Biological Description

Specificity Phospho-mTOR (Ser2481) Antibody [G3C12] detects endogenous levels of total mTOR protein only when it is phosphorylated at Ser2481.
Background Phospho-mTOR Ser2481 marks the autophosphorylation of Ser2481 within the C-terminal regulatory domain of mTOR, mammalian target of rapamycin, a 2,549-amino acid Ser/Thr kinase of the PIKK family that assembles into two distinct multiprotein complexes, rapamycin-sensitive mTORC1 mTOR-Raptor-mLST8-PRAS40-DEPTOR sensing nutrients, amino acids, and energy and rapamycin-insensitive or resistant mTORC2 mTOR-Rictor-mSin1-mLST8-DEPTOR-Protor, acting as a master controller of cell growth, metabolism, and survival. Ser2481 resides in a recently evolved vertebrate-specific C-terminal hydrophobic motif or activation loop region 2430-2450 aa implicated in kinase autoinhibition relief; intact mTORC2 is strictly required for pSer2481, abolished by Rictor or mSin1 knockdown or Sin1-/- MEFs, distinguishing it from mTORC1-specific pSer2448 Akt, S6K1, rapamycin-sensitive. It serves as a biomarker of intact, catalytically active mTORC2: pSer2481 indicates functional assembly enabling mTORC2's signature outputs, Akt Ser473 phosphorylation hydrophobic motif priming, PKCα activation, actin cytoskeleton organization, independent of mTORC1 effects like S6K1 T389 or 4E-BP1 Thr37/46 translation control. pSer2481 monitors mTORC2-mediated spatial-temporal regulation of anabolism, lipid and protein synthesis, cell motility and proliferation, and stress responses; rapamycin and prolonged rapalogs suppress pSer2481 in rapamycin-sensitive cancer lines, predicting mTORC2 disassembly and revealing context-dependent vulnerabilities. Elevated pSer2481 correlates with active mTORC2 in tumors such as HCC and breast cancer, driving oncogenesis via Akt and PKC hyperactivation and serves as a pharmacodynamic readout for rapalog efficacy, superior to indirect Akt pS473 due to PI3K confounding.

Usage Information

Application WB, IF Dilution
WB IF
1:500 - 1:5000 1:20 - 1:200
Reactivity Human
Source Rabbit Monoclonal Antibody MW 288 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
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.
 
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: 250 mA, 180 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 1:500), 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.
IF
Experimental Protocol:
 
Sample Preparation
1. Adherent Cells: Place a clean, sterile coverslip in a culture dish. Once the cells grow to near confluence as a monolayer, remove the coverslip for further use.
2. Suspension Cells: Seed the cells onto a clean, sterile slide coated with poly-L-lysine.
3. Frozen Sections: Allow the slide to thaw at room temperature. Wash it with pure water or PBS for 2 times, 3 minutes each time.
4. Paraffin Sections: Deparaffinization and rehydration. Wash the slide with pure water or PBS for 3 times, 3 minutes each time. Then perform antigen retrieval.
 
Fixation
1. Fix the cell coverslips/spots or tissue sections at room temperature using a fixative such as 4% paraformaldehyde (4% PFA) for 10-15 minutes.
2. Wash the sample with PBS for 3 times, 3 minutes each time.
 
Permeabilization
1.Add a detergent such as 0.1–0.3% Triton X-100 to the sample and incubate at room temperature for 10–20 minutes.
(Note: This step is only required for intracellular antigens. For antigens expressed on the cell membrane, this step is unnecessary.)
Wash the sample with PBS for 3 times, 3 minutes each time.
 
Blocking
Add blocking solution and incubate at room temperature for at least 1 hour. (Common blocking solutions include: serum from the same source as the secondary antibody, BSA, or goat serum.)
Note: Ensure the sample remains moist during and after the blocking step to prevent drying, which can lead to high background.
 
Immunofluorescence Staining (Day 1)
1. Remove the blocking solution and add the diluted primary antibody.
2. Incubate the sample in a humidified chamber at 4°C overnight.
 
Immunofluorescence Staining (Day 2)
1. Remove the primary antibody and wash with PBST for 3 times, 5 minutes each time.
2. Add the diluted fluorescent secondary antibody and incubate in the dark at 4°C for 1–2 hours.
3. Remove the secondary antibody and wash with PBST for 3 times, 5 minutes each time.
4. Add diluted DAPI and incubate at room temperature in the dark for 5–10 minutes.
5. Wash with PBST for 3 times, 5 minutes each time.
 
Mounting
1. Mount the sample with an anti-fade mounting medium.
2. Allow the slide to dry at room temperature overnight in the dark.
3. Store the slide in a slide storage box at 4°C, protected from light.
 

References

  • https://pubmed.ncbi.nlm.nih.gov/19244117/
  • https://pubmed.ncbi.nlm.nih.gov/19244117/

Application Data

WB

Validated by Selleck

  • F3969-wb
    Lane 1: A549, Lane 2: A549 (EGF treated)