PLCG1 encodes phospholipase C gamma 1, a critical enzyme that mediates production of second messengers diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3), regulating intracellular calcium signaling and downstream pathways 1. The enzyme becomes activated in response to receptor tyrosine kinase signaling and plays essential roles in T cell activation, with mutations frequently identified in adult T cell leukemia/lymphoma 2. Mechanistically, PLCG1 promotes calcium flux, ERK phosphorylation, and NF-κB signaling, with hyperactive variants causing enhanced LAT condensation and sustained pathway activation 3. Disease relevance is significant, as gain-of-function PLCG1 mutations cause immune dysregulation disorders characterized by inflammatory T cell and monocyte responses 1. In cancer contexts, PLCG1 contributes to drug resistance mechanisms and promotes cell survival through ERK-dependent pathways 34. Clinically, PLCG1 dysfunction is implicated in cellular senescence through calcium overload when chaperone-mediated autophagy is impaired 5, and serves as a potential therapeutic target with PLCγ1 inhibitors showing promise in reversing inflammatory gene expression profiles 1. The protein's central role in calcium homeostasis and immune signaling makes it a critical regulator of both normal T cell function and pathological immune responses.