Glycosylphosphatidylinositol (GPI) is a type of glycolipid that anchors proteins to the cell membrane. It consists of a carbohydrate moiety linked to a phosphatidylinositol molecule, which is embedded in the lipid bilayer. GPI anchors help in stabilizing proteins and play a crucial role in cell signaling and interactions. GPI-anchored proteins are involved in various biological processes, including immune responses and cell adhesion. They are found in many organisms, from yeast to humans, and their dysfunction can lead to diseases. Understanding GPI and its functions is important for developing therapeutic strategies for related health issues.