RRC ID 18527
著者 van der Poel S, Wolthoorn J, van den Heuvel D, Egmond M, Groux-Degroote S, Neumann S, Gerritsen H, van Meer G, Sprong H.
タイトル Hyperacidification of trans-Golgi network and endo/lysosomes in melanocytes by glucosylceramide-dependent V-ATPase activity.
ジャーナル Traffic
Abstract Sphingolipids are considered to play a key role in protein sorting and membrane trafficking. In melanocytic cells, sorting of lysosomal and melanosomal proteins requires the sphingolipid glucosylceramide (GlcCer). This sorting information is located in the lumenal domain of melanosomal proteins. We found that two processes dependent on lumenal pH, protein sialylation and lysosomal acid lipase (LAL) activity were aberrant in GM95 melanocyte cells, which do not produce glycosphingolipids. Using fluorescence lifetime imaging microscopy (FLIM), we found that the lumenal pH in the trans-Golgi network and lysosomes of wild-type melanocyte MEB4 cells are >1 pH unit lower than GM95 cells and fibroblasts. In addition to the lower pH found in vivo, the in vitro activity of the proton pump, the vacuolar-type H(+) -translocating ATPase (V-ATPase), was twofold higher in MEB4 compared to GM95 cells. The apparent K(i) for inhibition of the V-ATPase by concanamycin A and archazolid A, which share a common binding site on the c-ring, was lower in glycosphingolipid-deficient GM95 cells. No difference between the MEB4 and GM95 cells was found for the V-ATPase inhibitors apicularen A and salicylihalimide. We conclude that hyperacidification in MEB4 cells requires glycosphingolipids and propose that low pH is necessary for protein sorting and melanosome biogenesis. Furthermore, we suggest that glycosphingolipids are indirectly involved in protein sorting and melanosome biogenesis by stimulating the proton pump, possibly through binding of GlcCer. These experiments establish, for the first time, a link between pH, glycosphingolipids and melanosome biogenesis in melanocytic MEB4 cells, to suggest a role for glycosphingolipids in hyperacidification in melanocytes.
巻・号 12(11)
ページ 1634-47
公開日 2011-11-1
DOI 10.1111/j.1600-0854.2011.01263.x
PMID 21810155
MeSH Binding Sites / physiology Endosomes / metabolism* Fibroblasts / metabolism Glucosylceramides / biosynthesis Glucosylceramides / metabolism* Glycosphingolipids / biosynthesis Glycosphingolipids / metabolism HeLa Cells Humans Hydrogen-Ion Concentration Lipase / metabolism Lysosomes / metabolism* Macrolides / pharmacology Melanocytes / metabolism* Melanosomes / metabolism Mutation Protein Transport Proton Pumps / metabolism Thiazoles / pharmacology Tumor Cells, Cultured Vacuolar Proton-Translocating ATPases / metabolism* trans-Golgi Network / metabolism*
IF 4.045
引用数 19
WOS 分野 CELL BIOLOGY
リソース情報
ヒト・動物細胞 MEB4(RCB1027) GM95(RCB1026)