Development and Characterization of Novel Molecular Probes for Ca/Calmodulin-Dependent Protein Kinase Kinase, Derived from STO-609.

Ca/calmodulin-dependent protein kinase kinase (CaMKK) activates particular multifunctional kinases, including CaMKI, CaMKIV, and 5'AMP-activated protein kinase (AMPK), resulting in the regulation of various Ca-dependent cellular processes, including neuronal, metabolic, and pathophysiological pathways. We developed and characterized a novel pan-CaMKK inhibitor, TIM-063 (2-hydroxy-3-nitro-7-benzo[de]benzo[4,5]imidazo[2,1-]isoquinolin-7-one) derived from STO-609 (7-benzimidazo[2,1-]benz[de]isoquinoline-7-one-3-carboxylic acid), and an inactive analogue (TIM-062) as molecular probes for the analysis of CaMKK-mediated cellular responses. Unlike STO-609, TIM-063 had an inhibitory activity against CaMKK isoforms (CaMKKα and CaMKKβ) with a similar potency ( = 0.