Phospho-Stat2 (Tyr 690) Rabbit mAb

Catalog No.: F0554

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Biological Description

Specificity Phospho-Stat2 (Tyr 690) Rabbit mAb recognizes endogenous levels of Stat2 protein only when phosphorylated at Tyr690.
Background Phospho-STAT2 (Tyr690) refers to the tyrosine-phosphorylated form of the STAT2 (Signal Transducer and Activator of Transcription 2) protein, specifically phosphorylated at the tyrosine residue at position 690. STAT2 is a multidomain protein, an essential transcription factor in type I IFN mediated anti-viral and anti-proliferative signaling. Structurally, it is composed of an N-terminal domain (ND), coiled-coil domain (CCD), DNA-binding domain (DBD), linker domain (LD), Src homology 2 (SH2) domain, and a transactivation domain (TAD). Upon stimulation by type I interferons (IFN-α/β), receptor-associated kinases TYK2 and JAK1 phosphorylate STAT2 at Tyr690, which lies just C-terminal to the SH2 domain. This phosphorylation is essential for STAT2 dimerization (often with STAT1), nuclear translocation, and the formation of the ISGF3 complex (with IRF9), enabling the activation of interferon-stimulated genes (ISGs). STAT2 is ubiquitously expressed, especially in immune cells, and its phosphorylation is crucial for initiating antiviral and anti-proliferative responses. Tyr690 phosphorylation acts as a molecular switch that converts cytoplasmic STAT2 into an active transcriptional regulator, and its absence disrupts downstream interferon signaling, compromising immune defense.

Usage Information

Application WB, IF, FCM Dilution
WB IF FCM
1:1000 1:50 - 1:100 1:100 - 1:400
Reactivity Human, Rat
Source Rabbit MW 97 kDa, 113 kDa
Storage Buffer PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN₃
Storage
(from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years
IF
Experimental Protocol:
 
Specimen Preparation 
1. Aspirate liquid, then cover cells to a depth of 2–3 mm with 4% Paraformaldehyde diluted in 1X PBS.
NOTE: Paraformaldehyde is toxic, use only in a fume hood.
2. Fix cells for 15 min at room temperature.
3. Aspirate fixative, rinse three times in 1X PBS for 5 min each.
4. Proceed with Immunostaining.
 
Immunostaining
1. Add theblocking buffer and incubate for 60 min at RT.
2. Prepare primary antibody diluent in antibody dilution buffer as recommended .
3. Aspirate blocking solution, apply diluted primary antibody.
4. Incubate overnight at 4°C.
5. Rinse three times in 1X PBS for 5 min each.
6. Incubate specimens in fluorochrome-conjugated secondary antibody diluted in antibody dilution buffer for 1–2 hr at room temperature in the dark.
7. Rinse three times in 1X PBS for 5 min each.
8. Mount slides usingmounting medium with DAPI and cover with coverslips.
9. For best results, allow mountant to cure overnight at room temperature. For long-term storage, store slides flat at 46°C protected from light.
 
WB
Experimental Protocol:
 
Sample preparation
1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail),and homogenize the tissue at a low temperature.
2. Adherent cell: Aspirate the culture medium and wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) and put the sample on ice for 5 min.
66. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) and put the sample on ice for 5 min.
4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant;
5. Remove a small volume of lysate to determine the protein concentration;
6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 68 min after cool down on ice.
 
Electrophoretic separation
1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 10%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations
2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 213 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.)
 
Transfer membrane
1. Take out the converter, soak the clip and consumables in the pre-cooled converter;
2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer;
66. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip";
4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications
Recommended conditions for wet transfer: 200 mA, 120 min.
( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.)
 
Block
1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes;
2. Incubate the film in the blocking solution for 1 hour at room temperature;
3. Wash the film with TBST for 3 times, 68 minutes each time.
 
Antibody incubation
1. Use 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:1000), gently shake and incubate with the film at 4°C overnight;
2. Wash the film with TBST 3 times, 5 minutes each time;
3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour;
4. After incubation, wash the film with TBST 3 times for 68 minutes each time.
 
Antibody staining
1452. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly;
2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.

Application Data