Molecular cloning and characterization of a lipid phosphohydrolase that degrades sphingosine-1-phosphate and induces cell death
Molecular cloning and characterization of a lipid phosphohydrolase that degrades sphingosine-1-phosphate and induces cell death
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DOI：
10.1073/pnas.120146897
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发表时间：
2000-07-05
影响因子：
11.1
通讯作者：
Spiegel, S
中科院分区：
文献类型：
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作者：
Mandala, SM;Thornton, R;Spiegel, S
鞘氨醇和鞘氨醇-1-磷酸(SPP)是相互转化的鞘磷脂代谢物，对细胞生长和凋亡具有相反的作用。根据与LBP1的序列同源性，我们报道了哺乳动物SPP磷酸酶(MSPP1)的克隆、鉴定和特性。LBP1是一种调节酵母中磷酸化狮身人面像碱基水平的脂质磷酸水解酶。这种疏水性酶含有2型脂质磷酸水解酶保守序列基序，对SPP具有底物专一性。部分纯化的Myc标记的mSPP1对SPP也有很高的去磷酸化活性。在酵母中表达时，mSPP1可以部分替代LBP1的功能。转导mSPP1的人胚胎肾HEK293细胞膜组分能显著降解SPP，但不能降解溶血磷脂酸、磷脂酸或神经酰胺-1-磷酸。在NIH3T3成纤维细胞中增强mSPP1的表达，不仅降低了SPP水平，提高了神经酰胺水平，而且显著降低了存活率，并诱导了细胞凋亡的特征。综上所述，我们的结果表明，SPP磷酸水解酶可能调节哺乳动物细胞中鞘磷脂代谢产物水平之间的动态平衡，从而影响细胞命运。
Sphingosine and sphingosine-1-phosphate (SPP) are interconvertible sphingolipid metabolites with opposing effects on cell growth and apoptosis. Based on sequence homology with LBP1, a lipid phosphohydrolase that regulates the levels of phosphorylated sphingoid bases in yeast, we report here the cloning, identification, and characterization of a mammalian SPP phosphatase (mSPP1). This hydrophobic enzyme, which contains the type 2 lipid phosphohydrolase conserved sequence motif, shows substrate specificity for SPP. Partially purified Myc-tagged mSPP1 was also highly active at dephosphorylating SPP. When expressed in yeast, mSPP1 can partially substitute for the function of LBP1. Membrane fractions from human embryonic kidney HEK293 cells transfected with mSPP1 markedly degraded SPP but not lysophosphatidic acid, phosphatidic acid, or ceramide-1-phosphate. Enforced expression of mSPP1 in NIH 3T3 fibroblasts not only decreased SPP and enhanced ceramide levels, it also markedly diminished survival and induced the characteristic traits of apoptosis. Collectively, our results suggest that SPP phosphohydrolase may regulate the dynamic balance between sphingolipid metabolite levels in mammalian cells and consequently influence cell fate.