P38 mitogen-activated protein kinases

P38 mitogen-activated protein kinases are a class of mitogen-activated protein kinases that 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 Hog1p MAP kinase, which participates in a signalling cascade controlling cellular responses to cytokines and stress.

Four p38 MAP kinases, p38-α (MAPK14), -β (MAPK11), -γ (MAPK12 / ERK6), and -δ (MAPK13 / 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 Thr-180 and Tyr-182. Activated p38 MAP kinase has been shown to phosphorylate and activate MAPKAP kinase 2 and to phosphorylate the transcription factors ATF2, Mac and MEF2. p38 also has been shown to phosphorylate post-transcriptional regulating factors like TTP.

P38 inhibitors
P38 inhibitors are being sought for possible therapeutic effect on autoimmune diseases and inflammatory processes, e.g. pamapimod. Some have started clinical trials, e.g. PH-797804 for COPD.