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REACTIVITY
H
Product Includes Volume Solution Color
Chk1 Ab Coated Microwells 96 tests
P-Chk1 (S317) Detection Ab 11 ml Green
Anti-rabbit 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 Blue
Cell Lysis Buffer (10X) 9803 15 ml Yellowish

Order Details

Custom Ordering Details: When ordering five or more kits, please contact us for processing time and pricing at sales@cellsignal.com.
Page

ELISA Colormetric

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

The PathScan® Phospho-Chk1 (Ser317) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of Chk1 when phosphorylated at Ser317. An Chk1 Mouse Antibody has been coated onto the microwells. After incubation with cell lysates, Chk1 (phospho and nonphospho) is captured by the coated antibody. Following extensive washing, a Phospho-Chk1 (Ser317) Rabbit Detection Antibody is added to detect phosphorylation of Ser317 on the captured Chk1 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 the absorbance for this developed color is proportional to the quantity of Chk1 phosphorylated at Ser317.

Antibodies in kit are custom formulations specific to kit.


Specificity / Sensitivity

CST's PathScan® Phospho-Chk1 (Ser317) Sandwich ELISA Kit #7870 detects endogenous levels of Chk1 protein when phosphorylated at Ser317. As shown in Figure 1, a significant induction of Chk1 phosphorylation at Ser317 can be detected in HeLa cells following treatment with UV using the Phospho-Chk1 (Ser317) Sandwich ELISA Kit #7870. The levels of total Chk1 (phospho and nonphospho) remain unchanged as shown by Western analysis and by PathScan® Total Chk1 Sandwich ELISA Kit #7872 (Figure 1). 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

Chk1 kinase acts downstream of ATM/ATR kinase and plays an important role in DNA damage checkpoint control, embryonic development, and tumor suppression (1). Activation of Chk1 involves phosphorylation at Ser317 and Ser345 by ATM/ATR, followed by autophosphorylation of Ser296. Activation occurs in response to blocked DNA replication and certain forms of genotoxic stress (2). While phosphorylation at Ser345 serves to localize Chk1 to the nucleus following checkpoint activation (3), phosphorylation at Ser317 along with site-specific phosphorylation of PTEN allows for re-entry into the cell cycle following stalled DNA replication (4). Chk1 exerts its checkpoint mechanism on the cell cycle, in part, by regulating the cdc25 family of phosphatases. Chk1 phosphorylation of cdc25A targets it for proteolysis and inhibits its activity through 14-3-3 binding (5). Activated Chk1 can inactivate cdc25C via phosphorylation at Ser216, blocking the activation of cdc2 and transition into mitosis (6). Centrosomal Chk1 has been shown to phosphorylate cdc25B and inhibit its activation of CDK1-cyclin B1, thereby abrogating mitotic spindle formation and chromatin condensation (7). Furthermore, Chk1 plays a role in spindle checkpoint function through regulation of aurora B and BubR1 (8). Research studies have implicated Chk1 as a drug target for cancer therapy as its inhibition leads to cell death in many cancer cell lines (9).


1.  Liu, Q. et al. (2000) Genes Dev 14, 1448-59.

2.  Zhao, H. and Piwnica-Worms, H. (2001) Mol Cell Biol 21, 4129-39.

3.  Jiang, K. et al. (2003) J Biol Chem 278, 25207-17.

4.  Martin, S.A. and Ouchi, T. (2008) Mol Cancer Ther 7, 2509-16.

5.  Chen, M.S. et al. (2003) Mol Cell Biol 23, 7488-97.

6.  Zeng, Y. et al. (1998) Nature 395, 507-10.

7.  Löffler, H. et al. (2006) Cell Cycle 5, 2543-7.

8.  Zachos, G. et al. (2007) Dev Cell 12, 247-60.

9.  Garber, K. (2005) J Natl Cancer Inst 97, 1026-8.


Entrez-Gene Id 1111
Swiss-Prot Acc. O14757


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.