(A, B) GFP-SEPT12 filaments were gradually decreased, and the aggregates were gradually increased in a cAMP dose-dependent manner. GFP-SEPT12 was overexpressed in 293T cells with 0, 1, 5, and 10 mM cAMP treatment, and cells with GFP-filament fibers (A) and GFP aggregates (B) were counted. (C, D) PKACA2 regulates SEPT12-organized structures through Ser198. GFP-SEPT12 or GFP-SEPT12S198A with or without HA-PKACA2 was overexpressed in 293T cells, and cells with GFP-filament fibers (C) and GFP aggregates (D) were counted. Each quantification bar was based on the observation of more than 500 cells. The data are represented as the means ± SEM (n = 3). ** P < 0.01, and *** P < 0.001.