HSPH1 antibodies (e.g., Proteintech 13383-1-AP, Thermo Fisher 13383-1-AP) are polyclonal antibodies raised against the HSPH1 protein, a member of the HSP70 chaperone family. The immunogen is a fusion protein corresponding to residues 508–858 of human HSPH1 (UniProt ID: Q92598) . The antibody detects both HSP105α (constitutive cytoplasmic isoform) and HSP105β (inducible nuclear isoform) .
Key Features:
Western Blot (WB): Detects HSPH1 in lysates from MCF7, HeLa, Jurkat, and K-562 cells at dilutions of 1:500–1:2000 .
Immunohistochemistry (IHC): Validated in human colon, liver, and pancreatic cancer tissues (1:200–1:1200 dilution) .
Immunofluorescence (IF): Demonstrated in stress response studies involving HSP70 complexes .
HSPH1 functions as a molecular chaperone, preventing protein aggregation under stress and regulating proteasomal degradation . Key findings include:
Cancer Biology: Overexpressed in melanoma, breast, thyroid, and gastrointestinal cancers, where it exerts anti-apoptotic effects . High HSPH1 levels correlate with poor prognosis in esophageal and prostate cancers .
Immune Modulation: Facilitates CD8+ T cell stress responses in prostate cancer, enhancing tumor suppression .
Thermotolerance: Cooperates with HSPA1 and DNAJB1 to maintain proteostasis during heat stress, critical for tumor survival .
Upregulated in prostate cancer extracellular vesicles (EVs), with higher mRNA/protein levels in tumors vs. adjacent tissues .
Inhibition Studies: HSPH1 knockdown impedes esophageal tumor growth in mice . KNK437 (HSPH1 inhibitor) reduces STAT3 phosphorylation and lung injury in acute lung injury models .
Immune Checkpoint Blockade (ICB): HSPH1+ CD8+ T cells show reduced response to ICB, suggesting dual roles in immune regulation .
Prostate Cancer: HSPH1 in EVs promotes CD8+ T cell-mediated tumor suppression via IL2-MYC-IL2RA signaling .
Thermotolerance: HSPH1 stabilizes denatured proteins during heat stress, enabling rapid protein synthesis recovery .
Acute Lung Injury: IL-1β/KLF2/HSPH1 axis drives STAT3 activation, exacerbating inflammation .
HSPH1 (Heat Shock 105kDa/110kDa Protein 1) belongs to the highly conserved family of heat shock proteins that function primarily as molecular chaperones. These proteins facilitate proper folding of other cellular proteins, prevent protein aggregation, and target improperly folded proteins for degradation . HSPH1 specifically acts as a chaperone to prevent thermal aggregation in mammalian cells, making it crucial for cellular stress response mechanisms . The protein exists in two isoforms: alpha (858 amino acids) and beta (814 amino acids), which share 94% identity but may serve distinct functions under different cellular conditions . Research interest in HSPH1 stems from its fundamental role in protein quality control and potential implications in diseases involving protein misfolding.
Anti-HSPH1 antibodies differ primarily in four key aspects:
Target epitopes: Antibodies target different regions of the HSPH1 protein, such as those surrounding Pro819, AA 713-733, C-Terminal regions, AA 549-579, AA 659-858, or the full-length protein (AA 1-858) .
Host and clonality: Most commercially available antibodies are rabbit polyclonal, though mouse monoclonal options like clone #531104 are also available . The choice between polyclonal and monoclonal impacts specificity and applications.
Species reactivity: While many antibodies react with human, mouse, and rat HSPH1, some have broader reactivity including monkey, hamster, cow, sheep, and even Saccharomyces cerevisiae . Cross-reactivity should be verified experimentally as the high conservation (e.g., 92% identity between rat and human, 97% between rat and mouse) can affect specificity .
Applications compatibility: Different antibodies are optimized for specific techniques including Western Blotting, Immunohistochemistry, ELISA, Immunofluorescence, and Flow Cytometry .
HSPH1 antibodies require proper storage and handling to maintain their specificity and activity. While specific storage conditions may vary slightly between manufacturers, generally these antibodies should be stored at -20°C for long-term preservation. For working solutions, aliquoting is strongly recommended to avoid repeated freeze-thaw cycles, which can progressively degrade antibody performance through protein denaturation and aggregation . Storage buffers typically contain stabilizers like glycerol or bovine serum albumin that help maintain antibody conformation. For daily use, antibodies can be kept at 4°C for short periods (1-2 weeks), but extended storage at this temperature may lead to bacterial contamination or reduced activity. Always centrifuge antibody solutions briefly before opening to collect liquid potentially dispersed on tube walls during shipping or storage. Record dates of reconstitution and track the number of freeze-thaw cycles to maintain experimental reproducibility.
Rigorous validation of HSPH1 antibodies requires a multi-approach strategy to ensure experimental results are reliable and reproducible:
Positive control testing: Utilize cell lines known to express HSPH1, such as HT-29 human colon adenocarcinoma, NIH-3T3 mouse embryonic fibroblasts, or Nb2-11 rat lymphoma cells, which demonstrate detectable levels of HSPH1 especially after heat shock treatment .
Heat shock induction: Compare antibody reactivity in untreated versus heat-shocked samples (e.g., 42°C for 30 minutes followed by recovery at 37°C for 3 hours), as demonstrated in the Western blot validation data from R&D Systems, which shows increased HSPH1 expression after heat stress .
Molecular weight verification: Confirm detection of the appropriate band size (~110 kDa on SDS-PAGE) despite calculated molecular weights of 96.4 kDa for alpha and 92 kDa for beta isoforms .
Knockdown/knockout controls: Employ siRNA knockdown or CRISPR/Cas9 knockout samples as negative controls to verify antibody specificity.
Cross-species reactivity assessment: Test reactivity against expected species targets, noting that rat HSPH1 has 92% identity to human and 97% identity to mouse HSPH1 .
Differentiating between HSPH1 alpha (858 aa) and beta (814 aa) isoforms presents a significant challenge due to their 94% sequence identity and similar molecular weights . A comprehensive experimental approach includes:
Isoform-specific antibodies: Select antibodies targeting regions that differ between isoforms. For example, antibodies recognizing unique sequences in the 44-amino acid region present in alpha but absent in beta isoform.
High-resolution gel electrophoresis: Employ gradient gels (e.g., 5-8%) with extended running times to maximize separation between the alpha (apparent MW ~110 kDa) and beta (apparent MW ~105 kDa) isoforms.
2D gel electrophoresis: Combine isoelectric focusing with SDS-PAGE to leverage potential pI differences between isoforms for improved separation.
Mass spectrometry: Perform tryptic digestion followed by LC-MS/MS to identify isoform-specific peptides, enabling precise identification and quantification of each isoform.
RT-PCR with isoform-specific primers: Design primers spanning the alternative splicing region to quantify mRNA expression of each isoform before protein analysis.
Cell-specific expression patterns: Utilize control samples with known differential expression of alpha and beta isoforms (e.g., beta is predominantly expressed under heat stress conditions in specific cell types).
Successful detection of HSPH1 by Western blotting requires attention to several critical parameters:
Sample preparation: Heat shock treatment (42°C for 30 minutes followed by recovery at 37°C for 3 hours) significantly increases HSPH1 expression, providing stronger signals for detection and validation . Use reducing conditions as demonstrated in R&D Systems' validation data .
Protein loading: Load adequate protein (typically 20-50 μg of total protein) to detect endogenous levels of HSPH1. For heat-shocked samples, reduced amounts may be sufficient.
Antibody selection and concentration: Select antibodies validated for Western blotting and optimize primary antibody concentration (typically 0.5-1 μg/mL, as used in R&D Systems' protocol) . Different antibodies may require different blocking solutions and incubation conditions.
Gel percentage and transfer conditions: Use lower percentage gels (7-10%) for optimal resolution of the high molecular weight HSPH1 (apparent MW 105-110 kDa). Wet transfer is recommended for large proteins, with extended transfer times.
Detection system compatibility: Choose secondary antibodies and detection systems compatible with your primary antibody host species. HRP-conjugated secondary antibodies work effectively with chemiluminescent detection systems, as demonstrated in published protocols .
Buffer optimization: Use Immunoblot Buffer Group 2 as recommended by R&D Systems or equivalent buffer systems optimized for detection of high molecular weight proteins .
Non-specific binding and background issues in HSPH1 immunohistochemistry can be addressed through systematic troubleshooting:
Antibody dilution optimization: Titrate antibody concentrations to identify the optimal dilution that maximizes specific signal while minimizing background. For example, mouse ESC immunofluorescence protocols have successfully used 1:200 dilution of HSPH1 antibody .
Blocking protocol enhancement: Implement robust blocking with a combination of normal serum (1% normal goat serum) and BSA (5%) as successfully demonstrated in mouse embryonic stem cell staining . Extended blocking times (1-2 hours at room temperature) may further reduce background.
Fixation method consideration: For HSPH1 detection, 4% paraformaldehyde freshly prepared with NaOH has proven effective, preserving epitope accessibility while maintaining cellular architecture . Compare multiple fixation methods to identify optimal conditions for your specific tissue/cell type.
Permeabilization optimization: Adjust permeabilization conditions (e.g., 0.3% Triton X-100 concentration and incubation time) to balance antibody access to intracellular epitopes with preservation of morphology .
Antigen retrieval method selection: Compare heat-induced epitope retrieval methods (citrate buffer, pH 6.0 versus EDTA buffer, pH 9.0) to enhance epitope accessibility while maintaining tissue integrity.
Secondary antibody controls: Include controls omitting primary antibody to identify non-specific binding of secondary antibodies or endogenous peroxidase/phosphatase activity.
Co-immunoprecipitation (Co-IP) with HSPH1 antibodies requires careful experimental design:
Antibody selection: Choose antibodies affinity-purified using epitope-specific immunogens with demonstrated specificity for endogenous HSPH1. Polyclonal antibodies often perform better in Co-IP due to recognition of multiple epitopes.
Lysis buffer composition: Optimize lysis conditions to preserve protein-protein interactions involving HSPH1 while effectively extracting the protein from cellular compartments. For chaperone interactions, non-ionic detergents (0.5-1% NP-40 or Triton X-100) in physiological salt concentrations are recommended.
Pre-clearing strategy: Implement sample pre-clearing with appropriate control IgG and protein A/G beads to minimize non-specific binding, particularly important for highly abundant heat shock proteins.
Cross-linking consideration: For transient or weak interactions, consider mild cross-linking (0.5-2% formaldehyde for 10 minutes) before lysis to stabilize complexes.
Washing stringency balance: Determine optimal washing conditions to remove non-specific interactions while preserving true HSPH1 complexes. A gradient of salt concentrations can help establish the right balance.
Control experiments: Include isotype-matched IgG controls, reciprocal Co-IPs (when antibodies to interaction partners are available), and validation in HSPH1-depleted samples to confirm specificity.
Detection strategy: For Western blot detection of co-immunoprecipitated complexes, select antibodies recognizing different epitopes than those used for immunoprecipitation to avoid heavy chain interference.
Designing robust experiments to study HSPH1 expression under stress conditions requires:
Stress induction protocols: Implement multiple stress paradigms beyond heat shock, including:
Heat shock: 42°C for 30 minutes followed by recovery at 37°C for various timepoints (1, 3, 6, 12, 24 hours)
Oxidative stress: H₂O₂ treatment (0.1-1 mM for 0.5-3 hours)
ER stress: tunicamycin or thapsigargin treatment
Hypoxia: 1-5% O₂ exposure
Nutrient deprivation: serum starvation or glucose limitation
Time course design: Analyze both immediate (0-6 hours) and delayed (12-72 hours) responses to capture both direct stress responses and adaptive mechanisms.
Quantification methods: Employ multiple quantification approaches:
Western blot with densitometry for protein level quantification
qRT-PCR for transcript level analysis of both alpha and beta isoforms
Immunofluorescence for subcellular localization changes
Cell type considerations: Compare responses in different cell types (e.g., HT-29 human colon adenocarcinoma, NIH-3T3 mouse embryonic fibroblasts, Nb2-11 rat lymphoma) as HSPH1 regulation may vary by cellular context.
Controls and normalization: Include appropriate housekeeping controls (β-actin, GAPDH) stable under your chosen stress conditions. For heat shock studies, include known heat shock proteins (HSP70, HSP90) as positive controls.
Statistical analysis: Conduct experiments with biological triplicates and technical replicates, applying appropriate statistical tests based on data distribution and experimental design.
Selecting appropriate cell lines for HSPH1 functional studies involves several critical considerations:
Baseline expression profiling: Characterize baseline HSPH1 expression in candidate cell lines using Western blot and qRT-PCR to identify those with detectable but not excessive expression levels. HT-29, NIH-3T3, and Nb2-11 have demonstrated useful HSPH1 expression profiles .
Isoform expression ratio: Determine the alpha/beta isoform ratio in candidate cell lines, as this may influence functional outcomes of manipulation experiments.
Stress response characteristics: Evaluate how candidate cell lines respond to stress conditions relevant to your research question. Some cell lines exhibit robust heat shock responses (as observed in HT-29, NIH-3T3, and Nb2-11) while others may be more responsive to different stressors.
Transfection/transduction efficiency: Assess the amenability of candidate cell lines to your planned genetic manipulation techniques (transfection, viral transduction, CRISPR-Cas9 editing).
Functional assay compatibility: Ensure compatibility with downstream functional assays such as viability measurement, protein aggregation quantification, and chaperone activity assessment.
Species considerations: Select cell lines appropriate for your research question, noting cross-species conservation (92% identity between rat and human HSPH1; 97% between rat and mouse HSPH1) when translating findings between model systems.
Biological relevance: Choose cell lines relevant to the biological context of your research question (e.g., neuron-derived lines for neurodegenerative disease studies, cancer cell lines for oncology applications).
Antibody validation controls:
Expression manipulation controls:
Empty vector controls for overexpression studies
Non-targeting siRNA/shRNA for knockdown experiments
Wild-type cells alongside CRISPR-edited lines
Stress response controls:
Unstressed/untreated cells as baseline controls
Time-matched controls for each experimental timepoint
Positive control proteins (HSP70, HSP90) that respond to the same stressors
Subcellular localization controls:
Co-staining with compartment markers (e.g., DAPI for nucleus, phalloidin for actin cytoskeleton)
Fractionation quality controls (markers for cytoplasmic, nuclear, membrane fractions)
Functional assay controls:
Chaperone activity: Known substrate proteins
Protein aggregation: Positive aggregation inducers
Cell viability: Positive death inducers
Colony morphology controls (for stem cell studies):
Comparing HSPH1 expression across tissues requires standardized approaches to overcome technical and biological variability:
Tissue collection and preservation standardization:
Implement consistent collection protocols minimizing ischemia time
Standardize fixation/preservation methods (e.g., flash freezing, fixed time in formalin)
Document and control for relevant variables (e.g., age, sex, treatment status)
Multiple detection methodologies:
Western blot for protein level quantification
IHC/IF for localization and cell-type specific expression
qRT-PCR for transcript level analysis
Proteomics for unbiased quantification
Normalization strategy optimization:
Identify stable reference genes/proteins specific to each tissue type
Consider global normalization methods (total protein staining) to overcome housekeeping protein variability between tissues
Calculate relative rather than absolute expression when appropriate
Semi-quantitative IHC approach:
Implement standardized scoring systems (H-score, Allred score)
Use digital pathology quantification with consistent thresholding
Include standardized positive controls on each slide
Cross-reactivity assessment:
Technical replicate planning:
Include biological triplicates minimum
Analyze multiple tissue sections/extracts per sample
Consider batch effects in experimental design
Interpreting HSPH1 isoform expression differences requires sophisticated analysis:
Isoform-specific quantification:
Context-dependent expression patterns:
Evaluate whether observed changes reflect typical stress responses (e.g., heat shock typically induces both isoforms but with different kinetics)
Consider cell-type specific regulatory mechanisms based on established patterns (e.g., higher expression in round versus flattened embryonic stem cell colonies)
Functional correlation analysis:
Correlate isoform ratio changes with functional outcomes (e.g., protein aggregation, cell survival)
Determine whether observed changes are upstream drivers or downstream consequences of the biological process under study
Temporal dynamics evaluation:
Analyze time course data to distinguish between early regulatory events and secondary adaptive responses
Consider differential stability of isoforms when interpreting steady-state measurements
Statistical robustness assessment:
Apply appropriate statistical tests accounting for data distribution
Implement correction for multiple testing when examining isoform expression across numerous conditions
Evolutionary conservation consideration:
Selecting appropriate statistical methods for HSPH1 studies depends on experimental design:
Before applying statistical tests:
Evaluate data distribution (normal vs. non-normal) using Shapiro-Wilk or Kolmogorov-Smirnov tests
Check for homogeneity of variance with Levene's test
Identify and address outliers through principled approaches
For comparing two groups:
Normally distributed data: Independent t-test (unpaired samples) or paired t-test (paired samples)
Non-normally distributed data: Mann-Whitney U test (unpaired) or Wilcoxon signed-rank test (paired)
For comparing multiple groups:
Normally distributed data: One-way ANOVA with appropriate post-hoc tests (Tukey for all pairwise comparisons, Dunnett for comparisons to control)
Non-normally distributed data: Kruskal-Wallis with Dunn's post-hoc test
For factorial designs: Two-way or multi-way ANOVA with interaction term analysis
For time course experiments:
Repeated measures ANOVA for normally distributed data
Mixed-effects models for handling missing timepoints or irregular sampling
Area under curve (AUC) analysis to compress temporal data for simplified comparison
For correlation analyses:
Pearson correlation for normally distributed continuous variables
Spearman correlation for non-normally distributed or ordinal data
Multiple regression for controlling confounding variables
For high-dimensional data:
Correction for multiple testing (Bonferroni, Benjamini-Hochberg)
Dimension reduction techniques (PCA, t-SNE) for visualizing patterns
Hierarchical clustering for identifying expression pattern similarities
Reconciling contradictory HSPH1 detection results requires systematic investigation:
Method-specific limitations assessment:
Western blot: Protein extraction efficiency, antibody specificity, linear detection range
qRT-PCR: Primer specificity, amplification efficiency, reference gene stability
IHC/IF: Fixation effects, epitope accessibility, background fluorescence
Mass spectrometry: Peptide recovery, ionization efficiency, isoform-specific peptide detection
Technical vs. biological variability differentiation:
Replicate experiments to distinguish random variation from consistent methodological differences
Control for batch effects through experimental design and statistical adjustment
Implement standardized protocols to minimize technical variables
Antibody-specific considerations:
Sample preparation impact:
Resolution limitations:
Integrated data analysis approach:
Implement weighted analysis considering the relative strengths/limitations of each method
Triangulate results by adding orthogonal methods when two approaches conflict
Comparing HSPH1 antibody performance across research groups requires careful analysis:
Antibody source and validation variability:
Determine whether identical antibody clones/catalog numbers were used or just similar target regions
Compare validation protocols between groups (e.g., knockout controls, specificity testing)
Evaluate lot-to-lot variability in antibody production that might explain discrepancies
Protocol differences assessment:
Compare key protocol parameters (antibody concentration, incubation time/temperature, blocking conditions)
Identify different buffer systems used (e.g., Immunoblot Buffer Group 2 as used in some Western blot protocols)
Examine sample preparation methods (cell lysis, tissue processing, antigen retrieval)
Cell/tissue variability consideration:
Analyze baseline HSPH1 expression differences in experimental models between groups
Consider passage number effects in cell lines
Evaluate genetic background differences in model organisms
Detection system comparison:
Assess sensitivity differences between detection methods (chemiluminescence vs. fluorescence)
Compare digital image acquisition and processing approaches
Evaluate quantification strategies (densitometry methods, normalization approaches)
Stress induction standardization:
Compare heat shock protocols (temperature, duration, recovery time)
Evaluate other stress induction methods that might affect HSPH1 expression or conformation
Consider non-standardized environmental stressors (incubator CO₂ variations, media differences)
Reporting standards evaluation:
Assess completeness of methods reporting (antibody catalog numbers, dilutions, exposure times)
Consider whether negative results might be underreported
Implement standardized reporting using established guidelines (e.g., ARRIVE guidelines for animal studies)
Interpreting HSPH1 localization from immunofluorescence requires detailed analysis:
Subcellular pattern characterization:
Document predominant localization patterns (cytoplasmic, nuclear, membrane-associated)
Note whether observed patterns match expected HSPH1 localization (primarily cytoplasmic, as observed in mouse embryonic stem cells)
Quantify distribution patterns using intensity profiles or compartment ratio measurements
Co-localization analysis with organelle markers:
Implement robust co-localization quantification (Pearson's correlation, Manders' overlap coefficient)
Control for random overlap in densely packed cellular regions
Consider three-dimensional distribution using confocal z-stacks rather than single optical sections
Physiological state consideration:
Fixation and permeabilization artifacts:
Antibody penetration assessment:
Verify antibody access to different subcellular compartments
Consider epitope masking in protein complexes or aggregates
Implement antigen retrieval optimization when necessary
Technical parameters standardization:
Control image acquisition settings (exposure, gain, offset)
Implement consistent thresholding in intensity quantification
Address potential bleed-through or cross-talk in multi-channel imaging
The study of HSPH1 is being transformed by several cutting-edge technologies:
CRISPR-based approaches:
CRISPR-Cas9 knockout models for precise functional analysis
CRISPRi/CRISPRa for tunable expression modulation
CRISPR-based endogenous tagging to visualize HSPH1 without antibodies
Advanced imaging technologies:
Super-resolution microscopy (STORM, PALM) for nanoscale localization
Live-cell imaging with photoconvertible fluorescent protein fusions
Correlative light and electron microscopy for ultrastructural context
Single-cell analysis platforms:
Single-cell RNA-seq for expression heterogeneity assessment
Single-cell proteomics for protein level variance
Spatial transcriptomics for tissue context preservation
Interactome mapping tools:
Proximity labeling (BioID, APEX) for identifying dynamic interaction partners
Thermal proteome profiling to assess protein stability changes
Cross-linking mass spectrometry for structural interaction details
Structural biology advances:
Cryo-EM for high-resolution structures of HSPH1 complexes
Hydrogen-deuterium exchange mass spectrometry for conformational dynamics
AlphaFold2 predictions to guide functional domain analysis
Organoid and tissue-chip systems:
3D organoid cultures for physiologically relevant expression studies
Microphysiological systems for tissue-specific HSPH1 function
Patient-derived models for personalized disease relevance
Several promising research directions are emerging for HSPH1 in disease contexts:
Neurodegenerative disorders:
HSPH1's interaction with misfolded proteins in Alzheimer's, Parkinson's, and ALS
Differential roles of alpha vs. beta isoforms in protein aggregation prevention
Potential therapeutic strategies enhancing HSPH1 chaperone activity
Cancer biology:
HSPH1 contribution to proteostasis in rapidly dividing tumor cells
Role in therapy resistance mechanisms
Potential as a biomarker or therapeutic target, particularly in heat shock protein-dependent cancers
Inflammatory conditions:
HSPH1's potential immunomodulatory functions
Role in cellular responses to inflammatory stressors
Interaction with damage-associated molecular patterns (DAMPs)
Developmental biology:
Aging research:
Decline in chaperone function as a contributor to age-related proteostasis collapse
HSPH1 as a potential intervention target for age-related pathologies
Relationship between stress resistance and longevity through HSPH1 pathways
Drug discovery approaches:
High-throughput screening for HSPH1 modulators
Structure-based drug design targeting specific functional domains
Exosome-based delivery of functional HSPH1 for therapeutic applications