Ganglioside glycosyltransferases organize in distinct multienzyme complexes in CHO-K1 cells.

摘要: The synthesis of gangliosides is compartmentalized in the Golgi complex. In most cells, glycosylation LacCer, GM3, and GD3 to form higher order species (GA2, GM2, GD2, GM1, GD1b) displaced toward distal aspects trans-Golgi network, where involved transferases (GalNAcT GalT2) physical functional associations. Glycosylation simple GD3, on other hand, more proximal compartments, we investigate here whether (GalT1, SialT1, SialT2) share property forming Co-immunoprecipitation experiments from membranes CHO-K1 cells expressing epitope-tagged versions these enzymes indicate that GalT1, SialT2 associate physically a SialT1-dependent manner their N-terminal domains participate interactions. Microscopic fluorescence resonance energy transfer recovery after photobleaching living confirmed interactions, addition showing apparatus localization complexes, mapped formation endoplasmic reticulum. Neither co-immunoprecipitation nor detected interactions between either GalT2 or GalNAcT GalT1 SialT1 SialT2. These results, triple color imaging Golgi-derived microvesicles nocodazole-treated suggest ganglioside organized distinct units each formed by associations particular glycosyltransferases, which concentrate different sub-Golgi compartments.