Identification of the ability of highly charged nanomolar inhibitors of protein kinases to cross plasma membranes and carry a protein into cells

A fluorescently labeled adenosine–oligoarginine conjugate (ARC), nanomolar bisubstrate analogue-type inhibitor of basophilic protein kinases PKA and PKC, readily enters cells of different origin and localizes into cytoplasm and nucleus. Moreover, the biotinylated derivative of ARC is able to deliver avidin, a non-covalently attached protein cargo, into cells.