ITPR1 Knockout HAP1 Polyclonal Cells are a polyclonal population of HAP1 cells bearing CRISPR/Cas9-mediated disruption of the ITPR1 gene, generating a functional knockout model for intracellular calcium signaling studies. This pool contains diverse editing outcomes, reflecting the heterogeneous nature of polyclonal CRISPR/Cas9 editing, without clonal isolation. ITPR1 encodes the IP3 receptor type 1, an endoplasmic reticulum-resident calcium release channel activated by inositol 1,4,5-trisphosphate.
The HAP1 cell line is a near-haploid human line derived from a male chronic myeloid leukemia patient, displaying fibroblast-like morphology. Its near-haploid karyotype simplifies gene disruption, as targeting a single allele is sufficient for loss-of-function. HAP1 cells are favored for genetic screens and functional genomics due to their rapid growth and high-throughput compatibility, providing a leukemic background relevant to cancer research.
ITPR1 functions as a calcium channel downstream of phospholipase C (PLC). Stimuli activating GPCRs or RTKs trigger PLC?? or PLC?? to generate IP3, which binds ITPR1 and opens the channel, releasing Ca2+ from the ER into the cytosol. This second messenger activates calmodulin (CaM), the phosphatase calcineurin, and CaMKII, leading to dephosphorylation and nuclear translocation of NFAT transcription factors and induction of genes like FOS and JUN. Calcium also stimulates PKC and the MAPK/ERK cascade, where ERK1/2 phosphorylates CREB and NF-??B, integrating signals to regulate proliferation, differentiation, and apoptosis. ITPR1 activity is modulated by interacting proteins including Homer, CABP1, RACK1, FKBP12, IRBIT, and ER chaperones GRP78 and calreticulin, and it can heteromerize with ITPR2 and ITPR3.
In HAP1 cells, ITPR1 knockout abolishes IP3-dependent calcium mobilization, allowing mechanistic dissection of calcium-dependent leukemic signaling. HAP1 cells express relevant GPCRs and RTKs, enabling direct interrogation of ITPR1??s role in oncogenic pathways. The near-haploid genetics ensure consistent loss-of-function across the population, making it an ideal model for analyzing calcium??s impact on proliferation, apoptosis resistance, and metabolic adaptation in cancer.
Applications include live-cell calcium imaging with Fluo-4, IP3-induced calcium release assays, and western blotting for phospho-ERK or phospho-AKT to assess downstream signaling. Proliferation, apoptosis, and NFAT luciferase reporter assays enable systematic evaluation of ITPR1-dependent cellular processes. Co-immunoprecipitation identifies interacting partners in the absence of endogenous ITPR1, and RNA-seq reveals transcriptomic changes. The polyclonal pool supports high-throughput screens for IP3 receptor modulators and can be used for single-cell clone derivation. For more information, contact Ascent Research.
