We examined the role of glycosphingolipid-and cholesterol-enriched microdomains, or rafts,
in the sorting of digestive enzymes into zymogen granules destined for apical secretion and
in granule formation. Isolated membranes of zymogen granules from pancreatic acinar cells
showed an enrichment in cholesterol and sphingomyelin and formed detergent-insoluble
glycolipid-enriched complexes. These complexes floated to the lighter fractions of sucrose
density gradients and contained the glycosylphosphatidylinositol (GPI)-anchored …