The LRPAP1 Knockout Raji Polyclonal Cells constitute a CRISPR/Cas9-edited polyclonal knockout cell population, generated by targeted gene disruption of the LRPAP1 locus in the human B lymphocyte Raji cell line. This loss-of-function model enables detailed investigation of LRPAP1 chaperone activity within a suspension-adapted, Epstein-Barr virus (EBV)-positive lymphoblastoid background. The polyclonal nature preserves population-level heterogeneity while abolishing wild-type protein expression, providing a robust tool for functional genomics in endocytic receptor biology. Researchers can utilize these cells to dissect ligand internalization, receptor trafficking, and downstream signaling pathways controlled by low-density lipoprotein receptor (LDLR) family members.
The parental Raji cell line was derived from a male patient with Burkitt lymphoma and maintains latent EBV infection. These suspension-grown, non-adherent B lymphocytes are widely employed as models for B lymphocyte biology, EBV latency mechanisms, and immune response studies. Their transformed phenotype supports stable propagation and compatibility with high-throughput screening platforms. The EBV-positive status adds relevance for investigations intersecting viral pathogenesis with host metabolic or endocytic functions, expanding the utility of the knockout system beyond classical lipoprotein receptor research.
LRPAP1 functions as an endoplasmic reticulum (ER) chaperone that binds selectively to the ligand-binding domains of LDLR family members??including LRP1, LRP2 (megalin), VLDLR, and ApoER2??preventing premature interaction with extracellular ligands such as ApoE and ??2-macroglobulin. This interaction ensures correct folding and facilitates receptor trafficking through the secretory pathway to the cell surface. LRPAP1 disruption leads to ER retention and proteasomal degradation of these receptors, thereby blocking clathrin-mediated endocytosis and downstream signal transduction. The chaperone network is regulated by the ER stress response and feedback from receptor expression levels, and it is intimately connected to lipoprotein metabolism and neuronal receptor sorting.
In Raji cells, LRPAP1 knockout offers unique opportunities to explore B-cell-specific endocytic dynamics and the potential influence of EBV latency on receptor processing. Since megalin and LRP1 participate in antigen uptake and immune signaling, their loss on B lymphoblasts may alter lipoprotein scavenging and cytokine responsiveness. The model also provides a cellular platform for examining LRPAP1-related autosomal recessive nonsyndromic hearing loss, as receptor mistrafficking mirrors pathogenic mechanisms observed in affected tissues. Additionally, the EBV context allows probing of viral manipulation of host chaperone and trafficking pathways.
These polyclonal knockout cells facilitate a wide array of experimental applications, including fluorescent ligand uptake assays using labeled ApoE or ??2-macroglobulin to measure endocytic activity, Western blotting for LRP1/LRP2 stability, flow cytometry for surface receptor quantification, and co-immunoprecipitation to map chaperone?Creceptor complexes. Researchers can perform RT-qPCR or RNA-seq to profile transcriptional changes and phospho-signaling analyses to assess downstream pathway activation. The model is suited for drug screens targeting LRP1-related disorders and for engineering complex in vitro systems to study lipoprotein metabolism. For further technical specifications, please contact Ascent Research.
