Cleaved-KLK11 (I54) Antibody

What is the Cleaved-KLK11 (I54) Antibody and what does it specifically detect?

The Cleaved-KLK11 (I54) Polyclonal Antibody is a specialized research tool that detects endogenous levels of fragment of activated KLK11 protein resulting from cleavage adjacent to isoleucine at position 54 (I54). This antibody was developed using synthesized peptides derived from human Kallikrein-11 in the amino acid range 35-84 as immunogens . It specifically recognizes the cleaved, activated form of KLK11, making it particularly useful for studying KLK11 activation in biological samples.

What are the recommended applications for the Cleaved-KLK11 (I54) Antibody?

The antibody has been validated for Western Blot analysis with recommended dilutions of 1/500 - 1/2000 and for ELISA applications at a dilution of 1/10000 . While these are the established applications, researchers should note that the antibody may function in other assays but requires validation for those specific applications. When using this antibody in Western Blot applications, researchers should expect to detect the cleaved fragment of KLK11 that results from proteolytic processing at the I54 position.

What is known about KLK11's enzymatic activity and specificity?

KLK11 exhibits dual specificity, demonstrating both trypsin-like and chymotrypsin-like cleavage activities . This means KLK11 can cleave after positively charged amino acids (arginine or lysine) like trypsin, but also shows activity toward hydrophobic amino acids like chymotrypsin. This dual specificity is relatively uncommon among kallikreins, as only KLK1, KLK11, and KLK14 display this characteristic . This information is particularly relevant when designing experiments to study KLK11 substrates or when developing inhibitors against its activity.

Table 1: Specificity classification of KLK11 compared to other kallikreins and methods used for determination .

How should I optimize Western Blot protocols when using the Cleaved-KLK11 (I54) Antibody?

When optimizing Western Blot protocols with the Cleaved-KLK11 (I54) Antibody, consider the following methodological approach:

• Sample preparation: Extract proteins using buffers containing protease inhibitors to prevent artificial proteolysis.

• Dilution optimization: Begin with the recommended 1/1000 dilution, then adjust based on signal strength.

• Blocking optimization: Use 5% BSA in PBS to reduce background (the antibody formulation contains BSA) .

• Controls: Include both cleaved and uncleaved KLK11 samples to verify specificity.

• Expected results: Look for specific bands representing the cleaved fragment of KLK11 resulting from processing at I54.

The antibody is provided at a concentration of 1 mg/ml in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide . This formulation ensures stability during storage at -20°C with an expected shelf life of approximately one year.

What are the best experimental approaches to study KLK11 activation in tissue samples?

To effectively study KLK11 activation in tissue samples:

• Tissue processing: Snap-freeze tissues immediately after collection to preserve the activation state of proteases.

• Extraction protocol: Use a combination of TRIzol reagent and RNA isolation kits for gene expression studies, as documented in KLK11 breast cancer research .

• Protein extraction: For protein studies, use buffers containing protease inhibitor cocktails that don't inhibit serine proteases if you're studying active KLK11.

• Multiple detection methods: Employ both the Cleaved-KLK11 (I54) Antibody for protein detection and RT-PCR for transcript analysis.

• RT-PCR protocol: For gene expression studies, follow validated protocols using primers such as:

  • KLK11 forward: 5'-CCG CTA CAT AGT TCA CCT GG-3'

  • KLK11 reverse: 5'-AGG TGT GAG GCA GGC GTA ACT-3'

How can I validate the specificity of the Cleaved-KLK11 (I54) Antibody in my experimental system?

To rigorously validate the specificity of the Cleaved-KLK11 (I54) Antibody:

• Peptide competition assay: Pre-incubate the antibody with excess immunizing peptide before application to samples. Specific signals should disappear or significantly decrease.

• Recombinant protein controls: Test the antibody against recombinant KLK11 in both uncleaved and cleaved forms.

• Knockout/knockdown validation: Compare signals between KLK11 knockout/knockdown samples and wild-type controls.

• Mass spectrometry correlation: Confirm the presence of cleaved KLK11 fragments in your samples using mass spectrometry approaches similar to those used in kallikrein activation studies .

• Cross-reactivity assessment: Test for potential cross-reactivity with other kallikreins, particularly those with similar cleavage sites or sequence homology.

How can the Cleaved-KLK11 (I54) Antibody be utilized to investigate KLK11's role in cancer progression?

The Cleaved-KLK11 (I54) Antibody provides a powerful tool for investigating KLK11's role in cancer progression through several methodological approaches:

• Expression correlation analysis: Compare cleaved KLK11 levels across tumor stages and grades using immunohistochemistry or Western blot analysis.

• Prognostic biomarker evaluation: Recent research has identified associations between KLK11 expression and breast cancer prognostic features, including significant down-regulation in elderly patients and those with perineural invasion .

• Activation pathway mapping: Use the antibody to identify upstream proteases responsible for KLK11 activation in cancer microenvironments.

• Substrate identification: Combine the antibody with proteomics approaches to identify cancer-relevant substrates of activated KLK11.

• Therapeutic response monitoring: Assess changes in cleaved KLK11 levels in response to various therapeutic interventions.

Research has shown that changes in KLK11 expression correlate with tumor size, grade, mitotic score, necrosis, calcification, lymphatic invasion, hormone receptor status, and Ki67 expression in breast cancer , suggesting complex roles in cancer biology that warrant further investigation.

What is known about the post-translational modifications of KLK11 and how might they affect antibody recognition?

Post-translational modifications significantly impact KLK11 function and antibody recognition:

• Proteolytic processing: KLK11 undergoes specific proteolytic activation. Matrix metalloproteinase-20 (MMP-20) has been shown to correctly process pro-KLK11 at the P1-P1' position, generating the mature active enzyme . The Cleaved-KLK11 (I54) Antibody specifically recognizes this activated form.

• Glycosylation impacts: Like other kallikreins, KLK11 may undergo glycosylation, potentially affecting antibody epitope accessibility. Research on kallikreins broadly indicates that glycosylation can modulate enzymatic activity and protein-protein interactions .

• Cofactor interactions: Heparan sulfate and other cofactors can modulate kallikrein activity and potentially alter conformation, which might affect epitope accessibility .

• Internal cleavage sites: Researchers should be aware that approximately 40% of KLK11 may undergo internal cleavage at other sites beyond I54, potentially generating additional fragments that may or may not be recognized by the antibody .

• Sample preparation considerations: Denaturing conditions in Western blot applications may expose epitopes that are masked in native conformations, potentially affecting antibody performance across different applications.

How can Cleaved-KLK11 (I54) Antibody be used in multiplex assays to study protease cascades?

Developing multiplex assays to study protease cascades involving KLK11 requires sophisticated methodological approaches:

• Co-immunoprecipitation strategy: Use the Cleaved-KLK11 (I54) Antibody to immunoprecipitate KLK11 and its interacting partners, followed by mass spectrometry to identify components of the protease cascade.

• Proximity ligation assay: Combine the KLK11 antibody with antibodies against potential activators (like MMP-20) or substrates to visualize protein-protein interactions in situ.

• Sequential immunodepletion: Systematically deplete specific proteases from complex biological samples to map activation hierarchies involving KLK11.

• Activity-based protein profiling: Combine the antibody with activity-based probes to simultaneously assess KLK11 abundance and activity.

• Live cell imaging: Develop FRET-based reporters that can monitor KLK11 activation in real-time, using the epitope information from the Cleaved-KLK11 (I54) Antibody to design appropriate reporters.

For accurate results in multiplex assays, researchers should carefully validate antibody combinations to ensure no cross-reactivity or interference occurs between detection systems.

What are common pitfalls when using the Cleaved-KLK11 (I54) Antibody and how can they be addressed?

Researchers may encounter several challenges when working with the Cleaved-KLK11 (I54) Antibody:

• False negatives due to low abundance: KLK11 may be expressed at low levels in some tissues. Use sensitive detection methods like chemiluminescence with signal enhancement for Western blots or consider sample enrichment through immunoprecipitation.

• Cross-reactivity with other kallikreins: Given the sequence homology among kallikrein family members, validate specificity by testing against recombinant kallikreins, particularly those with similar activation sites.

• Sample degradation: KLK11 is prone to proteolytic processing. Always use fresh samples with appropriate protease inhibitors, and avoid repeated freeze-thaw cycles.

• Epitope masking: Complex formation or post-translational modifications may mask the I54 cleavage site. Consider multiple extraction methods and denaturation conditions.

• Batch-to-batch variability: As a polyclonal antibody, there may be lot-to-lot variations. Always include positive controls from previous successful experiments when using a new lot.

How should I interpret conflicting results between KLK11 transcript levels and cleaved protein detection?

When faced with discrepancies between KLK11 transcript levels and cleaved protein detection:

What quality control measures should be implemented when using the Cleaved-KLK11 (I54) Antibody in clinical research?

For clinical research applications, implement these rigorous quality control measures:

• Antibody validation: Before clinical sample analysis, validate antibody performance using:

  • Positive controls (samples with known KLK11 activation)

  • Negative controls (KLK11-deficient samples)

  • Isotype controls (to assess non-specific binding)

• Standardization protocol: Develop standard operating procedures including:

  • Sample collection and processing timelines

  • Consistent antibody dilutions and incubation conditions

  • Standardized quantification methods

• Reference standards inclusion: Include calibration curves using recombinant cleaved KLK11 to enable quantitative comparisons across experiments and patient cohorts.

• Inter-laboratory validation: For multi-center studies, implement proficiency testing to ensure consistent results across different laboratories.

• Blinded analysis: Conduct blinded assessments of clinical samples to prevent bias, particularly when correlating KLK11 activation with clinical outcomes.

How is the Cleaved-KLK11 (I54) Antibody being used to investigate KLK11's role in diverse physiological processes?

Current research employs the Cleaved-KLK11 (I54) Antibody to explore KLK11's diverse functions:

• Neurological functions: KLK11 is expressed in the hippocampus , suggesting potential roles in neural function or pathology that researchers are investigating using tissue-specific activation studies.

• Reproductive biology: With high expression in prostate and testis , KLK11 activation patterns are being studied in reproductive physiology and pathology, including prostate cancer.

• Extracellular matrix remodeling: Researchers are investigating KLK11's role in ECM processing, given its extracellular localization and protease activity .

• Golgi apparatus functioning: The subcellular localization of KLK11 in the Golgi apparatus has prompted investigations into its role in protein processing and secretion pathways.

• Extracellular vesicle biology: With KLK11 detected in extracellular exosomes , researchers are exploring its potential roles in intercellular communication and signaling.

What are emerging methods for studying KLK11 activation in complex biological samples?

Cutting-edge methodologies for studying KLK11 activation include:

• Activity-based protein profiling (ABPP): Using selective probes to monitor active KLK11 in complex biological samples, complementing the detection of cleaved forms with the antibody.

• Proteomics-based degradomics: Identifying the specific substrates of activated KLK11, providing insights into its functional roles in different physiological and pathological contexts.

• Single-cell analysis: Applying advanced techniques to study KLK11 activation at the single-cell level, revealing heterogeneity in protease activation within tissues.

• CRISPR-based genetic models: Developing systems with modified KLK11 cleavage sites to study the functional consequences of altered activation patterns.

• Advanced mass spectrometry: Using targeted approaches to detect specific KLK11 cleavage fragments in complex samples, complementing antibody-based detection methods .

How might understanding KLK11 activation contribute to the development of novel therapeutic approaches?

Understanding KLK11 activation has significant therapeutic implications:

• Diagnostic biomarker development: Changes in KLK11 expression and activation states could serve as diagnostic or prognostic markers in breast cancer and potentially other malignancies .

• Therapeutic target identification: Elucidating KLK11 activation mechanisms might reveal novel targets for therapeutic intervention, particularly in cancers where KLK11 plays a regulatory role.

• Protease inhibitor design: Detailed knowledge of KLK11 activation and activity could facilitate the development of specific inhibitors targeting its active site or exosites.

• Antibody-based therapeutics: The epitope specificity of the Cleaved-KLK11 (I54) Antibody provides a template for developing therapeutic antibodies that selectively target activated KLK11.

• Activation modulation strategies: Understanding the proteases responsible for KLK11 activation, such as MMP-20 , opens avenues for indirectly modulating KLK11 activity by targeting its activators.