The AP5S1 Knockout HT29 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the human HT-29 colorectal adenocarcinoma cell line. This product enables loss-of-function studies of AP5S1, the gene encoding the sigma subunit of the AP-5 adaptor complex, which is critical for endosomal sorting and lysosomal targeting. The polyclonal format provides a heterogeneous pool of edited cells suitable for population-level analyses without single-cell cloning artifacts.
HT-29 cells are a widely used human intestinal epithelial cell line with epithelial morphology, originally isolated from a colorectal adenocarcinoma. They serve as a well-established model for intestinal epithelial biology, colorectal cancer research, and drug screening due to their adherent growth and tumorigenic properties. Their robust experimental handling and well-characterized signaling networks make them an ideal host for studying endocytic and lysosomal pathways impacted by AP5S1 disruption.
AP5S1 encodes the ??5 subunit of the heterotetrameric AP-5 adaptor complex, which also includes AP5Z1, AP5M1, and AP5B1. This complex operates in a clathrin-independent endosomal sorting mechanism, mediating the retrieval of the cation-independent mannose-6-phosphate receptor (M6PR) from late endosomes to the trans-Golgi network, thereby ensuring proper delivery of lysosomal enzymes. AP5S1 function is transcriptionally regulated by TFEB, a master regulator of lysosomal biogenesis, and its activity is tightly linked to autophagic flux. Disruption of AP5S1 leads to mislocalization of M6PR and lysosomal enzymes, resulting in impaired lysosomal degradation and autophagy, phenotypes relevant to neurodegenerative disorders such as hereditary spastic paraplegia type 48 (SPG48).
In the HT-29 colorectal adenocarcinoma background, disruption of AP5S1 provides a powerful tool to dissect the role of endosomal sorting and lysosomal function in cancer cell biology. HT-29 cells exhibit high basal autophagy and are commonly used to study tumor cell responses to metabolic stress and chemotherapeutic agents. Loss of AP5S1 in this epithelial context may sensitize cells to lysosomal inhibitors such as chloroquine and alter the trafficking of signaling receptors, offering insights into how endocytic pathway dysregulation contributes to cancer progression and drug resistance. Furthermore, these cells enable the investigation of non-neuronal cell-type-specific consequences of AP-5 deficiency, complementing research on SPG48.
Researchers can employ these AP5S1 knockout HT29 polyclonal cells for a wide range of functional and pharmacological studies. Typical applications include Western blotting for AP-5 subunits to verify disruption, immunofluorescence microscopy to assess LAMP1 and M6PR subcellular distribution, lysosomal enzyme activity measurements, and autophagy flux assays monitoring LC3-II turnover in the presence of lysosomal inhibitors. Endocytosis assays using transferrin can reveal cargo sorting defects, while drug sensitivity assays with chloroquine can elucidate lysosomal stress responses. This knockout model is also suited for screening small molecules that modulate autophagy or restore lysosomal function, thus facilitating drug discovery for cancer and neurodegenerative diseases. For further information, please contact Ascent Research.
