LASS5 is a bona fide dihydroceramide synthase that selectively utilizes palmitoyl-CoA as acyl donor

J Biol Chem. 2005 Oct 7;280(40):33735-8. doi: 10.1074/jbc.M506485200. Epub 2005 Aug 12.


We demonstrated recently (Riebeling, C., Allegood, J.C., Wang, E., Merrill, A. H. Jr., and Futerman, A. H. (2003) J. Biol. Chem. 278, 43452-43459) that upon over-expression in human embryonic kidney cells, longevity assurance gene homolog 5 (LASS5, previously named TRH4) elevates the synthesis of (dihydro)ceramides selectively enriched in palmitic acid. To determine whether LASS5 is a bona fide dihydroceramide synthase or, alternatively, whether it modifies an endogenous dihydroceramide synthase, we over-expressed LASS5 with a hemagglutinin (HA) tag at the C terminus, solubilized it using digitonin, and purified it by immunoprecipitation. Solubilized LASS5-HA displays the same fatty acid selectivity as the membrane-bound enzyme. After elution from agarose beads, only one band could be detected by SDS-PAGE, and its identity was confirmed to be LASS5 by mass spectrometry. Dihydroceramide synthase activity of the eluted LASS5-HA protein was totally dependent on exogenously added phospholipids. Moreover, eluted LASS5-HA was highly selective toward palmitoyl-CoA as acyl donor and was inhibited by the (dihydro)ceramide synthase inhibitor, fumonisin B1. This study identifies LASS5 as a genuine dihydroceramide synthase and demonstrates that mammalian dihydroceramide synthases do not require additional subunits for their activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Ceramides / metabolism*
  • Gene Expression Regulation
  • Hemagglutinins
  • Humans
  • Immunoprecipitation
  • Kidney / cytology
  • Mass Spectrometry
  • Membrane Proteins / metabolism*
  • Oxidoreductases / metabolism*
  • Palmitoyl Coenzyme A / metabolism*
  • Sphingosine N-Acyltransferase


  • Ceramides
  • Hemagglutinins
  • Membrane Proteins
  • Palmitoyl Coenzyme A
  • Oxidoreductases
  • dihydroceramide synthase
  • CERS1 protein, human
  • CERS5 protein, human
  • Sphingosine N-Acyltransferase