MAPKAPK3 Protein, Human (sf9, GST)

MAPKAPK3 protein is a stress-activated serine/threonine-protein kinase with a diverse role in cellular processes, including cytokine production, endocytosis, cell migration, chromatin remodeling, and transcriptional regulation. Upon exposure to stress, MAPKAPK3 is phosphorylated and activated by MAP kinase p38-alpha/MAPK14, resulting in the phosphorylation of specific substrates. Sharing functional similarity and substrate specificity with MAPKAPK2, MAPKAPK3 exhibits lower kinase activity and protein expression levels. It phosphorylates key proteins like HSP27/HSPB1, KRT18, KRT20, RCSD1, RPS6KA3, TAB3, and TTP/ZFP36. In response to stress, MAPKAPK3 mediates the phosphorylation of HSP27/HSPB1, leading to the dissociation of HSP27/HSPB1 from large small heat-shock protein (sHsps) oligomers and impairing their chaperone activities. Notably, MAPKAPK3 plays a role in the inflammatory response by post-transcriptionally regulating TNF and IL6 production. It achieves this by phosphorylating AU-rich element (AREs)-binding proteins, such as TTP/ZFP36, influencing the stability and translation of TNF and IL6 mRNAs. Additionally, MAPKAPK3 is involved in the toll-like receptor signaling pathway in dendritic cells, contributing to acute TLR-induced macropinocytosis. Furthermore, it acts as a modulator of Polycomb-mediated repression, adding another layer to its regulatory functions in cellular processes.