Figure 1. Treatment of A-431 cells with EGF stimulates phosphorylation of Stat1 at Tyr701 but does not effect the level of total Stat1. The relationship between lysate protein concentration from untreated and EGF-treated A-431 cells and the absorbance at 450 nm using the FastScan™ Phospho-Stat1 (Tyr701) ELISA Kit #40716 is shown in the upper figure. The corresponding western blots using phospho-Stat1 (Tyr701) antibody (left panel) and Stat1 antibody (right panel) are shown in the lower figure. After serum starvation, A-431 cells were either left untreated or treated with 100 ng/mL EGF for 5 minutes at 37°C, then lysed.
|Product Includes||Volume (with Count)||Solution Color|
|FastScan™ ELISA Microwell Strip Plate, 96 Well 53257||1 x 96 tests|
|Stat1 Rabbit Capture mAb||1 x 1 ea||Green (Lyophilized)|
|Phospho-Stat1 (Tyr701) Rabbit HRP-linked mAb||1 x 1 ea||Red (Lyophilized)|
|FastScan™ ELISA Capture Antibody Diluent||1 x 3 ml||Green|
|FastScan™ ELISA HRP Antibody Diluent||1 x 3 ml|
|TMB Substrate 7004||1 x 11 ml|
|STOP Solution 7002||1 x 11 ml|
|Sealing Tape||1 x 1 ea|
|ELISA Wash Buffer (20X) 9801||1 x 25 ml|
|FastScan™ ELISA Cell Extraction Buffer (5X) 69905||1 x 10 ml|
|FastScan™ ELISA Cell Extraction Enhancer Solution (50X) 25243||1 x 1 ml|
|FastScan™ ELISA Kit #40716 Positive Control Type 1||1 x 1 ea|
NOTE: Prepare solutions with deionized/purified water or equivalent.
Prepare only as much reagent as needed on the day of the experiment.
*IMPORTANT: The provided FastScan™ ELISA Cell Extraction Enhancer Solution (50X) may precipitate when stored at 4°C. To dissolve, warm briefly at 37°C and mix gently. The FastScan™ ELISA Cell Extraction Enhancer Solution (50X) can be stored at room temperature to avoid precipitation.
NOTE: The 1X Cell Extraction Buffer contains phosphatase inhibitors. Protease inhibitors should be added to the 1X Cell Extraction Buffer immediately prior to lysing cells. Additional phosphatase inhibitors can also be added (e.g. Protease/Phosphatase Inhibitor Cocktail (100X) #5872, not supplied).
NOTE: A select number of FastScan™ ELISA kits do not contain a positive control, please refer to Product Includes table on the datasheet for a list of included reagents. Should you need support on how to generate a positive control for those kits, contact CST technical support at [email protected].
For adherent cells
For suspension cells
NOTE: Equilibrate all materials and prepared reagents to room temperature prior to running the assay.
*NOTE: Certain FastScan™ ELISA Kits may require additional washes at this step. Any requirements for additional washes will be specifically noted in the product “Description” of the kit’s datasheet.
NOTE: Initial color of positive reaction is blue, which changes to yellow upon addition of STOP Solution.
posted May 2018
revised November 2019
Protocol Id: 1924
The FastScan™ Phospho-Stat1 (Tyr701) ELISA Kit is a sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of Stat1 when phosphorylated at Tyr701. To perform the assay, sample is incubated with a capture antibody conjugated with a proprietary tag and a second detection antibody linked to HRP, forming a sandwich with phospho-Stat1 (Tyr701) in solution. This entire complex is immobilized to the plate via an anti-tag antibody. The wells are then washed to remove unbound material. TMB is then added. The magnitude of observed signal is proportional to the quantity of phospho-Stat1 (Tyr701). Antibodies in kit are custom formulations specific to kit.
The FastScan™ Phospho-Stat1 (Tyr701) ELISA Kit detects endogenous levels of Stat1 when phosphorylated at Tyr701 as shown in 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.
The Stat1 transcription factor is activated in response to a large number of ligands (1) and is essential for responsiveness to IFN-α and IFN-γ (2,3). Phosphorylation of Stat1 at Tyr701 induces Stat1 dimerization, nuclear translocation, and DNA binding (4). Stat1 protein exists as a pair of isoforms, Stat1α (91 kDa) and the splice variant Stat1β (84 kDa). In most cells, both isoforms are activated by IFN-α, but only Stat1α is activated by IFN-γ. The inappropriate activation of Stat1 occurs in many tumors (5). In addition to tyrosine phosphorylation, Stat1 is also phosphorylated at Ser727 through a p38 mitogen-activated protein kinase (MAPK)-dependent pathway in response to IFN-α and other cellular stresses (6). Serine phosphorylation may be required for the maximal induction of Stat1-mediated gene activation.
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