The HERPUD2 Knockout HEK293T Polyclonal Cells are a CRISPR/Cas9-edited polyclonal cell population derived from the HEK293T human embryonic kidney cell line, engineered for targeted disruption of the HERPUD2 gene. This knockout model provides a powerful tool to investigate the function of HERPUD2, an endoplasmic reticulum (ER) stress sensor that promotes cell survival through ER-associated degradation (ERAD). The polyclonal format consists of a heterogeneous pool of cells carrying diverse CRISPR-induced indel mutations at the HERPUD2 locus, enabling robust and reproducible loss-of-function studies without the clonal selection bottleneck. By eliminating HERPUD2 expression, researchers can directly assess its role in the unfolded protein response (UPR) and its contribution to cellular adaptation under ER stress conditions.
The host cell line, HEK293T, is a widely used derivative of HEK293 cells that stably expresses the SV40 large T antigen, facilitating high-level episomal replication of plasmids containing the SV40 origin of replication. This characteristic endows HEK293T cells with exceptionally high transfection efficiency, making them ideal for protein expression, retroviral and lentiviral production, and large-scale transient protein production. Originating from human embryonic kidney epithelium, HEK293T cells retain key features of renal epithelial physiology, yet their robust growth properties and amenability to genetic manipulation have made them a preferred platform for studying fundamental cellular processes, including stress responses and signaling pathways. The combination of HERPUD2 knockout and the well-characterized HEK293T background provides a versatile system for mechanistic dissection of ER stress pathways.
HERPUD2 is an ER-resident protein transcriptionally induced by ER stress through the action of transcription factors ATF6, XBP1, and ATF4. Acting as a scaffold and adaptor, HERPUD2 recruits key ERAD machinery components, including VCP/p97, the E3 ubiquitin ligase HRD1, SEL1L, OS9, and Derlin-1, to facilitate the extraction and proteasomal degradation of misfolded polypeptides. Functionally, HERPUD2 sits downstream of the canonical UPR sensors BiP/GRP78, IRE1??, and PERK, and it opposes the terminal UPR effector CHOP, thereby attenuating apoptotic signaling and promoting cell survival. Its activity is linked to the induction of anti-apoptotic Bcl-2 family members, forming a cytoprotective circuit that buffers cells against proteotoxic stress. Consequently, loss of HERPUD2 perturbs ERAD efficiency and sensitizes cells to ER stress-induced apoptosis, as evidenced by increased CHOP expression and caspase activation following treatment with ER stressors such as tunicamycin or thapsigargin.
Within the HEK293T context, the HERPUD2 knockout model is particularly valuable for interrogating the interplay between protein secretory capacity and ER quality control. HEK293T cells possess a highly active secretory pathway due to their embryonic kidney origin, making them susceptible to ER stress when challenged with high-level recombinant protein expression or pathological insults. HERPUD2 disruption in these cells provides a clean genetic background to study the homeostatic regulation of the UPR and ERAD without the confounding effects of chemical stressors, allowing researchers to dissect endogenous signaling dynamics. This model is relevant to disease areas such as cancer, where tumors exploit HERPUD2-mediated prosurvival pathways to endure chronic ER stress; neurodegenerative disorders, where ERAD failure leads to accumulation of aggregation-prone proteins; and metabolic diseases characterized by persistent UPR activation.
Researchers can employ this knockout model in a variety of experimental settings, including Western blotting to monitor changes in UPR markers (e.g., BiP, CHOP, phospho-IRE1??), RT-qPCR to quantify XBP1 mRNA splicing and CHOP transcript levels, and cell viability assays following treatment with ER stress inducers. Apoptosis regulation can be assessed using Annexin V staining, and subcellular ER morphology changes can be visualized with ER-Tracker dyes. Co-immunoprecipitation studies using ectopic expression systems can help map HERPUD2-interacting protein networks, while high-throughput screening campaigns can identify small molecules that modulate ER stress responses in a HERPUD2-dependent manner. For further technical details or customized applications, please contact Ascent Research.
