Capturing conformational transitions of full-length PDK1 that dictate kinase substrate selectivity.

PDK1 is a constitutively active master kinase that can phosphorylate and activate as many as 24 enzymes, all belonging to the AGC family of serine-threonine protein kinases. In this issue of Science Signaling , Sacerdoti et al . uncover how allosteric communication between different functional domains directs the selectivity of PDK1 toward particular subsets of substrates.