PEX2 Antibody

PEX2 Antibody: Definition and Function

PEX2 is an integral peroxisomal membrane protein with two transmembrane domains and a cytosol-facing zinc RING domain. It functions as an E3 ubiquitin ligase, tagging peroxisomal membrane proteins for degradation during amino acid starvation or basal turnover . Antibodies targeting PEX2 enable researchers to study its localization, expression, and role in peroxisomal dynamics.

Key Features of PEX2 Antibodies

• Target: Peroxisomal Biogenesis Factor 2 (PEX2), also known as PXMP3.

• Applications: Western blotting (WB), immunohistochemistry (IHC), immunofluorescence (IF), and ELISA.

• Reactivity: Primarily human, with cross-reactivity in rodent, cow, dog, guinea pig, horse, and rabbit models .

Experimental Techniques

1. Western Blotting:

   • Quantifies PEX2 expression levels in cell lysates or purified peroxisomal membranes .

   • Example: HEK293–HA-Ub cells transfected with PEX2-FLAG show enriched ubiquitinated peroxisomal proteins .

2. Immunohistochemistry (IHC):

   • Visualizes PEX2 localization in tissue sections.

   • Used to study peroxisomal clustering and density in starvation-induced pexophagy .

3. Immunofluorescence (IF):

   • Colocalizes PEX2 with peroxisomal markers (e.g., PMP70) in live or fixed cells .

Clinical and Diagnostic Use

• Peroxisomal Disorders: Mutations in PEX2 cause Zellweger syndrome and infantile Refsum disease. Antibodies aid in diagnosing these conditions .

• Pexophagy Studies: PEX2 antibodies confirm its role in autophagy receptor NBR1-mediated peroxisome degradation .

Validation and Specificity

• Knockdown/Rescue Experiments: PEX2 siRNA depletion abolishes starvation-induced pexophagy in HeLa cells, rescued by siRNA-resistant PEX2 constructs .

• Peroxisomal Isolation: PEX2 is enriched in medium/heavy fractions of purified peroxisomes, distinct from ER/mitochondrial markers .

Cross-Reactivity and Validation

• Positive Controls: Use HEK293 cells overexpressing PEX2-FLAG or PMP34-GFP to confirm specificity .

• Off-Target Risks: Polyclonal antibodies may bind non-specific epitopes. Blocking peptides or pre-absorption recommended .

Limitations

• Preservatives: Sodium azide in some formulations poses handling risks .

• Species Variability: Reactivity with non-human models (e.g., cow, dog) requires experimental validation .

Peroxisomal Biogenesis Disorders

• Zellweger Spectrum: PEX2 mutations (e.g., C247R, W223X) disrupt peroxisome assembly, leading to neurodevelopmental defects .

• Diagnostic Utility: Antibodies enable detection of aberrant PEX2 expression in patient-derived cells .

Therapeutic Implications

• Pexophagy Dysregulation: PEX2 inhibitors may modulate peroxisome turnover in metabolic diseases .