I. Development of new assays for probing carbohydrate-carbohydrate interactions utilizing glycolipid monolayers. II. Insights into the fine specificity and minimal valency of carbohydrate-carbohydrate interactions obtained with glycolipid micelles and gl

Carbohydrate-carbohydrate binding events mediate cellular adhesion and activate signal transduction of the c-Src pathway in B16 melanoma variants. The carbohydrates involved in this molecular recognition are GM3, which is present in elevated levels on the surface of the cancer cells, and lactosyl ceramide which is incorporated in endothelia cell membranes. We developed a new assay to detect Carbohydrate-Carbohydrate Interactions (CCI) using Langmuir monolayers and water soluble glycoconjugates. We also investigated the specificity of this interaction using Langmuir film balance techniques and chemical derivatives. A monolayer consisting of GM3-DPPC was employed to mimic the glycosphingolipid signaling domains which are present in cellular membranes. Following monolayer formation, glycolipid micelles or glycodendrimers are injected into the subphase and presented to the interface. Subtle differences in structure within carbohydrate headgroups of the glycolipids results in significant perturbations of the association between monolayer and micelle. Varying dendrimer generations also causes significant changes in CCI. These differences contribute to the fine specificity associated with carbohydrate-carbohydrate recognition.