1-DEOXY-SPHINGOID BASE AND 1-DEOXYDIHYDROCER BIOSYNTHESIS IN MAMALS

哺乳动物中 1-脱氧-鞘氨醇碱和 1-脱氧二氢生物合成

• 批准号: 8170944
• 负责人: ALFRED Harrison MERRILL
• 金额: $ 1.75万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8170944
• 关键词: Alanine; Anabolism; Animals; Back; Categories; Cell Line; Cells; Chinese Hamster Ovary Cell; Computer Retrieval of Information on Scientific Projects Database; Enzymes; Equilibrium; Fumonisin B1; Funding; Genes; Glycine; Grant; Human; Institution; Kidney; Lipids; Liver; Mammalian Cell; Mus; Mutation; Mycotoxins; Palmitates; Palmitoyl Coenzyme A; Physical condensation; Play; Reaction; Regulation; Relative (related person); Reporting; Research; Research Personnel; Resources; Role; Serine; Site; Source; Threonine; United States National Institutes of Health; analog; base; dihydroceramide; novel; serine palmitoyltransferase; sphinganine

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A novel sphingoid base, 1-deoxysphinganine (1-deoxySa), was recently reported (Zitomer et al., J. Biol. Chem. 284:4786, 2009) to accumulate in fumonisin B1 (FB1) treated cells in culture and in livers and kidneys from mice exposed to this mycotoxin. 1-Deoxysphinganine was shown to arise from condensation of L-alanine with palmitoyl-CoA by following the incorporation of [13C]-L-alanine or [13C]palmitate into [13C]-1-deoxySa by cells in culture. Serine palmitoyltransferase (SPT) was established to be responsible for this reaction because it was absent in a CHO cell line (LY-B) that lacks SPT activity (due to mutation of the LCB1 gene) and restored when wild-type LCB1 was stably transfected back into the cells. This sphingoid base is produced by cells in culture and animals (including humans) under normal conditions (i.e., FB1 is not required for its biosynthesis), but is metabolized to 1-deoxydihydroceramides rather than accumulating as the free sphingoid base. We have determined that glycine is utilized by SPT to synthesize 1-desoxymethyl-sphinganine (1-desoxySa), which is metabolized to 1-desoxymethyl-dihydroceramides. In contrast, L-threonine was not found to be utilized to make a sphingoid base analog. Therefore, SPT is a tri-functional enzyme with the capacity to utilize serine, alanine or glycine to synthesize three categories of sphingoid bases. Furthermore, the distribution of these products is dependent on the relative amounts of the respective precursors available at the site of synthesis. Since 1-deoxy- and 1-desoxymethyl-sphingoid bases are naturally produced by mammalian cells, and the amounts appear to be controlled by the balance of important intermediary metabolites, it seems likely that these novel lipids play significant roles in cell regulation.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目及 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 最近报道了一种新型鞘氨醇碱 1-脱氧二氢鞘氨醇 (1-deoxySa)（Zitomer 等人，J. Biol. Chem. 284:4786, 2009）在培养物和肝脏中伏马菌素 B1 (FB1) 处理的细胞中积累以及暴露于这种霉菌毒素的小鼠的肾脏。 1-脱氧二氢鞘氨醇是由培养细胞将[13C]-L-丙氨酸或[13C]棕榈酸酯掺入[13C]-1-脱氧Sa后L-丙氨酸与棕榈酰辅酶A缩合而产生的。丝氨酸棕榈酰转移酶 (SPT) 被确定为导致该反应的原因，因为它在缺乏 SPT 活性（由于 LCB1 基因突变）的 CHO 细胞系 (LY-B) 中不存在，并且在稳定转染野生型 LCB1 时恢复。回到细胞中。这种鞘氨醇碱是在正常条件下由培养物和动物（包括人类）中的细胞产生的（即，其生物合成不需要 FB1），但会代谢为 1-脱氧二氢神经酰胺，而不是作为游离鞘氨醇碱积累。我们已经确定，SPT 利用甘氨酸合成 1-脱氧甲基-二氢鞘氨醇 (1-desoxySa)，后者代谢为 1-脱氧甲基-二氢神经酰胺。相比之下，未发现 L-苏氨酸可用于制备鞘氨醇碱类似物。因此，SPT是一种三功能酶，能够利用丝氨酸、丙氨酸或甘氨酸合成三类鞘氨醇碱基。此外，这些产物的分布取决于合成地点可用的各个前体的相对量。由于 1-脱氧-和 1-脱氧甲基-鞘氨醇碱是由哺乳动物细胞自然产生的，并且其数量似乎受到重要中间代谢物的平衡控制，因此这些新型脂质似乎在细胞调节中发挥着重要作用。