TNFAIP2 Antibody

What is TNFAIP2 and what cellular processes is it involved in?

TNFAIP2 is a primary response gene of TNFα, highly expressed in immune cells and the urinary bladder. The protein functions as a multifunctional mediator involved in several critical cellular processes including inflammation, angiogenesis, tunneling nanotube (TNT) formation, and regulation of cell proliferation and migration . It belongs to the SEC6 family of proteins and has been shown to play significant roles in actin cytoskeleton modulation and cell morphology regulation through interactions with small GTPases . TNFAIP2 is differentially expressed during development and capillary tube-like formation in vitro, and its expression is induced by TNFα and other proinflammatory factors .

Which cell types normally express TNFAIP2?

Immunohistochemical analysis reveals that TNFAIP2 is normally expressed by follicular dendritic cells, interdigitating dendritic cells, and macrophages, but not by lymphoid cells in secondary lymphoid tissues . Within germinal centers, the largest collections of TNFAIP2-positive cells are localized to reactive germinal centers of secondary follicles in the typical pattern of follicular dendritic cells . Additionally, tingible body macrophages within germinal centers weakly stain for TNFAIP2, while scattered interdigitating dendritic cells and macrophages in the inter-follicular regions of secondary lymphoid tissues also express TNFAIP2 . Double-labeling studies with markers like CD23 (for follicular dendritic cells) and S100 (for interdigitating dendritic cells) confirm the co-localization of TNFAIP2 with these cell-type specific markers .

What are the molecular characteristics of TNFAIP2?

TNFAIP2 protein consists of 654 amino acids with a calculated molecular weight of 73 kDa, which corresponds to its observed molecular weight in experimental settings . The gene encoding TNFAIP2 has the GenBank Accession Number BC128449 and NCBI Gene ID 7127 . The protein is identified in the UniProt database with ID Q03169 . Structurally, TNFAIP2 expresses in both cytoplasmic and nuclear compartments, with expression patterns varying depending on the cell type and physiological context .

How do I validate an anti-TNFAIP2 antibody for my research?

Validation of TNFAIP2 antibodies should follow a multi-step approach:

• Western Blot Validation: Confirm antibody reactivity against endogenous TNFAIP2 in cell lines known to express the protein, such as HeLa and HepG2 cells . Verify that the detected band appears at the expected molecular weight of approximately 73 kDa .

• Positive Controls: Use tissues or cell types with established TNFAIP2 expression. Secondary lymphoid tissues containing follicular dendritic cells, interdigitating dendritic cells, and macrophages serve as excellent positive controls .

• Specificity Testing: Perform comparative analyses using different antibodies targeting different epitopes of TNFAIP2 to confirm specificity .

• Enhanced Validation Techniques: Consider siRNA knockdown experiments to confirm decreased antibody-based staining intensity upon TNFAIP2 downregulation, or use GFP-tagged TNFAIP2 to evaluate overlap between antibody staining and GFP signal .

What dilutions are recommended for TNFAIP2 antibody applications?

It is strongly recommended that researchers titrate the antibody in each testing system to obtain optimal results, as the ideal concentration may vary depending on the specific sample type and experimental conditions .

How can I use TNFAIP2 antibodies to study protein interactions?

TNFAIP2 has been identified to interact with at least six proteins, making interaction studies particularly valuable. To investigate these interactions:

• Co-immunoprecipitation: Use anti-TNFAIP2 antibodies to pull down protein complexes from cell lysates, followed by Western blot analysis to detect interacting partners such as actin, Rac1, Cdc42, or RalA . Previous studies have demonstrated that TNFAIP2 interacts with actin and is involved in the formation of actin-based membrane protrusions in NPC-TW02 cells .

• GST-pulldown assays: For direct interaction studies, GST-pulldown assays have shown that TNFAIP2 directly interacts with Rac1 but not Cdc42, despite regulating both small GTPases .

• Double labeling immunofluorescence: This technique can be employed to visualize co-localization of TNFAIP2 with potential interaction partners in cells. Similar approaches have been used to demonstrate co-localization of TNFAIP2 with CD23 in follicular dendritic cells and with S100 in interdigitating dendritic cells .

What are the applications of TNFAIP2 antibodies in cancer research?

TNFAIP2 antibodies have significant applications in cancer research:

• Diagnostic Marker: TNFAIP2 serves as a useful marker for distinguishing primary mediastinal (thymic) large B cell lymphoma from diffuse large B cell lymphoma with a sensitivity of 87% and specificity of 96% . Immunohistochemical staining for TNFAIP2 can be used to identify malignant Reed-Sternberg cells in classical Hodgkin lymphoma .

• Metastasis Studies: TNFAIP2 expression correlates with distant metastasis-free survival in nasopharyngeal carcinoma patients. In high TNFAIP2 expression groups, 40.5% of patients developed distant metastasis compared to only 12.1% in low expression groups . Antibodies can be used to stratify patients and investigate mechanisms of metastasis.

• Tumor Identification: TNFAIP2 antibodies show strong staining in 100% of follicular dendritic cell sarcomas and histiocytic sarcomas, making them valuable for tumor identification and classification .

How does TNFAIP2 contribute to tunneling nanotube formation?

TNFAIP2 plays a critical role in the formation of tunneling nanotubes (TNTs), which are actin-based membrane protrusions that facilitate intercellular communication. The mechanisms involve:

• Interaction with Small GTPases: TNFAIP2 directly interacts with the small GTPase RalA to induce membrane nanotube formation in HeLa cells . This interaction appears to be specific and functionally significant for TNT formation.

• Actin Cytoskeleton Modulation: TNFAIP2 interacts with actin and regulates the actin cytoskeleton required for membrane protrusion formation . Through its effects on actin dynamics, TNFAIP2 helps establish the structural framework for TNTs.

• Protein Complex Formation: TNFAIP2 has been shown to interact with leucocyte-specific transcript 1 (LST1) to mediate the formation of functional nanotubes . This indicates that TNFAIP2 functions within a larger protein complex to regulate TNT formation.

To study these functions, researchers can use TNFAIP2 antibodies in combination with fluorescent labeling of actin structures, live-cell imaging techniques, and co-immunoprecipitation experiments to visualize and analyze the dynamics of TNT formation in various cellular contexts.

What is the significance of TNFAIP2 in cell migration and cancer progression?

TNFAIP2 has emerged as an important regulator of cell migration and cancer progression through several mechanisms:

• Actin-Based Protrusion Formation: TNFAIP2 associates with actin and modulates actin-based protrusion formation, thereby promoting the migration of nasopharyngeal carcinoma cells . This function appears to be directly linked to metastatic potential.

• Clinical Correlation with Metastasis: High TNFAIP2 expression in nasopharyngeal carcinoma specimens correlates with increased distant metastasis (40.5% in high expression vs. 12.1% in low expression groups) . This suggests TNFAIP2 might serve as a prognostic marker.

• Functional Impact on Invasion: Knockdown studies have demonstrated that reducing TNFAIP2 expression in nasopharyngeal carcinoma HK1 cells dramatically reduces cell migration and invasion capabilities without significantly affecting cell growth . This indicates a specific role in facilitating invasive behavior.

Researchers investigating these aspects can employ TNFAIP2 antibodies for immunohistochemical studies of patient samples, protein expression analysis in cell lines with varying metastatic potential, and functional studies involving migration and invasion assays following TNFAIP2 manipulation.

What are the optimal storage and handling conditions for TNFAIP2 antibodies?

To maintain antibody effectiveness, follow these storage and handling guidelines:

• Storage Temperature: Store TNFAIP2 antibodies at -20°C for long-term stability. They are typically stable for one year after shipment when stored properly .

• Buffer Composition: TNFAIP2 antibodies are commonly supplied in PBS with 0.02% sodium azide and 50% glycerol at pH 7.3, which helps maintain stability .

• Aliquoting: For antibodies stored at -20°C, aliquoting is generally unnecessary, though it may be advisable for frequently used antibodies to prevent freeze-thaw cycles .

• Special Considerations: Some TNFAIP2 antibody preparations (particularly in 20μl sizes) may contain 0.1% BSA as a stabilizer . Be aware of this when designing experiments where BSA might interfere.

How should I score TNFAIP2 expression in immunohistochemistry studies?

When evaluating TNFAIP2 expression in immunohistochemical studies, researchers should employ a systematic scoring approach:

• Quantitative Assessment: Record the percentage of tumor cells showing positive staining for TNFAIP2 .

• Intensity Scoring: Use a standardized intensity scale such as:

  • (−) = no staining detected

  • (1+) = weak staining

  • (2+) = moderate staining

  • (3+) = strong staining

• Positivity Threshold: A case is typically scored as positive if at least 50% of the tumor cells stain positive for TNFAIP2 with an intensity of 1+, 2+, or 3+ .

• Internal Controls: Utilize intra-tumoral macrophages and dendritic cells as internal positive controls for staining quality assessment .

• Localization Assessment: Note that positive staining cells typically show reactivity for TNFAIP2 in both the cytoplasm and nucleus, and this localization pattern may have biological significance .