| Here we report that histone acetyltransferase ( HAT ) HBO 1 , a MYST family protein , interacts with CDK 11 ( p 58 ) in vitro and in vivo . ^^^ CDK 11 ( p 58 ) and HBO 1 colocalize in the cell nucleus . ^^^ Recombinant CDK 11 ( p 58 ) enhances the HAT activity of HBO 1 significantly in vitro . ^^^ Meanwhile , overexpression of CDK 11 ( p 58 ) in mammalian cells leads to the enhanced HAT activity of HBO 1 towards free histones . ^^^ Thus , we conclude that CDK 11 ( p 58 ) is a new interacting protein and a novel regulator of HBO 1 . ^^^ |