Bidirectional and synergistic allosteric regulation by metabolites of the kinase PDK1

GROSS, LZF; SACERDOTI, M; LEROUX, AE; SCHULZE, J; HICKS, KG; RUTTER, J; GHODE, A; ANAND, GS; KLINKE, S; BIONDI, RM

Evento online debido a la pandemia de coronavirus

Congreso; XLIX Reunión Anual de la Sociedad Argentina de Biofísica (SAB); 2021

Sociedad Argentina de Biofísica (SAB)

Phosphoinositide-dependent protein kinase 1 (PDK1) is a master AGC kinase of the PI3K signalling pathway that phosphorylates at least other 23 AGC kinases, being PKB/Akt the most relevant substrate for growth and cell survival, and therefore a potential drug target for cancer treatment. Over the years, our laboratory used a chemical and structural biology approach to study and characterize in detail the mechanism of regulation of the catalytic domain of PDK1. We demonstrated an allosteric regulation from a regulatory site to the active site, as well as the existence of the reverse process. This bidirectional allosteric mechanism of regulation between both pockets can therefore be modulated by small molecules that bind to their specific orthosteric site and either enhance or inhibit interactions at the allosteric site. Considering this, it is not surprising that while the pharmaceutical industry has been developing compounds that bind at the ATP-binding site of kinases, they unwillingly developed drugs that affect protein kinase–protein interactions. We now provide further evidence of the bidirectional system using H/D exchange - MS experiments and show how this is a powerful technique for describing combinatorial coupling effects of a cooperative ligand pair binding at noncontiguous sites. On the other hand, could metabolites bind at the active site of protein kinases and physiologically regulate the formation of protein kinase complexes? Here I present the crystal structure of the catalytic domain of PDK1 in complex with a metabolite bound to the ATP-binding site and compare the structure of the complex and allosteric effects of this metabolite to the crystal structures and allosteric effects of the metabolites Adenine and Adenosine. The findings open the possibility that the physiological regulation of the kinase complexes may be modulated by metabolites and implies that the metabolic state of cells could directly feedback to the regulation of cell signalling.