title: Oxidative stress elicited by modifying the ceramide acyl chain length reduces the rate of clathrin-mediated endocytosis.
abstract: Sphingolipids modulate clathrin-mediated endocytosis (CME) by altering the biophysical properties of membranes. We now examine CME in astrocytes cultured from ceramide synthase 2 (CerS2) null mice, which have an altered sphingolipid acyl chain composition. The rate of endocytosis of low-density lipoprotein and transferrin, which are internalized via CME, was reduced in CerS2 null astrocytes, although the rate of caveolin-mediated endocytosis was unaltered. Levels of clathrin heavy chain were increased, which was due to decreased levels of Hsc70 (also known as HSPA8), a protein involved in clathrin uncoating. Hsc70 levels were decreased because of lower levels of binding of Sp1 to position -68 in the Hsc70 promoter. Levels of Sp1 were downregulated due to oxidative stress, which was elevated fourfold in CerS2 null astrocytes. Furthermore, induction of oxidative stress in wild-type astrocytes decreased the rate of CME, whereas amelioration of oxidative stress in CerS2 null astrocytes reversed the decrease. Our data are consistent with the notion that sphingolipids not only change membrane biophysical properties but also that changes in their composition can result in downstream effects that indirectly impinge upon a number of cellular pathways, such as CME.
authors.affiliation: Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Giora
authors.initials: G
authors.lastname: Volpert
authors.affiliation: Department of Biological Services, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Shifra
authors.initials: S
authors.lastname: Ben-Dor
authors.affiliation: Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Ohad
authors.initials: O
authors.lastname: Tarcic
authors.affiliation: School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Duan
authors.affiliation: Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Hospital, Jerusalem 91120, Israel.|The Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Hospital, Jerusalem 91120, Israel.
authors.forename: Ann
authors.initials: A
authors.lastname: Saada
authors.affiliation: School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA.
authors.forename: Alfred H
authors.initials: AH
authors.lastname: Merrill
authors.affiliation: Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Pewzner-Jung
authors.affiliation: Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel tony.futerman@weizmann.ac.il.
authors.forename: Anthony H
authors.identifier: 0000-0003-0013-0115
authors.initials: AH
authors.lastname: Futerman
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002518:Ceramides / Q000737:chemistry / Q000378:metabolism*; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis / Q000235:genetics; D008099:Liver / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D018384:Oxidative Stress / Q000235:genetics / Q000276:immunology*; D015202:Protein Engineering; D015398:Signal Transduction; D013107:Sphingolipids / Q000378:metabolism*; D051049:Sphingosine N-Acyltransferase / Q000235:genetics / Q000378:metabolism*
chemical_list: D002518:Ceramides; D002966:Clathrin; D013107:Sphingolipids; C580723:Cers2 protein, mouse; D051049:Sphingosine N-Acyltransferase
keywords: Clathrin-mediated endocytosis; Hsc70; Reactive oxygen species; Sp1; Very long-chain ceramides