MAPKAPK2 and atrial fibrillation: We found that the expression level of total c-Jun protein was up-regulated, whereas the expression levels of total MAPKAPK2 protein was slightly reduced after application of 2.0μM and 3.0μM AF, and expression levels of total HSP27 protein were slightly increased after application of 2.0 μM AF, but reduced after 3.0μM AF (Fig 4A and 4B).