The GPR161 Knockout HeLa Polyclonal Cells product provides a CRISPR/Cas9-mediated loss-of-function model generated through targeted disruption of the human GPR161 gene in a HeLa cell background. This polyclonal knockout cell population is designed to abolish GPR161 protein expression, eliminating its constitutive negative regulation of Sonic hedgehog (Shh) pathway activity. By removing this ciliary GPCR, the model enables researchers to dissect GPR161-dependent signaling mechanisms and pathway crosstalk in a human epithelial context. The polyclonal nature ensures representation of multiple editing events, facilitating robust population-level analyses without reliance on single-cell-derived clones.
The parental HeLa cell line is a widely used human cervical adenocarcinoma epithelial model, originally derived from a patient with HPV-18 infection. The cells harbor integrated HPV-18 sequences that inactivate the p53 and retinoblastoma (Rb) tumor suppressors, providing a cancer-relevant background with deregulated cell cycle control. HeLa cells exhibit robust growth characteristics and are amenable to standard transfection and CRISPR workflows. While not a classical ciliary model, HeLa cells can assemble primary cilia under specific culture conditions, permitting investigation of ciliary protein trafficking and Shh signaling components in a transformed epithelial setting.
GPR161 is an orphan G protein-coupled receptor that preferentially localizes to primary cilia and functions as a key negative regulator of the Shh pathway. In the absence of Shh ligand, GPR161 constitutively couples to the G??s subunit to stimulate adenylyl cyclase, elevating intracellular cAMP levels and promoting protein kinase A (PKA) activation. Active PKA phosphorylates Gli2 and Gli3 transcription factors, targeting them for proteolytic processing into transcriptional repressor forms that suppress Shh target genes such as GLI1, PTCH1, and HHIP. Upon Shh binding to Patched1 (PTCH1), the pathway relieve inhibition of Smoothened (SMO), triggering intraflagellar transport (IFT)-dependent removal of GPR161 from the cilium. This diminishes cAMP/PKA signaling, allowing full-length Gli activators to accumulate and induce target gene expression. GPR161 removal is mediated by regulators including GRK2, beta-arrestin2, and the Shh/PTCH1/SMO axis. Its downstream effects are transduced through cAMP production, PKA-mediated phosphorylation of Gli2/Gli3, and subsequent repression of Shh transcriptional output. The receptor interacts physically and functionally with components such as the IFT-B complex, adenylyl cyclase isoforms, PKA regulatory subunits, and beta-arrestin2, positioning it at the interface of ciliary trafficking and Shh signal transduction.
In the HeLa context, disruption of GPR161 is predicted to relieve constitutive repression of Shh target genes, resulting in low-level, ligand-independent pathway activation. This creates a permissive background for studying the regulatory logic of Shh signaling in a cell type lacking the complex ciliary architecture of untransformed epithelial cells. Given the HeLa line’s origins and its widespread use in cancer biology, the GPR161 knockout model provides a unique platform to interrogate how ciliary GPCR function intersects with oncogenic pathways. Researchers can investigate whether loss of GPR161-mediated repression alters proliferative, migratory, or invasive properties under varying Shh ligand conditions, and may uncover context-dependent roles for this receptor in tumor cell signaling. The model also facilitates examination of ciliary protein trafficking dynamics in transformed cells, as GPR161 localization to primary cilia is dynamically regulated by IFT machinery.
This product is suitable for a wide range of experimental applications, including dissecting Shh pathway regulation, probing ciliary protein trafficking, and performing drug screening for Hedgehog pathway modulators. Researchers can validate knockout efficiency using Sanger or next-generation sequencing of the CRISPR target locus, combined with RT-qPCR and Western blotting to assess GPR161 mRNA and protein levels. Functional studies may employ Gli-luciferase reporter assays to quantify pathway output, qPCR for endogenous Shh target genes (GLI1, PTCH1, HHIP), and direct cAMP measurement to gauge receptor coupling. Immunofluorescence co-staining for ciliary markers such as ARL13B and acetylated tubulin can confirm altered receptor localization. Downstream phenotypic assays, including cell proliferation, migration, and invasion, provide readouts for Shh-dependent and independent roles of GPR161 in cancer cell behavior. For additional information or technical support, please contact Ascent Research.
