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Rabbit (DA1E) mAb IgG XP® Isotype Control (Sepharose Bead Conjugate) #3423
Immunoprecipitation of extracts from HeLa cells, untreated or TPA-treated, using Rabbit (DA1E) mAb IgG XP® Isotype Control (Sepharose Bead Conjugate) (Lanes 1 and 2) or Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (D13.14.4E) XP® Rabbit mAb (Sepharose Bead Conjugate) #3510 (Lanes 3 and 4). The blot was probed using Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (E10) Mouse mAb #9106.Learn more about how we got this image
Gallery: Rabbit (DA1E) mAb IgG XP® Isotype Control (Sepharose Bead Conjugate) #3423
Immunoprecipitation for Analysis by Western Blotting
This protocol is intended for immunoprecipitation of native proteins for analysis by western immunoblot or kinase activity.
A. Solutions and Reagents
NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalently purified water.
- 20X Phosphate Buffered Saline (PBS): (#9808).
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 20 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: To minimize masking caused by denatured IgG heavy chains (~50 kDa), we recommend using Mouse Anti-Rabbit IgG (Light-Chain Specific) (L57A3) mAb (#3677) or Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127). To minimize masking caused by denatured IgG light chains (~25 kDa), we recommend using Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127).
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
protocol id: 27
Add 10 µl of well-vortexed beads to 200 µl of cell lysate at 1 mg/ml in 1X Cell Lysis Buffer (10X) #9803. See protocol for more details.
Rabbit (DA1E) mAb IgG XP® Isotype Control is not directed against any known antigen. It functions as a control for rabbit IgG monoclonal antibodies.
Control antibodies are used to estimate the non-specific binding of target primary antibodies due to Fc receptor binding or other protein-protein interactions.
For Research Use Only. Not For Use In Diagnostic Procedures. Cell Signaling Technology® is a trademark of Cell Signaling Technology, Inc. XP® is a trademark of Cell Signaling Technology, Inc.