Characterization of CaMKIIα holoenzyme stability.

Ca /calmodulin-dependent protein kinase II (CaMKII) is a Ser/Thr kinase necessary for long-term memory formation and other Ca -dependent signaling cascades such as fertilization. Here, we investigated the stability of CaMKIIα using a combination of differential scanning calorimetry (DSC), X-ray crystallography, and mass photometry (MP). The kinase domain has a low thermal stability (apparent T = 36°C), which is slightly stabilized by ATP/MgCl binding (apparent T = 40°C) and significantly stabilized by regulatory segment binding (apparent T = 60°C).