LY6G6F (lymphocyte antigen 6 family member G6F) is a type I transmembrane protein belonging to the immunoglobulin superfamily that functions as a cell-surface receptor involved in signal transduction. The protein contains four extracellular immunoglobulin-like domains and a cytoplasmic tail with a conserved tyrosine residue (Y281) within a YXN motif 1. Upon phosphorylation, this tyrosine serves as a docking site for adaptor proteins Grb2 and Grb7, coupling LY6G6F to downstream Ras-MAP kinase signaling pathways 1. The protein is expressed on platelet surfaces and becomes phosphorylated in response to collagen-related peptide stimulation through the GPVI collagen receptor 2. Clinically, LY6G6F shows diagnostic relevance across multiple disease contexts. In respiratory syncytial virus (RSV) infection, LY6G6F was identified as a key immune-related gene associated with CD56 bright natural killer cell responses 3. The protein also emerged as a plasma biomarker candidate for cardia gastric cancer progression, contributing to diagnostic panels distinguishing cardia low-grade dysplasia, high-grade dysplasia, and cancer from healthy controls with AUC values exceeding 0.91 4. Additionally, elevated leukocyte LY6G6F expression correlates with superior frontal gyrus atrophy in granulin mutation carriers with frontotemporal lobar degeneration, suggesting involvement in neuroinflammatory pathways underlying neurodegeneration 5.