GPRIN3 (G protein-regulated inducer of neurite outgrowth 3) is a membrane-localized protein involved in neurite outgrowth and cellular signaling. GPRIN3 interacts with β-arrestin 2 and is essential for dopamine receptor-dependent signaling cascades in the striatum, where it mediates G protein-independent signaling and regulates dopaminergic behaviors 1. The protein requires a di-cysteine motif for proper plasma membrane localization 1. In cancer biology, GPRIN3 functions as an oncogenic target. It is upregulated in gastric cancer and promotes cell cycle progression, proliferation, migration, and invasion through Wnt/β-catenin pathway activation; microRNA-6838-5p suppresses these malignant phenotypes by targeting GPRIN3 2. GPRIN3 also serves as a prognostic biomarker in colon cancer, functioning as part of a T cell signature gene panel predictive of patient outcomes 3. Genetically, GPRIN3 has been identified as a risk locus across multiple diseases. Integrative proteogenomic analyses revealed GPRIN3 as a potential intracranial aneurysm risk gene associated with cell cycle regulation 4. GPRIN3 was identified as a causal gene for dementia with Lewy bodies in East Asian populations through transcriptome-wide association analysis in the substantia nigra 5, and as a risk locus for gallstone disease in Latino populations 6. Environmental neurotoxicant rotenone alters epigenetic patterns at GPRIN3 regulatory regions in Parkinson's disease contexts 7.