Description General description Contains 5 mg of the MEK inhibitor PD 98059 (Cat. No. 513000), 1 mg each of the MAP kinase inhibitors SB 202190 (Cat. No. 559388) and SB 203580 (Cat. No. 559389), and 1 mg of the negative control, SB 202474 (Cat. No. 559387). Supplied with a data sheet. MAP (mitogen-activated protein) kinases are ubiquitous serine/threonine kinases that are activated by a wide variety of extracellular signals. The MAP kinase cascade plays a crucial role in signal transduction from the membrane to the nucleus and appears to be highly conserved throughout evolution. In mammalian cells, this cascade is activated by both tyrosine kinase receptors and G-protein coupled receptors. MAP kinase activation, an essential step in triggering cell cycle progression, leads to changes in properties of cytoplasmic, membrane-associated and nuclear proteins. A unique feature of MAP kinases is that their full activation requires phosphorylation of both a threonine residue and a tyrosine residue which are separated by a single amino acid. This phosphorylation is brought about by the action of MAP kinase kinase (MEK), a dual specificity kinase. Once activated, MAP kinase relays signals downstream by phosphorylating various other protein kinases and regulatory proteins. Following activation, MAP kinases translocate from the cytosol into the nucleus and phosphorylate a number of transcription factors leading to changes in gene expression. Supplied with a data sheet. Packaging 1 set in Glass bottle Biochem/physiol Actions Primary Target p38 kinase Target IC50: 350 nM, 600 nM Warning Toxicity: Standard Handling (A) Reconstitution Following reconstitution, aliquot and store at -20°C.