stard3 Antibody
Description
Introduction to STARD3 Antibody
The STARD3 antibody is a specialized immunological tool targeting STARD3 (StAR-related lipid transfer domain-3), a protein involved in cholesterol transport between the endoplasmic reticulum (ER) and endosomes. STARD3 is co-amplified with HER2 in breast cancer and has emerged as a biomarker for HER2-positive tumors . The antibody enables detection of STARD3 expression in tissues and cell lines, aiding in both basic research and clinical diagnostics.
Key Antibody Features
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3G11 Hybridoma: A monoclonal mouse antibody generated against recombinant STARD3 protein, validated for Western blot and immunofluorescence .
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Specificity: Recognizes STARD3 but not other START domain proteins (e.g., STARD1, STARD4–6) .
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Subcellular Localization: Granular cytoplasmic staining in endosomes, consistent with STARD3’s role in ER-endosome contact sites .
Validation Data
Diagnostic Utility
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Predictive Value: STARD3 negativity on pretreatment biopsies correlates with a lack of pathological complete response (pCR) after neoadjuvant therapy (sensitivity: 96%, specificity: 23%) .
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Association with HER2: STARD3 mRNA and protein levels are strongly correlated with HER2 amplification (p < 0.001) .
Cholesterol Transport Dynamics
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ER-Endosome Contacts: STARD3 requires VAP proteins to tether ER and endosomes, facilitating cholesterol transfer .
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Plasma Membrane (PM) Cholesterol Depletion: Cells overexpressing STARD3 show reduced PM cholesterol (via GFP-D4 staining) and resistance to amphotericin B .
Key Mutant Studies
Clinical and Research Implications
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Therapeutic Targeting: STARD3 inhibitors are under investigation for HER2+ cancers, with preclinical efficacy in reducing tumor cell survival .
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Biomarker Potential: STARD3 IHC could stratify HER2+ patients unlikely to respond to standard therapies, guiding personalized treatment .
Limitations and Future Directions
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
