Dual specificity kinase. Is activated by cytokines and environmental stress in vivo. Catalyzes the concomitant phosphorylation of a threonine and a tyrosine residue in the MAP kinase p38. Wang W, et al. (2002) Mol Cell Biol , 22(10): 3389-403. Raingeaud J, et al. (1996) Mol Cell Biol, 16(3): 1247-55.