HSP90AA1 Antibody

What is HSP90AA1 and what cellular functions does it perform?

HSP90AA1 functions as a molecular chaperone that promotes the maturation, structural maintenance, and proper regulation of specific target proteins involved in cell cycle control and signal transduction. Its activity is linked to an ATP-driven functional cycle that induces conformational changes in client proteins, facilitating their activation. HSP90AA1 interacts dynamically with various co-chaperones that modulate its substrate recognition, ATPase cycle, and chaperone function. Beyond its primary chaperone role, HSP90AA1 plays critical roles in mitochondrial protein import and transcriptional regulation . This 84.7 kilodalton protein is also known by several alternative names including HSP90, HSP90A, HSPCa, heat shock protein HSP 90-alpha, and EL52 .

How should I select the most appropriate HSP90AA1 antibody for my experiment?

Selecting the appropriate HSP90AA1 antibody requires consideration of multiple factors:

For example, if studying both isoforms, an antibody like the rabbit monoclonal against Hsp90 alpha + beta would be appropriate as it reacts with human, mouse, and rat samples and is validated for multiple applications including WB, IHC, ICC/IF, IP, and Flow Cytometry .

In which tissues and cell types is HSP90AA1 typically expressed?

HSP90AA1 demonstrates wide tissue distribution with variable expression levels. According to published literature, HSP90AA1 expression has been documented in:

• Peripheral blood lymphocytes

• Middle temporal gyrus

• Placenta and teratocarcinoma

• Brain and heart tissue

• Liver and pituitary

• T-cells and platelets

• Various cancer cell types including cervix carcinoma, renal cell carcinoma, melanoma, and leukemic T-cells

When designing experiments, researchers should consider this broad expression pattern and include appropriate positive control tissues based on their experimental system.

What are the optimized protocols for HSP90AA1 antibody use in Western blotting?

For optimal Western blot results with HSP90AA1 antibodies, follow this methodological approach:

• Sample preparation: Lyse cells in RIPA buffer supplemented with protease inhibitors; heat samples at 95°C for 5 minutes in reducing sample buffer.

• Gel electrophoresis: Load 10-30 μg of protein per lane on 8-10% SDS-PAGE gels.

• Transfer: Use PVDF membranes for better protein retention.

• Blocking: Block with 5% non-fat dry milk in TBST for 1 hour at room temperature.

• Primary antibody: Dilute HSP90AA1 antibody 1:500-1:2000 in blocking buffer; incubate overnight at 4°C .

• Secondary antibody: Use appropriate HRP-conjugated secondary antibody at 1:5000-1:10000 dilution.

• Detection: Develop using enhanced chemiluminescence and expect a band at approximately 90 kDa.

For troubleshooting, ensure complete transfer of high molecular weight proteins by using longer transfer times or specialized transfer systems designed for larger proteins.

How should I optimize immunohistochemistry protocols for HSP90AA1 detection?

For effective immunohistochemical detection of HSP90AA1:

• Fixation: Use 4% paraformaldehyde (PFA) for optimal tissue preservation and antibody penetration .

• Antigen retrieval: Perform heat-induced epitope retrieval in citrate buffer (pH 6.0) for 20 minutes.

• Blocking: Block with 5-10% normal serum from the same species as the secondary antibody.

• Primary antibody: Apply HSP90AA1 antibody at 1:50-1:200 dilution and incubate overnight at 4°C .

• Detection system: Use a polymer-based detection system for enhanced sensitivity.

• Counterstaining: Counterstain with hematoxylin for nuclear visualization.

• Controls: Include positive control tissues (such as lymphocytes or cancer cell lines) and negative controls (primary antibody omission).

When analyzing results, note that HSP90AA1 can show both cytoplasmic and nuclear localization depending on the cell type and physiological state .

What are the proper storage and handling conditions to maintain HSP90AA1 antibody activity?

To preserve antibody functionality and prevent degradation:

• Long-term storage: Store antibodies at -20°C in manufacturer-recommended buffer.

• Working stock: For frequent use, small aliquots can be stored at 4°C for up to one month.

• Aliquoting: Divide antibody stock into single-use aliquots to avoid repeated freeze-thaw cycles.

• Buffer composition: Typical storage buffer consists of PBS with 0.02% sodium azide and protein stabilizers.

• Handling: Thaw antibodies completely before use and mix gently by flicking the tube (avoid vortexing).

• Contamination prevention: Use sterile techniques when handling antibody solutions .

Proper storage significantly impacts experimental reproducibility; degraded antibodies often result in weak signals or increased background.

How can I differentiate between specific and non-specific signals when using HSP90AA1 antibodies?

To distinguish genuine HSP90AA1 signals from artifacts:

• Molecular weight verification: HSP90AA1 should appear at approximately 90 kDa (84.7 kDa) .

• Positive controls: Include lysates from cells known to express high levels of HSP90AA1 (HeLa, Jurkat, MCF7) .

• Negative controls: When possible, use HSP90AA1 knockdown/knockout samples.

• Peptide competition: Pre-incubate antibody with immunizing peptide to confirm specificity.

• Multiple antibodies: Validate findings using antibodies targeting different HSP90AA1 epitopes.

• Subcellular localization: Confirm expected localization pattern (both cytoplasmic and nuclear staining may be observed) .

Additionally, be aware that HSP90AA1 expression varies across tissues, and subcellular localization can change depending on cellular conditions and stress status.

Why might I observe nuclear staining with HSP90AA1 antibodies, and is this expected?

Nuclear localization of HSP90AA1 is a legitimate finding in many cell types. According to published data:

• HSP90AA1 generally expresses in the nucleus of peripheral blood lymphocytes .

• Nuclear localization is consistent with HSP90AA1's role in transcriptional regulation and interactions with nuclear proteins .

• The distribution between nuclear and cytoplasmic compartments can vary depending on:

  • Cell type and differentiation state

  • Cell cycle phase

  • Stress conditions (heat shock, oxidative stress)

  • Post-translational modifications of HSP90AA1

If nuclear staining seems unexpected in your experimental system, verify using subcellular fractionation followed by Western blotting to confirm the presence of HSP90AA1 in nuclear fractions.

What are common technical issues when using HSP90AA1 antibodies and how can they be resolved?

Common technical challenges and their solutions include:

For particularly challenging applications, consider technique-specific optimization strategies such as extended primary antibody incubation times or signal amplification systems.

How can HSP90AA1 antibodies be utilized to study protein-protein interactions and co-chaperone networks?

To investigate HSP90AA1 interactions with client proteins and co-chaperones:

• Co-immunoprecipitation (Co-IP):

  • Use HSP90AA1 antibodies to pull down the protein complex

  • Analyze co-precipitating proteins by Western blot or mass spectrometry

  • Reverse Co-IP with antibodies against suspected interacting partners

• Proximity Ligation Assay (PLA):

  • Visualize protein interactions in situ with single-molecule resolution

  • Requires antibodies against both HSP90AA1 and its potential interacting partner

  • Generates fluorescent signals only when proteins are within 30-40 nm

• FRET/BRET approaches:

  • Tag HSP90AA1 and interacting proteins with appropriate fluorophores/luminescent proteins

  • Measure energy transfer as indicator of molecular proximity

• ChIP-seq analysis:

  • Utilize HSP90AA1 antibodies to identify genomic regions where HSP90AA1 participates in transcriptional complexes

  • Combine with RNA-seq to correlate with transcriptional outcomes

These approaches are particularly valuable for understanding how HSP90AA1 functions within larger chaperoning complexes and how these interactions may be altered in disease states .

What methodologies can detect post-translational modifications (PTMs) of HSP90AA1?

HSP90AA1 undergoes multiple PTMs that regulate its function. To study these modifications:

• Modification-specific antibodies:

  • Use antibodies that specifically recognize phosphorylated, acetylated, or other modified forms of HSP90AA1

  • Validate specificity using appropriate controls (e.g., phosphatase treatment)

• Mass spectrometry-based approaches:

  • Immunoprecipitate HSP90AA1 using validated antibodies

  • Analyze by LC-MS/MS to identify and quantify PTMs

  • Consider enrichment strategies for specific modifications

• 2D gel electrophoresis:

  • Separate HSP90AA1 isoforms based on charge differences caused by PTMs

  • Follow with Western blotting using HSP90AA1 antibodies

• Pharmacological interventions:

  • Use inhibitors of specific modifying enzymes to manipulate PTM status

  • Monitor changes using modification-specific antibodies

Each approach provides different and complementary information about the dynamic regulation of HSP90AA1 through post-translational modifications.

How can HSP90AA1 antibodies contribute to cancer research and drug development?

HSP90AA1 antibodies are valuable tools in cancer research due to HSP90's role in stabilizing oncogenic proteins. Key methodological approaches include:

• Expression profiling:

  • Quantify HSP90AA1 levels across tumor samples using immunohistochemistry or Western blotting

  • Correlate expression with clinical parameters and outcomes

• Client protein analysis:

  • Monitor effects of HSP90 inhibitors on client protein stability

  • Use HSP90AA1 antibodies to track drug engagement with the target

• Drug mechanism studies:

  • Investigate how HSP90 inhibitors affect HSP90AA1 localization and complex formation

  • Study compensatory mechanisms upon HSP90 inhibition

• Biomarker development:

  • Evaluate HSP90AA1 or its modified forms as potential predictive biomarkers for response to HSP90 inhibitors

  • Develop immunoassays for monitoring treatment effects

• Combination therapy investigations:

  • Use HSP90AA1 antibodies to study mechanistic basis for synergistic drug interactions

  • Monitor changes in HSP90AA1 complexes during combination treatments

These approaches contribute to both fundamental understanding of HSP90AA1 in cancer biology and practical applications in drug discovery and development .

How are HSP90AA1 antibodies being used to study extracellular and exosomal HSP90?

Recent research has identified HSP90AA1 in extracellular spaces and exosomes, suggesting roles beyond intracellular chaperoning. To investigate these functions:

• Exosome isolation and characterization:

  • Isolate exosomes using ultracentrifugation or commercial kits

  • Confirm HSP90AA1 presence using Western blotting

  • Investigate HSP90AA1 localization (surface vs. lumen) using protease protection assays

• Extracellular HSP90AA1 detection:

  • Develop ELISA systems using HSP90AA1 antibodies for quantification in biological fluids

  • Analyze conditioned media from different cell types to profile secretion patterns

• Functional studies:

  • Neutralize extracellular HSP90AA1 using antibodies to assess its role in cell-cell communication

  • Evaluate effects on immune cell activation and inflammatory responses

These applications are expanding our understanding of HSP90AA1's non-canonical functions in intercellular signaling and potential roles in disease pathogenesis.

What considerations are important when designing multiplex assays involving HSP90AA1 antibodies?

For effective multiplexed detection of HSP90AA1 alongside other proteins:

• Antibody compatibility assessment:

  • Select HSP90AA1 antibodies from different host species than other target antibodies

  • Verify minimal cross-reactivity between secondary antibodies

• Spectral separation strategies:

  • Choose fluorophores with minimal spectral overlap for immunofluorescence

  • When using chromogenic detection, select enzymes producing distinct colors

• Optimization approaches:

  • Titrate each antibody individually before combining

  • Consider sequential rather than simultaneous incubation if interference occurs

  • Include appropriate controls for each target protein

• Data analysis considerations:

  • Account for potential bleed-through in fluorescence channels

  • Normalize HSP90AA1 signals appropriately when comparing across samples

Properly designed multiplex assays can provide valuable insights into how HSP90AA1 expression and localization correlate with client proteins or co-chaperones in various physiological and pathological states.