The AAK1 knockout HT29 polyclonal cells constitute a CRISPR/Cas9-edited heterogeneous cell population designed to disrupt AAK1 gene function in the human HT29 colorectal adenocarcinoma background. As a mixed clonal population, these cells provide a robust loss-of-function model for studying clathrin-mediated endocytosis and receptor trafficking without single-cell clonal selection, facilitating reproducible high-throughput and pooled screening experiments.
HT29 human colorectal adenocarcinoma cells are an established epithelial model that retains enterocytic differentiation capacity under specific culture conditions. Widely employed in biomedical research, this cell line models intestinal epithelial physiology, colorectal cancer progression, drug absorption, and differentiation mechanisms. Its malignant origin and epithelial phenotype provide a physiologically relevant platform for investigating oncogenic signaling and receptor-mediated endocytosis in a colonic tumor context.
AAK1 encodes an adaptor-associated kinase that phosphorylates the mu2 subunit (AP2M1) of the AP2 complex at Thr156, strengthening its interaction with tyrosine-based sorting motifs on cargo receptors such as EGFR and transferrin receptor. This key phosphorylation step promotes clathrin-coated pit assembly and accelerates endocytosis. AAK1 functions downstream of SRC family kinases and is recruited to the plasma membrane through interactions with AP2 subunits (AP2A1, AP2B1, AP2S1), clathrin heavy chain, and accessory factors like Numb and Rab5. Downstream, AAK1-dependent phosphorylation enhances dynamin-mediated vesicle scission and influences endosomal sorting, ultimately regulating receptor degradation, recycling, or signaling output.
Disruption of AAK1 in the HT29 colorectal cancer model impairs clathrin-mediated internalization of receptors such as EGFR, thereby perturbing downstream signaling pathways that drive proliferation, survival, and differentiation. Because EGFR trafficking is frequently dysregulated in colorectal cancer, this knockout system allows precise dissection of receptor dynamics linked to tumorigenesis and therapeutic resistance. HT29 cells also serve as a model of intestinal epithelial endocytosis, and loss of AAK1 can be exploited to examine how receptor downregulation modulates responses to growth factors, nutrients, and chemotherapeutic agents absorbed transcellularly.
This AAK1 knockout polyclonal cell product is suited for fluorescence-based transferrin uptake and EGFR internalization assays, immunofluorescence imaging of clathrin-coated pits, flow cytometric quantification of surface receptor levels, and phospho-AP2M1 Western blot analysis. It also supports dose-response studies with endocytosis inhibitors or siRNAs for target validation, as well as high-throughput screens for novel endocytosis modulators. The model can be applied to investigations of Notch signaling and viral entry mechanisms. For additional information or technical support, contact Ascent Research.
