DHS1 Antibody
Description
Definition and Target
The DHS1 antibody is a research tool designed to detect and study deoxyhypusine synthase 1 (DHS1), an enzyme critical for the post-translational modification of eukaryotic translation initiation factor 5A (eIF5A). This modification, termed hypusination, involves the covalent attachment of the hypusine residue to eIF5A, a process essential for cell proliferation, differentiation, and survival in eukaryotes .
Molecular and Functional Characteristics
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Enzyme Activity: DHS1 catalyzes the first step of hypusine biosynthesis by transferring an aminobutyl moiety from spermidine to a conserved lysine residue on eIF5A .
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Structural Insights:
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Gene Essentiality: Genetic silencing of EhDHS1 in E. histolytica results in arrested growth, underscoring its indispensability .
Enzymatic Activity and Substrate Specificity
| Parameter | EhDHS1 Activity (pmol/min/mg) | EhDHS1/DHS2 Complex Activity (µmol/min/mg) |
|---|---|---|
| Substrate: eIF5A1 | 13.0 ± 1.0 | 26.1 ± 6.0 |
| Substrate: eIF5A2 | 9.4 ± 2.3 | 22.4 ± 10.0 |
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Cooperative Function: While EhDHS2 alone lacks catalytic activity, its partnership with EhDHS1 restores enzymatic function, enabling efficient hypusination of both eIF5A isoforms (eIF5A1 and eIF5A2) .
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Developmental Regulation: In Entamoeba invadens, EhDHS1 expression increases during excystation (a differentiation stage), whereas EhDHS2 decreases, suggesting stage-specific roles .
Therapeutic Implications
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Drug Target Potential: The hypusination pathway is absent in humans, making DHS1 a promising target for anti-parasitic drug development .
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Functional Redundancy: The presence of two DHS isoforms in protozoan parasites highlights evolutionary adaptations to maintain hypusination under stress .
Applications of DHS1 Antibody
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Biochemical Assays: Quantifying DHS1 expression and activity in parasite lysates .
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Localization Studies: Tracking DHS1 distribution during life cycle stages (e.g., trophozoites vs. cysts) .
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Drug Screening: Evaluating inhibitors targeting DHS1-eIF5A interactions .
Challenges and Future Directions
Product Specs
Constituents: 50% Glycerol, 0.01M Phosphate Buffered Saline (PBS), pH 7.4
Target Background
Q&A
How were antiphospholipid antibodies (aPL) quantified in the Dallas Heart Study (DHS) cohorts, and what thresholds defined clinical relevance?
Antibodies were measured using solid-phase assays (Quanta Lite kits) to detect IgG, IgM, and IgA isotypes of aPL, including anti-cardiolipin (aCL), anti-β2-glycoprotein I (aβ2GPI), and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies .
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Methodological considerations:
What cohort design features minimized bias in DHS1/DHS2 antibody studies?
The DHS cohorts prioritized:
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Diversity: 51.3% Black, 14.0% Hispanic, and 32.8% White participants .
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Longitudinal tracking: ASCVD events (myocardial infarction, stroke) were adjudicated over 15+ years post-baseline .
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Exclusion criteria: Participants with autoimmune diseases or immunosuppressive therapies were excluded to reduce confounding .
How were antinuclear antibodies (ANA) linked to aPL in DHS1?
ANA testing (via Quanta Lite ANA at 1:160 dilution in DHS1) revealed:
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4.8% ANA positivity in the general population, aligning with epidemiological norms .
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Significant associations between ANA and moderate/high-titer aβ2GPI IgA (P = 0.02) and aPS/PT IgG/IgM (P < 0.01) .
How did researchers resolve contradictory findings in sex- and race-based aPL prevalence?
Initial analysis suggested higher aCL IgM in females, but stratification by titer thresholds eliminated this disparity:
| Antibody Isotype | Female Prevalence (≥40 units) | Male Prevalence (≥40 units) | P-Value |
|---|---|---|---|
| aCL IgM | 2.1% | 1.9% | 0.82 |
| aPS/PT IgM | 1.3% | 1.5% | 0.71 |
Method: Logistic regression with Bonferroni correction for multiple comparisons .
What statistical approaches addressed missing ANA data in DHS1/DHS2 linkage studies?
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Multiple imputation: Used for 12% missing ANA data in DHS1, leveraging baseline covariates (age, sex, CRP levels) .
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Sensitivity analysis: Compared complete-case vs. imputed models to confirm robustness .
Why did longitudinal ASCVD risk models exclude low-titer aPL?
Low-titer aPL (20–39 units) showed no significant hazard ratio (HR = 1.12, 95% CI 0.89–1.41), whereas moderate/high titers had HR = 1.98 (CI 1.32–2.97) .
How were discrepancies in racial aPL prevalence reconciled despite comparable baseline ASCVD risk?
| Antibody | Black Participants (%) | White Participants (%) | P-Value |
|---|---|---|---|
| Any aPL (≥20 units) | 14.8 | 14.2 | 0.67 |
| aβ2GPI IgA | 2.1 | 3.0 | 0.09 |
Resolution: No significant differences persisted after adjusting for socioeconomic factors and healthcare access .
What explained the lack of correlation between ANA and ASCVD outcomes despite aPL associations?
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ANA positivity correlated with aPL (P = 0.001) but not independently with ASCVD (HR = 1.04, CI 0.76–1.42) .
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Hypothesis: ANA may mark generalized autoimmunity without direct atherogenic effects .
Methodological Recommendations
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Antibody validation: Use knockout controls (as in YCharOS ) to confirm specificity, given 60% of commercial antibodies cross-react .
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Titer stratification: Apply clinical thresholds (e.g., ≥40 units) to reduce noise in epidemiological studies .
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Cohort diversity: Over-sample underrepresented groups to mitigate enrollment biases seen in APS trials .
