apbb1ip Antibody

What is APBB1IP and why is it significant in research?

APBB1IP is a Rap1-binding protein that functions as a regulator of leukocyte recruitment and pathogen clearance through complement-mediated phagocytosis. Originally identified as a binding partner of amyloid β (A4) precursor protein-binding, family B, member 1 (APBB1), it belongs to the MRL (Mig-10/RIAM/Lamellipodin) family of adaptor proteins . APBB1IP plays crucial roles in integrin activation machinery and is required for Rap1-induced affinity changes in β1 and β2 integrins in T cells, as well as activation of αIIbβ3 integrin in platelets . Recent research has highlighted its importance in cancer research due to its potential role in immune infiltration and as a prognostic biomarker in various cancer types .

What types of APBB1IP antibodies are available for research applications?

Researchers have access to multiple APBB1IP antibodies targeting different epitopes:

• N-Terminal antibodies: Target the amino-terminal region of APBB1IP, useful for detecting full-length protein

• Internal region antibodies: Recognize sequences within the central portion of the protein

• C-Terminal antibodies: Target the carboxy-terminal region (e.g., AA 647-666)

• Specific amino acid sequence antibodies: Target defined sequences such as AA 38-87, AA 71-120, or AA 188-421

These antibodies come in various formats including polyclonal and monoclonal varieties with different host species (primarily rabbit and mouse), offering flexibility for different experimental designs .

How does APBB1IP function in cellular processes?

APBB1IP functions as an intrinsic element of integrin activation machinery. It mediates Rap1-induced affinity changes in integrins, particularly in immune cells. The protein contains a proline-rich region at the C terminus and a highly conserved pattern of 27 amino acids in a predicted coiled-coil region immediately N-terminal to the RA domain . Through these structural elements, APBB1IP participates in:

• Activation and modulation of innate immune responses

• Regulation of leukocyte recruitment

• Facilitation of pathogen clearance via complement-mediated phagocytosis

• Cancer cell migration and invasion (APBB1IP-depleted melanoma cells show decreased migration directionality)

What are the optimal protocols for Western blotting with APBB1IP antibodies?

When performing Western blotting with APBB1IP antibodies, researchers should follow these methodological guidelines:

• Sample preparation: Lyse cells or tissues in a compatible buffer containing protease inhibitors to prevent protein degradation

• Antibody concentration: Use APBB1IP antibodies at 0.2-1 μg/mL concentration, though optimal conditions should be determined empirically for each experimental setup

• Controls: Include a blocking peptide control (such as catalog no. 33R-8076) to test for antibody specificity

• Storage and handling: Store reconstituted antibody at 4°C for short-term use or aliquot and store at -20°C for long-term storage; avoid repeated freeze/thaw cycles

For reconstitution of lyophilized antibody, add 50 μL of distilled water to achieve a final concentration of 1 mg/mL in PBS buffer .

How can researchers validate APBB1IP antibody specificity?

Validating antibody specificity is crucial for reliable results. Researchers should employ multiple approaches:

• Blocking peptide assays: Use a specific blocking peptide (like catalog no. 33R-8076) in parallel experiments to confirm signal specificity

• Multiple antibody validation: Use antibodies targeting different epitopes of APBB1IP to cross-validate results

• Knockout/knockdown controls: Compare results in samples with normal versus reduced APBB1IP expression

• Cross-reactivity testing: Verify specificity across species when working with multispecies-reactive antibodies (antibodies are available with reactivity to human, mouse, rat, cow, dog, guinea pig, rabbit, horse, and even zebrafish)

What techniques beyond Western blotting can be used with APBB1IP antibodies?

While Western blotting is commonly used, APBB1IP antibodies can be employed in multiple techniques:

• Immunohistochemistry (IHC): For tissue section analysis (both frozen and paraffin-embedded sections)

• Immunocytochemistry (ICC): For cellular localization studies

• Immunoprecipitation (IP): To isolate APBB1IP and its binding partners

• Flow cytometry (FACS): For quantitative analysis of APBB1IP in cell populations

• ELISA: For quantitative measurement of APBB1IP levels

• Immunofluorescence (IF): For subcellular localization studies

Select antibodies specifically validated for your technique of interest, as not all antibodies perform equally across different applications.

How does APBB1IP expression vary across cancer types and what are the prognostic implications?

APBB1IP shows differential expression patterns across cancer types with significant prognostic implications:

The survival advantage or disadvantage associated with APBB1IP expression varies by cancer type. For instance, high expression predicts shorter recurrence-free survival in LGG and PRAD, but better disease-free survival in ACC, CESC, KIRP, and UCEC .

What is the relationship between APBB1IP expression and immune cell infiltration in tumors?

APBB1IP expression shows significant correlation with immune cell infiltration across multiple cancer types:

• Negative correlation with tumor purity: In most cancer types, APBB1IP expression negatively correlates with tumor purity, suggesting its expression in tumor tissues may be influenced by infiltrating immune cells

• Positive correlation with immune cell infiltration: Higher APBB1IP expression is associated with increased infiltration of immune cells, particularly in:

  • BRCA (Breast Cancer)

  • CESC (Cervical Squamous Cell Carcinoma)

  • HNSC (Head and Neck Squamous Cell Carcinoma)

  • PRAD (Prostate Adenocarcinoma)

  • SKCM (Skin Cutaneous Melanoma)

  • TGCT (Testicular Germ Cell Tumors)

  • UCEC (Uterine Corpus Endometrial Carcinoma)

• Specific immune cell associations: APBB1IP expression particularly correlates with CD8+ T cells and NK cells infiltration, suggesting its potential role in cytotoxic anti-tumor immunity

Some cancer types (CHOL, DLBC, MESO, and UVM) showed no significant correlation between APBB1IP expression and immune cell infiltration .

How can APBB1IP antibodies be used to study tumor immune microenvironment?

APBB1IP antibodies can provide valuable insights into tumor immune microenvironments through several methodological approaches:

• Multiplexed immunohistochemistry: Using APBB1IP antibodies alongside markers for different immune cell populations to characterize spatial relationships between APBB1IP expression and immune infiltrates

• Flow cytometry analysis: Determining APBB1IP expression levels in specific immune cell subsets within the tumor microenvironment

• Correlation studies: Comparing APBB1IP expression with established immune regulators to understand potential functional relationships

• Functional assays: Assessing how antibody-mediated blocking of APBB1IP affects immune cell migration, adhesion, and function within tumor contexts

Research has shown that APBB1IP upregulation correlates with increased immune cell infiltration, particularly CD8+ T cells and NK cells, suggesting APBB1IP may play a role in regulating anti-tumor immune responses .

How can researchers investigate APBB1IP's role in integrin activation using specific antibodies?

Investigating APBB1IP's role in integrin activation requires specialized approaches:

• Co-immunoprecipitation studies: Use APBB1IP antibodies to pull down protein complexes and identify integrin-associated proteins

• Proximity ligation assays: Detect protein-protein interactions between APBB1IP and integrins in situ

• Functional blocking studies: Apply APBB1IP antibodies to live cells to determine if they interfere with integrin-dependent processes

• Phosphorylation-specific assays: Use phospho-specific antibodies to monitor APBB1IP activation status following integrin stimulation

APBB1IP functions as an intrinsic element of the integrin activation machinery and is required for Rap1-induced affinity changes in β1 and β2 integrins in T cells. It also participates in Rap1-mediated activation of αIIbβ3 integrin in platelets .

What approaches can be used to study APBB1IP interactions with Rap1 and other binding partners?

Studying APBB1IP's interactions with Rap1 and other partners requires specialized techniques:

• Yeast two-hybrid screening: APBB1IP was originally identified as interacting with Rap1 using this approach

• GST pull-down assays: Using purified GST-tagged Rap1 protein to capture APBB1IP from cell lysates

• FRET/BRET assays: For real-time monitoring of protein-protein interactions in living cells

• Protein microarrays: To identify novel interaction partners

• Domain-specific antibodies: Using antibodies targeting specific domains of APBB1IP (such as the RA domain) to understand domain-specific interactions

APBB1IP belongs to the MRL family of adaptor proteins with a proline-rich region at the C terminus and a highly conserved pattern of 27 amino acids in a predicted coiled-coil region N-terminal to the RA domain, which are important for its protein interactions .

How can APBB1IP expression analysis contribute to cancer classification and prognosis?

APBB1IP expression analysis offers significant value for cancer classification and prognosis through several methodological approaches:

• Transcriptomic profiling: Analysis of APBB1IP mRNA expression across cancer types using RNA-seq data from databases like TCGA

• Immunohistochemical scoring: Development of standardized scoring systems for APBB1IP protein expression in tumor tissues

• Multivariate Cox regression models: Construction of prognostic models incorporating APBB1IP expression with other biomarkers

• Immune contextualization: Correlation of APBB1IP expression with immune cell infiltration markers for improved prognostic accuracy

Research has demonstrated that APBB1IP expression has prognostic significance in multiple cancer types, though the direction of association varies by cancer. For example, high APBB1IP expression predicts poor prognosis in LGG and UVM but better outcomes in CESC, HNSC, KIRP, SKCM, THYM, and UCEC .

What are common issues encountered when using APBB1IP antibodies and how can they be resolved?

Researchers may encounter several technical challenges when working with APBB1IP antibodies:

• Non-specific binding:

  • Problem: Background signals or multiple bands in Western blots

  • Solution: Optimize blocking conditions, use more stringent washing, include blocking peptide controls, and titrate antibody concentration (recommended range: 0.2-1 μg/mL)

• Poor signal intensity:

  • Problem: Weak detection of APBB1IP

  • Solution: Increase antibody concentration, extend incubation time, enhance detection systems, and ensure proper sample preparation to prevent protein degradation

• Inconsistent results across experiments:

  • Problem: Variable staining patterns or intensity

  • Solution: Standardize protocols, use positive controls, prepare fresh working solutions, and avoid freeze/thaw cycles of antibody (store at 4°C for short-term use or aliquot and store at -20°C)

• Cross-reactivity issues:

  • Problem: Signals in unexpected species or tissues

  • Solution: Verify species reactivity specifications (available antibodies react with human, rat, mouse, cow, dog, guinea pig, rabbit, horse, and zebrafish depending on the specific antibody)

What controls should be included when using APBB1IP antibodies in experiments?

Proper experimental controls are essential for reliable results:

• Positive controls: Include samples known to express APBB1IP (based on literature or previous experiments)

• Negative controls: Include samples known not to express APBB1IP or use knockdown/knockout samples

• Blocking peptide controls: Use specific blocking peptides (such as catalog no. 33R-8076) to confirm antibody specificity

• Isotype controls: Include appropriate isotype-matched antibodies to control for non-specific binding

• Secondary antibody only controls: Omit primary antibody to detect potential non-specific signals from secondary antibodies

• Loading controls: For Western blotting, include housekeeping protein detection to normalize protein loading

How should researchers interpret variations in APBB1IP detection across different tissues and cancer types?

Interpreting variations in APBB1IP detection requires careful consideration:

• Baseline expression differences: Understand that APBB1IP has tissue-specific expression patterns, with higher expression in immune-rich tissues

• Cancer-specific alterations: Recognize that APBB1IP expression varies across cancer types, with some showing upregulation (GBM, KIRC, KIRP, STAD) and others downregulation (BLCA, BRCA, COAD, LUAD, LUSC, PAAD, READ)

• Correlation with immune infiltration: Consider that APBB1IP expression often correlates with immune cell infiltration, particularly in BRCA, CESC, HNSC, PRAD, SKCM, TGCT, and UCEC

• Prognostic implications: Interpret expression levels in the context of cancer-specific prognostic associations (e.g., high expression is associated with poor prognosis in LGG and UVM but better prognosis in CESC, HNSC, KIRP, SKCM, THYM, and UCEC)

• Technical considerations: Account for differences in antibody performance across tissue types and fixation methods

What emerging applications of APBB1IP antibodies show promise for future research?

Several emerging applications of APBB1IP antibodies present exciting opportunities:

• Immune checkpoint therapy response prediction: Investigating APBB1IP expression as a potential biomarker for immunotherapy response

• Spatial transcriptomics integration: Combining APBB1IP antibody staining with spatial transcriptomic data to understand its role in the tumor microenvironment architecture

• Single-cell analysis: Using APBB1IP antibodies in single-cell protein analysis to understand cell-type specific expression patterns

• Therapeutic targeting: Developing function-blocking antibodies targeting APBB1IP for potential therapeutic applications in cancer

• Liquid biopsy development: Exploring APBB1IP detection in circulating immune cells as a non-invasive biomarker

How might APBB1IP research contribute to understanding the tumor immune microenvironment?

APBB1IP research has significant potential to enhance our understanding of tumor immune microenvironments:

• Immune cell recruitment mechanisms: APBB1IP's role as a regulator of leukocyte recruitment suggests it may influence immune cell trafficking to tumors

• Integrin-mediated immune functions: As an integrin activation regulator, APBB1IP may impact immune cell adhesion, migration, and function within the tumor microenvironment

• Prognostic stratification: APBB1IP expression patterns could help stratify patients based on their tumor immune landscape

• Therapy response prediction: APBB1IP expression and its correlation with immune infiltrates may predict response to immunotherapies

• Novel therapeutic targets: Understanding APBB1IP's role may reveal new targets for enhancing anti-tumor immunity

Research has shown that APBB1IP upregulation correlates with increased immune cell infiltration, particularly CD8+ T cells and NK cells, suggesting it plays a role in regulating anti-tumor immune responses .

What technological advancements might enhance APBB1IP antibody applications in research?

Future technological developments could significantly expand APBB1IP antibody applications:

• Multiplexed imaging technologies: Advanced multiplexed imaging allowing simultaneous detection of APBB1IP alongside dozens of other markers

• Mass cytometry applications: Development of metal-conjugated APBB1IP antibodies for high-dimensional cytometry analysis

• In vivo imaging probes: Creation of antibody-based imaging agents for non-invasive visualization of APBB1IP expression

• PROTAC/degrader development: Using antibody-derived targeting moieties to develop proteolysis-targeting chimeras for APBB1IP

• Nanobody and single-domain antibody formats: Development of smaller antibody formats for improved tissue penetration and novel applications