PSMB8 Knockout HAP1 Cell Line

The choice depends on whether you are studying PSMB8 (LMP7, β5i)'s role as a catalytic subunit of the immunoproteasome or modeling proteasome-associated autoinflammatory syndromes (PRAAS, including CANDLE/Nakajo-Nishimura syndrome). The Knockout line is the standard tool for asking whether the immunoproteasome (where LMP7 replaces β5 of the standard proteasome) is required for these activities — immunoproteasome generates MHC class I peptides with improved hydrophobicity and altered cleavage specificity. Overexpression is useful for studying immunoproteasome assembly or for testing reconstitution with mutant subunits. For immunoproteasome research, the EDITGENE PSMB8 Knockout in HAP1 is highly informative — particularly when combined with the parallel PSMB10 Knockout (also available) for comprehensive immunoproteasome characterization. PRAAS-associated PSMB8 mutations enable disease genotype-function studies. Rescue with wild-type or catalytically-dead LMP7 is the standard specificity control. The knockout is a critical specificity tool for immunoproteasome-selective inhibitors (KZR-616/zetomipzomib, ONX-0914) in autoimmune disease drug development.

Primary applications: • Immunoproteasome assembly: native PAGE and subunit composition analysis to assess immunoproteasome formation in the absence of LMP7. • Proteasome catalytic activity: chymotrypsin-like (LMP7), trypsin-like (MECL-1), and caspase-like (LMP2) activities measured by fluorogenic substrate assays. • MHC class I antigen presentation: immunopeptidomics analysis to characterize peptide repertoire changes in LMP7-deficient cells (with IFN-γ stimulation to induce immunoproteasome). • Immunoproteasome inhibitor specificity: critical genetic control for KZR-616 (zetomipzomib), ONX-0914 (PR-957), and other LMP7-selective inhibitors in autoimmune disease development. EDITGENE recommends this model for researchers investigating immunoproteasome biology, autoinflammatory syndrome mechanisms, and immunoproteasome-targeted therapeutic development.

Yes. LMP7 rescue experiments require attention to proteasome assembly: • Construct design: use a codon-modified PSMB8 sequence with a small C-terminal tag (FLAG, HA, but very small tags preferred — proteasome subunit incorporation is sensitive to tag size). LMP7 is incorporated as a precursor that undergoes autocatalytic activation. • Catalytically-dead rescue: the T1A mutation in the active site threonine abolishes chymotrypsin-like activity and is the standard specificity control. • PRAAS mutation rescue: patient-derived PSMB8 mutations enable disease genotype-function correlation studies. • Functional readout: rescue should restore immunoproteasome assembly, chymotrypsin-like activity (LLE-AMC fluorogenic substrate), and IFN-γ-induced immunoproteasome formation. HAP1-specific considerations: • Diploidization: HAP1 cells gradually diploidize during extended culture — confirm ploidy by flow cytometry at the time of phenotypic assay. • Integration site sensitivity: position effects on transgene expression are more pronounced in near-haploid backgrounds; generating multiple independent rescue clones is strongly recommended. • Transduction efficiency: HAP1 transduces with lentivirus at moderate efficiency — increase MOI compared to standard immortalized lines.