| First Author | Lahiri S | Year | 2005 |
| Journal | J Biol Chem | Volume | 280 |
| Issue | 40 | Pages | 33735-8 |
| PubMed ID | 16100120 | Mgi Jnum | J:117507 |
| Mgi Id | MGI:3696624 | Doi | 10.1074/jbc.M506485200 |
| Citation | Lahiri S, et al. (2005) LASS5 is a bona fide dihydroceramide synthase that selectively utilizes palmitoyl-CoA as acyl donor. J Biol Chem 280(40):33735-8 |
| abstractText | 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. |
