Western blot analysis of extracts from Hela cells, untreated or TPA-treated, using Phospho-MEK1/2 (Ser217/221) (41G9) RmAb #9154 (upper) or MEK1/2 (D1A5) Rabbit mAb #8727 (lower).
Boil for 3 minutes prior to use. Load 20 µl of phosphorylated and nonphosphorylated MEK1/2 Control Cell Extracts per lane.
Supplied in SDS Sample Buffer: 62.5 mM Tris-HCl (pH 6.8 at 25°C), 2% w/v SDS, 10% glycerol, 50 mM DTT, 0.01% w/v phenol red or bromophenol blue. Store at –20°C or at –80°C for long term storage.
Nonphosporylated MEK1/2 Control Cell Extracts: Total cell extracts from HeLa cells, serum starved overnight serve as a negative control. Supplied in SDS Sample Buffer.
Phosphorylated MEK1/2 Control Cell Extracts: Total cell extracts from HeLa cells, serum starved overnight then treated with 200 nM TPA #4174 for 15 minutes to serve as a positive control. Supplied in SDS Sample Buffer.
MEK1 and MEK2, also called MAPK or Erk kinases, are dual-specificity protein kinases that function in a mitogen activated protein kinase cascade controlling cell growth and differentiation (1-3). Activation of MEK1 and MEK2 occurs through phosphorylation of two serine residues at positions 217 and 221, located in the activation loop of subdomain VIII, by Raf-like molecules. MEK1/2 is activated by a wide variety of growth factors and cytokines and also by membrane depolarization and calcium influx (1-4). Constitutively active forms of MEK1/2 are sufficient for the transformation of NIH/3T3 cells or the differentiation of PC-12 cells (4). MEK activates p44 and p42 MAP kinase by phosphorylating both threonine and tyrosine residues at sites located within the activation loop of kinase subdomain VIII.
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