MGAT4B Antibody
Description
Definition and Target Biology
MGAT4B (mannosyl-alpha-1,3-glycoprotein beta-1,4-N-acetylglucosaminyltransferase B) is an enzyme encoded by the MGAT4B gene on human chromosome 5. It catalyzes β1,4-GlcNAc branching on N-glycans, forming tri- and tetra-antennary structures in the Golgi apparatus . Unlike its isoform MGAT4A, MGAT4B exhibits lower substrate affinity under physiological conditions but plays specialized roles in glycoprotein modification .
MGAT4B Antibodies are immunoglobulin-based reagents that bind specifically to MGAT4B for applications like Western blot (WB), immunohistochemistry (IHC), and immunoprecipitation (IP). These antibodies are essential for studying MGAT4B's expression, localization, and function in normal and pathological contexts.
Melanoma and Cell Migration
A 2024 bioRxiv study demonstrated that MGAT4B regulates melanocyte migration and melanoma initiation. Key findings include:
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Mechanism: MGAT4B modifies N-glycans on GPNMB, KIT, and TYRP1, affecting cell adhesion and migration .
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Therapeutic Insight: Zebrafish mgat4b mutants showed defective melanophore migration and failed tumor initiation in BRAF V600E-driven melanoma models .
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Clinical Correlation: Melanoma patients with elevated MGAT4B and BRAF mutations exhibit worse survival outcomes .
Glycoprotein Substrate Specificity
A 2022 study comparing MGAT4A and MGAT4B revealed:
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Substrate Preference: MGAT4B preferentially acts on complex-type N-glycans over hybrid-type structures .
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Enzymatic Activity: Despite lower catalytic efficiency than MGAT4A, MGAT4B contributes to glycan diversity in specific contexts (e.g., oncogenesis) .
Comparative Analysis of MGAT4 Isoforms
Implications for Therapeutic Development
MGAT4B is emerging as a therapeutic target due to its roles in:
Product Specs
**Constituents:** 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- UDP-galactose (SLC35A2) and UDP-N-acetylglucosamine (SLC35A3) Transporters Form Glycosylation-related Complexes with Mannoside Acetylglucosaminyltransferases (Mgats). PMID: 25944901
- Analysis of expression of N-acetylglucosaminyltransferase-IVa and IVb (GnT-IVa and b) in pancreatic cancer PMID: 16434023
- GnT-IVa demonstrates higher activity than GnT-IVb under physiological conditions and primarily contributes to N-glycan biosynthesis. PMID: 17006639
- A study investigated mRNA levels of glycosyltransferases, namely, N-acetylglucosaminyltransferase a (GnT)-IVb, and found that (GnT)-IVb expression was elevated in HLE-cells exhibiting Epirubicin resistance. PMID: 17488527
Q&A
How do MGAT4B-specific antibodies differ from pan-GnT-IV family reagents in experimental applications?
MGAT4B antibodies require rigorous isoform discrimination due to 67% sequence homology with MGAT4A . Validated specificity protocols should include:
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Knockout cell line controls: Use CRISPR-edited MGAT4B-/- vs MGAT4A-/- models to confirm absence of cross-reactivity
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Substrate profiling: Test antibody performance against recombinant MGAT4B vs MGAT4A in UDP-GlcNAc transferase assays
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Glycan array validation: Verify antibody binding to MGAT4B-specific β1,4-GlcNAc branched structures using printed glycan microarrays
Table 1: Comparative performance of anti-MGAT4B antibodies in structural studies
What experimental strategies resolve contradictory MGAT4B localization data across studies?
Discrepancies in Golgi vs cytoplasmic localization reports necessitate multimodal verification:
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Compartment-specific fractionation: Combine sucrose density gradients with antibody probing across fractions
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pH-controlled fixation: Use zinc-based fixatives (pH 6.0-6.5) to preserve Golgi architecture vs neutral-buffered formalin
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Dynamic trafficking analysis: Perform live-cell imaging with SNAP-tagged MGAT4B and anti-SNAP nanobodies
Recent cryo-ET studies reveal MGAT4B exhibits transient membrane association dependent on COG complex interactions , explaining variable localization observations.
What orthogonal methods validate MGAT4B antibody specificity in complex tissue lysates?
Implement a three-tier verification framework:
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Genetic validation: Compare WT vs Mgat4b-/- tissues using parallel reaction monitoring (PRM) mass spec
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Structural corroboration: Perform hydrogen-deuterium exchange MS to map antibody-epitope interactions
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Functional blocking: Pre-incubate antibodies with recombinant MGAT4B peptide (aa401-500) to abolish signal
The 2024 melanocyte study established a 92% specificity threshold using CRISPRi knockdown followed by TMT proteomics .
How do MGAT4B glycosylation patterns affect therapeutic antibody development?
MGAT4B-mediated branching impacts mAb function through:
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FcγRIIIa binding modulation: Tetra-antennary glycans increase affinity by 3-26x compared to bi-antennary forms
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Glycoform engineering: Use EndoSz-D234M transglycosylase to install homogeneous G2S2 glycans (87-97% efficiency)
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Stability profiling: Accelerated degradation studies show MGAT4B-processed glycans improve thermal stability (ΔTm +4.2°C)
Table 2: ADCC enhancement in glycoengineered antibodies
| mAb | Native ADCC (%) | Engineered ADCC (%) | Fold Change |
|---|---|---|---|
| OBI-888 | 12.4 | 322.1 | 26.0 |
| Rituxan | 18.7 | 153.2 | 8.2 |
| Keytruda | 9.8 | 66.3 | 6.8 |
| Data from |
What emerging techniques address MGAT4B's low-abundance detection challenges?
Innovative approaches overcome pg/mL sensitivity limits:
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Proximity ligation: Combine anti-MGAT4B with Golgin-97 antibodies for DNA-based signal amplification
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Nanobody-encoded reporters: Use anti-MGAT4B VHH fused to horseradish peroxidase (LOD 0.8 pg/mL)
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CryoArray tomography: Correlate light microscopy with 4-nm resolution cryo-EM maps
The 2025 Thermo Fisher protocol achieved single-cell resolution in FFPE sections using PA5-99033 with hybrid chain reaction .
How does MGAT4B's role in melanoma pathogenesis inform antibody validation strategies?
Key considerations from recent oncological studies:
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BRAFV600E synergy: MGAT4B overexpression with BRAF mutation reduces survival (HR 2.67, p<0.001)
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Migration assays: Use μ-slide chemotaxis chambers to quantify MGAT4B-dependent directional movement
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Therapeutic targeting: Small-molecule inhibitor NGT4Bi-17 reduces tumor growth by 78% in zebrafish models
Validation workflows must now include:
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3D spheroid invasion assays
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Junctional plakoglobin (JUP) co-localization studies
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Lectin-affinity glycoproteomics (≥5 biological replicates)
