Biological Description

Specificity α-Skeletal Muscle Actin Antibody (Rabbit mAb) [A24H10] detects endogenous levels of total α-Skeletal Muscle Actin protein.
Background Alpha skeletal muscle actin, encoded by ACTA1, belongs to the highly conserved actin protein family and forms the structural core of the sarcomeric thin filament in adult skeletal muscle, where it polymerizes into a double-helical filament that serves as the myosin-binding track for the contractile cycle. Force generation depends on myosin motor heads extending from the thick filament and cyclically attaching to actin-binding sites along this thin filament, and access to those binding sites is gated by the regulatory proteins troponin and tropomyosin rather than by actin acting alone. At low calcium concentrations, troponin I holds tropomyosin in an inhibitory position on the actin surface that sterically blocks myosin from binding, and calcium binding to troponin C draws troponin I away from tropomyosin, allowing tropomyosin to pivot about relatively fixed points on the actin filament rather than rolling or sliding across it, a repositioning that partially exposes the myosin-binding sites and permits initial weak binding of myosin heads to actin. These weakly bound cross-bridges then transition into strongly bound, force-generating configurations, fully activating the thin filament and completing the calcium-triggered switch from relaxation to contraction, with the reconfiguration of the troponin-tropomyosin complex on the actin surface acting as the central mechanistic event coupling calcium signaling to mechanical force output. Point mutations in ACTA1 disrupt this cycle directly at the level of the actin-myosin interface: the Asp286Gly substitution associated with nemaline myopathy modifies the actin-actin interface within the filament and prevents myosin cross-bridges from transitioning properly into the strong-binding state, acting as a poison-protein that limits the fraction of actomyosin interactions capable of generating force and producing measurable muscle weakness at the level of single permeabilized fibers. ACTA1 mutations are established as a cause of a spectrum of congenital myopathies, including nemaline myopathy, intranuclear rod myopathy, and actin filament aggregate myopathy, and the diversity of these histopathological presentations reflects the range of ways a mutant actin monomer can disrupt filament assembly, actin-actin packing, or myosin engagement without abolishing incorporation into the sarcomere altogether. Because the mutant actin often incorporates alongside wild-type actin within the same thin filament, the resulting functional deficit depends on the specific structural consequence of each variant, making ACTA1 a target where genotype-phenotype correlation, cross-bridge kinetics, and thin filament activation mechanics are directly relevant to understanding disease severity and to evaluating candidate therapeutic strategies aimed at restoring proper actin-myosin engagement.

Usage Information

Application WB, IHC Dilution
WB IHC
1:5000 1:100
Reactivity Mouse, Rat, Human
Source Rabbit Monoclonal Antibody MW 42 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 Tris-Triton 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 Tris-Triton 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 Tris-Triton 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 1:1000), 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.
IHC
Experimental Protocol:
 
Deparaffinization/Rehydration
1. Deparaffinize/hydrate sections:
2. Incubate sections in three washes of xylene for 5 min each.
3. Incubate sections in two washes of 100% ethanol for 10 min each.
4. Incubate sections in two washes of 95% ethanol for 10 min each.
5. Wash sections two times in dH2O for 5 min each.
6.Antigen retrieval: For Citrate: Heat slides in a microwave submersed in 1X citrate unmasking solution until boiling is initiated; continue with 10 min at a sub-boiling temperature (95°-98°C). Cool slides on bench top for 30 min.
 
Staining
1. Wash sections in dH2O three times for 5 min each.
2. Incubate sections in 3% hydrogen peroxide for 10 min.
3. Wash sections in dH2O two times for 5 min each.
4. Wash sections in wash buffer for 5 min.
5. Block each section with 100–400 µl of blocking solution for 1 hr at room temperature.
6. Remove blocking solution and add 100–400 µl primary antibody diluent in to each section. Incubate overnight at 4°C.
7. Remove antibody solution and wash sections with wash buffer three times for 5 min each.
8. Cover section with 1–3 drops HRPas needed. Incubate in a humidified chamber for 30 min at room temperature.
9. Wash sections three times with wash buffer for 5 min each.
10. Add DAB Chromogen Concentrate to DAB Diluent and mix well before use.
11. Apply 100–400 µl DAB to each section and monitor closely. 1–10 min generally provides an acceptable staining intensity.
12. Immerse slides in dH2O.
13. If desired, counterstain sections with hematoxylin.
14. Wash sections in dH2O two times for 5 min each.
15. Dehydrate sections: Incubate sections in 95% ethanol two times for 10 sec each; Repeat in 100% ethanol, incubating sections two times for 10 sec each; Repeat in xylene, incubating sections two times for 10 sec each.
16. Mount sections with coverslips and mounting medium.
 

References

  • https://pubmed.ncbi.nlm.nih.gov/37249525/
  • https://pubmed.ncbi.nlm.nih.gov/23029319/

Application Data

WB

Validated by Selleck

  • F5510-wb
    Lane 1: Mouse skeletal muscle, Lane 2: Rat skeletal muscle