Phosphatidylinositol 3-kinase (PI3K) is an enzyme that plays a crucial role in cellular functions, including growth, proliferation, and survival. It is involved in signaling pathways that help cells respond to various stimuli, such as hormones and nutrients. By converting a specific lipid, phosphatidylinositol 4,5-bisphosphate, into phosphatidylinositol 3,4,5-trisphosphate, PI3K activates other proteins that regulate these essential processes. The activity of PI3K is important in many biological contexts, including metabolism, cell cycle regulation, and immune responses. Dysregulation of PI3K signaling is associated with various diseases, including cancer and metabolic disorders, making it a target for therapeutic interventions.