This Cell Signaling Technology (CST) antibody is immobilized via covalent binding of primary amino groups to N-hydroxysuccinimide (NHS)-activated Sepharose® beads. Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (D13.14.4E) XP® Rabbit mAb (Sepharose® Bead Conjugate) is useful for immunoprecipitation assays. The unconjugated Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (D13.14.4E) XP® Rabbit mAb (#4370) reacts with human, mouse, rat, monkey, mink, pig, Saccharomyces cerevisiae, Drosophila melanogaster, hamster, bovine and zebrafish Phospho-p44/42 MAPK protein. CST expects that Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (D13.14.4E) XP® Rabbit mAb (Sepharose® Bead Conjugate) will also recognize phospho MAPK in these species.
Product Usage Information
Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM NaCl, 100 µg/ml BSA, 50% glycerol. Store at –20°C. Do not aliquot the antibodies.
10X Cell Lysis Buffer: (#9803) 20 mM Tris (pH 7.5), 150 mM NaCl, 1 mM EDTA, 1 mM EGTA, 1% Triton X-100, 2.5 mM Sodium pyrophosphate, 1 mM β-glycerophosphate, 1 mM Na3VO4, 1 μg/ml Leupeptin
NOTE: CST recommends adding 1 mM PMSF (#8553) before use*.
3X SDS Sample Buffer: (#7722) 187.5 mM Tris-HCl (pH 6.8 at 25°C), 6% w/v SDS, 30% glycerol, 150 mM DTT, 0.03% w/v bromophenol blue
10X Kinase Buffer (for kinase assays): (#9802) To Prepare 1 ml of 1X kinase buffer, add 100 µl 10X kinase buffer to 900 µl dH2O, mix.
ATP (10 mM) (for kinase assays): (#9804) To prepare 0.5 ml of ATP (200 µM), add 10 µl ATP (10 mM) to 490 µl 1X kinase buffer.
B. Preparing Cell Lysates
Aspirate media. Treat cells by adding fresh media containing regulator for desired time.
To harvest cells under nondenaturing conditions, remove media and rinse cells once with ice-cold PBS.
Remove PBS and add 0.5 ml 1X ice-cold cell lysis buffer to each plate (10 cm) and incubate the plates on ice for 5 minutes.
Scrape cells off the plates and transfer to microcentrifuge tubes. Keep on ice.
Sonicate samples on ice three times for 5 seconds each.
Microcentrifuge for 10 minutes at 4°C, 14,000 x g, and transfer the supernatant to a new tube. If necessary, lysate can be stored at –80°C.
Take 200 μl cell lysate and add 10 μl of the immobilized antibody, incubate with rotation overnight at 4°C.
Microcentrifuge for 30 seconds at 4°C. Wash pellet five times with 500 μl of 1X cell lysis buffer. Keep on ice during washes.
Proceed to sample analysis by western blotting or kinase activity (section D).
D. Sample Analysis
Proceed to one of the following specific set of steps.
For Analysis by Western Immunoblotting
Resuspend the pellet with 20 µl 3X SDS sample buffer. Vortex, then microcentrifuge for 30 sec at 14,000 x g.
Heat the sample to 95–100°C for 2-5 min and microcentrifuge for 1 min at 14,000 x g.
Load the sample (15–30 µl) on a 4–20% gel for SDS-PAGE.
Analyze sample by western blot (see Western Immunoblotting Protocol).
NOTE: When using primary antibodies produced in rabbit to detect proteins with a molecular weight in the range of 50 kDa, we recommend using Mouse Anti-Rabbit IgG (Light-Chain Specific) (D4W3E) mAb (#45262) or Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127) as a secondary antibody to minimize interference produced by denatured rabbit heavy chain. For proteins with a molecular weight in the range of 25 kDa, Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127) is recommended to minimize interference produced by denatured mouse light chain.
When using primary antibodies produced in mouse to detect proteins with a molecular weight in the range of 50 kDa, we recommend using Rabbit Anti-Mouse IgG (Light Chain Specific) (D3V2A) mAb (HRP Conjugate) (#58802) as a secondary antibody to minimize interference produced by denatured mouse heavy chain.
For Analysis by Kinase Assay
Wash pellet twice with 500 µl 1X kinase buffer. Keep on ice.
Suspend pellet in 40 µl 1X kinase buffer supplemented with 200 µM ATP and appropriate substrate.
Incubate for 30 min at 30°C.
Terminate reaction with 20 µl 3X SDS sample buffer. Vortex, then microcentrifuge for 30 sec.
Transfer supernatant containing phosphorylated substrate to another tube.
Heat the sample to 95–100°C for 2–5 min and microcentrifuge for 1 min at 14,000 x g.
Load the sample (15–30 µl) on SDS-PAGE (4–20%).
posted December 2007
revised October 2021
Protocol Id: 27
Specificity / Sensitivity
Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (D13.14.4E) XP® Rabbit mAb (Sepharose® Bead Conjugate) detects endogenous levels of p44 and p42 MAP kinase (Erk1 and Erk2) when dually phosphorylated at Thr202 and Tyr204 of Erk1 (Thr185 and Tyr187 of Erk2), and singly phosphorylated at Thr202. This antibody does not cross-react with the corresponding phosphorylated residues of either JNK/SAPK or p38 MAP kinases.
Human, Mouse, Rat, Hamster, Monkey, Mink, D. melanogaster, Zebrafish, Bovine, Dog, Pig, S. cerevisiae
Species predicted to react based on 100% sequence homology:
The antigen sequence used to produce this antibody shares 100% sequence homology with the species listed here, but reactivity has not been tested or confirmed to work by CST. Use of this product with these species is not covered under our Antibody Performance Guarantee.
Chicken, C. elegans
Source / Purification
Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Thr202/Tyr204 of human p44 MAP kinase.
Mitogen-activated protein kinases (MAPKs) are a widely conserved family of serine/threonine protein kinases involved in many cellular programs, such as cell proliferation, differentiation, motility, and death. The p44/42 MAPK (Erk1/2) signaling pathway can be activated in response to a diverse range of extracellular stimuli, including mitogens, growth factors, and cytokines (1-3), and research investigators consider it an important target in the diagnosis and treatment of cancer (4). Upon stimulation, a sequential three-part protein kinase cascade is initiated, consisting of a MAP kinase kinase kinase (MAPKKK or MAP3K), a MAP kinase kinase (MAPKK or MAP2K), and a MAP kinase (MAPK). Multiple p44/42 MAP3Ks have been identified, including members of the Raf family, as well as Mos and Tpl2/COT. MEK1 and MEK2 are the primary MAPKKs in this pathway (5,6). MEK1 and MEK2 activate p44 and p42 through phosphorylation of activation loop residues Thr202/Tyr204 and Thr185/Tyr187, respectively. Several downstream targets of p44/42 have been identified, including p90RSK (7) and the transcription factor Elk-1 (8,9). p44/42 are negatively regulated by a family of dual-specificity (Thr/Tyr) MAPK phosphatases, known as DUSPs or MKPs (10), along with MEK inhibitors, such as U0126 and PD98059.
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