Sphingomyelin homeostasis is required to form functional enzymatic domains at the trans-Golgi network.
Bottom Line: Do lipids such as sphingomyelin (SM) that are known to assemble into specific membrane domains play a role in the organization and function of transmembrane proteins?We found that TGN46, which cycles between the TGN and the plasma membrane, was not sialylated by a sialyltransferase at the TGN and that this enzyme and its substrate TGN46 could not physically interact with each other.Our results suggest that SM organizes transmembrane proteins into functional enzymatic domains at the TGN.
Affiliation: Cell and Developmental Biology Programme, Centre for Genomic Regulation, 08003 Barcelona, Spain Universitat Pompeu Fabra, 08002 Barcelona, Spain.Show MeSH
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Mentions: We tested the effects of d-cer-C6 on the Golgi membrane morphology by visualizing the ultrastructure of the cells by electron microscopy. The Golgi stacks appeared to be composed of curled, concentric cisternae upon treatment with d-cer-C6 compared with the flat cisternae in carrier (ethanol) or l-cer-C6–treated cells (Fig. 2 A). We confirmed that these curled membranes contain the TGN marker ST-GFP by cryoimmunoelectron microscopy (Fig. 2 B).
Affiliation: Cell and Developmental Biology Programme, Centre for Genomic Regulation, 08003 Barcelona, Spain Universitat Pompeu Fabra, 08002 Barcelona, Spain.