Premium
Elevation Of Sphingoid Bases In Hek293 Cells Increases C18‐(Dihydro)Ceramide Biosynthesis Via Alteration Of LASS1 (Cers1) Expression, Activity And Subcellular Localization
Author(s) -
Liu Ying,
Haynes Christopher,
Allegood Jeremy,
Kelly Samuel,
Wang Elaine,
Merrill Alfred
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a237-b
Subject(s) - ceramide , sphingolipid , biosynthesis , biochemistry , hek 293 cells , enzyme , chemistry , ceramide synthase , subcellular localization , serine , lipid signaling , biology , microbiology and biotechnology , gene , apoptosis
Ceramide biosynthesis involves the acylation of sphingoid bases by ceramide synthases (CerS) that are selective for different categories of fatty acyl‐CoA's; for example, CerS1 (LASS1) is selective for stearoyl‐CoA and produces C18‐(dihydro)Cer. Mass spectrometric analysis of the sphingolipids of Hek 293 cells with elevated sphinganine due to increased biosynthesis (by stable overexpression of serine palmitoyltransferase) or addition of exogenous sphingoid base(s) revealed increases in the proportion of C18‐(dihydro)Cer relative to other Cer subspecies. This increase was due to an increase in CerS1 mRNA expression (by QRT‐PCR) and enzymatic activity (by in vitro enzymatic assay); therefore, elevated sphingoid bases induce CerS1 by what appears to be “feed‐forward” regulation. In addition, however, analysis of the subcellular localization of CerS1‐GFP also suggests that CerS1‐GFP is located in both ER and Golgi, and the increases in C18‐(dihydro)Cer may also involve retention of CerS1 in the ER where it could have greater access to its substrates, or be modulated by other topologic factors. This work was collaborated with David Uhlinger, Johnson & Johnson Company and funded by NIH grant GM069338.