title: Up-regulation of ceramide glucosyltransferase during the differentiation of U937 cells.
abstract: The phorbol ester tetradecanoylphorbol acetate (TPA) induces promyelocytic leukaemia cells to differentiate to macrophage-like cells in vitro. During the course of this differentiation, the cells adhere to the bottom of the culture dish, a process that requires an increase in cell surface glycosphingolipids (GSLs). We examined the cellular content of glucosylceramide (GlcCer), the simplest of the GSLs, in a TPA-treated leukaemia cell line, U937. Following TPA treatment, we observed a 3.5-fold increase in GlcCer levels that was caused by enhanced activity of ceramide glucosyltransferase (GlcT-1), which catalyses ceramide glycosylation. Furthermore, in TPA-treated cell GlcT-1 amounts were increased at both the mRNA and protein levels. We also found decreased activity of lactosylceramide synthase in TPA-treated cells, which could also contribute to the increase in cellular GlcCer content.
authors.affiliation: Laboratory for Animal Cell Engineering, Niigata University of Pharmacy and Applied Life Sciences (NUPALS), 265-1 Higashijima, Akiha-ku, Niigata-shi Niigata 956-8603, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Aida
authors.forename: Syouta
authors.initials: S
authors.lastname: Higuchi
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Michiyo
authors.initials: M
authors.lastname: Nagano-Ito
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Aoi
authors.initials: A
authors.lastname: Banba
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Shimizu
authors.forename: Asako
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Mayuko
authors.initials: M
authors.lastname: Saga
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ichikawa
mesh_terms: D002448:Cell Adhesion; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D005700:Galactosyltransferases / Q000378:metabolism; D005963:Glucosylceramides / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000201:enzymology / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D005963:Glucosylceramides; D012333:RNA, Messenger; D005700:Galactosyltransferases; D005964:Glucosyltransferases; C039090:UDPgalactose-glucosylceramide galactosyltransferase; C023246:ceramide glucosyltransferase; D013755:Tetradecanoylphorbol Acetate