title: A novel inhibitor of ceramide trafficking from the endoplasmic reticulum to the site of sphingomyelin synthesis.
abstract: Ceramide produced at the endoplasmic reticulum (ER) is transported to the lumen of the Golgi apparatus for conversion to sphingomyelin (SM). N-(3-Hydroxy-1-hydroxymethyl-3-phenylpropyl)dodecanamide (HPA-12) is a novel analog of ceramide. Metabolic labeling experiments showed that HPA-12 inhibits conversion of ceramide to SM, but not to glucosylceramide, in Chinese hamster ovary cells. Cultivation of cells with HPA-12 significantly reduced the content of SM. HPA-12 did not inhibit the activity of SM synthase. The inhibition of SM formation by HPA-12 was abrogated when the Golgi apparatus was made to merge with the ER by brefeldin A. Moreover, HPA-12 inhibited redistribution of a fluorescent analog of ceramide, N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-d-erythro-sphingosine (C(5)-DMB-Cer), from intracellular membranes to the Golgi region. Among four stereoisomers of the drug, (1R,3S)-HPA-12, [corrected] which resembles natural ceramide stereochemically, was found to be the most active, although (1R,3S)-HPA-12 [corrected] did not affect ER-to-Golgi trafficking of protein. Interestingly, (1R,3S)-HPA-12 [corrected] inhibited conversion of ceramide to SM little in mutant cells defective in an ATP- and cytosol-dependent pathway of ceramide transport. These results indicated that (1R,3S)-HPA-12 [corrected] inhibits ceramide trafficking from the ER to the site of SM synthesis, possibly due to an antagonistic interaction with a ceramide-recognizing factor(s) involved in the ATP- and cytosol-dependent pathway.
authors.affiliation: Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yasuda
authors.forename: H
authors.initials: H
authors.lastname: Kitagawa
authors.forename: M
authors.initials: M
authors.lastname: Ueno
authors.forename: H
authors.initials: H
authors.lastname: Ishitani
authors.forename: M
authors.initials: M
authors.lastname: Fukasawa
authors.forename: M
authors.initials: M
authors.lastname: Nishijima
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
authors.forename: K
authors.initials: K
authors.lastname: Hanada
mesh_terms: D000577:Amides / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport; D016466:CHO Cells; D002518:Ceramides / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006028:Glycosphingolipids / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D013109:Sphingomyelins / Q000096:biosynthesis* / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D000577:Amides; D002518:Ceramides; D006028:Glycosphingolipids; C441643:N-(3-hydroxy-1-hydroxymethyl-3-phenylpropyl)dodecanamide; D013109:Sphingomyelins