The ICMT Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population designed to disrupt the human ICMT gene, which encodes isoprenylcysteine carboxyl methyltransferase. This product comprises a heterogeneous pool of HAP1 cells bearing targeted gene disruption via CRISPR/Cas9-mediated genome editing, providing a physiologically relevant loss-of-function model for studying the final step of CAAX protein processing. The polyclonal format offers a rapid and cost-effective means to interrogate ICMT-dependent phenotypes without the need for single-cell cloning, enabling robust functional genomics screens and pathway analysis in a near-haploid background. Researchers can utilize this knockout model to dissect the methylation-dependent regulation of small GTPase trafficking and signaling in a human cell context.
Derived from the KBM-7 near-haploid chronic myeloid leukemia (CML) cell line, the HAP1 host cells are a human fibroblast-like line with a stable haploid karyotype. This unique genetic characteristic eliminates the masking effects of a second allele, ensuring unambiguous genotype?Cphenotype correlations following CRISPR/Cas9-mediated gene disruption. HAP1 cells retain key features of their CML origin, including expression of the BCR-ABL1 fusion oncogene, making them a pertinent model for studying leukemia-relevant signaling networks. The adherent, epithelial-like morphology and reliable growth characteristics further facilitate standardized cell-based assays, and the haploid nature simplifies data interpretation in genetic perturbation experiments.
The ICMT protein catalyzes the carboxyl methylation of isoprenylated C-terminal cysteine residues in CAAX motif proteins, a critical step that enhances the hydrophobicity of small GTPases and stabilizes their membrane association. ICMT functions downstream of farnesyltransferase, geranylgeranyltransferase type I, and RCE1 protease, and directly interacts with prenylated CAAX substrates and components of the endomembrane system. Its primary targets include the RAS, RHO, and RAP family GTPases, as well as RAC1, which subsequently propagate signals through pathways such as RAS?CRAF?CMEK?CERK and RHO?CROCK. By methylating the prenylcysteine residue, ICMT ensures proper spatiotemporal activation of these molecular switches; loss of ICMT activity compromises membrane targeting, attenuates effector coupling, and ultimately leads to reduced proliferative and survival signaling.
In the HAP1 leukemia cell background, disruption of ICMT is expected to substantially impair oncogenic signaling cascades driven by RAS and RHO GTPases, which are frequently hyperactivated in CML and other hematopoietic malignancies. The haploid genotype amplifies the phenotypic consequences of ICMT loss, providing a sensitive system to detect alterations in cell proliferation, colony formation, and drug sensitivity. Because the BCR-ABL1 oncoprotein engages RAS?CMAPK and RHO?CROCK pathways to enforce leukemogenesis, this knockout model offers a targeted platform to explore the intersection of protein prenylation and tyrosine kinase signaling, potentially revealing synthetic vulnerabilities or resistance mechanisms relevant to kinase inhibitor therapy.
This ICMT knockout pool is suited for a range of research applications, including the investigation of RAS-driven oncogenic signaling, screening of small-molecule inhibitors targeting the protein prenylation pathway, and functional analysis of CAAX protein methylation in cancer. The polyclonal population can be used in assays such as western blotting for ICMT and downstream effectors, membrane fractionation to assess GTPase localization, RAS activation assays, phospho-ERK analysis, and cell proliferation or migration assays. Additionally, drug sensitivity studies with tyrosine kinase inhibitors or prenylation inhibitors in this leukemia background can illuminate resistance mechanisms. For further details, please contact Ascent Research.
