Cleaved-ITGA5 (F42) Antibody

What is Cleaved-ITGA5 (F42) Antibody and what specific epitope does it recognize?

The Cleaved-ITGA5 (F42) Antibody is a rabbit polyclonal antibody that specifically detects endogenous levels of fragment of activated Integrin Alpha 5 Heavy Chain (HC) protein resulting from cleavage adjacent to phenylalanine 42 (F42). This antibody was generated against a synthesized peptide derived from the human ITGA5 at the amino acid range 23-72, which represents the N-terminal region of the protein . The antibody is highly specific for the cleaved form of ITGA5, making it valuable for studying post-translational modifications and activation states of integrin alpha-5.

How does ITGA5 cleavage affect its biological function?

Proteolytic cleavage of ITGA5 by proprotein convertase subtilisin/kexin type 5 (PCSK5) mediates activation of the precursor . This post-translational modification is critical for proper functioning of ITGA5. Upon cleavage, ITGA5 can effectively dimerize with ITGB1 (integrin beta-1) to form the functional heterodimer ITGA5:ITGB1, which serves as a receptor for fibronectin and fibrinogen. The heterodimer recognizes the Arg-Gly-Asp (R-G-D) sequence in its ligands and mediates R-G-D-dependent cell adhesion to fibronectin (FN1) and fibrillin-1 (FBN1) . Additionally, the cleaved form of ITGA5 participates in various signaling pathways, including those involved in cell migration, survival, and proliferation, which are particularly relevant in cancer progression and metastasis .

What are the validated applications for Cleaved-ITGA5 (F42) Antibody and their recommended protocols?

The Cleaved-ITGA5 (F42) Antibody has been validated for Western Blot (WB) and ELISA applications .

Western Blot Protocol:

• Recommended dilution range: 1:500-1:2000

• Sample preparation: Lyse cells in buffer containing protease inhibitors

• Load 20-30 μg of protein per lane on 5-20% SDS-PAGE gel

• Transfer to nitrocellulose membrane at 150 mA for 50-90 minutes

• Block with 5% non-fat milk in TBS for 1.5 hours at room temperature

• Incubate with primary antibody overnight at 4°C

• Wash with TBS-0.1% Tween (3 times, 5 minutes each)

• Incubate with HRP-conjugated secondary antibody (anti-rabbit IgG) at 1:5000 dilution for 1.5 hours at room temperature

• Develop using enhanced chemiluminescence (ECL) detection system

ELISA Protocol:

• Recommended dilution: 1:10000

• Coat plate with target antigen

• Block with appropriate blocking buffer

• Add diluted primary antibody and incubate

• Wash thoroughly

• Add enzyme-conjugated secondary antibody

• Develop with appropriate substrate and read absorbance

What cell and tissue types have been successfully used with this antibody?

Based on the validation data, Cleaved-ITGA5 (F42) Antibody has been successfully used with:

Cell Lines:

• Human A549 cells

• Human HeLa cells

• Human 293 cells

• Rat PC-12 cells

Tissue Types:

• Human placenta tissue

• Rat brain tissue

• Mouse brain tissue

• Rat bladder tissue

The antibody has shown specific detection of ITGA5 in these samples, with the protein appearing at approximately 130 kDa in Western blot analysis, although the calculated molecular weight is about 115 kDa .

What are the optimal storage conditions and stability parameters for Cleaved-ITGA5 (F42) Antibody?

Storage Conditions:

• Store at -20°C or -80°C upon receipt

• Avoid repeated freeze-thaw cycles

• For long-term storage (up to 1 year), maintain at -20°C

• After reconstitution (if applicable), aliquot and store at -20°C

Formulation and Stability:

• The antibody is supplied as a liquid in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide

• Concentration: 1 mg/mL (may vary by lot)

• Stability: Up to 1 year from the date of receipt when stored properly

• pH: 7.4

What are common technical challenges when using this antibody and how can they be addressed?

Challenge 1: High Background in Western Blot

• Solution: Increase blocking time (2-3 hours), use 5% BSA instead of milk for blocking, increase washing steps (5 times, 5 minutes each), and optimize primary antibody dilution (start with 1:1000).

Challenge 2: Weak or No Signal

• Solution: Verify protein expression in your samples, increase protein loading (40-50 μg), decrease antibody dilution (1:500), extend primary antibody incubation (overnight at 4°C), and use fresh ECL reagent.

Challenge 3: Multiple Bands

• Solution: Verify sample integrity (add protease inhibitors), optimize SDS-PAGE conditions (use 7.5% gel for better resolution of high molecular weight proteins), and increase stringency of washing buffer (add 0.2% Tween-20).

Challenge 4: Inconsistent Results

• Solution: Standardize lysate preparation, use positive controls (e.g., human placenta tissue lysate), maintain consistent transfer conditions, and avoid repeated freeze-thaw cycles of the antibody.

How can Cleaved-ITGA5 (F42) Antibody be used to study integrin activation in cancer progression?

The Cleaved-ITGA5 (F42) Antibody offers a powerful tool for investigating integrin activation in cancer progression, particularly in breast cancer bone metastasis. Research has shown that ITGA5 is highly expressed in bone metastases compared to lung, liver, or brain metastases . By specifically detecting the cleaved, activated form of ITGA5, researchers can:

• Assess Activation Status: Measure the ratio of cleaved to uncleaved ITGA5 in different cancer stages to correlate with invasiveness and metastatic potential.

• Monitor Treatment Response: Evaluate changes in ITGA5 activation following treatment with integrin-targeting therapies such as volociximab (M200), which has been shown to reduce tumor cell colonization of bone marrow .

• Study Metastatic Mechanisms: Investigate how ITGA5 cleavage influences:

  • Tumor cell adhesion to fibronectin

  • Cell migration capabilities

  • Survival pathways

  • Colonization of bone marrow

• Develop Prognostic Tools: High ITGA5 expression in primary tumors correlates with the presence of disseminated tumor cells in bone marrow aspirates from early-stage breast cancer patients (p = 0.039) and predicts poor bone metastasis-free survival (HR = 1.36, p = 0.018) . The cleaved form detection could potentially serve as a more specific prognostic marker.

• Experimental Design Recommendation: Compare primary tumors and matched metastatic lesions using both total ITGA5 antibody and Cleaved-ITGA5 (F42) Antibody to determine if activation, rather than just expression, drives metastatic behavior.

What methodological approaches can be used to study ITGA5 cleavage in relation to PCSK5 activity?

To investigate the relationship between PCSK5 activity and ITGA5 cleavage, researchers can employ the following methodological approaches:

• Co-expression Studies:

  • Transfect cells with varying levels of PCSK5 and analyze ITGA5 cleavage using Cleaved-ITGA5 (F42) Antibody via Western blot

  • Create a dose-response curve to correlate PCSK5 expression with ITGA5 cleavage efficiency

• PCSK5 Inhibition Experiments:

  • Use pharmacological inhibitors of PCSK5 or siRNA/shRNA knockdown

  • Monitor changes in cleaved ITGA5 levels using the antibody

  • Assess functional consequences on cell adhesion, migration, and invasion

• Proteolytic Processing Analysis:

  • Perform pulse-chase experiments to track ITGA5 processing over time

  • Use site-directed mutagenesis to modify the cleavage site and analyze resistance to cleavage

  • Compare processing in different cell types with varying PCSK5 expression levels

• In vitro Cleavage Assay:

  • Incubate recombinant ITGA5 with purified PCSK5

  • Use Cleaved-ITGA5 (F42) Antibody to detect the cleavage products

  • Optimize conditions (pH, temperature, cofactors) to determine optimal PCSK5 activity

• Subcellular Localization Studies:

  • Perform immunofluorescence co-localization experiments with PCSK5 and ITGA5

  • Use cell fractionation followed by Western blot with Cleaved-ITGA5 (F42) Antibody to determine where cleavage occurs

How can this antibody be integrated into multi-parameter analysis of integrin signaling pathways?

The Cleaved-ITGA5 (F42) Antibody can be integrated into multi-parameter analysis of integrin signaling through several advanced methodological approaches:

• Multiplexed Western Blot Analysis:

  • Simultaneously probe for cleaved ITGA5 and downstream signaling molecules (FAK, Src, Paxillin)

  • Use different fluorophore-conjugated secondary antibodies for quantitative assessment of activation ratios

  • Create an activation signature by normalizing phosphorylated forms to total protein levels

• Flow Cytometry Applications:

  • Develop protocols for intracellular staining of cleaved ITGA5

  • Combine with surface markers and phospho-specific antibodies for signaling molecules

  • Analyze at single-cell level to assess heterogeneity in activation states

• Proximity Ligation Assay (PLA):

  • Detect protein-protein interactions between cleaved ITGA5 and binding partners

  • Visualize and quantify specific interactions in situ

  • Compare interaction networks in normal versus pathological states

• Mass Cytometry (CyTOF):

  • Metal-label the Cleaved-ITGA5 (F42) Antibody for use in high-dimensional analyses

  • Simultaneously measure multiple parameters (30+) in single cells

  • Create comprehensive signaling network maps in different cellular states

• Phospho-proteomics Integration:

  • Correlate cleaved ITGA5 levels with global phosphorylation changes

  • Identify novel phosphorylation events dependent on ITGA5 activation

  • Map the temporal dynamics of signaling cascades following integrin activation

What experimental approaches can be used to investigate the role of cleaved ITGA5 in bone metastasis models?

To investigate the role of cleaved ITGA5 in bone metastasis, researchers can employ several experimental approaches:

• In vivo Metastasis Models:

  • Intracardiac or intratibial injection of cancer cells with modulated ITGA5 expression/cleavage

  • Monitor bone colonization through bioluminescence imaging

  • Analyze bone lesions through micro-CT scanning and histomorphometry

  • Use Cleaved-ITGA5 (F42) Antibody for immunohistochemical analysis of tumor sections

• Ex vivo Bone Metastasis Assays:

  • Co-culture cancer cells with bone explants or calvaria

  • Analyze cancer cell behavior (adhesion, invasion, proliferation)

  • Measure osteolytic activity through calcium release assays

  • Immunostain sections with Cleaved-ITGA5 (F42) Antibody to localize activated integrin

• Functional Analysis Protocol:

  • Generate stable cell lines with ITGA5 mutants resistant to cleavage

  • Compare their metastatic potential with wild-type ITGA5-expressing cells

  • Analyze:

    • Adhesion to bone matrix components (fibronectin, collagen)

    • Migration and invasion through bone-mimicking matrices

    • Interaction with bone stromal cells (osteoblasts, osteoclasts)

    • Survival under bone microenvironment conditions

• Therapeutic Intervention Studies:

  • Test antibodies targeting cleaved ITGA5 (like volociximab/M200)

  • Administer at different stages of metastasis (prevention vs. established disease)

  • Measure outcomes:

    • Tumor burden reduction

    • Bone lesion prevention

    • Survival improvement

    • Mechanistic changes in tumor-bone interactions

How can researchers differentiate between effects mediated by cleaved versus uncleaved ITGA5 in experimental systems?

Differentiating between effects mediated by cleaved versus uncleaved ITGA5 requires sophisticated experimental designs:

• Comparative Analysis Using Multiple Antibodies:

  • Use Cleaved-ITGA5 (F42) Antibody alongside antibodies recognizing total ITGA5

  • Create a ratio of cleaved to total ITGA5 to normalize for expression differences

  • Correlate this activation ratio with functional outcomes

• Genetic Engineering Approaches:

  • Generate cleavage-resistant ITGA5 mutants (modify F42 adjacent residues)

  • Create constitutively "pre-cleaved" ITGA5 constructs

  • Compare phenotypes in isogenic cell lines expressing these variants

• Temporal Analysis Protocol:

  • Induce ITGA5 cleavage through physiological stimuli or PCSK5 overexpression

  • Collect time-course samples for Western blot analysis with Cleaved-ITGA5 (F42) Antibody

  • Simultaneously monitor functional changes (adhesion, signaling, migration)

  • Establish temporal relationships between cleavage and functional outcomes

• Cell-Free Reconstitution Systems:

  • Purify cleaved and uncleaved forms of ITGA5

  • Reconstitute with ITGB1 in artificial membrane systems

  • Compare binding kinetics to ligands (fibronectin, RGD peptides)

  • Analyze structural differences through biophysical methods

• Domain-Specific Inhibition:

  • Develop peptides or small molecules that specifically bind to exposed regions after cleavage

  • Use these inhibitors alongside Cleaved-ITGA5 (F42) Antibody to validate target engagement

  • Assess functional consequences of specifically blocking the cleaved form

What are the key considerations when quantifying Cleaved-ITGA5 (F42) levels in Western blot experiments?

When quantifying Cleaved-ITGA5 (F42) levels in Western blot experiments, researchers should consider:

• Sample Preparation Standardization:

  • Use consistent lysis buffers with protease inhibitors to prevent artificial cleavage

  • Process all samples simultaneously to minimize technical variation

  • Include phosphatase inhibitors if analyzing associated phosphorylation events

• Loading Controls and Normalization:

  • Use appropriate housekeeping proteins (β-actin, GAPDH, or vinculin)

  • Consider normalizing to total ITGA5 rather than housekeeping proteins when studying activation status

  • Use recombinant cleaved ITGA5 as a positive control for absolute quantification

• Quantification Methodology:

  • Use linear range detection methods (fluorescent secondary antibodies preferred over ECL)

  • Perform multiple exposures to ensure signal is within linear range

  • Use band density analysis software with background subtraction

  • Express results as cleaved/total ITGA5 ratio when studying activation

• Statistical Analysis Considerations:

  • Account for both biological and technical replicates

  • Use appropriate statistical tests based on data distribution

  • Consider power analysis to determine sample size needed for reliable detection of differences

• Common Pitfalls to Avoid:

  • Signal saturation leading to underestimation of differences

  • Inconsistent transfer efficiency across the membrane

  • Cross-reactivity with other integrin family members

  • Variability in cleaved ITGA5 levels due to cell culture conditions or passage number

How can researchers validate that signals detected with Cleaved-ITGA5 (F42) Antibody represent specific cleaved forms rather than degradation products?

To validate the specificity of signals detected with Cleaved-ITGA5 (F42) Antibody:

• Controlled Proteolysis Experiments:

  • Generate recombinant ITGA5 and subject it to controlled PCSK5 cleavage

  • Compare migration pattern with endogenous cleaved ITGA5

  • Perform peptide competition assays using the immunizing peptide (amino acids 23-72)

• PCSK5 Modulation Studies:

  • Overexpress or knock down PCSK5 and observe corresponding changes in cleaved ITGA5 signal

  • Use PCSK5 inhibitors and monitor reduction in cleaved ITGA5

  • These experiments help confirm the signal is due to specific enzymatic processing

• Mass Spectrometry Validation:

  • Immunoprecipitate ITGA5 and analyze by mass spectrometry

  • Identify peptide fragments to confirm cleavage at the expected site

  • Compare with Western blot results using Cleaved-ITGA5 (F42) Antibody

• Antibody Specificity Tests:

  • Pre-absorb antibody with cleaved ITGA5 peptide before Western blotting

  • Test antibody on ITGA5 knockout samples as negative controls

  • Compare with other antibodies targeting different epitopes of ITGA5

• Size and Pattern Analysis:

  • True cleaved ITGA5 should appear at a consistent molecular weight (~130 kDa observed vs. 115 kDa calculated)

  • Random degradation products typically show multiple bands with variable intensity

  • Cleavage should be enhanced by specific physiological stimuli but not by general cell stress