The LMBRD2 Knockout Raji Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population targeting the LMBRD2 gene in human Raji B lymphocytes. This heterogeneous pool of gene-disrupted cells provides a loss-of-function model for studying LMBRD2-dependent lysosomal positioning and mTORC1 signaling, suitable for applications where clonal homogeneity is not required.
Raji cells are derived from a Burkitt lymphoma patient, are Epstein-Barr virus-positive, and express B cell markers CD19, CD20, and CD22. Widely used in immunology and cancer research, they serve as an immortalized model for B cell signaling and lymphoma. Knocking out LMBRD2 in this background allows investigation of lysosomal biology within a relevant B lymphocyte malignancy context.
LMBRD2 is a lysosomal membrane protein essential for tethering the BLOC-1-related complex (BORC) to lysosomes, interacting with BORC subunits BLOC1S1, BLOC1S2, and KXD1. This anchoring enables lysosome peripheral positioning via Arl8b and SKIP, which is critical for mTORC1 recruitment to lysosomes upon amino acid sensing. At the lysosome, mTORC1 is activated by the Ragulator complex (LAMTOR1-5) and Rag GTPases, leading to phosphorylation of S6K1 and 4E-BP1 that drives protein synthesis and inhibits autophagy through ULK1 and TFEB suppression. Upstream regulators include amino acids (leucine, arginine), growth factor signaling (insulin/IGF-1), and AMPK.
In Raji cells, LMBRD2 knockout offers a system to dissect lysosomal positioning and mTORC1 signaling in B lymphocytes, where metabolic reprogramming is crucial for activation and lymphoma development. Loss of LMBRD2 is anticipated to mislocalize lysosomes, dampen mTORC1 activation, and alter autophagy, providing insights into metabolic dysregulation in Burkitt lymphoma. The polyclonal population also allows examination of phenotypic heterogeneity in disrupted lysosomal trafficking and signaling.
This model supports diverse applications, including immunofluorescence analysis of LAMP1 and lysosome distribution, flow cytometry for phospho-S6, and western blotting of p-S6K1, p-4E-BP1, and LC3-II to gauge mTORC1 activity and autophagy. Transcriptional effects on TFEB targets can be measured by RT-qPCR or RNA-seq, and metabolic flux analyses or mTOR inhibitor sensitivity screenings can be performed. These experiments are valuable for probing B cell biology, lymphoma metabolism, and therapeutic responses. For more information, contact Ascent Research.
