Glycosylphosphatidylinositols (GPIs) are complex molecules that serve as anchors for proteins on the cell surface. They consist of a carbohydrate portion linked to a phosphatidylinositol lipid tail, allowing proteins to attach to cell membranes. GPIs play a crucial role in various biological processes, including cell signaling and immune responses. These molecules are found in many organisms, including humans and yeast. GPIs help in the proper localization of proteins, influencing their function and stability. Abnormalities in GPI anchoring can lead to various diseases, highlighting their importance in cellular health and communication.