P38 mitogen-activated protein kinases

P38 mitogen-activated protein kinases are a class of mitogen-activated protein kinases which are responsive to stress stimuli, such as cytokines, ultraviolet irradiation, heat shock, and osmotic shock, and are involved in cell differentiation and apoptosis.

p38 MAP Kinase (MAPK), also called RK or CSBP, is the mammalian orthologue of the yeast HOG kinase which participates in a signalling cascade controlling cellular responses to cytokines and stress.

Four isoforms of p38 MAP kinase, p38α, -β, -gamma (also known as ERK6 or SAPK3) and -δ(also known as SAPK4) have been identified. Similar to the SAPK/JNK pathway, p38 MAP kinase is activated by a variety of cellular stresses including osmotic shock, inflammatory cytokines, lipopolysaccharides (LPS), Ultraviolet light and growth factors.

MKK3 and SEK activate p38 MAP kinase by phosphorylation at Thr180 and Tyr182, Activated p38 MAP kinase has been shown to phosphorylate and activate MAPKAP kinase 2 and to phosphorylate the transcription factors ATF-2, Mac and MEF2.