Mitogen-activated kinase kinase 1, MAPKK1
human, recombinant, E. coli
For in vitro use only!
Shipping: shipped on dry ice
Storage Conditions: store at -80 °C
avoid freeze/thaw cycles
Shelf Life: 12 months
Molecular Weight: 69.7 kDa
Accession number: NM_002755
Purity: > 90 % (SDS-PAGE)
Form: liquid (Supplied in 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 0.1 mM EGTA, 270 mM sucrose and 1 mM DTT)
Activity: > 500,000 U/mg (1 Unit is defined as the amount of MEK1 which activates inactive ERK1 (0.3 mg/ml) by 1 U/min using 100 μM ATP at 30°C. 1 U ERK1 activity is defined as 1 pmol phosphate transferred to myelin basic protein (0.2 mg/ml) per min using 125 μM ATP at 30°C).
Several key growth factors, cytokines, and protooncogenes transduce their growth- and differentiationpromoting signals through the mitogen-activated protein kinase or extracellular signal-regulated protein kinase (ERK) cascade. MAP (mitogen-activated protein) kinases are activated by a family of dual specificity kinases called MEKs (MAP kinase/Erk Kinase). MEK1 can be activated by Raf by phosphorylation on serine 218 and serine 222. Mutation of these sites to acidic residues leads to constitutively active MEK1 in some cases. Given the central role of the ERK/mitogen-activated protein kinase pathway in mediating growth-promoting signals for a diverse group of upstream stimuli, inhibitors of MEK, as a key central mediator, could have significant clinical benefit in the treatment of breast and other cancers. The human recombinant MEK1, activated by two amino acid exchanges (S218D, S222D), was expressed in E. coli and purified by gluthatione sepharose and gelfiltration. It is suitable for labeling MEK1 substrates and for activation of ERK1 and ERK2. The N-terminal GST-Tag facilitates the protein`s application in typical GST pull-down assays.
Alessandrini et al. (1996) Mek1 phosphorylation site mutants activate Raf-1 in NIH 3T3 cells. J. Biol. Chem. 271:31612.
Schramek et al. (1997) Constitutively active mutant of the mitogenactivated protein kinase kinase MEK1 induces epithelial dedifferentiation and growth inhibition in madin-darby canine kidney-C7 cells. J. Bio. Chem. 272:11426.
Allen et al. (2003) CI-1040 (PD184352), a targeted signal transduction inhibitor of MEK (MAPKK). Sem. Oncol. 30:105.