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REACTIVITY
H M R Mk
Product Includes Volume Solution Color
4E-BP1 (T37/46) Ab Coated Microwells 96 tests
4E-BP1 Detection Ab 11 ml Green
Anti-mouse IgG, HRP-linked Antibody 11 ml Red
TMB Substrate 7004 11 ml Colorless
STOP Solution 7002 11 ml Colorless
Sealing Tape 2 sheets
ELISA Wash Buffer (20X) 25 ml Colorless
ELISA Sample Diluent 25 ml
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-4E-BP1 (Thr37/46) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of 4E-BP1 when phosphorylated at Thr37/46. A Phospho-4E-BP1 (Thr37/46) Rabbit Antibody has been coated onto the microwells. After incubation with cell lysates, phospho-4E-BP1 (Thr37/46) is captured by the coated antibody. Following extensive washing, a 4E-BP1 Mouse Detection Antibody is added to detect the captured phospho-4E-BP1 protein. Anti-mouse IgG, HRP-linked Antibody #7076 is then used to recognize the bound detection antibody. HRP substrate, TMB, is added to develop color. The magnitude of absorbance for this developed color is proportional to the quantity of 4E-BP1 phosphorylated at Thr37/46.

Antibodies in kit are custom formulations specific to kit.


Specificity / Sensitivity

CST's PathScan® Phospho-4E-BP1 (Thr37/46) Sandwich ELISA Kit detects endogenous levels of phospho-4E-BP1 when phosphoryated at Thr37/46. As shown in Figure 1, using the Phospho-4E-BP1 (Thr37/46) ELISA Kit #7216, a significant induction of 4E-BP1 phosphorylation at Thr37/46 is detected in serum and amino acid starved HEK-293T cells treated with insulin for 30 minutes after replenishing the amino acids. This kit detects proteins from the indicated species, as determined through in-house testing, but may also detect homologous proteins from other species.


Species Reactivity: Human, Mouse, Rat, Monkey

Translation repressor protein 4E-BP1 (also known as PHAS-1) inhibits cap-dependent translation by binding to the translation initiation factor eIF4E. Hyperphosphorylation of 4E-BP1 disrupts this interaction and results in activation of cap-dependent translation (1). Both the PI3 kinase/Akt pathway and FRAP/mTOR kinase regulate 4E-BP1 activity (2,3). Multiple 4E-BP1 residues are phosphorylated in vivo (4). While phosphorylation by FRAP/mTOR at Thr37 and Thr46 does not prevent the binding of 4E-BP1 to eIF4E, it is thought to prime 4E-BP1 for subsequent phosphorylation at Ser65 and Thr70 (5).


1.  Pause, A. et al. (1994) Nature 371, 762-7.

2.  Brunn, G.J. et al. (1997) Science 277, 99-101.

3.  Gingras, A.C. et al. (1998) Genes Dev 12, 502-13.

4.  Fadden, P. et al. (1997) J Biol Chem 272, 10240-7.

5.  Gingras, A.C. et al. (1999) Genes Dev 13, 1422-37.


Entrez-Gene Id 1978
Swiss-Prot Acc. Q13541


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.