The KEAP1 Knockout HAP1 Polyclonal Cells product comprises a CRISPR/Cas9-edited polyclonal knockout cell population derived from the near-haploid HAP1 human cell line, designed for robust disruption of the KEAP1 gene (Homo sapiens). This polyclonal knockout model provides a heterogeneous pool of edited cells, enabling researchers to study loss-of-function phenotypes in the context of the NRF2 antioxidant pathway without the limitations of single-cell clonal selection. KEAP1 (Kelch-like ECH-associated protein 1) serves as a critical substrate adaptor for the CUL3-dependent E3 ubiquitin ligase complex, and its ablation is instrumental for dissecting cellular responses to oxidative and electrophilic stress.
HAP1 cells originate from the KBM-7 chronic myeloid leukemia-derived line and exhibit a near-haploid karyotype, making them exceptionally tractable for gene-editing applications and functional genomics studies. The near-haploid nature facilitates efficient CRISPR/Cas9-mediated gene disruption by targeting a single allele, minimizing the complexity of diploid compensation. This host cell background is well-characterized for its suitability in high-throughput screening, signal transduction analysis, and proteasomal degradation studies, providing a streamlined system to investigate KEAP1-dependent regulatory mechanisms.
Mechanistically, KEAP1 operates as a substrate adaptor for the CUL3-RBX1 E3 ubiquitin ligase complex, continuously targeting the transcription factor NFE2L2 (NRF2) for proteasomal degradation under basal conditions. KEAP1 interacts directly with NRF2 via its Kelch domains, while also engaging regulatory proteins such as SQSTM1/p62, PGAM5, and IKBKB. The KEAP1-NRF2 pathway is activated by upstream signals including reactive oxygen species (ROS) and electrophiles like sulforaphane, which modify critical cysteine residues in KEAP1??particularly Cys151, Cys273, and Cys288??thereby disrupting NRF2 ubiquitination. This leads to NRF2 nuclear translocation and transcriptional activation of cytoprotective genes via Antioxidant Response Elements (ARE). Downstream NRF2 targets include HMOX1, NQO1, GCLM, GSTA1, and TXNRD1, among others involved in glutathione synthesis, xenobiotic metabolism, and redox homeostasis. Interplay with additional factors such as DPP3 and PRKCA further modulates KEAP1-NRF2 dynamics, underscoring the intricate network regulated by KEAP1.
In the HAP1 cellular context, KEAP1 disruption results in constitutive stabilization and nuclear accumulation of NRF2, leading to sustained expression of ARE-driven genes independent of exogenous stressors. This genetic background is particularly advantageous for studying the KEAP1-NRF2 axis due to the absence of confounding diploid heterozygosity, enabling clearer genotype-phenotype correlations. The polyclonal population reflects a spectrum of editing events, offering a robust system to assess bulk cellular responses relevant to oncogenic NRF2 activation, chemoresistance mechanisms, and the role of antioxidant signaling in neurodegenerative and metabolic disorders. Researchers can leverage this model to evaluate the impact of KEAP1 loss on cellular redox balance, proteasomal activity, and interaction with autophagy regulators like SQSTM1/p62.
This KEAP1 knockout polyclonal cell product is ideally suited for a broad range of experimental applications, including quantitative assessment of NRF2 target gene expression via RT-qPCR or RNA-seq, monitoring of oxidative stress responses using ROS-sensitive probes, and functional analyses of ARE-driven transcriptional activity with luciferase reporter assays. The model facilitates investigation into drug resistance phenotypes in cancer biology, where NRF2 hyperactivation is linked to poor prognosis, as well as toxicology screening to identify KEAP1-dependent xenobiotic metabolism pathways. Western blotting for KEAP1, NRF2, and effector proteins like HMOX1 and NQO1, combined with ubiquitination assays, permits detailed biochemical interrogation of the CUL3-KEAP1-RBX1 ubiquitin ligase complex. Additionally, cell viability assays under oxidative challenge (e.g., hydrogen peroxide or paraquat treatment) enable evaluation of cytoprotective capacity. For additional information or customized support, please contact Ascent Research.
