Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
Plant J. 2010 Jan;61(2):234-48. doi: 10.1111/j.1365-313X.2009.04046.x. Epub 2009 Oct 12.
The proper spatial and temporal expression and localization of mitogen-activated protein kinases (MAPKs) is essential for developmental and cellular signalling in all eukaryotes. Here, we analysed expression, subcellular localization and function of MPK6 in roots of Arabidopsis thaliana using wild-type plants and three mpk6 knock-out mutant lines. The MPK6 promoter showed two expression maxima in the most apical part of the root meristem and in the root transition zone. This expression pattern was highly consistent with 'no root' and 'short root' phenotypes, as well as with ectopic cell divisions and aberrant cell division planes, resulting in disordered cell files in the roots of these mpk6 knock-out mutants. In dividing root cells, MPK6 was localized on the subcellular level to distinct fine spots in the pre-prophase band and phragmoplast, representing the two most important cytoskeletal structures controlling the cell division plane. By combining subcellular fractionation and microscopic in situ and in vivo co-localization methods, MPK6 was localized to the plasma membrane (PM) and the trans-Golgi network (TGN). In summary, these data suggest that MPK6 localizing to mitotic microtubules, secretory TGN vesicles and the PM is involved in cell division plane control and root development in Arabidopsis.
丝裂原活化蛋白激酶（MAPKs）的适当时空表达和定位对于所有真核生物的发育和细胞信号转导至关重要。在这里，我们使用野生型植物和三个 mpk6 敲除突变体系分析了拟南芥根中 MPK6 的表达、亚细胞定位和功能。MPK6 启动子在根分生组织的最顶端部分和根过渡区显示出两个表达最大值。这种表达模式与“无根”和“短根”表型以及异位细胞分裂和异常细胞分裂平面高度一致，导致这些 mpk6 敲除突变体根中的细胞文件紊乱。在分裂的根细胞中，MPK6 在亚细胞水平上定位于前期带和胞质板的独特细点，代表控制细胞分裂平面的两个最重要的细胞骨架结构。通过结合亚细胞分级分离和显微镜原位和活体共定位方法，MPK6 被定位到质膜（PM）和高尔基网络（TGN）。总之，这些数据表明，定位于有丝分裂微管、分泌性 TGN 囊泡和 PM 的 MPK6 参与了拟南芥的细胞分裂平面控制和根发育。
