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REACTIVITY
Product Includes Volume Solution Color
MEK1 Mouse mAb Coated Microwells 96 tests
Phospho-MEK1/2 (Ser217/221) Rabbit Detection Antibody 1 Ea Green (Lyophilized)
Anti-rabbit IgG, HRP-linked Antibody (ELISA Formulated) 1 Ea Red (Lyophilized)
Detection Antibody Diluent 11 ml Green
HRP Diluent 11 ml Red
TMB Substrate 7004 11 ml Colorless
STOP Solution 7002 11 ml Colorless
ELISA Wash Buffer (20X) 25 ml Colorless
ELISA Sample Diluent 25 ml Blue
Sealing Tape 2 sheets
Cell Lysis Buffer (10X) 9803 15 ml Yellowish
Page

ELISA Colorimetric

NOTE: Refer to product-specific datasheets or product webpage for assay incubation temperature.

A. Solutions and Reagents

NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.

  1. 20X Phosphate Buffered Saline (PBS): (#9808) To prepare 1 L PBS: add 50 ml 10X PBS to 950 ml dH2O, mix.
  2. Bring all microwell strips to room temperature before use.
  3. Prepare 1X Wash Buffer by diluting 20X Wash Buffer (included in each PathScan® Sandwich ELISA Kit) in dH2O.
  4. 1X Cell Lysis Buffer: 10X Cell Lysis Buffer (#9803): To prepare 10 ml of 1X Cell Lysis Buffer, add 1 ml of 10X Cell Lysis Buffer to 9 ml of dH2O, mix. Buffer can be stored at 4°C for short-term use (1–2 weeks).

    Recommended: Add 1 mM phenylmethylsulfonyl fluoride (PMSF) (#8553) immediately before use.

    NOTE: Refer to product-specific datasheet or webpage for lysis buffer recommendation.

  5. TMB Substrate: (#7004).
  6. STOP Solution: (#7002).

B. Preparing Cell Lysates

For adherent cells

  1. Aspirate media when the culture reaches 80–90% confluence. Treat cells by adding fresh media containing regulator for desired time.
  2. Remove media and rinse cells once with ice-cold 1X PBS.
  3. Remove PBS and add 0.5 ml ice-cold 1X cell lysis buffer plus 1 mM PMSF to each plate (10 cm diameter) and incubate the plate on ice for 5 min.
  4. Scrape cells off the plate and transfer to an appropriate tube. Keep on ice.
  5. Sonicate lysates on ice.
  6. Microcentrifuge for 10 min (x14,000 rpm) at 4°C and transfer the supernatant to a new tube. The supernatant is the cell lysate. Store at -80°C in single-use aliquots.

For suspension cells

  1. Remove media by low speed centrifugation (~1,200 rpm) when the culture reaches 0.5–1.0 x 106 viable cells/ml. Treat cells by adding fresh media containing regulator for desired time.
  2. Collect cells by low speed centrifugation (~1,200 rpm) and wash once with 5–10 ml ice-cold 1X PBS.
  3. Cells harvested from 50 ml of growth media can be lysed in 2.0 ml of 1X cell lysis buffer plus 1 mM PMSF.
  4. Sonicate lysates on ice.
  5. Microcentrifuge for 10 min (x14,000 rpm) at 4°C and transfer the supernatant to a new tube. The supernatant is the cell lysate. Store at -80°C in single-use aliquots.

C. Test Procedure

  1. After the microwell strips have reached room temperature, break off the required number of microwells. Place the microwells in the strip holder. Unused microwells must be resealed in the storage bag and stored at 4°C immediately.
  2. Cell lysates can be undiluted or diluted with sample diluent (supplied in each PathScan® Sandwich ELISA Kit, blue color). Individual datasheets or product webpage for each kit provide information regarding an appropriate dilution factor for lysates and kit assay results.
  3. Add 100 µl of each undiluted or diluted cell lysate to the appropriate well. Seal with tape and press firmly onto top of microwells. Incubate the plate for 2 hr at 37°C. Alternatively, the plate can be incubated overnight at 4°C.
  4. Gently remove the tape and wash wells:
    1. Discard plate contents into a receptacle.
    2. Wash 4 times with 1X wash buffer, 200 µl each time per well.
    3. For each wash, strike plates on fresh paper towels hard enough to remove the residual solution in each well, but do not allow wells to completely dry at any time.
    4. Clean the underside of all wells with a lint-free tissue.
  5. Add 100 µl of detection antibody (green color) to each well. Seal with tape and incubate the plate at 37°C for 1 hr.
  6. Repeat wash procedure (Section C, Step 4).
  7. Add 100 µl of HRP-linked secondary antibody (red color) to each well. Seal with tape and incubate the plate for 30 min at 37°C.
  8. Repeat wash procedure (Section C, Step 4).
  9. Add 100 µl of TMB substrate to each well. Seal with tape and incubate the plate for 10 min at 37°C or 30 min at 25°C.
  10. Add 100 µl of STOP solution to each well. Shake gently for a few seconds.

    NOTE: Initial color of positive reaction is blue, which changes to yellow upon addition of STOP solution.

  11. Read results
    1. Visual Determination: Read within 30 min after adding STOP solution.
    2. Spectrophotometric Determination: Wipe underside of wells with a lint-free tissue. Read absorbance at 450 nm within 30 min after adding STOP solution.

posted June 2005

revised November 2013

protocol id: 21

Product Description

CST's PathScan® Phospho-MEK1 (Ser217/221) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of Phospho-MEK1 (Ser217/221) protein. MEK1 Mouse mAb has been coated onto the microwells. After incubation with cell lysates, total MEK1 protein (phospho- and nonphospho-) is captured by the coated antibody. Following extensive washing, a Phospho-MEK1/2 Antibody is added to detect the captured phospho-MEK1 protein. Anti-rabbit IgG, HRP-linked antibody is then used to recognize the bound detection antibody. HRP substrate, TMB, is added to develop color. The magnitude of optical density for this developed color is proportional to the quantity of phospho-MEK1 protein.

Antibodies in kit are custom formulations specific to kit.


Specificity / Sensitivity

CST's PathScan® Phospho-MEK1 (Ser217/221) Sandwich ELISA Kit detects endogenous levels of phospho-MEK1 protein. A significant induction of MEK1 phosphorylation in PMA-treated NIH/3T3 cells can be detected using this kit, #7175. However, the level of total MEK1 protein detected by PathScan® Total MEK1 Sandwich ELISA Kit #7165 remains unchanged (Figure 1). This kit can also be used to detect phosphorylated MEK1 protein in human 293 cells. This kit detects proteins from the indicated species, as determined through in-house testing, but may also detect homologous proteins from other species.


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.


Entrez-Gene Id 5604, 5605
Swiss-Prot Acc. Q02750, P36507


For Research Use Only. Not For Use In Diagnostic Procedures.
Cell Signaling Technology® is a trademark of Cell Signaling Technology, Inc.
PathScan® is a trademark of Cell Signaling Technology, Inc.