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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).

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Product Description

Nonphosporylated MEK1/2 Cell Extracts: Total cell extracts from HeLa cells prepared without treatment, serve as a negative control. Supplied in SDS Sample Buffer. Store at -20ºC.

Phosphorylated MEK1/2 Cell Extracts: Total cell extracts from HeLa cells prepared with TPA treatment (200 nM, 15 min) serve as a positive control. Supplied in SDS Sample Buffer. Store at -20ºC.


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.


1.  Crews, C.M. et al. (1992) Science 258, 478-480.

2.  Alessi, D.R. et al. (1994) EMBO J. 13, 1610-1619.

3.  Rosen, L.B. et al. (1994) Neuron 12, 1207-1221.

4.  Cowley, S. et al. (1994) Cell 77, 841-852.



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