, we conclude that CDK11^p58 is a new interacting protein and a novel regulator of HBO1. Both of the proteins may be involved in the regulation of eukaryotic transcription.