MAP kinase-activated protein kinase 3 (MAPKAPK3)

Following stress, it is phosphorylated and activated by MAP kinase p38- alpha/MAPK14, resulting in phosphorylation of substrates. Phosphorylates serine in the peptide sequence, Hyd-X-R-X(2)-S, where Hyd is a large hydrophobic residue.

MAPKAPK2 and MAPKAPK3, share the exact same function and substrate specificity, but MAPKAPK3 kinase activity and degree in protein expression are lower in comparison to MAPKAPK2. Phosphorylates HSP27/HSPB1, KRT18, KRT20, RCSD1, RPS6KA3, TAB3 and TTP/ZFP36.