title: LASS3 (longevity assurance homologue 3) is a mainly testis-specific (dihydro)ceramide synthase with relatively broad substrate specificity.
abstract: The LASS (longevity assurance homologue) family members are highly conserved from yeasts to mammals. Five mouse and human LASS family members, namely LASS1, LASS2, LASS4, LASS5 and LASS6, have been identified and characterized. In the present study we cloned two transcriptional variants of hitherto-uncharacterized mouse LASS3 cDNA, which encode a 384-amino-acid protein (LASS3) and a 419-amino-acid protein (LASS3-long). In vivo, [3H]dihydrosphingosine labelling and electrospray-ionization MS revealed that overproduction of either LASS3 isoform results in increases in several ceramide species, with some preference toward those having middle- to long-chain-fatty acyl-CoAs. A similar substrate preference was observed in an in vitro (dihydro)ceramide synthase assay. These results indicate that LASS3 possesses (dihydro)ceramide synthesis activity with relatively broad substrate specificity. We also found that, except for a weak display in skin, LASS3 mRNA expression is limited almost solely to testis, implying that LASS3 plays an important role in this gland.
authors.affiliation: Laboratory of Biomembrane and Biofunctional Chemistry, Faculty of Advanced Life Sciences, Hokkaido University, Kita 21-jo, Nishi 11-choume, Kita-ku, Sapporo 001-0021, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Mizutani
authors.forename: Akio
authors.initials: A
authors.lastname: Kihara
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051049:Sphingosine N-Acyltransferase; D013379:Substrate Specificity; D013737:Testis / Q000201:enzymology*
chemical_list: D010088:Oxidoreductases; C473786:dihydroceramide synthase; C513562:CerS3 protein, mouse; D051049:Sphingosine N-Acyltransferase