The PSMC3 (Proteasome 26S Subunit, ATPase 3) antibody is a crucial tool for studying the 26S proteasome, a large multi-subunit complex responsible for ubiquitin-dependent protein degradation in eukaryotic cells. PSMC3. also known as TBP1 or Rpt5. is an ATPase subunit of the 19S regulatory particle that binds and unfolds polyubiquitinated substrates, facilitating their translocation into the proteolytic 20S core. This subunit plays a central role in maintaining proteostasis, regulating processes like cell cycle progression, DNA repair, and stress responses. Antibodies targeting PSMC3 are widely used to investigate proteasome composition, activity, and dysfunction in diseases such as cancer (where proteasome activity is often dysregulated) and neurodegenerative disorders (e.g., Alzheimer’s, Parkinson’s) characterized by protein aggregation. They are employed in techniques like Western blotting, immunoprecipitation, and immunofluorescence to assess proteasome expression, localization, or interactions. Some antibodies distinguish PSMC3 isoforms or post-translational modifications (e.g., phosphorylation), enabling studies on regulatory mechanisms. Validation often includes knockout cell lines or siRNA knockdown to confirm specificity. Research applications extend to evaluating proteasome inhibitors (e.g., bortezomib) in cancer therapy or exploring transcriptional regulation via PSMC3’s non-proteasomal roles, such as interacting with nuclear hormone receptors.