RNA-dependent protein kinase (PKR) is crucial for the innate immune response, cell growth, proliferation, signal transduction and apoptosis. The activation process of PKR has been studied for many years and is still under debate. To obtain new insight into the mechanism of PKR activation, we solved the crystal structure of a latent mutant of the PKR kinase domain (PKR-KD) in the apo form at a resolution of 2.9 Å. The overall structure of PKR-KD is similar to previously reported structures. Structural analysis revealed a classical back-to-back dimer and a newly defined face-to-face dimer. Analytical ultracentrifugation experiments, electrostatic surface maps and the model of PKR-KD in complex with the eIF2 substrate all support that the face-to-face dimer is more reflective of PKR in solution. Our results provide new information on PKR dimerization and its activation mechanism. PKR, dimerization, crystal structure, PKR activation Citation:Li F Z, Li S W, Wang Z, et al. Structure of the kinase domain of human RNA-dependent protein kinase with K296R mutation reveals a face-to-face dimer.

This study demonstrates the highly variable expression patterns of CRABP-II and FABP5 in medulloblastoma cells and their correlation with RA sensitivities.