SCUBE3 Antibody

What is SCUBE3 and what are its key structural domains?

SCUBE3 is a secreted glycoprotein belonging to the SCUBE family of proteins. It contains a N-terminal signal peptide sequence, multiple EGF-like domains, an N-linked glycosylated spacer region, and a C-terminal CUB domain . The protein is 993 amino acids in length with a calculated molecular weight of approximately 109 kDa, though it is often observed at around 130 kDa in Western blots due to post-translational modifications . SCUBE3 forms homo-oligomers and can also form hetero-oligomers with SCUBE1, and may undergo C-terminal proteolytic cleavage following translation .

What is the biological function of SCUBE3?

SCUBE3 functions as a BMP2/BMP4 co-receptor that recruits BMP receptor complexes into raft microdomains and positively modulates signaling by augmenting specific interactions between BMPs and BMP type I receptors . It also binds to TGFBR2 and activates TGF-β signaling, potentially serving as an endogenous autocrine and paracrine ligand of TGFBR2 . In lung cancer cells, SCUBE3 protein can be cleaved by MMP2 and MMP9, leading to TGF-β receptor activation, increased Smad2/3 transcriptional activity, and upregulation of proteins such as TGF-β1, VEGF, Snail, and Slug . Additionally, SCUBE3 has been implicated in zebrafish fast fiber myogenesis by modulating fgf8 signaling during embryogenesis .

Where is SCUBE3 expressed in normal tissues?

SCUBE3 is highly expressed in primary osteoblasts and bones, making it an important protein in bone cell biology . It is also expressed to a lesser extent in the heart, with studies showing that overexpression of SCUBE3 in mice induced cardiac hypertrophy, suggesting a role in cardiac growth regulation . The gene encoding SCUBE3 maps to human chromosome 6p21.31, a region associated with a rare form of metabolic bone disease known as Paget's disease .

SCUBE3 Antibody Technical Specifications

For optimal performance, SCUBE3 antibodies should generally be stored at -20°C for long-term stability (up to one year) . Some antibodies can be stored at 4°C for up to three months . It is important to avoid repeated freeze/thaw cycles to maintain antibody integrity. Most SCUBE3 antibodies are supplied in PBS buffer containing preservatives such as 0.02% sodium azide and stabilizers like 50% glycerol at pH 7.3-7.4 . For antibodies provided in small volumes (e.g., 20μl), some manufacturers indicate that aliquoting is unnecessary for -20°C storage . Always refer to the manufacturer's specific storage and handling recommendations for your particular antibody.

What are the validated applications for SCUBE3 antibodies?

SCUBE3 antibodies have been validated for multiple experimental applications:

• Western Blotting (WB): Most antibodies are validated for WB with recommended dilutions ranging from 1:200-1:1000 .

• Enzyme-Linked Immunosorbent Assay (ELISA): Several antibodies are validated for ELISA applications with typical dilutions of 1:500-1:1000 .

• Immunohistochemistry (IHC): Both paraffin-embedded (IHC-P) and frozen sections (IHC-F) can be analyzed using various SCUBE3 antibodies with recommended dilutions of 1:20-1:200 .

• Immunocytochemistry (ICC): Several antibodies are suitable for detecting SCUBE3 in cultured cells .

• Immunofluorescence (IF): Both cell and tissue immunofluorescence applications are validated for some SCUBE3 antibodies .

The specific applications validated for each antibody vary, so researchers should check the manufacturer's specifications for their antibody of interest.

How can I optimize antigen retrieval for SCUBE3 immunohistochemistry?

For optimal SCUBE3 detection in tissue sections, proper antigen retrieval is crucial. According to the search results, TE buffer at pH 9.0 is recommended for antigen retrieval in IHC applications . Alternatively, citrate buffer at pH 6.0 can be used if TE buffer does not provide satisfactory results. The specific antigen retrieval method may need to be optimized depending on tissue fixation conditions, tissue type, and the specific epitope targeted by the antibody. For bone tissues, which highly express SCUBE3, additional considerations for decalcification protocols may be necessary to ensure proper antigen exposure while maintaining tissue morphology. Always include positive control tissues (such as human kidney tissue, which has been validated for SCUBE3 IHC) to confirm the efficacy of your antigen retrieval protocol .

What is the expected molecular weight of SCUBE3 in Western blots?

• Approximately 130 kDa as reported by Proteintech (antibody 16773-1-AP)

• Around 68 kDa as reported by Boster Bio (antibody A09090)

This discrepancy between calculated and observed molecular weights may be attributed to several factors:

• Post-translational modifications, particularly N-glycosylation, as SCUBE3 is a secreted glycoprotein

• Proteolytic processing that SCUBE3 may undergo, especially in different cellular contexts

• Alternative splicing, as some sources indicate the existence of multiple SCUBE3 isoforms

When performing Western blots, it is advisable to include appropriate positive controls to confirm the specific band corresponding to SCUBE3 in your experimental system.

How can SCUBE3 antibodies be used to study developmental disorders?

SCUBE3 loss-of-function has been associated with a recognizable recessive developmental disorder characterized by reduced growth, skeletal features, distinctive craniofacial appearance, and dental anomalies . SCUBE3 antibodies can be instrumental in studying these disorders through several approaches:

• Comparative expression analysis: Using antibodies to compare SCUBE3 expression patterns between normal and affected tissues can reveal dysregulated expression associated with developmental abnormalities.

• Functional validation studies: Antibodies can help evaluate the impact of disease-causing variants on protein synthesis, secretion, and function. Studies have shown that disease-causing variants have variable impacts on transcript processing, protein secretion and function, and disrupt BMP signaling regulation .

• Pathway analysis: Since SCUBE3 acts as a BMP2/BMP4 co-receptor and positively modulates signaling, antibodies can be used to study how mutations affect the recruitment of BMP receptor complexes into raft microdomains and the subsequent signaling cascade.

• Animal model validation: In Scube3-/- mice, which show craniofacial and dental defects, reduced body size, and defective endochondral bone growth due to impaired BMP-mediated chondrogenesis and ossification, antibodies can be used to validate the disease mechanisms and potential therapeutic interventions .

What role does SCUBE3 play in cancer, and how can antibodies help investigate this?

SCUBE3 has been implicated in cancer progression, particularly in lung cancer where it promotes cell mobility and invasiveness . SCUBE3 antibodies can be valuable tools for investigating its role in cancer through several methodological approaches:

• Expression profiling: Antibodies can be used to assess SCUBE3 expression levels and patterns across different cancer types and stages through immunohistochemistry and tissue microarray analysis.

• Mechanism studies: Since SCUBE3 has been shown to be an endogenous TGF-β receptor ligand in lung cancer cells, antibodies can help investigate the activation of TGF-β receptor signaling pathways. In these cells, secreted SCUBE3 protein is cleaved by MMP2 and MMP9, which activates the TGF-β receptor, increases Smad2/3 transcriptional activity, and upregulates expression of proteins such as TGF-β1, VEGF, Snail, and Slug .

• Functional blockade: Neutralizing antibodies against SCUBE3 could potentially block its interaction with receptors, providing insights into its necessity for cancer cell migration and invasion.

• Biomarker development: SCUBE3 antibodies could be used to develop diagnostic or prognostic assays if expression levels correlate with disease progression or treatment response.

How can I study SCUBE3 interactions with FGF8 and FGFR4?

Research has shown that SCUBE3 specifically interacts with FGF8 and FGFR4, but not FGFR1, on the plasma membrane . To study these interactions:

• Co-immunoprecipitation: Use SCUBE3 antibodies to pull down protein complexes and then probe for FGF8 or FGFR4 to confirm physical interactions.

• Confocal immunofluorescence: Utilize SCUBE3 antibodies in combination with FGF8 or FGFR4 antibodies to examine co-localization at the plasma membrane, as has been previously demonstrated .

• Luciferase reporter assays: Assess the functional impact of SCUBE3 on FGF8 signaling using FGF-responsive luciferase reporters such as FiRE-Luc, which has been used to show that SCUBE3 affects FGF8 signaling .

• Knockdown validation: Use SCUBE3 shRNA approaches (as demonstrated in C2C12 myoblasts) to confirm the specificity of antibody detection and to assess the effect of SCUBE3 depletion on FGFR4 expression, which has been shown to be specifically downregulated after SCUBE3 knockdown .

What controls should I include when using SCUBE3 antibodies?

To ensure the reliability and specificity of SCUBE3 antibody detection, several controls should be included:

• Positive tissue controls: Mouse kidney tissue, mouse lung tissue, and human kidney tissue have been validated as positive controls for SCUBE3 detection .

• Blocking peptide controls: For some antibodies, competing peptides corresponding to the immunogen are available and can be used to confirm antibody specificity .

• Knockdown/knockout controls: SCUBE3 shRNA or knockout models provide excellent negative controls to validate antibody specificity .

• Cross-reactivity controls: Check for potential cross-reactivity with other SCUBE family members (SCUBE1, SCUBE2). Some antibodies specifically note no cross-reactivity with other family members .

• Isotype controls: Use an irrelevant antibody of the same isotype and host species as the SCUBE3 antibody to control for non-specific binding.

• Secondary antibody controls: Omit the primary antibody to assess background from the detection system.

How can I troubleshoot weak or non-specific signals in SCUBE3 Western blots?

When experiencing issues with SCUBE3 detection in Western blots:

• For weak signals:

  • Increase antibody concentration (try 1:200 instead of 1:1000)

  • Extend incubation time (overnight at 4°C)

  • Use more sensitive detection methods (chemiluminescent substrates with longer exposure times)

  • Enrich for SCUBE3 by immunoprecipitation before Western blotting

  • Ensure sample preparation preserves SCUBE3 (especially important for secreted proteins)

• For non-specific bands:

  • Optimize blocking conditions (try different blocking agents: 5% BSA vs. 5% non-fat milk)

  • Increase washing stringency (more washes, higher salt concentration)

  • Use the appropriate molecular weight reference (SCUBE3 may appear at 68 kDa or 130 kDa depending on the antibody and sample)

  • Use positive controls to identify the correct band

  • Consider using blocking peptides to identify specific bands

• For high background:

  • Dilute the antibody further

  • Reduce exposure time

  • Use fresher antibody (avoid degraded antibodies)

  • Ensure thorough washing between steps

What information should I report when publishing research using SCUBE3 antibodies?

When publishing research involving SCUBE3 antibodies, include the following information to ensure reproducibility:

• Complete antibody information:

  • Manufacturer and catalog number (e.g., Proteintech 16773-1-AP)

  • Host species and clonality (e.g., rabbit polyclonal)

  • Immunogen information (e.g., amino acids 807-993 of human SCUBE3)

• Experimental details:

  • Dilution used for each application

  • Antigen retrieval method for IHC (e.g., TE buffer pH 9.0 or citrate buffer pH 6.0)

  • Incubation conditions (time, temperature)

  • Detection method

• Validation procedures:

  • Controls used (positive, negative, blocking peptides)

  • Verification of specificity (e.g., knockdown validation)

• Complete raw data or representative images:

  • For Western blots: include molecular weight markers

  • For IHC/ICC: include scale bars and magnification information

This comprehensive reporting ensures that other researchers can reproduce and build upon your findings.