The ANXA13 Knockout HK-2 Cell Line is a CRISPR/Cas9-edited knockout cell line featuring targeted disruption of the ANXA13 gene in HK-2 human proximal tubule epithelial cells. This loss-of-function model enables investigation of annexin A13 roles in apical membrane organization, epithelial polarity, and membrane trafficking. The CRISPR/Cas9-mediated gene disruption ablates ANXA13 protein function, providing a tool to dissect signaling networks governing renal epithelial barrier integrity and transport.
The HK-2 cell line is an immortalized human proximal tubule epithelial model established by HPV-16 E6/E7 transduction. These cells maintain polarized morphology, brush border enzyme expression, and transport activities characteristic of primary epithelium, making them well-suited for reabsorption, secretion, and nephrotoxicity studies. Their renal origin renders them an appropriate host for genetic perturbation to study epithelial polarity and disease mechanisms.
ANXA13 is a calcium-dependent phospholipid-binding protein essential for apical trafficking and epithelial polarity. It is transcriptionally regulated by CDX2 and HNF4A in a tissue-specific manner and functions downstream of calcium signaling. ANXA13 interacts with flotillin-1 and flotillin-2 to organize lipid rafts, facilitates apical localization of SLC9A3 (NHE3), and directs actin cytoskeleton rearrangement. Within the Cdc42-Par complex signaling axis, it associates with Par3 and aPKC, contributing to tight junction assembly via interactions with ZO-1 and occludin. Crosstalk with Wnt signaling further modulates polarity and junctional integrity.
In HK-2 cells, ANXA13 knockout disrupts flotillin-mediated raft organization, impairing apical protein delivery and epithelial barrier function. Phenotypically, this leads to altered junctional marker distribution, reduced transepithelial electrical resistance (TEER), and increased paracellular permeability. The model thus facilitates studies of renal polarity defects relevant to nephrotoxicity, transport dysfunction, and the interplay between lipid rafts, actin dynamics, and tight junctions.
Applications include nephrotoxicity screening using TEER and fluorescent tracer permeability assays, and epithelial polarity and trafficking studies via immunofluorescence for ZO-1, occludin, and flotillins, coupled with apical surface biotinylation. The cell line supports renal disease modeling, drug sensitivity, and wound healing assays. ANXA13 disruption can be confirmed by Western blotting and RT-qPCR, while downstream effects are assessed through functional assays. For further technical details, contact Ascent Research.
