rab-3 Antibody

Definition and Biological Context of Rab-3 Antibody

Rab-3 antibodies are immunological tools targeting Rab3 GTPases, a subfamily of small monomeric G-proteins critical for regulating vesicle trafficking and exocytosis in neurons, endocrine cells, and secretory tissues . These antibodies enable detection and functional analysis of Rab3 isoforms (Rab3A, Rab3B, Rab3C, Rab3D), which localize to secretory vesicles and synaptic terminals .

Key Features of Rab3 Proteins Targeted by Antibodies

Antibody Design and Specificity

Rab-3 antibodies are typically raised against recombinant protein fragments (e.g., residues 154–227 of human Rab3C) . Pan-Rab3 antibodies recognize all isoforms due to sequence homology, while isoform-specific antibodies (e.g., anti-Rab3A ab3335) distinguish individual variants .

Validation Data

• Western Blot: Detects bands at ~27 kDa in brain lysates .

• Immunohistochemistry: Labels synaptic vesicles in neurons but not Golgi apparatus, confirming specificity .

• Functional Blocking: Anti-Rab3A antibodies inhibit Ca²⁺-triggered acrosomal exocytosis in sperm .

Synaptic Vesicle Regulation

• Knockout Mouse Models: Triple Rab3A/B/C knockout mice exhibit reduced synaptic vesicle pools and altered neurotransmitter release .

• C. elegans Studies: rab-3 mutants show depleted synaptic vesicles at neuromuscular junctions and impaired acetylcholine transmission .

Exocytosis Mechanisms

Common Pitfalls and Solutions

• Cross-Reactivity: Pan-Rab3 antibodies may detect multiple isoforms; confirm with knockout controls .

• Functional Assays: Use pre-adsorption with recombinant Rab3 proteins to validate blocking efficacy .

• Tissue Specificity: Rab3D antibodies perform better in pituitary samples than brain due to expression levels .

Clinical and Translational Relevance

• Warburg Micro Syndrome: Mutations in Rab3 GAP (p130 subunit) correlate with synaptic dysfunction and intellectual disability .

• Ethanol Sensitivity: Rab3A is implicated as a presynaptic target for ethanol-induced neuroadaptation .