The ARL8B Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population of HAP1 cells with targeted disruption of the ARL8B gene. This knockout model provides a loss-of-function system for studying ARL8B-dependent processes without the need for transient knockdown approaches. The polyclonal format captures a diverse range of editing events, offering a robust tool for functional genomics screens and lysosomal trafficking studies.
HAP1 is a human near-haploid, fibroblast-like adherent cell line derived from the KBM-7 chronic myeloid leukemia line. Its haploid genome makes it particularly amenable to CRISPR/Cas9-mediated gene disruption, as only a single allele needs to be targeted to achieve functional knockout. HAP1 cells are widely employed in functional genomics, genetic interaction screens, and drug sensitivity assays due to their stable karyotype and ease of manipulation.
ARL8B encodes a small GTPase of the ADP-ribosylation factor-like family that localizes primarily to lysosomes. Activation by the BORC complex on lysosomal membranes enables ARL8B to recruit the effector protein PLEKHM2/SKIP, which directly couples lysosomes to the plus-end-directed motor kinesin-1 (KIF5B). This interaction drives the anterograde transport of lysosomes along microtubules toward the cell periphery. ARL8B activity is regulated upstream by the Ragulator complex and RAB7 GTPase, and it functions downstream of amino acid and growth factor signaling. By controlling lysosome positioning, ARL8B influences the spatial activation of mTORC1 and inter-organelle contacts, thereby integrating nutrient sensing with cytoskeletal dynamics.
In HAP1 cells, ARL8B knockout disrupts peripheral lysosome distribution, likely altering mTORC1 signaling and autophagy flux. The haploid background ensures immediate loss-of-function phenotypes without compensatory effects from a second allele, making this polyclonal population ideal for studying lysosomal trafficking deficiencies. The adherent, fibroblast-like morphology of HAP1 facilitates high-resolution imaging of lysosome dynamics. Moreover, because HAP1 retains many features of chronic myeloid leukemia cells, this model offers a unique platform to explore the intersection of oncogenic signaling and lysosomal biology.
This ARL8B knockout HAP1 polyclonal cell model is suited for a wide range of applications including lysosomal biology and trafficking assays, cancer metastasis and migration studies, mTORC1 signaling interrogations, and host-pathogen interaction investigations. Representative assays include immunofluorescence staining for LAMP1/2 to assess lysosome distribution, LysoTracker live-cell imaging, co-immunoprecipitation of ARL8B-SKIP interactions, phospho-S6K immunoblotting for mTORC1 activity, and transwell migration/invasion assays. The polyclonal format also enables pooled CRISPR screens for genetic modifiers of lysosomal positioning. For further information or custom requests, please contact Ascent Research.
