S100A5 Antibody
Description
Overview of S100A5 Antibody
Target Protein: S100A5 (UniProt ID: P33763), a member of the S100 family of calcium-binding proteins, encoded by the S100A5 gene (NCBI Gene ID: 6276).
Antibody Characteristics:
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Host Species: Rabbit
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Isotype: IgG
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Clonality: Polyclonal
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Immunogen: S100A5 fusion protein (Ag12342)
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Molecular Weight: 13 kDa (calculated), 11 kDa (observed)
Research Applications
The S100A5 antibody (e.g., Proteintech 17924-1-AP) is validated for multiple applications:
| Application | Tested Reactivity | Recommended Dilution |
|---|---|---|
| Western Blot (WB) | HepG2 cells, human kidney/liver tissue | 1:500–1:3000 |
| Immunohistochemistry (IHC) | Human brain/meningioma tissue | 1:50–1:500 |
| Immunofluorescence (IF) | HepG2 cells | 1:20–1:200 |
Key Validation:
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IHC staining confirmed in human brain tissue with TE buffer (pH 9.0) antigen retrieval .
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WB detects a single band at ~11 kDa in SH-SY5Y neuroblastoma cells .
Role in Cancer Biology
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Immunosuppression in Bladder Cancer (BLCA):
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S100A5 inhibits CD8⁺ T-cell recruitment by suppressing pro-inflammatory chemokines (e.g., CXCL9/10) .
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High S100A5 expression correlates with reduced tumor-infiltrating immune cells (e.g., NK cells, dendritic cells) and attenuated anti-PD-1/PD-L1 therapy efficacy .
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Spatially exclusive distribution between S100A5⁺ tumor cells and CD8⁺ T cells in BLCA tissues .
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| Functional Impact | Mechanism |
|---|---|
| Tumor proliferation/invasion | Acts as an oncogene |
| Immunotherapy resistance | Reduces CD8⁺ T-cell cytotoxicity |
Therapeutic Implications
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Targeting S100A5 in preclinical models synergizes with anti-PD-1 therapy, converting "cold" tumors (immune-excluded) to "hot" tumors (immune-infiltrated) .
Clinical and Experimental Relevance
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Biomarker Potential: S100A5 expression inversely correlates with cytotoxic immune cell infiltration, serving as a predictor of immunotherapy response in BLCA .
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Disease Associations: Beyond cancer, S100A5 is implicated in neurological contexts, though its antibody is primarily utilized in oncology research .
Product Specs
Target Background
- Isothermal titration calorimetry revealed that human S100A5 and S100A6 bind distinct but overlapping sets of peptides with diverse sequences and biochemical properties. Reversion of a single historical mutation in human S100A5 restored its ability to bind an S100A6-specific peptide. This suggests that the specificity of S100 peptide interfaces is likely crucial for the biological functions of these proteins. PMID: 29240404
- Research indicates that pentamidine inhibits the binding between S100A5 and the V domain of receptor for advanced glycation end products (RAGE). This finding holds promise for the development of new anti-proliferative drugs. PMID: 27297108
- S100A5 interacts with RAGE-v through the periphery of the dimer interface. PMID: 28017722
- S100A5 is strongly expressed in the cells and fibers of the hippocampus at 12 weeks gestation and then decreases with age. In the temporal cortex, S100A5 expression is detected from 12 weeks onwards, peaks between 20 and 24 weeks, and then decreases with age. PMID: 12645008
- Solution structures of S100A5 in both apo (calcium-free) and Ca(II)-loaded forms have been determined, revealing conformational rearrangements upon calcium binding. Notably, significant mobility was observed in the hinge loop of apo-S100A5, which was not quenched in the calcium-bound form. PMID: 19536568
