BLOC1S3 Antibody Protocol: WB, IHC & IF Applications

BLOC1S3 Antibody is a key immunological tool for detecting and localizing the BLOC1S3 protein, a subunit of the biogenesis of lysosome-related organelles complex-1 (BLOC-1), enabling researchers to investigate lysosomal trafficking, organelle biogenesis, and related pathological mechanisms.

Product SKU

Ab349731

Target Protein

BLOC1S3 (Biogenesis of Lysosome-Related Organelles Complex-1, Subunit 3)

Recommended Applications

Western Blot (WB), Immunohistochemistry (IHC), Immunofluorescence (IF)

Supplier Reference

absea#OC-662

Protein Function

BLOC1S3 is a subunit of BLOC-1 complex involved in the biogenesis of lysosome-related organelles such as melanosomes and platelet dense granules

Storage Recommendation

Store at -20°C; avoid repeated freeze-thaw cycles

Background: BLOC1S3 and the BLOC-1 Complex

BLOC1S3 (Biogenesis of Lysosome-Related Organelles Complex-1, Subunit 3) encodes a protein subunit of the BLOC-1 complex, a hetero-octameric assembly essential for the biogenesis of lysosome-related organelles (LROs) such as melanosomes in melanocytes and dense granules in platelets. Mutations or dysregulation of BLOC-1 subunits, including BLOC1S3, are associated with Hermansky-Pudlak Syndrome (HPS), a rare autosomal recessive disorder characterized by oculocutaneous albinism, bleeding diathesis, and, in some subtypes, pulmonary fibrosis. Reliable detection of BLOC1S3 protein expression is therefore important for studies of organelle trafficking, pigmentation disorders, and platelet function research.

Materials and Reagents

Before beginning, ensure the following materials are available:

• BLOC1S3 Antibody (Ab349731) — Aladdin Scientific
• Appropriate cell or tissue lysates, or tissue sections (human, mouse, or rat as applicable)
• SDS-PAGE gel and Western blot transfer apparatus (for WB application)
• PVDF or nitrocellulose membrane
• Blocking buffer: 5% non-fat dry milk or 5% BSA in TBST
• Secondary antibody conjugated to HRP (for WB) or fluorophore (for IF)
• Antigen retrieval buffer (for IHC/IF on FFPE sections): citrate buffer pH 6.0 or EDTA buffer pH 9.0
• PBS and PBST (PBS + 0.1% Tween-20)
• ECL detection reagent (for WB)
• Mounting medium with DAPI (for IF)
• Standard laboratory equipment: centrifuge, gel electrophoresis system, imaging system

Step-by-Step Protocol

Western Blot (WB)

1. Sample preparation: Lyse cells or homogenize tissue in RIPA buffer supplemented with protease inhibitors. Determine protein concentration by BCA or Bradford assay. Load 20–40 µg total protein per lane.
2. Electrophoresis: Resolve proteins on a 12–15% SDS-PAGE gel under reducing conditions, then transfer to PVDF membrane.
3. Blocking: Block membrane for 1 hour at room temperature in 5% non-fat milk in TBST.
4. Primary antibody incubation: Dilute BLOC1S3 Antibody (Ab349731) in blocking buffer at the manufacturer-recommended dilution. Incubate overnight at 4°C with gentle rocking.
5. Washing: Wash membrane 3 × 10 minutes in TBST.
6. Secondary antibody: Incubate with appropriate HRP-conjugated secondary antibody for 1 hour at room temperature.
7. Detection: Wash 3 × 10 minutes in TBST, then apply ECL reagent and image using a chemiluminescence imaging system. Expected band size should correspond to the predicted molecular weight of BLOC1S3.

Immunohistochemistry (IHC)

1. Section preparation: Deparaffinize FFPE sections through xylene and graded ethanol series to water.
2. Antigen retrieval: Heat sections in citrate buffer (pH 6.0) or EDTA buffer (pH 9.0) for 10–20 minutes.
3. Blocking: Block endogenous peroxidase with 3% H₂O₂ for 10 minutes, then block with 5% normal serum in PBS for 30 minutes.
4. Primary antibody: Apply BLOC1S3 Antibody (Ab349731) at recommended dilution; incubate overnight at 4°C in a humidified chamber.
5. Detection: Apply secondary antibody and HRP-polymer detection system. Develop with DAB chromogen, counterstain with hematoxylin, dehydrate, and mount.

Immunofluorescence (IF)

1. Cell fixation: Fix cells on coverslips with 4% paraformaldehyde for 15 minutes at room temperature.
2. Permeabilization: Permeabilize with 0.1–0.3% Triton X-100 in PBS for 10 minutes.
3. Blocking: Block with 5% BSA or normal serum in PBST for 30–60 minutes.
4. Primary antibody: Incubate with BLOC1S3 Antibody (Ab349731) at recommended dilution overnight at 4°C.
5. Secondary antibody: Incubate with fluorophore-conjugated secondary antibody for 1 hour at room temperature, protected from light.
6. Mounting: Wash, then mount coverslips with DAPI-containing mounting medium. Image using confocal or widefield fluorescence microscope.

Troubleshooting and Optimization Tips

• No signal (WB): Verify protein transfer efficiency; try increasing primary antibody concentration or extending incubation time. Confirm target expression in your cell/tissue model.
• High background: Increase washing stringency (more washes, longer duration). Optimize blocking conditions or reduce primary antibody concentration.
• Non-specific bands: Use freshly prepared lysis buffer with phosphatase and protease inhibitors. Confirm correct secondary antibody species compatibility.
• Weak IHC signal: Optimize antigen retrieval method and duration. Consider titrating the primary antibody concentration.
• High autofluorescence (IF): Treat sections with autofluorescence quenching reagent prior to antibody incubation. Ensure fixation time is not excessive.
• Always include positive and negative controls in each experiment to validate antibody performance and exclude technical artifacts.

Data Interpretation and Expected Results

When using BLOC1S3 Antibody (Ab349731) in Western blot applications, a specific band corresponding to the predicted molecular weight of BLOC1S3 protein should be observed. In immunohistochemistry and immunofluorescence experiments, BLOC1S3 signal is expected to localize to intracellular vesicular/endosomal compartments consistent with its role in BLOC-1 complex function and lysosome-related organelle biogenesis. Researchers should always compare signals with appropriate negative controls (primary antibody omitted) and, where available, with knockdown or knockout cell lines to confirm specificity. Any unexpected band sizes or staining patterns should be noted and further validated.

Frequently asked questions

What applications is the BLOC1S3 Antibody (Ab349731) validated for?

The BLOC1S3 Antibody (Ab349731) is recommended for use in Western blot (WB), immunohistochemistry (IHC), and immunofluorescence (IF) applications. Users should confirm optimal working dilutions empirically for their specific experimental system.

What is the biological role of BLOC1S3, and why is it important to study?

BLOC1S3 is a subunit of the BLOC-1 complex, which is required for the normal biogenesis of lysosome-related organelles such as melanosomes and platelet dense granules. Mutations in BLOC1S3 are linked to Hermansky-Pudlak Syndrome, making it a relevant target in studies of pigmentation disorders, platelet biology, and lysosomal trafficking pathways.

How should the BLOC1S3 Antibody be stored to maintain activity?

It is generally recommended to store antibodies such as Ab349731 at -20°C and to avoid repeated freeze-thaw cycles, which can degrade antibody performance. For short-term use, aliquoting upon receipt and storing at 4°C for up to one month is typically acceptable. Always refer to the product datasheet for specific storage instructions.

What controls should be included when using BLOC1S3 Antibody?

Researchers should include a no-primary-antibody negative control to assess non-specific secondary antibody binding, and a positive control using a cell line or tissue known to express BLOC1S3. Where possible, a BLOC1S3 knockdown or knockout sample should be used to definitively confirm antibody specificity.

Can this antibody be used across multiple species?

Species reactivity depends on the specific immunogen and validation data for Ab349731. Users should consult the product datasheet to confirm which species (e.g., human, mouse, rat) have been validated. Cross-reactivity with non-validated species should be empirically tested before use.

References

1. Starcevic M, Dell'Angelica EC. Identification of snapin and three novel proteins (BLOS1, BLOS2, and BLOS3/reduced pigmentation) as subunits of biogenesis of lysosome-related organelles complex-1 (BLOC-1). J Biol Chem. 2004;279(27):28393-28401. doi:10.1074/jbc.M402435200
2. Di Pietro SM, Dell'Angelica EC. The biogenesis of lysosomes and lysosome-related organelles, one cargo at a time. Traffic. 2005;6(7):525-533. doi:10.1111/j.1600-0854.2005.00294.x
3. Huizing M, Helip-Wooley A, Westbroek W, Gunay-Aygun M, Gahl WA. Disorders of lysosome-related organelle biogenesis: clinical and molecular genetics. Annu Rev Genomics Hum Genet. 2008;9:359-386. doi:10.1146/annurev.genom.9.081307.164303

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.