The HEATR5B Knockout Jurkat Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout population of Jurkat human T lymphocytes with disrupted expression of the HEATR5B gene. HEATR5B encodes a scaffold protein featuring HEAT repeats and localizes to lysosomes; it is implicated in mTORC1 signaling and autophagy. The heterogeneous polyclonal pool avoids clonal bias and is supplied as a suspension culture suitable for immediate experimental use.
Jurkat cells are immortalized human T lymphoblasts derived from a T cell leukemia patient. They are PTEN-deficient, resulting in constitutive PI3K/Akt pathway activation and hyperactive mTORC1 signaling, which drives deregulated growth and survival. As a suspension line, Jurkat cells are widely used to study T cell receptor signaling, apoptosis, and immune function. This oncogene-driven background provides a stringent system for evaluating modulators of the PI3K/Akt/mTOR axis and dissecting mTORC1 regulatory inputs beyond receptor-proximal signals.
HEATR5B is a scaffold protein that localizes to lysosomes and directly interacts with RHEB, a GTPase essential for mTORC1 activation. It facilitates recruitment of mTORC1 complex components to the lysosomal surface, thereby coupling nutrient and growth factor cues to mTORC1 kinase activity. In the canonical pathway, growth factors signal via RTK?CPI3K?CAkt to inhibit TSC1/2, relieving RHEB suppression, while amino acids engage Rag GTPases and the LAMTOR/Ragulator complex for lysosomal tethering; HEATR5B enhances RHEB?CmTORC1 coupling. Consequently, HEATR5B loss is expected to reduce phosphorylation of mTORC1 substrates S6K and 4EBP1, and may impair ULK1-mediated autophagy initiation and lysosomal trafficking.
In PTEN-deficient Jurkat cells, constitutive PI3K/Akt signaling drives persistent mTORC1 activity, promoting leukemogenic growth. Introducing HEATR5B knockout allows dissection of whether lysosomal scaffold-mediated mTORC1 regulation can operate independently of this hyperactive input, potentially identifying HEATR5B as a rate-limiting vulnerability in T cell leukemia. Moreover, the Jurkat T cell context enables investigation of how mTORC1/autophagy perturbations affect T cell receptor signaling, activation marker expression, and effector functions. The polyclonal knockout population reduces clone-specific artifacts and better reflects biological variability.
This model supports signaling studies via Western blotting for p-S6K and p-4EBP1, autophagy flux assays using LC3-II turnover, and lysosomal staining. Flow cytometry enables quantification of T cell activation markers (e.g., CD69, CD25), while proliferation/viability assays gauge mTORC1-dependent growth. It is also suitable for mTORC1 inhibitor screening and functional genomics in PTEN-deficient leukemia. Co-immunoprecipitation can assess mTORC1 complex integrity upon HEATR5B loss. For more information, contact Ascent Research.
