The GRIPAP1 Knockout NCI-H1975 Polyclonal Cells constitute a polyclonal knockout cell population generated via CRISPR/Cas9-mediated disruption of the GRIPAP1 gene in the human NCI-H1975 non-small cell lung carcinoma line. This product provides a genetically mixed loss-of-function model tailored for investigating GRIPAP1 function within an EGFR-mutant lung adenocarcinoma background. The polyclonal nature captures a spectrum of gene-editing events, making it well-suited for pooled functional analyses that reflect cellular heterogeneity.
The parental NCI-H1975 cell line is an adherent epithelial culture derived from a female patient with non-small cell lung adenocarcinoma. These cells are homozygous for the EGFR L858R activating mutation and the T790M gatekeeper mutation, which together render them sensitive to first-generation EGFR tyrosine kinase inhibitors (TKIs) while also modeling acquired resistance via the T790M alteration. As a canonical model of EGFR-mutant lung cancer, NCI-H1975 is extensively used to dissect mechanisms of drug sensitivity and resistance.
GRIPAP1 encodes GRASP-1, a guanine nucleotide exchange factor (GEF) for the small GTPases Rab4 and Rab5. Through these effectors, GRASP-1 coordinates endosomal sorting and recycling of internalized membrane receptors, notably the epidermal growth factor receptor (EGFR) and the AMPA receptor subunit GluA2. GRASP-1 operates in a complex with the scaffolding protein GRIP1, the clathrin adaptor AP-2, and PICK1, coupling endocytic uptake to receptor routing decisions. It is regulated upstream by EGFR/Ras cascades and neuronal calcium/CaMKII signals. Downstream, GRASP-1-dependent Rab4 and Rab5 activation governs early endosome dynamics and the efficiency of receptor recycling to the cell surface, thereby tuning the amplitude and duration of ERK1/2 and AKT signaling. Thus, GRIPAP1 sits at a key interface between endosomal trafficking and proliferative/synaptic signal transduction.
In the NCI-H1975 background, GRIPAP1 knockout is expected to disrupt EGFR recycling, lowering steady-state surface EGFR and dampening downstream MAPK/ERK and PI3K/AKT pathway activity. Because the growth and survival of these cells are reliant on mutant EGFR signaling, loss of GRIPAP1 may augment sensitivity to EGFR TKIs such as erlotinib or osimertinib, or modify the development of resistance. The polyclonal configuration further enables the study of heterogeneous response patterns resembling intratumoral diversity.
Researchers can apply this product in Western blotting for phospho-ERK and AKT, surface biotinylation and flow cytometry to measure EGFR recycling, and immunofluorescence to examine Rab4/Rab5 localization. Additional assays include Transwell migration/invasion tests and dose?Cresponse profiling with EGFR inhibitors. Co-immunoprecipitation can assess GRIPAP1?CGRIP1 interaction, and RT-qPCR can monitor transcriptional outcomes. These approaches render the polyclonal knockout cells a versatile platform for investigating endocytic control of oncogenic signaling, EGFR TKI resistance, and metastatic behavior. For further information, contact Ascent Research.
