Sphingolipids Containing Very-Long-Chain Fatty Acids Define a Secretory Pathway for Specific Polar Plasma Membrane Protein Targeting in Arabidopsis
Sphingolipids Containing Very-Long-Chain Fatty Acids Define a Secretory Pathway for Specific Polar Plasma Membrane Protein Targeting in Arabidopsis
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DOI：
10.1105/tpc.110.080473
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发表时间：
2011-06-01
期刊：
影响因子：
11.6
通讯作者：
Faure, Jean-Denis
中科院分区：
文献类型：
--
作者：
Markham, Jonathan E.;Molino, Diana;Faure, Jean-Denis
鞘脂是一类参与膜运输和细胞极性的结构性膜脂质。拟南芥中的神经酰胺合酶家族的功能分析表明存在两种选择性的酰基链长度的活动。极长的酰基链（C > 18个碳）而不是长链鞘脂是植物发育所必需的。极长链脂肪酸鞘脂水平的降低特别会导致生长素依赖性的侧根萌发抑制，这与细胞质中质膜生长素载体AUX 1和PIN 1的选择性聚集有关。极性生长素载体的靶向缺陷的特征在于Rab-A2（a）-和Rab-A1（e）-标记的早期内体沿着分泌途径的特异性聚集。这些聚集体与细胞质中膜结构的积累和囊泡碎片化相关。总之，具有很长酰基链的鞘脂定义了具有特定内膜隔室和极性生长素运输蛋白货物的运输途径。
Sphingolipids are a class of structural membrane lipids involved in membrane trafficking and cell polarity. Functional analysis of the ceramide synthase family in Arabidopsis thaliana demonstrates the existence of two activities selective for the length of the acyl chains. Very-long-acyl-chain (C > 18 carbons) but not long-chain sphingolipids are essential for plant development. Reduction of very-long-chain fatty acid sphingolipid levels leads in particular to auxin-dependent inhibition of lateral root emergence that is associated with selective aggregation of the plasma membrane auxin carriers AUX1 and PIN1 in the cytosol. Defective targeting of polar auxin carriers is characterized by specific aggregation of Rab-A2(a)- and Rab-A1(e)-labeled early endosomes along the secretory pathway. These aggregates correlate with the accumulation of membrane structures and vesicle fragmentation in the cytosol. In conclusion, sphingolipids with very long acyl chains define a trafficking pathway with specific endomembrane compartments and polar auxin transport protein cargoes.