Selection of DNA ligands for protein kinase C-delta.

Protein kinase Cs are a family of serine and threonine kinases that mediate a wide variety of cellular signalling processes such as cell growth, differentiation, apoptosis and tumor development. We have selected high-affinity DNA aptamers for PKCdelta by capillary electrophoresis based SELEX (systematic evolution of ligands by exponential enrichment, CE-SELEX). We have demonstrated that fluorescently tagged PB9 aptamer can specifically recognize PKCdelta under in vitro conditions. The Kd of the aptamer-protein binding is 122 nM. These aptamers will enable us to apply fluorescently labelled probes to study the spatiotemporal dynamics and activation of individual endogenous PKC isoforms during various cell signalling processes.