Septin9 Antibody

What is Septin9 and why is it important for researchers?

Septin9 (SEPT9) belongs to the septin family of GTPase proteins that play critical roles in cell division, cytoskeletal organization, and membrane-remodeling events. SEPT9 has been implicated in tumorigenesis and various cellular processes, making it an important target for research . The protein is particularly prominent in lymphoid tissues and exists in 15 different isoforms through the combination of five alternate amino termini and three alternate carboxy termini . These diverse isoforms allow SEPT9 to perform various functional roles within cells, with its major function being tumor suppression. Mutations in the SEPT9 gene have been linked to conditions including neuritis, hereditary neuralgic amyotrophy, and a wide range of cancers .

How do I choose the appropriate Septin9 antibody for my research?

Selecting the right Septin9 antibody depends on several factors:

• Experimental technique: Different antibodies are optimized for specific applications. For example:

  • For Western blotting: Consider antibodies validated for WB like 10769-1-AP (1:5000-1:50000 dilution)

  • For immunohistochemistry: A302-353A works well at 1:200 dilution

  • For immunofluorescence: The 10C10 clone works at 1:10-1:50 dilution

• Species reactivity: Ensure the antibody recognizes Septin9 in your experimental model:

  • For human-only studies: Several options including 2C6 clone

  • For multi-species studies: Consider 10C10 (reacts with dog, human, mouse and rat) or 10769-1-AP

• Antibody type: Choose between:

  • Monoclonal (like 2C6, 10C10) for high specificity

  • Polyclonal (like A302-353A) for potentially higher sensitivity

• Epitope recognition: Consider which region of Septin9 you want to target:

  • C-terminal specific antibodies (amino acids 57-85)

  • Middle region antibodies (residues 100-150)

What are the common applications for Septin9 antibodies?

Septin9 antibodies can be utilized across multiple experimental platforms:

• Western Blotting (WB): Detect Septin9 protein expression levels and isoforms in cell lysates or tissue extracts

• Immunohistochemistry (IHC): Visualize Septin9 distribution in tissue sections, including cancer tissues

• Immunofluorescence (IF): Examine subcellular localization, showing filamentous patterns near the plasma membrane

• Immunoprecipitation (IP): Isolate Septin9 protein complexes to study interacting partners

• Flow Cytometry (FC): Analyze Septin9 expression in individual cells

• ELISA: Quantify Septin9 levels in various samples

What are the recommended protocols for Western blotting with Septin9 antibodies?

For optimal Western blotting results with Septin9 antibodies:

• Sample preparation:

  • Use whole cell lysates from relevant tissues or cell lines (HeLa cells, brain tissue, and spleen tissue work well)

  • Load appropriate amounts of protein (5-50 μg for direct WB)

• Antibody dilution:

  • Primary antibody: Use at 0.04-0.4 μg/ml for A302-353A or 1:5000-1:50000 for 10769-1-AP

  • Secondary antibody: Select based on primary antibody host species (anti-rabbit or anti-mouse)

• Detection:

  • Chemiluminescence works well with exposure times between 1-3 seconds for optimal visualization

  • Expected molecular weight: approximately 64 kDa for the main Septin9 isoform

• Controls:

  • Include positive controls such as HeLa cells, which express detectable levels of Septin9

  • Consider running samples from multiple tissues to confirm specificity

How should I optimize immunohistochemistry protocols with Septin9 antibodies?

For successful Septin9 immunohistochemistry:

• Tissue preparation:

  • Use formalin-fixed, paraffin-embedded (FFPE) sections

  • Test with validated tissues like human breast carcinoma, pancreas cancer tissue, colon tissue, or testis tissue

• Antigen retrieval:

  • Preferred method: TE buffer pH 9.0

  • Alternative method: citrate buffer pH 6.0

• Antibody concentration:

  • Use at 1:200-1:2000 dilution for 10769-1-AP

  • For A302-353A, a 1:200 dilution (1μg/ml) has been validated

• Detection system:

  • DAB (3,3'-diaminobenzidine) works well for visualizing Septin9 staining patterns

• Counterstaining:

  • Use hematoxylin for nuclear visualization to provide context for Septin9 localization

What are the best practices for immunofluorescence experiments with Septin9 antibodies?

For immunofluorescence studies examining Septin9 localization:

• Cell selection:

  • HeLa cells show good expression and are widely used

  • Other validated cell lines include hTERT-RPE, HepG2, and A431 cells

• Fixation method:

  • Paraformaldehyde fixation preserves filamentous structures

  • Cold methanol can be used for cytoskeletal proteins like Septin9

• Antibody dilution:

  • Use 10C10 at 1:10-1:50 dilution

  • For 10769-1-AP, use 1:50-1:500 dilution

• Visualization pattern:

  • Look for filamentous patterns near the plasma membrane, which is characteristic of Septin9

  • Co-staining with other septins or cytoskeletal markers can provide context

• Validation:

  • Using two different Septin9 antibodies that recognize different epitopes can confirm specificity, as demonstrated with 10C10 and a Septin9 polyclonal antibody

How can I distinguish between different Septin9 isoforms using antibodies?

Distinguishing between the 15 different Septin9 isoforms requires strategic approaches:

• Epitope-specific antibodies:

  • Select antibodies targeting specific regions that differ between isoforms

  • Antibodies targeting the N-terminal region (AA 1-110) may help differentiate isoforms with varying N-termini

  • C-terminal specific antibodies can identify isoforms with different C-termini

• Western blot analysis:

  • Use high-resolution SDS-PAGE (8-10%) to separate closely migrating isoforms

  • Run longer gels to achieve better separation of similar molecular weight isoforms

  • Compare molecular weights against known isoform standards

• Two-dimensional gel electrophoresis:

  • Combine isoelectric focusing with SDS-PAGE to separate isoforms based on both charge and size

  • Follow with Western blotting using Septin9 antibodies

• RT-PCR validation:

  • Design primers specific to different isoform transcripts

  • Correlate protein detection with mRNA expression patterns

• Mass spectrometry:

  • After immunoprecipitation with Septin9 antibodies, perform mass spectrometry analysis to identify peptides unique to specific isoforms

What approaches can I use to study Septin9 protein interactions?

For investigating Septin9 protein interaction networks:

• Co-immunoprecipitation (Co-IP):

  • Use antibodies suitable for IP such as 10C10 (1:10-1:50) or 2C6

  • Prepare lysates using gentle lysis buffers to preserve protein complexes

  • For A302-353A, use 3 μg antibody per mg of lysate

  • Validate findings with reciprocal Co-IPs using antibodies against suspected interaction partners

• Proximity ligation assay (PLA):

  • Combine Septin9 antibodies with antibodies against suspected interaction partners

  • Look for punctate signals indicating proteins in close proximity (<40 nm)

• Immunofluorescence co-localization:

  • Use Septin9 antibodies in combination with antibodies against other cytoskeletal components or suspected interaction partners

  • Perform quantitative co-localization analysis

• Pull-down assays:

  • Express tagged Septin9 and use affinity purification followed by immunoblotting with antibodies against suspected partners

  • Compare results with endogenous Septin9 immunoprecipitation

• Cross-linking mass spectrometry:

  • Cross-link protein complexes in living cells

  • Immunoprecipitate using Septin9 antibodies

  • Identify cross-linked peptides by mass spectrometry

How do I troubleshoot weak or non-specific signals in Septin9 antibody experiments?

When encountering issues with Septin9 antibody experiments:

• Weak or absent signals in Western blots:

  • Increase protein loading (up to 50 μg)

  • Reduce antibody dilution (increase concentration)

  • Extend primary antibody incubation time (overnight at 4°C)

  • Optimize detection method (consider enhanced chemiluminescence substrates)

  • Ensure target protein is present in your sample (use positive controls like HeLa cells)

• Non-specific bands in Western blots:

  • Increase blocking time or concentration

  • Include additional washing steps

  • Dilute antibody further (1:50000 for 10769-1-AP)

  • Use more stringent washing conditions

  • Test alternative blocking agents (BSA vs. non-fat dry milk)

• Background in immunohistochemistry/immunofluorescence:

  • Optimize antibody dilution (start with manufacturer recommendations)

  • Extend blocking time

  • Include additional washing steps

  • Verify specificity using knockout/knockdown controls

  • Test different antigen retrieval methods (TE buffer pH 9.0 vs. citrate buffer pH 6.0)

• No signal in immunoprecipitation:

  • Ensure antibody is suitable for IP applications

  • Increase antibody amount (up to 4.0 μg for 10769-1-AP)

  • Use gentler lysis conditions to preserve epitopes

  • Consider a different antibody clone if epitope might be masked in native conformation

How do I interpret Septin9 localization patterns in different cell types?

Interpreting Septin9 localization requires understanding its context-dependent patterns:

• Normal cellular patterns:

  • Filamentous structures near the plasma membrane are typical

  • Association with actin filaments, microtubules, or other cytoskeletal components

  • Localization may change during cell cycle (especially during cytokinesis)

• Cell-type specific variations:

  • Compare patterns across validated cell lines (HeLa, hTERT-RPE, HepG2, A431)

  • Document differences between normal and cancerous cells of the same tissue origin

  • Consider co-staining with cell-type specific markers

• Quantitative assessment:

  • Measure signal intensity in different subcellular compartments

  • Track changes in localization patterns following experimental treatments

  • Compare with other septin family members to identify unique vs. shared localization features

• Validation approaches:

  • Use multiple antibodies recognizing different epitopes

  • Correlate with GFP-tagged Septin9 expression patterns

  • Verify patterns are abolished in knockout/knockdown cells

What are the implications of altered Septin9 expression in disease models?

Understanding Septin9 expression changes in pathological contexts:

• Cancer models:

  • Septin9 is upregulated in various tumors, including ovarian cancer

  • Compare expression levels between normal and tumor tissues

  • Correlate expression with tumor grade, stage, and patient outcomes

  • Identify which isoforms show altered expression in specific cancer types

• Neurological disorders:

  • Assess Septin9 expression in models of hereditary neuralgic amyotrophy

  • Look for mutations or altered expression in neuritis models

  • Examine distribution in neuronal vs. glial cells

• Experimental manipulation:

  • Monitor effects of Septin9 knockdown/knockout on cellular functions

  • Test whether expression changes correlate with alterations in cytoskeletal organization

  • Assess impact on cell division, migration, and membrane dynamics

• Therapeutic implications:

  • Determine whether Septin9 could serve as a biomarker for disease detection or progression

  • Evaluate whether targeting Septin9 or its interactions might have therapeutic potential

How can I resolve contradictory results between different Septin9 antibodies?

When different Septin9 antibodies yield inconsistent results:

• Epitope mapping:

  • Determine exactly which regions of Septin9 each antibody recognizes:

    • C-terminal region (AA 57-85)

    • Middle region (residues 100-150)

    • N-terminal regions (AA 1-110, AA 26-125)

  • Consider whether epitopes might be differentially accessible in various experimental conditions

• Isoform specificity:

  • Evaluate whether antibodies recognize all 15 Septin9 isoforms or only specific ones

  • Compare molecular weights of detected bands to expected isoform sizes

  • Consider using isoform-specific RT-PCR to correlate with protein detection

• Validation strategies:

  • Test antibodies in Septin9 knockout/knockdown systems

  • Perform peptide competition assays to confirm specificity

  • Compare results between monoclonal and polyclonal antibodies

  • Check for cross-reactivity with other septin family members

• Technical considerations:

  • Optimize protocols specifically for each antibody

  • Consider whether fixation methods affect epitope accessibility differently

  • Test antibodies under both denaturing (Western blot) and native (IP, IF) conditions

How can Septin9 antibodies be used in studying cancer pathways?

Advanced applications for Septin9 antibodies in cancer research:

• Biomarker development:

  • Analyze Septin9 expression across cancer types and stages using tissue microarrays

  • Correlate expression patterns with patient outcomes

  • Determine whether specific isoforms have prognostic value

• Mechanistic studies:

  • Investigate Septin9's role in tumor suppression pathways

  • Study its interactions with oncogenes and tumor suppressor genes

  • Examine changes in Septin9 localization during malignant transformation

• Therapeutic targeting:

  • Use antibodies to identify and validate Septin9 interaction partners as potential drug targets

  • Develop assays to screen compounds that modulate Septin9 function

  • Monitor Septin9 expression changes in response to treatments

• Experimental approaches:

  • Combine Septin9 immunoprecipitation with mass spectrometry to identify cancer-specific interaction partners

  • Use ChIP-seq with transcription factors that regulate Septin9 expression

  • Perform high-content screening using Septin9 antibodies to identify compounds affecting its expression or localization

What are the best approaches for studying Septin9 in neurological disease models?

Specialized methods for investigating Septin9 in neurological contexts:

• Tissue-specific analysis:

  • Optimize immunohistochemistry protocols for neural tissues

  • Compare Septin9 expression and localization between affected and unaffected regions

  • Examine co-localization with neuronal and glial markers

• Models for hereditary neuralgic amyotrophy:

  • Use Septin9 antibodies to characterize expression in patient-derived samples

  • Develop assays to study the effects of disease-associated mutations

  • Examine changes in interaction partners in disease models

• Functional studies:

  • Investigate Septin9's role in axonal transport

  • Study its impact on neuronal cytoskeletal organization

  • Examine potential roles in myelination by co-staining with myelin markers

• Therapeutic implications:

  • Develop assays to screen compounds that might stabilize mutant Septin9

  • Monitor changes in Septin9 expression or localization in response to potential therapies

How can advanced imaging techniques enhance Septin9 antibody research?

Cutting-edge imaging approaches for Septin9 investigation:

• Super-resolution microscopy:

  • Use techniques like STORM, PALM, or SIM with Septin9 antibodies to visualize filamentous structures beyond the diffraction limit

  • Examine nanoscale organization of Septin9 in relation to other cytoskeletal components

  • Track dynamic changes in Septin9 organization during cellular processes

• Live-cell imaging:

  • Combine antibody fragments with cell-penetrating peptides for live-cell studies

  • Correlate findings with fixed-cell antibody staining

  • Track Septin9 dynamics during cell division, migration, or response to stimuli

• Multi-spectral imaging:

  • Use Septin9 antibodies in combination with other cellular markers

  • Perform multiplexed imaging to examine relationships with multiple proteins simultaneously

  • Analyze co-localization quantitatively across different cellular compartments

• Correlative light and electron microscopy (CLEM):

  • Use Septin9 antibodies for immunogold labeling

  • Correlate fluorescence patterns with ultrastructural features

  • Examine Septin9 association with specific membrane domains or cytoskeletal structures at nanometer resolution