MAPK activity in pseudostratified renal epithelium, which exhibits different cell cycle phases in one layer of cells.
Pseudostratified epithelium, characterized by cells in different cell cycle phases within one epithelial structure, exhibits mitotic nuclei (yellow) at the apical side, while S-phase nuclei are located on the basal surface and those in G1/2 occupy the middle epithelial zone. MAPK activity, as detected by phosphorylated ERK1/2 and depicted in red, is activated in some of the middle zone G1- and apical S-phase cells. As shown by Ihermann-Hella et al., MAPK activity is crucial for mediating the transition from G1- to S-phase and regulating epithelial cell adhesion. See Ihermann-Hella et al.
Image Credit: Anneliis Ihermann-Hella