Selective Stimulation of Caveolar Endocytosis by Glycosphingolipids and Cholesterol

• DOI: 10.1091/mbc.e04-03-0189
• Publication Date: 2004-04-27T00:53:32Z
• Authors: Deepak K. Sharma; Jennifer C. Brown; Amit Choudhury; Timothy E. Peterson; Eileen Holicky; David L. Marks; Robert Simari; Robert G. Parton; Richard E. Pagano
• Keywords: Internalization; Sphingolipid; Caveolin; Caveolin 1

Internalization of some plasma membrane constituents, bacterial toxins, and viruses occurs via caveolae; however, the factors that regulate caveolar internalization are still unclear. Here, we demonstrate a brief treatment cultured cells with natural or synthetic glycosphingolipids (GSLs) elevation cholesterol (either by acute mbeta-cyclodextrin/cholesterol alteration growth conditions) dramatically stimulates endocytosis little no effect on other endocytic mechanisms. These treatments also stimulated movement GFP-labeled vesicles in transfected caveolin-1-GFP reduced number surface-connected caveolae seen electron microscopy. In contrast, overexpression caveolin-1 decreased uptake, but GSLs reversed this endocytosis. Stimulation did not occur using ceramide phosphatidylcholine was due to GSL degradation because similar results were obtained nonhydrolyzable analog. Stimulated required src kinase PKC-alpha activity as shown i) use pharmacological inhibitors, ii) expression inactive dominant negative PKCalpha, iii) stimulation upon addition cholesterol. suggest is regulated balance caveolin-1, cholesterol, at membrane.