The rice dynamin-related protein DRP2B mediates membrane trafficking, and thereby plays a critical role in secondary cell wall cellulose biosynthesis.
The rice dynamin-related protein DRP2B mediates membrane trafficking, and thereby plays a critical role in secondary cell wall cellulose biosynthesis.
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DOI：
10.1111/j.1365-313x.2010.04308.x
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发表时间：
2010-08
期刊：
影响因子：
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通讯作者：
Guangyan Xiong;Rui Li;Q. Qian;Xueqin Song;Xiangling Liu;Yanchun Yu;D. Zeng;J. Wan;Jiayang Li;Yihua Zhou
中科院分区：
文献类型：
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作者：
Guangyan Xiong;Rui Li;Q. Qian;Xueqin Song;Xiangling Liu;Yanchun Yu;D. Zeng;J. Wan;Jiayang Li;Yihua Zhou
细胞质膜与胞内隔室之间的膜运输是调控细胞壁多糖沉积和代谢的重要过程。动力蛋白相关蛋白（Dynamin-related protein, DRPs）参与细胞膜的管化和囊泡形成，与细胞壁的生物发生密切相关。然而，DRPs参与细胞壁形成的分子机制尚不清楚。在这里，我们报告了脆性Culm3 （BC3）的功能特征，该基因编码OsDRP2B。与BC3在机械组织中的表达一致，BC3突变降低了机械强度，这是由于纤维素含量降低和次级壁结构改变所致。OsDRP2B是水稻（Oryza sativa L.） DRP2亚家族的三个成员之一，通过体外生化分析被鉴定为真正的膜相关动力蛋白。荧光标记的OsDRP2B和原生质细胞中的几个隔室标记物的亚细胞定位表明，该蛋白不仅存在于PM和网格蛋白介导的囊泡中，而且还靶向反式高尔基网络（TGN）。在表达绿色荧光蛋白标记OsDRP2B的转基因植物中进行的FM4-64摄取试验证实了其参与内吞途径。BC3突变和过表达改变了PM和膜系统中纤维素合成酶催化亚基4 （OsCESA4）的丰度。所有这些发现使我们得出结论，OsDRP2B参与了内吞途径，可能也参与了后高尔基膜运输。OsDRP2B突变扰乱了对次生细胞壁正常纤维素生物合成至关重要的膜运输，从而导致水稻植株机械性能下降。
Membrane trafficking between the plasma membrane (PM) and intracellular compartments is an important process that regulates the deposition and metabolism of cell wall polysaccharides. Dynamin-related proteins (DRPs), which function in membrane tubulation and vesiculation are closely associated with cell wall biogenesis. However, the molecular mechanisms by which DRPs participate in cell wall formation are poorly understood. Here, we report the functional characterization of Brittle Culm3 (BC3), a gene encoding OsDRP2B. Consistent with the expression of BC3 in mechanical tissues, the bc3 mutation reduces mechanical strength, which results from decreased cellulose content and altered secondary wall structure. OsDRP2B, one of three members of the DRP2 subfamily in rice (Oryza sativa L.), was identified as an authentic membrane-associated dynamin via in vitro biochemical analyses. Subcellular localization of fluorescence-tagged OsDRP2B and several compartment markers in protoplast cells showed that this protein not only lies at the PM and the clathrin-mediated vesicles, but also is targeted to the trans-Golgi network (TGN). An FM4-64 uptake assay in transgenic plants that express green fluorescent protein-tagged OsDRP2B verified its involvement in an endocytic pathway. BC3 mutation and overexpression altered the abundance of cellulose synthase catalytic subunit 4 (OsCESA4) in the PM and in the endomembrane systems. All of these findings lead us to conclude that OsDRP2B participates in the endocytic pathway, probably as well as in post-Golgi membrane trafficking. Mutation of OsDRP2B disturbs the membrane trafficking that is essential for normal cellulose biosynthesis of the secondary cell wall, thereby leading to inferior mechanical properties in rice plants.