Prss22 Antibody

What is PRSS22 and why are antibodies against it important?

PRSS22 (Brain-specific serine protease 4) is an enzyme encoded by the PRSS22 gene in humans. It belongs to the trypsin family of serine proteases and is expressed in airways in a developmentally regulated manner . PRSS22 has recently gained significance as it is upregulated in breast cancer tissues compared to non-tumorous breast tissues . Antibodies against PRSS22 are important research tools because they enable detection, quantification, and functional analysis of this protein in various experimental contexts including western blotting, immunohistochemistry, and ELISA assays. These antibodies facilitate investigations into PRSS22's role in cancer progression and potential as a therapeutic target or biomarker.

What alternative names should researchers recognize for PRSS22?

When searching literature or ordering reagents, researchers should be aware that PRSS22 is known by several alternative designations:

• Brain-specific serine protease 4 (BSSP-4)

• BSSP4

• Serine protease 22

• Serine protease 26 (PRSS26)

• Tryptase epsilon

• SP001LA

• UNQ302/PRO343

This nomenclature diversity can sometimes cause confusion in literature searches or when ordering research reagents, so awareness of these alternative names ensures comprehensive research coverage.

What is the molecular weight and expected band size for PRSS22 in Western blots?

When performing Western blot analysis for PRSS22, researchers should expect to detect a band at approximately 34 kDa, which is the predicted molecular weight of the protein . This information is critical for proper identification of PRSS22 in experimental samples and distinguishing it from non-specific bands. When using human fetal lung lysate as a positive control, anti-PRSS22 antibody at 1/1000 dilution has been shown to effectively detect this 34 kDa band .

What types of anti-PRSS22 antibodies are commercially available?

The most common type documented in the research literature is rabbit polyclonal anti-PRSS22 antibody. These antibodies are typically generated against recombinant fragment protein within Human PRSS22 amino acid region 50-300 . This specific epitope selection is important for ensuring antibody specificity. The antibodies are generally suitable for Western blot (WB) and immunohistochemistry-paraffin (IHC-P) applications and have been validated to react with human samples . When selecting an antibody, researchers should consider the intended application, species reactivity, and the specific epitope recognized.

How should researchers validate a new PRSS22 antibody?

Validation of a new PRSS22 antibody should follow these methodological steps:

• Positive control selection: Use tissues or cells known to express PRSS22, such as human fetal lung or pancreas tissue .

• Application-specific validation:

  • For Western blot: Confirm single band at expected molecular weight (34 kDa)

  • For IHC-P: Compare staining pattern with known expression patterns

  • For ELISA: Establish standard curve with recombinant PRSS22 protein

• Specificity testing:

  • Test in PRSS22 knockout/knockdown samples

  • Perform peptide competition assays

  • Compare results with alternative antibodies targeting different epitopes

• Reproducibility assessment: Validate consistent results across multiple experiments under standardized conditions.

This systematic validation approach ensures reliable antibody performance in subsequent experiments.

What positive and negative controls are recommended for PRSS22 antibody testing?

Based on the available research data, recommended controls include:

Positive controls:

• Human fetal lung lysate for Western blot applications

• Human fetal pancreas tissue for immunohistochemistry applications

• Recombinant PRSS22 protein for ELISA standardization

Negative controls:

• Tissues known not to express PRSS22

• Samples treated with PRSS22-targeting siRNA or CRISPR knockout cells

• Isotype control antibodies for immunostaining

• Primary antibody omission controls

Using appropriate controls helps distinguish specific from non-specific signals and validates experimental results.

What are the optimal conditions for Western blotting with PRSS22 antibody?

For optimal Western blot detection of PRSS22, researchers should follow these methodological guidelines:

• Sample preparation: Prepare protein lysates from tissues or cells under denaturing conditions. Human fetal lung lysate serves as an effective positive control .

• Protein loading: Load 20-50 μg of total protein per lane.

• Antibody dilution: Use anti-PRSS22 antibody at 1/1000 dilution, though optimization may be required for different antibody lots .

• Expected results: Look for a distinct band at approximately 34 kDa, which is the predicted molecular weight of PRSS22 .

• Troubleshooting considerations:

  • Multiple bands may indicate protein degradation or post-translational modifications

  • Absence of signal may require increased antibody concentration or enhanced detection systems

This methodology provides a starting point that should be optimized for specific experimental conditions.

How should researchers perform immunohistochemistry using PRSS22 antibody?

For successful immunohistochemical detection of PRSS22 in tissue sections:

• Sample preparation: Use formalin-fixed, paraffin-embedded tissue sections (4-6 μm thickness).

• Antigen retrieval: Perform heat-induced epitope retrieval (HIER) using citrate buffer (pH 6.0) or other buffers as recommended by the antibody manufacturer.

• Antibody dilution: Start with 1/100 dilution of anti-PRSS22 antibody for paraffin sections . Optimize as needed.

• Detection system: Use an appropriate secondary antibody and detection system compatible with the host species of the primary antibody.

• Controls: Include human fetal pancreas tissue as a positive control . Always run parallel negative controls (primary antibody omitted).

• Evaluation: Assess both staining intensity and subcellular localization of PRSS22.

This protocol provides a foundation that should be adjusted based on specific tissue types and research questions.

What is the methodology for PRSS22 ELISA assays?

PRSS22 can be detected and quantified using double antibody-sandwich ELISA methods with the following protocol:

• Assay principle: The microplate is pre-coated with anti-PRSS22 antibody. Standards and samples are added to wells where PRSS22 binds to the immobilized antibody. After washing, biotinylated detection antibody is added, which binds to captured PRSS22. HRP-Streptavidin Conjugate (SABC) is added, followed by TMB substrate solution which generates a colorimetric reaction proportional to PRSS22 concentration .

• Sample types: Suitable for serum, plasma, cell culture supernatant, cell/tissue lysates, and other liquid samples .

• Performance characteristics:

  • Detection range: 0.156-10 ng/ml or 5-80 pg/ml (kit dependent)

  • Sensitivity: 0.094 ng/ml or 0.5 pg/ml (kit dependent)

  • Intra-assay precision: CV% <9%

  • Inter-assay precision: CV% <11%

• Data analysis: Calculate concentration using four-parameter logistic (4-PL) curve fit .

This standardized approach allows for reliable quantification of PRSS22 in experimental and clinical samples.

How does PRSS22 contribute to breast cancer metastasis?

PRSS22 promotes breast cancer metastasis through a multi-step molecular mechanism:

• Expression pattern: PRSS22 is upregulated in breast cancer tissues compared to non-tumorous breast tissues .

• Functional impact: Upregulation of PRSS22 promotes invasion and metastasis of breast cancer cells both in vitro and in vivo, while knockdown of PRSS22 inhibits these processes .

• Molecular mechanism: PRSS22 interacts with ANXA1 (Annexin A1) protein, as confirmed by protein mass spectrometry analysis, co-immunoprecipitation (Co-IP), and western blot assays .

• Signaling pathway activation: PRSS22 promotes the cleavage of ANXA1, generating an N-terminal peptide that initiates the FPR2/ERK signaling axis, ultimately increasing breast cancer aggressiveness .

This mechanistic pathway highlights PRSS22 as a potential therapeutic target for preventing breast cancer metastasis.

What is the relationship between E2F1 transcription factor and PRSS22 expression?

E2F1 directly regulates PRSS22 expression through the following mechanism:

• Transcriptional activation: E2F1 directly binds to the PRSS22 promoter region and activates its transcription .

• Experimental evidence: This regulatory relationship has been established through multiple complementary approaches:

  • Dual luciferase assays

  • Bioinformatics analyses

  • Chromatin immunoprecipitation (ChIP) assays

• Functional significance: This finding establishes E2F1 as an upstream regulator in the PRSS22-mediated cancer progression pathway, suggesting that aberrant E2F1 activity in cancer may contribute to increased PRSS22 expression and subsequent metastatic potential .

This regulatory relationship provides additional insight into the transcriptional control of PRSS22 in cancer contexts.

How can PRSS22 antibodies be used to investigate the PRSS22-ANXA1-FPR2-ERK signaling axis?

PRSS22 antibodies serve as essential tools for investigating this signaling axis through multiple experimental approaches:

• Protein-protein interaction studies:

  • Co-immunoprecipitation using PRSS22 antibodies to pull down ANXA1 and associated proteins

  • Proximity ligation assays to visualize PRSS22-ANXA1 interactions in situ

• Functional analysis:

  • Western blotting to detect PRSS22-mediated cleavage of ANXA1

  • Immunofluorescence to examine co-localization of pathway components

  • ELISA to quantify protein levels in experimental conditions

• Pathway activation monitoring:

  • Western blotting for phosphorylated ERK following PRSS22 manipulation

  • Immunohistochemistry to correlate PRSS22 expression with pathway activation markers in tissue samples

• Therapeutic response assessment:

  • Measuring changes in PRSS22 and pathway components following experimental treatments

These approaches enable comprehensive investigation of how PRSS22 initiates this signaling cascade to promote cancer aggressiveness.

What are common issues with Western blotting for PRSS22 detection?

Researchers may encounter several challenges when detecting PRSS22 by Western blot:

• Multiple bands: PRSS22 may display multiple bands due to:

  • Post-translational modifications

  • Proteolytic processing

  • Alternatively spliced isoforms

  • Cross-reactivity with other serine proteases

• Weak signal: May result from:

  • Low PRSS22 expression in samples

  • Inefficient protein transfer

  • Suboptimal antibody concentration

  • Protein degradation during sample preparation

• High background: Could be caused by:

  • Insufficient blocking

  • Excessive antibody concentration

  • Inadequate washing

  • Non-specific binding

• Troubleshooting approaches:

  • Optimize protein extraction protocols

  • Test different antibody concentrations (start with 1/1000 dilution)

  • Include positive control (human fetal lung lysate)

  • Adjust blocking and washing conditions

Addressing these issues systematically improves the specificity and sensitivity of PRSS22 detection.

How can researchers improve specificity in PRSS22 ELISA assays?

To enhance specificity in PRSS22 ELISA assays, consider these methodological approaches:

• Sample preparation optimization:

  • Minimize matrix effects by appropriate dilution

  • Consider sample pre-treatment steps

  • Use recommended sample collection and storage procedures

• Assay execution:

  • Strictly follow the 4-hour assay protocol for double antibody-sandwich ELISA

  • Maintain precise incubation times and temperatures

  • Perform thorough washing between steps

• Controls implementation:

  • Include spike recovery tests

  • Run dilution linearity assessments

  • Use both high and low concentration controls

• Data analysis refinement:

  • Apply appropriate curve fitting (4-PL model recommended)

  • Establish acceptance criteria for standard curves

  • Validate results in the 0.156-10 ng/ml range

These approaches help minimize cross-reactivity with other analytes while maximizing PRSS22 detection sensitivity.

What factors affect immunohistochemical detection of PRSS22 in tissue samples?

Several factors can influence the quality of PRSS22 immunohistochemical staining:

• Tissue preparation factors:

  • Fixation type and duration

  • Processing conditions

  • Section thickness

  • Storage time of cut sections

• Antigen retrieval considerations:

  • Method selection (heat vs. enzymatic)

  • Buffer composition and pH

  • Duration and temperature

• Antibody-related factors:

  • Antibody concentration (start with 1/100 dilution)

  • Incubation time and temperature

  • Detection system sensitivity

  • Secondary antibody selection

• Tissue-specific considerations:

  • Endogenous peroxidase activity

  • Non-specific binding sites

  • Autofluorescence (for immunofluorescence)

  • Tissue-specific expression levels of PRSS22

Optimization of these parameters is essential for achieving specific and reproducible PRSS22 immunostaining in different tissue types.

How can PRSS22 antibodies be used in combination with other methods to study enzymatic activity?

Integrating PRSS22 antibodies with enzymatic assays provides comprehensive insights:

• Immunoprecipitation-activity assays:

  • Use PRSS22 antibodies to isolate the protein from complex samples

  • Measure enzymatic activity using the synthetic substrate H-D-Leu-Thr-Arg-pNA

  • Compare activity across different experimental conditions

• Activity-based protein profiling:

  • Combine activity-based probes with PRSS22 immunodetection

  • Distinguish active enzyme from inactive forms

  • Monitor changes in enzyme activity without altering protein levels

• Inhibitor screening applications:

  • Use antibodies to confirm target engagement of potential inhibitors

  • Correlate inhibition of enzymatic activity with phenotypic outcomes

  • Identify protein-protein interactions affected by inhibitor binding

• Substrate identification:

  • Combine PRSS22 overexpression/knockdown with antibody-based detection of potential substrates

  • Validate ANXA1 cleavage patterns using site-specific antibodies

  • Identify novel substrates through proteomics approaches

These integrated approaches provide mechanistic understanding beyond simple protein expression analysis.

What is the potential for PRSS22 as a biomarker in cancer diagnosis and prognosis?

PRSS22 shows promise as a cancer biomarker for several reasons:

• Expression pattern:

  • Upregulated in breast cancer tissues compared to non-tumorous tissues

  • Association with metastatic processes suggests potential prognostic value

• Detection methods:

  • Quantifiable by ELISA in various sample types with high sensitivity (0.094-0.5 pg/ml)

  • Detectable in tissues by immunohistochemistry using validated antibodies

  • Western blot analysis provides molecular weight confirmation

• Biological significance:

  • Mechanistic link to invasion and metastasis through ANXA1-FPR2-ERK signaling

  • E2F1-mediated transcriptional regulation provides connections to cell cycle control pathways

• Clinical application considerations:

  • Could help identify patients at higher risk for metastasis

  • Potential companion diagnostic for therapies targeting this pathway

  • May enhance current prognostic models when combined with other markers

Further clinical validation studies with larger patient cohorts are needed to establish definitive clinical utility.

What novel therapeutic strategies might target the PRSS22-ANXA1-FPR2-ERK pathway?

Research on PRSS22's role in cancer progression suggests several therapeutic approaches:

• Direct PRSS22 inhibition:

  • Small molecule inhibitors targeting the catalytic site

  • Biological inhibitors that prevent PRSS22-substrate interactions

  • Development of specific inhibitors based on substrate preference for H-D-Leu-Thr-Arg-pNA

• Blocking PRSS22-ANXA1 interaction:

  • Peptide-based inhibitors mimicking interaction domains

  • Small molecules disrupting protein-protein binding

  • Antibody-based therapeutics targeting interaction interfaces

• Downstream pathway intervention:

  • FPR2 antagonists preventing binding of cleaved ANXA1 N-terminal peptides

  • ERK pathway inhibitors blocking the ultimate signaling output

  • Combination approaches targeting multiple pathway components

• Transcriptional regulation:

  • Approaches targeting E2F1-mediated activation of PRSS22 transcription

  • Epigenetic modulators affecting PRSS22 promoter accessibility

• Antibody-drug conjugates:

  • PRSS22-targeting antibodies conjugated to cytotoxic agents

  • Selective delivery to PRSS22-overexpressing cancer cells

These strategies represent promising avenues for therapeutic development targeting this newly characterized pathway in cancer progression.