Epithelial cells display polarized distributions of proteins and lipids on the cellular surface. Apical and basolateral sorting, initiated in the TGN, leads to cellular asymmetry by recognition of sorting signals by known and unknown receptors. Isolation of the protein constituents from TGN derived transport vesicles have led to the identification of novel proteins, including VIP36; a protein homologous with mammalian and leguminous lectins, raising the possibility that it may recognize oligosaccharide ligands and be involved in apical sorting. These studies seek to identify the natural oligomeric state of VIP36 and characterize its natural carbohydrate ligands. Additionally, recycling of VIP36 from the cell surface to the TGN will be investigated using both site specific gene mutations and biochemical approaches. Further mutations or anti-sense nucleotides will be used to mistarget or block expression of VIP36, respectively. The effects of these perturbations on the sorting of natural VIP36 ligands will be analyzed.