Plasma membrane microdomains from hybrid aspen cells are involved in cell wall polysaccharide biosynthesis
Plasma membrane microdomains from hybrid aspen cells are involved in cell wall polysaccharide biosynthesis
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DOI：
10.1042/bj20082117
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发表时间：
2009-05-15
影响因子：
4.1
通讯作者：
Bulone, Vincent
中科院分区：
文献类型：
--
作者：
Bessueille, Laurence;Sindt, Nicolas;Bulone, Vincent
抗洗涤剂质膜微区（DRMs）最近从几种植物中分离出来。在动物细胞中，许多细胞功能，如信号转导、内吞和蛋白运输，都是由植物脂筏和DRMs所完成的。现有的数据基本上是基于protcomics和更多的方法，需要采取阐明的精确功能的个别群体的DRM在植物中。我们在这里报告的第一个分离纯化的质膜的树种，杂交白杨杨tremula x tremuloides，和他们的生化特性的DRM。用Triton X-100溶解质膜，并通过在蔗糖密度梯度中浮选来分离所得DRM。的DRM富含甾醇，鞘脂和糖基磷脂酰肌醇锚定蛋白，因此表现出类似的性质，从其他物种的DRM。然而，它们含有参与细胞壁多糖生物合成的关键碳水化合物脱氢酶，即胼胝质[（1 -> 3）-β-D-葡聚糖]和纤维素脱氢酶。这些酶与DRM的关联使用特定的葡聚糖合酶测定和抗体，以及用于表征由分离的DRM体外合成的多糖的生化和化学方法来证明。超过70%的总葡聚糖合酶活性存在于原始质膜与DRM馏分。除了揭示胼胝质和纤维素酶的脂质环境，我们的研究结果表明，DRM参与重要的细胞壁多糖的生物合成。这一新的概念表明植物膜微区在细胞生长和形态发生中的功能。
Detergent-resistant plasma membrane microdomains [DRMs (detergent-resistant membranes)] were isolated recently from several plant species. As for animal cells, a large range of cellular functions, such as signal transduction, endocytosis and protein trafficking, have been attributed to plant lipid rafts and DRMs. The data available are essentially based on protcomics and more approaches need to be undertaken to elucidate the precise function of individual populations of DRMs in plants. We report here the first isolation of DRMs from purified plasma membranes of a tree species, the hybrid aspen Populus tremula x tremuloides, and their biochemical characterization. Plasma membranes were solubilized with Triton X-100 and the resulting DRMs were isolated by flotation in sucrose density gradients. The DRMs were enriched in sterols, sphingolipids and glycosylphosphatidylinositol-anchored proteins and thus exhibited similar properties to DRMs from other species. However, they contained key carbohydrate synthases involved in cell wall polysaccharide biosynthesis, namely callose [(1 -> 3)-beta-D-glucan] and cellulose synthases. The association of these enzymes with DRMs was demonstrated using specific glucan synthase assays and antibodies, as well as biochemical and chemical approaches for the characterization of the polysaccharides synthesized in vitro by the isolated DRMs. More than 70% of the total glucan synthase activities present in the original plasma membranes was associated with the DRM fraction. In addition to shedding light on the lipid environment of callose and cellulose synthases, our results demonstrate the involvement of DRMs in the biosynthesis of important cell wall polysaccharides. This novel concept suggests a function of plant membrane microdomains in cell growth and morphogenesis.