De novo sphingolipid synthesis is essential for viability, but not for transport of glycosylphosphatidylinositol-anchored proteins, in African trypanosomes. Academic Article uri icon

Overview

MeSH

  • Animals
  • Cell Culture Techniques
  • Cell Survival
  • Ceramides
  • Fatty Acids, Monounsaturated
  • GPI-Linked Proteins
  • HeLa Cells
  • Humans
  • Lysosomes
  • Microscopy, Fluorescence
  • Protozoan Proteins

MeSH Major

  • Cell Cycle Proteins
  • Membrane Proteins
  • Protein Transport
  • Sphingolipids
  • Trypanosoma brucei brucei
  • Variant Surface Glycoproteins, Trypanosoma

abstract

  • De novo sphingolipid synthesis is required for the exit of glycosylphosphatidylinositol (GPI)-anchored membrane proteins from the endoplasmic reticulum in yeast. Using a pharmacological approach, we test the generality of this phenomenon by analyzing the transport of GPI-anchored cargo in widely divergent eukaryotic systems represented by African trypanosomes and HeLa cells. Myriocin, which blocks the first step of sphingolipid synthesis (serine + palmitate --> 3-ketodihydrosphingosine), inhibited the growth of cultured bloodstream parasites, and growth was rescued with exogenous 3-ketodihydrosphingosine. Myriocin also blocked metabolic incorporation of [3H]serine into base-resistant sphingolipids. Biochemical analyses indicate that the radiolabeled lipids are not sphingomyelin or inositol phosphorylceramide, suggesting that bloodstream trypanosomes synthesize novel sphingolipids. Inhibition of de novo sphingolipid synthesis with myriocin had no adverse effect on either general secretory trafficking or GPI-dependent trafficking in trypanosomes, and similar results were obtained with HeLa cells. A mild effect on endocytosis was seen for bloodstream trypanosomes after prolonged incubation with myriocin. These results indicate that de novo synthesis of sphingolipids is not a general requirement for secretory trafficking in eukaryotic cells. However, in contrast to the closely related kinetoplastid Leishmania major, de novo sphingolipid synthesis is essential for the viability of bloodstream-stage African trypanosomes.

publication date

  • March 2007

has subject area

  • Animals
  • Cell Culture Techniques
  • Cell Cycle Proteins
  • Cell Survival
  • Ceramides
  • Fatty Acids, Monounsaturated
  • GPI-Linked Proteins
  • HeLa Cells
  • Humans
  • Lysosomes
  • Membrane Proteins
  • Microscopy, Fluorescence
  • Protein Transport
  • Protozoan Proteins
  • Sphingolipids
  • Trypanosoma brucei brucei
  • Variant Surface Glycoproteins, Trypanosoma

Research

keywords

  • Journal Article

Identity

Language

  • eng

PubMed Central ID

  • PMC1828920

Digital Object Identifier (DOI)

  • 10.1128/EC.00283-06

PubMed ID

  • 17220466

Additional Document Info

start page

  • 454

end page

  • 464

volume

  • 6

number

  • 3