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.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 最近报道了一种新的鞘氨醇碱，1-脱氧鞘氨醇（1-deoxySa）（Zitomer等人，J. Biol. Chem. 284：4786，2009）在培养物中伏马菌素B1（FB 1）处理的细胞以及暴露于该真菌毒素的小鼠的肝脏和肾脏中积累。1-脱氧神经鞘氨醇被证明是由L-丙氨酸与棕榈酰-CoA的缩合产生的，这是通过培养中的细胞将[13 C]-L-丙氨酸或[13 C]棕榈酸酯掺入[13 C]-1-脱氧Sa中来实现的。确定丝氨酸棕榈酰转移酶（SPT）负责该反应，因为它在缺乏SPT活性（由于LCB 1基因突变）的CHO细胞系（LY-B）中不存在，并且当野生型LCB 1稳定转染回细胞时恢复。这种鞘氨醇碱由培养物和动物（包括人）中的细胞在正常条件下（即，FB 1不是其生物合成所必需的），但代谢为1-脱氧二氢神经酰胺，而不是积累为游离鞘氨醇碱。我们已经确定，甘氨酸是利用SPT合成1-脱氧甲基-神经鞘氨醇（1-desoxySa），这是代谢为1-脱氧甲基-二氢神经酰胺。相比之下，未发现L-苏氨酸用于制备类鞘氨醇碱类似物。因此，SPT是具有利用丝氨酸、丙氨酸或甘氨酸合成三类鞘氨醇碱的能力的三功能酶。此外，这些产物的分布取决于在合成地点可获得的相应前体的相对量。由于1-脱氧-和1-脱氧甲基-鞘氨醇碱是由哺乳动物细胞天然产生的，并且其量似乎受到重要中间代谢物平衡的控制，因此这些新脂质似乎在细胞调节中起重要作用。