The DNAJB4 Knockout AGS Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population targeting DNAJB4 in the AGS gastric adenocarcinoma epithelial cell line. This loss-of-function model enables systematic investigation of DNAJB4-mediated proteostasis, chaperone function, and stress signaling. The polyclonal format retains population-level heterogeneity, offering a robust system for functional genomics studies without the biases of single-cell clonal selection.
Derives from a human gastric adenocarcinoma, the AGS cell line is an extensively characterized epithelial model for gastric cancer biology, including drug sensitivity, oncogenic signaling, and apoptosis. Its epithelial origin and tumorigenic properties make it particularly suitable for studying genes involved in proteotoxic stress responses relevant to gastrointestinal malignancies.
DNAJB4, a member of the Hsp40 family, functions as a co-chaperone that directly binds HSP70 (HSPA1A/HSPA8) and stimulates its ATPase activity, thereby regulating protein folding, refolding, and degradation. It is essential for chaperone-mediated autophagy and aggresome formation, facilitating the clearance of misfolded and ubiquitinated proteins. Transcriptionally activated by HSF1 and HSF2 in response to heat shock and oxidative stress, DNAJB4 operates within a network including BAG3, HSP90, CHIP, HOP, and BAG2. This positions DNAJB4 at the intersection of the heat shock response and MAPK signaling pathways, controlling client protein fate through HSP70 chaperone cycles.
In AGS gastric adenocarcinoma cells, knockout of DNAJB4 impairs aggresome formation and autophagic degradation, leading to accumulation of misfolded proteins and heightened sensitivity to proteotoxic stress. This disruption can modulate chemosensitivity and apoptotic thresholds, providing a platform to study how co-chaperone dysfunction contributes to gastric cancer progression and therapeutic vulnerability. The model also holds relevance for neurodegenerative disorders where impaired clearance of toxic protein aggregates underlies pathology.
Researchers can employ this knockout model to investigate proteotoxic stress responses, chaperone-mediated autophagy mechanisms, and chemosensitivity in gastric cancer. Typical assays include co-immunoprecipitation of DNAJB4-HSP70 complexes, Western blotting for HSP70 and stress markers, annexin V/PI apoptosis assays, RT-qPCR analysis of heat shock gene expression, and cell viability assays under proteotoxic stress conditions. For further information or to discuss custom applications, please contact Ascent Research.
