Cell Signaling Technology

Product Pathways - MAPK Signaling

Phospho-MEK1/2 (Ser217/221) Antibody #9121

Applications Reactivity Sensitivity MW (kDa) Source
W IP H M R Mk Sc (C) Endogenous 45 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  C=Chicken  Sc=S. cerevisiae
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-MEK1/2 (Ser217/221) Antibody detects endogenous levels of MEK1/2 only when activated by phosphorylation at Ser217/221. This antibody does not cross-react with related kinases including activated SEK (MKK4), MKK3 or MKK6. It will also react with MEK1/2 singly phosphorylated at Ser217 and singly phosphorylated at Ser221.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues around Ser217/221 of human MEK1/2. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from untreated, TPA-treated or lambda phosphatase-treated HeLa cells, using Phospho-MEK 1/2 (Ser217/221) Antibody #9121 (upper) or MEK 1/2 Antibody #9122 (lower).

Background

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.

CST's Phospho- MEK1/2 (Ser217/221) Antibody selectively recognizes active MEK, i.e., only when phosphorylated at Ser217/221, and hence is an excellent marker of MEK1/2 activity.

  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.

Application References

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Companion Products

For Research Use Only. Not For Use In Diagnostic Procedures.

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