MAPKAPK5/PRAK

MAPKAPK5, known as PRAK or MK5, is activated by p38 and additionally by atypical mitogen-activated protein kinases ERK3 and ERK4, which bind its carboxy-terminal region and relocalize the enzyme, a partnership unique among MAPK-activated kinases. MK5 phosphorylates small heat shock proteins and participates in actin remodeling and cell migration. Its tumor biology is notable: PRAK mediates oncogene-induced senescence in a p53-dependent manner, and MAPKAPK5 deletion enhances chemical carcinogenesis in mice, supporting tumor-suppressive activity. Behavioral studies have additionally linked the kinase to anxiety-related phenotypes, extending its reach beyond inflammation into organismal physiology.