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Sphingoid base synthesis requirement for endocytosis in Saccharomyces cerevisiae
Author(s) -
Zanolari Bettina,
Friant Sylvie,
Funato Kouichi,
Sütterlin Christine,
Stevenson Brian J,
Riezman Howard
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.12.2824
Subject(s) - internalization , biology , endocytosis , saccharomyces cerevisiae , biochemistry , ceramide , endocytic cycle , sphingolipid , sphingosine , microbiology and biotechnology , phosphorylation , receptor , yeast , apoptosis
The internalization step of endocytosis in yeast requires actin and sterols for maximum efficiency. In addition, many receptors and plasma membrane proteins must be phosphorylated and ubiquitylated prior to internalization. The Saccharomyces cerevisiae end8‐1 mutant is allelic to lcb1 , a mutant defective in the first step of sphingoid base synthesis. Upon arrest of sphingoid base synthesis a rapid block in endocytosis is seen. This block can be overcome by exogenous sphingoid base. Under conditions where endogenous sphingosine base synthesis was blocked and exogenous sphingoid bases could not be converted to phosphorylated sphingoid bases or to ceramide, sphingoid bases could still suppress the endocytic defect. Therefore, the required lipid is most likely a sphingoid base. Interestingly, sphingoid base synthesis is required for proper actin organization, but is not required for receptor phosphorylation. This is the first case of a physiological role for sphingoid base synthesis, other than as a precursor for ceramide or phosphorylated sphingoid base synthesis.