fam168b Antibody

What is FAM168B protein and what are its known functions?

FAM168B, also known as MANI (Myelin-associated neurite-outgrowth inhibitor) or p20, is a protein that functions primarily as an inhibitor of neuronal axonal outgrowth. It exhibits regulatory activities in multiple signaling pathways, acting as a negative regulator of CDC42 and STAT3 while functioning as a positive regulator of STMN2 and CDC27 . The protein shows expression across various human tissues with particularly pronounced levels in brain tissue and certain immune cells . FAM168B has a canonical amino acid length of 195 residues and a protein mass of approximately 20.3 kilodaltons, although researchers have identified two distinct isoforms of the protein . Subcellularly, FAM168B localizes to both the cell membrane and cytoplasm, with notable expression patterns observed in cardiac and skeletal muscle tissues .

How is FAM168B expression distributed across different tissue types?

FAM168B exhibits a distinct tissue distribution pattern that is important for researchers to consider when designing experiments. The protein demonstrates widespread expression across human tissues, with particularly high expression levels documented in brain tissue and specific immune cell populations . The Human Protein Atlas data indicates that the RNA expression pattern can be used to cluster FAM168B with genes showing similar expression profiles across immune cells . Additionally, FAM168B shows notable expression in cardiac muscle and skeletal muscle tissues . Immunohistochemical analyses using FAM168B antibodies have successfully detected the protein in human skeletal muscle tissue, gastric cancer samples, and various cell lines including prostate adenocarcinoma (PC-3) and lung carcinoma (A549) cells . This distribution pattern suggests potential tissue-specific functions that warrant further investigation in specialized research contexts.

What are the common nomenclature and identification systems for FAM168B?

When conducting literature searches or database queries, researchers should be aware of the multiple designations for FAM168B. The protein is identified by several names in scientific literature and databases:

This nomenclature diversity is important to consider when performing comprehensive literature reviews or when cross-referencing findings across different databases and platforms .

What criteria should researchers consider when selecting a FAM168B antibody for their experiments?

When selecting a FAM168B antibody, researchers should evaluate several critical parameters to ensure experimental success:

• Experimental application compatibility: Verify that the antibody has been validated for your specific application (IHC-P, ICC/IF, Western Blot, ELISA) . For instance, some FAM168B antibodies have been specifically validated for immunohistochemistry on paraffin-embedded tissues and immunocytochemistry/immunofluorescence applications .

• Species reactivity: Confirm that the antibody recognizes FAM168B from your species of interest. Available antibodies predominantly show reactivity with human samples, though some may cross-react with mouse or rat proteins based on homology .

• Epitope recognition: Consider which region of the protein the antibody recognizes. Some antibodies target specific epitopes within amino acids 1-100 or 43-100 of the FAM168B protein .

• Clonality: Determine whether a polyclonal or monoclonal antibody best suits your research needs. The majority of available FAM168B antibodies are polyclonal, derived from rabbit hosts .

• Conjugation: If performing fluorescence-based applications, consider whether a conjugated antibody (such as FITC-conjugated) would streamline your workflow .

• Validation data: Review available immunostaining images and validation data to assess antibody performance in contexts similar to your experimental system .

These considerations will help ensure that the selected antibody performs optimally in your specific research context.

How can researchers validate the specificity of FAM168B antibodies in their experimental systems?

Validating antibody specificity is crucial for generating reliable research data. For FAM168B antibodies, researchers should implement the following validation strategies:

• Positive and negative control tissues: Use tissues known to express or lack FAM168B based on RNA expression data. Brain tissue, skeletal muscle, and certain immune cells serve as effective positive controls, while tissues with negligible expression can serve as negative controls .

• Peptide competition assays: Pre-incubate the antibody with the immunizing peptide to confirm binding specificity. A significant reduction in signal indicates specific antibody-antigen interaction.

• Genetic knockdown/knockout validation: Compare staining patterns between wild-type samples and those with reduced or eliminated FAM168B expression through siRNA, shRNA, or CRISPR-Cas9 approaches.

• Multiple antibody concordance: Utilize antibodies targeting different epitopes of FAM168B and confirm consistent staining patterns across antibodies.

• Western blot molecular weight confirmation: Verify that the detected protein corresponds to the expected molecular weight of FAM168B (approximately 20.3 kDa), accounting for potential post-translational modifications .

• Cross-species validation: When using antibodies in non-human samples, confirm specificity by testing in multiple species with varying degrees of protein homology.

These validation approaches should be documented and reported in publications to enhance experimental reproducibility and data reliability.

What are the optimal storage and handling conditions for maintaining FAM168B antibody activity?

Proper storage and handling of FAM168B antibodies are essential for maintaining their functionality over time. Based on manufacturer recommendations, researchers should adhere to the following guidelines:

• Storage temperature: Store antibodies at -20°C for long-term preservation. Avoid repeated freeze-thaw cycles which can compromise antibody integrity .

• Aliquoting: Upon receipt, divide the antibody into small working aliquots to minimize freeze-thaw cycles. Each aliquot should contain sufficient volume for single experiments .

• Light sensitivity: For fluorophore-conjugated antibodies (such as FITC-conjugated FAM168B antibodies), protect from light exposure during storage and handling to prevent photobleaching .

• Buffer compatibility: When diluting antibodies, use recommended buffers (typically PBS with stabilizing proteins) to maintain antibody structure and function.

• Working dilutions: Prepare working dilutions immediately before use rather than storing diluted antibodies for extended periods.

• Expiration monitoring: Track antibody age and observe for signs of degradation, such as precipitate formation or loss of activity in positive controls.

Following these storage and handling practices will help ensure consistent antibody performance across experiments and maximize the useful lifespan of these valuable reagents.

What are the established protocols for using FAM168B antibodies in immunohistochemistry applications?

For successful immunohistochemistry (IHC) with FAM168B antibodies, researchers should consider the following protocol elements based on validated methodologies:

• Sample preparation: Properly fix tissues in formalin and embed in paraffin. Section tissues at 4-6 μm thickness and mount on positively charged slides .

• Antigen retrieval: Perform heat-induced epitope retrieval using TE buffer at pH 9.0, which has been demonstrated as effective for FAM168B detection . This critical step unmasks epitopes that may be obscured during fixation.

• Antibody dilution: A working dilution of 1:100 has been validated for several FAM168B antibodies in IHC applications, though researchers should optimize this concentration for their specific antibody and tissue system .

• Incubation conditions: Incubate sections with primary antibody overnight at 4°C or for 1-2 hours at room temperature in a humidified chamber.

• Detection systems: Use appropriate secondary antibody systems (typically HRP-conjugated) followed by chromogenic development with DAB or other suitable substrates.

• Controls: Include both positive control tissues (skeletal muscle, gastric cancer tissue have been validated) and negative controls (primary antibody omission) in each experiment .

• Counterstaining: Apply hematoxylin counterstaining to visualize tissue architecture while maintaining visibility of specific FAM168B staining.

These protocol considerations have been effectively applied to detect FAM168B in human skeletal muscle tissue, gastric cancer samples, and other human tissues, enabling reliable protein localization studies .

How can researchers optimize FAM168B antibody detection in immunofluorescence applications?

Immunofluorescence applications require specific optimization strategies to achieve sensitive and specific detection of FAM168B:

These approaches have been effectively implemented to visualize FAM168B in cultured cell systems, revealing its distribution patterns within cellular compartments .

What are the critical considerations for Western blot analysis of FAM168B protein?

Western blot analysis of FAM168B requires attention to several technical considerations to achieve reliable detection:

• Sample preparation: Ensure complete protein extraction using buffers containing appropriate detergents (RIPA or NP-40 based buffers) and protease inhibitors to prevent degradation.

• Protein loading: Load sufficient protein (typically 20-50 μg of total protein) to detect FAM168B, which has a predicted molecular weight of approximately 20.3 kDa .

• Gel percentage: Use higher percentage (12-15%) SDS-PAGE gels to achieve optimal resolution of the relatively small FAM168B protein.

• Transfer conditions: Implement efficient transfer protocols for small proteins, potentially using PVDF membranes with 0.2 μm pore size rather than 0.45 μm to prevent protein pass-through.

• Blocking conditions: Optimize blocking conditions (typically 5% non-fat dry milk or BSA in TBST) to minimize background while preserving specific signal.

• Antibody concentration: Available data indicates that commercially available FAM168B antibodies can be effectively used for Western blot applications, with optimal dilutions determined through titration experiments .

• Detection method: Consider enhanced chemiluminescence (ECL) or fluorescent detection methods based on expected protein abundance and available imaging systems.

• Controls: Include positive control lysates from tissues known to express FAM168B, such as brain tissue or skeletal muscle .

These methodological considerations will help researchers achieve specific detection of FAM168B protein in Western blot applications, facilitating accurate quantification and characterization across experimental conditions.

How does FAM168B function as a neuronal axonal outgrowth inhibitor?

FAM168B (also known as MANI - Myelin-associated neurite-outgrowth inhibitor) functions as an inhibitor of neuronal axonal outgrowth through specific molecular mechanisms . Research indicates that FAM168B exerts its inhibitory effects through negative regulation of key signaling pathways involved in axonal growth and extension. Specifically, FAM168B has been characterized as a negative regulator of CDC42, a Rho GTPase that plays critical roles in cytoskeletal reorganization necessary for axon formation and elongation . Additionally, FAM168B negatively regulates STAT3 signaling, which is implicated in promoting neuronal survival and axon regeneration following injury .

The protein's inhibitory function places it in the broader context of myelin-associated inhibitory factors that regulate neuronal plasticity and regeneration. This is particularly relevant in the context of research on GSK249320, a monoclonal antibody designed to block the axon outgrowth inhibition molecule myelin-associated glycoprotein (MAG), which functions through similar inhibitory mechanisms . Studies in non-human primate models of ischemic cortical damage demonstrated that blocking these inhibitory pathways with GSK249320 facilitated functional recovery, suggesting therapeutic potential for targeting axonal outgrowth inhibitors .

The molecular interactions between FAM168B and its downstream effectors provide potential targets for interventions aimed at promoting neural regeneration and recovery following injury to the central nervous system.

What evidence exists for FAM168B's role in immune cell function and regulation?

While FAM168B has been primarily characterized for its role in neuronal function, emerging evidence suggests potential involvement in immune cell processes. RNA expression data from the Human Protein Atlas indicates that FAM168B shows notable expression in certain immune cell populations . The Atlas classification system includes FAM168B within expression clusters that contain genes with similar patterns across immune cells, suggesting potential functional relationships within immune contexts .

FAM168B's documented role as a regulator of STAT3 signaling is particularly interesting in the immune context, as STAT3 is a critical mediator of cytokine signaling and immune cell differentiation . This regulatory relationship suggests that FAM168B might influence immune cell development, activation, or function through modulation of STAT3-dependent pathways.

What is known about FAM168B's involvement in cancer biology?

The relationship between FAM168B and cancer pathobiology warrants investigation based on several lines of evidence. Immunohistochemical analyses have successfully detected FAM168B expression in multiple cancer tissue samples, including human gastric cancer and cervical cancer specimens . Additionally, FAM168B has been detected in cancer cell lines including PC-3 (prostate adenocarcinoma) and A549 (lung carcinoma), suggesting expression across diverse cancer types .

Mechanistically, FAM168B's documented roles as a negative regulator of STAT3 and CDC42 signaling pathways have particular relevance to cancer biology . STAT3 is frequently dysregulated in cancer and contributes to multiple hallmarks of malignancy including proliferation, survival, angiogenesis, and immune evasion. Similarly, CDC42 participates in controlling cell migration, invasion, and metastatic potential. Through its regulatory effects on these pathways, FAM168B might influence cancer cell behavior and malignant progression.

FAM168B's positive regulatory relationship with CDC27, a component of the anaphase-promoting complex involved in cell cycle regulation, suggests additional potential connections to cancer-related processes . Alterations in cell cycle control machinery represent a common feature of cancer cells, making this regulatory relationship potentially significant in oncogenic contexts.

While these associations suggest potential involvement in cancer-related processes, comprehensive studies specifically examining FAM168B's functional role in cancer initiation, progression, or therapeutic response remain limited. This represents an important area for future investigation, potentially revealing novel insights into cancer biology or identifying new therapeutic targets.

How can contradictory findings on FAM168B function be reconciled in experimental designs?

When encountering contradictory findings regarding FAM168B function, researchers should implement systematic approaches to reconcile these discrepancies:

• Context-dependent effects: Design experiments to test whether FAM168B's function varies across different cell types, tissue contexts, or developmental stages. The protein's role as both a negative regulator (of CDC42 and STAT3) and positive regulator (of STMN2 and CDC27) suggests complex, context-dependent functionality .

• Isoform-specific activities: Develop isoform-specific detection methods to determine whether the two identified isoforms of FAM168B exhibit distinct functional properties that might explain seemingly contradictory observations .

• Pathway interaction mapping: Employ pathway analysis approaches to map the network of interactions influenced by FAM168B, potentially revealing how seemingly contradictory effects might arise from differential pathway activation under varying experimental conditions.

• Post-translational modification analysis: Investigate whether post-translational modifications alter FAM168B function, potentially explaining different activities observed across experimental systems.

• Genetic background considerations: Control for genetic background effects by utilizing isogenic cell lines or animal models when comparing FAM168B functions across systems.

• Temporal dynamics: Implement time-course experiments to determine whether FAM168B exhibits different activities at different time points following stimulation or during developmental processes.

By systematically addressing these potential sources of variation, researchers can develop more nuanced models of FAM168B function that accommodate seemingly contradictory observations from diverse experimental systems.

What are the most promising approaches for investigating FAM168B's role in neurological recovery after injury?

The investigation of FAM168B's role in neurological recovery presents exciting research opportunities, particularly given its function as a myelin-associated neurite-outgrowth inhibitor . Several sophisticated approaches hold promise for advancing this research area:

• Conditional gene modulation: Develop conditional knockout or knockdown models of FAM168B that allow precise temporal control of protein expression following injury, enabling evaluation of its role during specific phases of the recovery process.

• Combinatorial therapeutic approaches: Design experiments that combine modulation of FAM168B with manipulation of other regeneration-associated pathways, potentially revealing synergistic effects that could inform comprehensive therapeutic strategies.

• Single-cell transcriptomics: Apply single-cell RNA sequencing to identify cell-specific changes in FAM168B expression following injury and during recovery, potentially revealing previously unrecognized cellular contexts of action.

• Advanced imaging techniques: Utilize techniques such as expansion microscopy or light-sheet microscopy combined with FAM168B antibody staining to visualize protein localization and dynamics during axonal regeneration with unprecedented resolution.

• Translational models: Building on the nonhuman primate studies of myelin-associated inhibitors , develop clinically relevant models that can directly assess the impact of FAM168B modulation on functional recovery outcomes.

• Antibody engineering: Develop function-blocking antibodies specifically targeting FAM168B, similar to the approach used with GSK249320 for myelin-associated glycoprotein , potentially providing both research tools and therapeutic candidates.

These approaches offer promising avenues for elucidating FAM168B's role in neurological recovery and potentially developing novel therapeutic strategies for promoting neural regeneration following injury.

What emerging technologies might advance our understanding of FAM168B protein interactions and regulatory networks?

Several cutting-edge technologies offer significant potential for deepening our understanding of FAM168B's molecular interactions and regulatory functions:

• Proximity labeling proteomics: Techniques such as BioID or APEX2 proximity labeling, where FAM168B is fused to a biotin ligase, could identify proteins that interact with or reside near FAM168B in living cells, potentially revealing previously unknown interaction partners.

• CRISPR-based screening: Genome-wide or focused CRISPR screening approaches could identify genes that modulate FAM168B function or that exhibit synthetic interactions, revealing new components of its regulatory network.

• Phosphoproteomics: Given FAM168B's regulatory relationships with signaling molecules like STAT3, comprehensive phosphoproteomic analysis following FAM168B modulation could map downstream phosphorylation events affected by the protein.

• Cryo-electron microscopy: Structural determination of FAM168B alone or in complex with interaction partners could provide crucial insights into its molecular mechanism of action and guide structure-based drug design efforts.

• Spatial transcriptomics: Integration of FAM168B antibody staining with spatial transcriptomics could reveal localized transcriptional programs associated with FAM168B expression across different tissue microenvironments.

• Organoid models: Examining FAM168B function in brain or immune organoids could provide insights into its role in complex, physiologically relevant three-dimensional environments that better recapitulate in vivo conditions.

• Integrative multi-omics approaches: Combining proteomics, transcriptomics, and metabolomics data following FAM168B manipulation could provide a systems-level understanding of its functional impact across multiple cellular processes.

These technological approaches offer promising avenues for elucidating FAM168B's molecular functions and regulatory networks, potentially revealing new biological insights and therapeutic opportunities.