Laboratory of Synthetic Biology, Institutes of Plant Physiology and Ecology, Chinese Academy of Science, Shanghai, China.
New Phytol. 2010 Aug;187(3):777-90. doi: 10.1111/j.1469-8137.2010.03315.x. Epub 2010 Jun 7.
*It is generally hypothesized that the synthesis of cellulose in higher plants is mediated by cellulose synthase complexes (CSCs) localized on the plasma membrane. However, CSCs have not been investigated thoroughly through their isolation. The availability of ample Populus tissue allowed Populus CSCs to be isolated and characterized in association with xylem differentiation. *The methods used here included co-immunoprecipitation, proteomic analysis, laser microdissection, immunolocalization and others. *Western blot analysis of the immunoprecipitated CSCs led to the identification of at least two types of CSC in the membrane protein of Populus xylem tissue. Proteomic analysis further revealed that the two types of CSC were assembled from different cellulose synthase proteins. Immunolocalization confirmed that both types of CSC were involved in secondary cell wall formation. In addition, a number of noncellulose synthase proteins were also identified in association with CSC precipitation. *The results indicate that two types of CSC participate in secondary wall formation in Populus, suggesting a new mechanism of cellulose formation involved in the thickening of wood cell walls. This study also suggests that the CSC machinery may be aided by other proteins in addition to cellulose synthase proteins.
通常假设高等植物的纤维素合成是由定位于质膜上的纤维素合酶复合物（CSC）介导的。然而，CSC 尚未通过其分离进行彻底研究。丰富的杨树组织的可用性允许与木质部分化相关联来分离和表征杨树 CSC。这里使用的方法包括共免疫沉淀、蛋白质组分析、激光微切割、免疫定位等。CSC 的免疫沉淀的 Western blot 分析导致在杨树木质部组织的膜蛋白中鉴定出至少两种类型的 CSC。蛋白质组分析进一步表明，这两种类型的 CSC 是由不同的纤维素合酶蛋白组装而成的。免疫定位证实这两种类型的 CSC 都参与次生细胞壁的形成。此外，还鉴定出与 CSC 沉淀相关的许多非纤维素合酶蛋白。结果表明，两种类型的 CSC 参与杨树次生壁的形成，这表明了一种涉及木细胞壁增厚的新的纤维素形成机制。本研究还表明，CSC 机制可能除了纤维素合酶蛋白外，还需要其他蛋白质的辅助。
