In Arabidopsis thaliana, 20 genes (MPKs) encode putative plant MAPKs, which can be grouped into four or five classes according to sequence similarity. All plant MAPKs are classified into the plant extracellular-regulated kinase/ERK (PERK) subfamily.
Mitogen-activated protein kinase (MAPK) cascades are among the most conserved signal transduction pathways in eukaryotes. MAPKs regulate a variety of cellular activities ranging from gene expression, cell proliferation, motility, metabolism and apoptosis. In Arabidopsis thaliana putative functions have been assigned to AtMPK3, AtMPK4 and AtMPK6 and all three MAPKs have been linked to diverse stress responses, including oxidative stress signaling, pathogen defense, drought, high salt, cold and touch.
