Biological Description

Specificity MST3 Antibody (Rabbit mAb) [F21L14] detects endogenous levels of total MST3 protein.
Background Mammalian sterile 20‑like kinase 3 (MST3, also termed STK24) is a Ste20‑related serine/threonine kinase that belongs to the germinal center kinase III subfamily and functions as a signaling node linking stress and polarity cues to cytoskeletal organization, cell migration, and cell death pathways. The protein contains an N‑terminal catalytic domain with the conserved HRD and DFG motifs required for kinase activity and a C‑terminal regulatory region with docking sequences for STRIPAK core subunits, endothelial polarity regulators, and other scaffolding proteins, and it is activated by phosphorylation within the activation loop and by release from STRIPAK‑mediated inhibition. MST3 localizes to the cytoplasm, Golgi region, and nucleus and associates with cytoskeletal and polarity complexes through interactions with CCM3 (PDCD10), STRNs, and other PP2A‑containing STRIPAK components, which position the kinase at sites where it can phosphorylate substrates involved in actin and microtubule remodeling and vesicular trafficking. MST3 phosphorylates and regulates proteins such as NDR family kinases and actin‑linked effectors and participates in cascades related to the Hippo pathway, where it contributes to NDR/LATS‑type kinase activation and to the control of proliferation, apoptosis, and junctional organization in epithelial and endothelial contexts. The kinase also modulates Rho family and p38/JNK MAPK–associated signaling modules through effects on cytoskeletal regulators and stress‑responsive targets, placing MST3 in pathways that integrate mechanical and oxidative inputs with changes in cell shape, motility, and survival. MST3 expression is detected in brain, heart, liver, and skeletal muscle, and its activity influences neuronal morphology, axonal outgrowth, and dendritic architecture through regulation of cytoskeletal dynamics and polarity complexes, linking this kinase to neuronal connectivity and vulnerability to apoptotic or degenerative signals. In epithelial and endothelial systems, MST3 contributes to barrier and polarity control and participates in CCM3–STRIPAK–MST3 axes that affect vascular integrity and lumen formation. Across tumors, altered MST3 expression or localization associates with changes in migration, invasion, and apoptosis.

Usage Information

Application WB, IF, FCM Dilution
WB IF FCM
1:5000 1:100-1:250 1:30
Reactivity Human
Source Rabbit Monoclonal Antibody MW 49 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),and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes.
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) , sonicate to lyse the cells, and incubate on ice for 30 minutes.
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) , sonicate to lyse the cells, and incubate on ice for 30 minutes.
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 for 1 hour at room temperature;
3. Wash the film with TBST for 3 times, 5 minutes each time.
 
Antibody incubation
1. Use primary antibody dilution buffer to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:5000), 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 120s is recommended)
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/12107159/
  • https://pubmed.ncbi.nlm.nih.gov/35413286/

Application Data

WB

Validated by Selleck

  • F3671-wb
    Lane 1: A431, Lane 2: Raji