RPA2B Antibody

Introduction to RPA2 and Its Antibodies

RPA2 (32 kDa), encoded by the RPA2 gene (NCBI: 6118), forms part of the RPA complex (RPA1/RPA2/RPA3) essential for DNA replication, repair, and damage response . Antibodies against RPA2 are vital tools for studying its role in:

• Stabilizing single-stranded DNA (ssDNA) during replication

• Recruiting repair proteins (e.g., RAD51, XPA) to damage sites

• Telomere maintenance and replication stress responses

DNA Repair and Replication

• Phosphorylation Dynamics: RPA2 phosphorylation at T21/S33 facilitates RAD51 recruitment during homologous recombination (HR) after hydroxyurea-induced replication stress . Cells expressing non-phosphorylatable RPA2 mutants (e.g., T21A/S33A) show defective RAD51 focus formation and increased chromosomal aberrations .

• Telomere Maintenance: A heterozygous RPA2 variant (Y256C) disrupts RFWD3-mediated ubiquitination, leading to telomere shortening and dysfunction. Somatic rescue events in POT1 or TERT were observed in patients with telomere biology disorders .

Clinical and Diagnostic Applications

• Autoimmunity: Anti-RPA2 autoantibodies are detected in systemic lupus erythematosus (SLE) sera, often co-migrating with other autoantigens like U1-A and ribosomal P proteins .

• Cancer Research: RPA2 hyperphosphorylation correlates with replication stress survival. Phospho-specific antibodies (e.g., ab109394) are used to study checkpoint activation in cancer models .

Technical Validation Data

• Specificity: Western blotting with ab76420 detects a single band at 29 kDa (predicted) / 32 kDa (observed) in human, mouse, and rat lysates .

• Functional Assays: RPA2 knockout cells exhibit sensitivity to DNA cross-linking agents (e.g., mitomycin-C), confirming its role in damage tolerance .

Limitations and Considerations

• Cross-Reactivity: Some antibodies (e.g., ab2175) show restricted reactivity to human samples .

• Phospho-Specificity: Antibodies like ab109394 require validation with phospho-peptide controls to avoid off-target signals .