Cell Signaling Technology

Product Pathways - MAPK Signaling

Phospho-MEK1 (Thr286) Antibody #9127

Applications Reactivity MW (kDa) Source
W IP IF-IC F H R Mk (M) 45 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  IF-IC=Immunofluorescence (Immunocytochemistry)  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-MEK1 (Thr286) Antibody detects endogenous levels of MEK1 phosphorylated at threonine 286. This antibody does not cross-react with phosphorylated MEK2.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic phospho-peptide (KLH-coupled) corresponding to residues surrounding Thr286 of human MEK1. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from A431, COS and PC12 cells, untreated or nocodazole-treated, using Phospho-MEK1 (Thr286) Antibody (upper) or MEK1 Antibody #9124 (lower).

IP

IP

Immunoprecipitation followed by Western blot analysis of extracts from COS cells, untreated or nocodazole-treated, using Phospho-MEK1 (Thr286) Antibody.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of untreated Jurkat cells, using Phospho-MEK1 (Thr286) Antibody versus propidium iodide (DNA content). The box indicates Phosho-MEK1 positive cells.


IF-IC

IF-IC

Confocal immunofluorescent analysis of mitotic HeLa cells labeled with Phospho-MEK1 (Thr286) Antibody (green). Actin filaments have been labeled with Alexa Fluor® 555 phalloidin (red). Blue pseudocolor = DRAQ5™ (fluorescent DNA dye).

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 (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 PC12 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.

MEK1 is phosphorylated at Ser298 by PAK1, which facilitates signal transduction from Raf to MEK1 and Erk2 (5-7). MEK1 is also phosphorylated by cdk5 at Thr286 in mitotic cells, causing negative feedback of the p44/42 MAP kinase pathway (8).

  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.
  5. Xu, B. et al. (1999) J. Biol. Chem. 274, 34029-34035.
  6. Coles, L.C. and Shaw, P.E. (2002) Oncogene 21, 2236-2244.
  7. Eblen, S. T. et al. (2002) Mol. Cell. Biol. 22, 6023-6033.
  8. Sharma, P. et al. (2002) J. Biol. Chem. 277, 528-534.

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