Effects on vesicular transport pathways at the late endosome in cells with limited very long-chain fatty acids

J Lipid Res. 2013 Mar;54(3):831-842. doi: 10.1194/jlr.M034678. Epub 2013 Jan 16.

Abstract

Very long-chain fatty acids (VLCFAs), fatty acids with chain-length greater than 20 carbons, possess a wide range of biological functions. However, their roles at the molecular level remain largely unknown. In the present study, we screened for multicopy suppressors that rescued temperature-sensitive growth of VLCFA-limited yeast cells, and we identified the VPS21 gene, encoding a Rab GTPase, as such a suppressor. When the vps21Δ mutation was introduced into a deletion mutant of the SUR4 gene, which encodes a VLCFA elongase, a synthetic growth defect was observed. Endosome-mediated vesicular trafficking pathways, including endocytosis and the carboxypeptidase Y (CPY) pathway, were severely impaired in sur4Δ vps21Δ double mutants, while the AP-3 pathway that bypasses the endosome was unaffected. In addition, the sur4Δ mutant also exhibited a synthetic growth defect when combined with the deletion of VPS3, which encodes a subunit of the class C core vacuole/endosome tethering (CORVET) complex that tethers transport vesicles to the late endosome/multivesicular body (MVB). These results suggest that, of all the intracellular trafficking pathways, requirement of VLCFAs is especially high in the endosomal pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / genetics
  • Cathepsin A / genetics
  • Cathepsin A / metabolism
  • Endosomes / metabolism*
  • Fatty Acids / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Vesicular Transport Proteins / genetics
  • rab GTP-Binding Proteins / genetics

Substances

  • Fatty Acids
  • Saccharomyces cerevisiae Proteins
  • VPS3 protein, S cerevisiae
  • Vesicular Transport Proteins
  • Acetyltransferases
  • SUR4 protein, S cerevisiae
  • Cathepsin A
  • VPS21 protein, S cerevisiae
  • rab GTP-Binding Proteins