Contribution of sams-1 and pmt-1 to lipid homoeostasis in adult Caenorhabditis elegans

J Biochem. 2011 May;149(5):529-38. doi: 10.1093/jb/mvr025. Epub 2011 Mar 9.


Accumulation of lipids inside the cell is primarily caused by disorders of lipid metabolism. S-adenosylmethionine synthetase (SAMS) produces SAM, an important methyl donor in various phospholipid methyltransferase reactions catalysed by phosphoethanolamine N-methyltransferase (PMT-1). A gel-based, quantitative proteomic analysis of the RNA interference (RNAi)-mediated inactivation of the pod-2 gene, which encodes acetyl-CoA carboxylase, showed a substantial down-regulation of SAMS-1. Consequently, RNAi of either sams-1 or pmt-1 caused a significant increase in lipid droplet size in the intestine of Caenorhabditis elegans. Lipid droplets exhibited increased triacylglycerol (TG) and decreased phosphatidylcholine (PC) levels, suggesting a reciprocal relationship between TG and PC regulation. These lipid-associated phenotypes were rescued by choline feeding. Among the five fat metabolism-related genes examined, two genes were highly induced by inactivation of sams-1 or pmt-1: pod-2 and stearoyl-CoA desaturase (fat-7). Thus, both SAMS-1 and PMT-1 were shown to contribute to the homoeostasis of TG and PC levels in C. elegans, which would provide an important survival strategy under harsh environmental conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans / cytology
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Choline / metabolism
  • Electrophoresis, Gel, Two-Dimensional
  • Homeostasis*
  • Humans
  • Lipid Metabolism*
  • Lipids / chemistry*
  • Methionine Adenosyltransferase / genetics
  • Methionine Adenosyltransferase / metabolism*
  • Methyltransferases / genetics
  • Methyltransferases / metabolism*
  • Phenotype
  • Proteome / analysis
  • RNA Interference


  • Caenorhabditis elegans Proteins
  • Lipids
  • Proteome
  • Methyltransferases
  • phosphoethanolamine methyltransferase
  • Methionine Adenosyltransferase
  • Choline