The MTMR3 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population derived from the human Raji B lymphoblastoid cell line, engineered for targeted disruption of the MTMR3 gene. This knockout model abolishes expression of MTMR3, a lipid phosphatase that specifically dephosphorylates phosphatidylinositol 3-phosphate (PI3P), providing a heterogeneous loss-of-function system for studying autophagy, endocytosis, and phosphoinositide signaling. The polyclonal format ensures a diverse pool of edited alleles, enabling population-level analyses without clonal selection bias.
Raji cells are an Epstein-Barr virus (EBV)-positive human Burkitt lymphoma B lymphoblastoid line, capable of robust antibody production and antigen presentation. Widely employed in lymphoma research and immune response studies, this cell line offers a well-characterized model for B cell biology. Its B lymphoblastoid context is particularly relevant for investigating endosomal trafficking and autophagy, processes integral to antigen processing and adaptive immunity.
MTMR3 functions as a phosphoinositide phosphatase that hydrolyzes PI3P, counteracting the activity of the class III PI3K Vps34?CBeclin1?CAtg14L complex on endosomal and autophagosomal membranes. This enzyme is regulated by upstream nutrient and energy sensors including mTOR and AMPK, as well as cellular stress signals. MTMR3 interacts directly with the PI3KC3 complex components Beclin1 and Vps34. Loss of MTMR3 leads to elevated PI3P levels, enhancing recruitment of downstream effectors such as EEA1, Hrs, and WIPI2, which promotes LC3-II lipidation and autophagosome formation. This disrupts endocytic trafficking dynamics, affecting Rab5 and EEA1-dependent early endosome function and ultimately altering lysosomal degradation pathways.
Within the Raji lymphoma background, MTMR3 knockout provides a relevant model for dissecting autophagy and endosomal pathways in B cell malignancies. Lymphoma cells frequently depend on autophagy for survival under metabolic stress and during acquisition of therapeutic resistance. MTMR3 disruption may lead to PI3P accumulation, potentially enhancing autophagic activity and stress resilience, while simultaneously altering antigen processing and MHC class II presentation. This model thus enables investigation of phosphoinositide signaling crosstalk with lymphocyte biology and cancer therapy responses.
These polyclonal knockout cells are well suited for a variety of research applications, including autophagy modulation studies via western blotting for LC3-II and p62, immunofluorescence detection of LC3 puncta, and autophagy flux assays. PI3P accumulation can be quantified using a PI3P ELISA, while endocytic trafficking is assessed by transferrin uptake and flow cytometry. The model is also applicable to phosphoinositide signaling and drug resistance investigations in B cell lymphoma. For further information or technical support, please contact Ascent Research.
