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Anti-Phospho-p53 (Ser20) Rabbit Antibody [J22P21]

Catalog No.: F2377

Application: Reactivity: Human

Usage Information

Dilution
WB1:1000-1:5000 IP1:10 - 1:100

Application
WB, IP

Reactivity
Human

Source
Rabbit

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

Predicted MW Observed MW
44 kDa 53 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight.

Positive Control	T-47D (treated with Etoposide)
Negative Control	T-47D

Exprimental Methods

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, Phosphatase 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, Phosphatase Inhibitor Cocktail) and put the sample on ice for 5 min. 3. 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, Phosphatase 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 5 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 150 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; 3. 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 ( recommending 5% BSA solution) for 1 hour at room temperature; 3. Wash the film with TBST for 3 times, 5 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 5 minutes each time. Antibody staining 1. 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. (Exposure time of at least 60s is recommended)

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, Phosphatase 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, Phosphatase Inhibitor Cocktail) and put the sample on ice for 5 min.

3. 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, Phosphatase 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 5 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 150 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;

3. 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 ( recommending 5% BSA solution) for 1 hour at room temperature;

3. Wash the film with TBST for 3 times, 5 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 5 minutes each time.

Antibody staining

1. 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. (Exposure time of at least 60s is recommended)

Datasheet & SDS

Biological Description

Specificity
Phospho-p53 (Ser20) Rabbit mAb detects endogenous levels of p53 protein only when phosphorylated at Ser20.

Subcellular Location
Cytoplasm, Cytoskeleton, Endoplasmic reticulum, Mitochondrion, Nucleus

Uniprot ID
P04637

Clone
J22P21

Synonym(s)
P53, TP53, Cellular tumor antigen p53, Antigen NY-CO-13, Phosphoprotein p53, Tumor suppressor p53

Background
p53 is a tumour suppressor and stress-activated transcription factor that maintains cellular integrity by integrating diverse environmental signals—such as DNA damage, viral infection, metabolic stress, and cytokine signaling—into coordinated gene expression programs regulating DNA repair, apoptosis, metabolism, and cell cycle arrest. Structurally, human p53 is a 393-amino-acid protein comprising an N-terminal transactivation domain (TAD), proline-rich domain (PRD), central DNA-binding domain, tetramerisation domain (TET), and C-terminal regulatory domain (REG), and is extensively regulated by post-translational modifications including phosphorylation, acetylation, methylation, and ubiquitin-like modifications. It is expressed in most tissues at low basal levels but rapidly stabilized and activated under stress. Among its phosphorylation sites, Ser20 in the TAD is highly conserved and critical for stabilizing p53–p300 interaction via a phospho-SDLxxLL motif, promoting DNA-dependent acetylation and transcriptional activation of p53 target genes. Ser20 phosphorylation is triggered by distinct kinases in a stress-specific manner—ATM-dependent (ionizing radiation), CK1 (DNA virus infection), AMPK (metabolic stress), and DAPK-1 (oncogene activation)—and is essential for efficient apoptotic activation, particularly in B-cells. Dysregulation of Ser20 phosphorylation impacts p53’s tumour suppressor function, contributes to cancer development, and influences aging-related processes, highlighting its importance as a convergence point for multiple signaling pathways and a potential therapeutic target.

Background

p53 is a tumour suppressor and stress-activated transcription factor that maintains cellular integrity by integrating diverse environmental signals—such as DNA damage, viral infection, metabolic stress, and cytokine signaling—into coordinated gene expression programs regulating DNA repair, apoptosis, metabolism, and cell cycle arrest. Structurally, human p53 is a 393-amino-acid protein comprising an N-terminal transactivation domain (TAD), proline-rich domain (PRD), central DNA-binding domain, tetramerisation domain (TET), and C-terminal regulatory domain (REG), and is extensively regulated by post-translational modifications including phosphorylation, acetylation, methylation, and ubiquitin-like modifications. It is expressed in most tissues at low basal levels but rapidly stabilized and activated under stress. Among its phosphorylation sites, Ser20 in the TAD is highly conserved and critical for stabilizing p53–p300 interaction via a phospho-SDLxxLL motif, promoting DNA-dependent acetylation and transcriptional activation of p53 target genes. Ser20 phosphorylation is triggered by distinct kinases in a stress-specific manner—ATM-dependent (ionizing radiation), CK1 (DNA virus infection), AMPK (metabolic stress), and DAPK-1 (oncogene activation)—and is essential for efficient apoptotic activation, particularly in B-cells. Dysregulation of Ser20 phosphorylation impacts p53’s tumour suppressor function, contributes to cancer development, and influences aging-related processes, highlighting its importance as a convergence point for multiple signaling pathways and a potential therapeutic target.

References
https://pubmed.ncbi.nlm.nih.gov/20157532/

Reference Table for Selecting PVDF Membrane Pore Size Specifications

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

Handling Instructions

Tel: +1-832-582-8158 Ext:3
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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%