玉米根细胞中类整合素蛋白与α-微管蛋白的共定位及其可能的相互作用(英文)

The Co-Localization and Possible Interactions of Integrin-like Protein and α-Tubulin in the Root Cells of Zea mays

采用间接免疫荧光标记法对玉米根细胞中的类整合素蛋白和细胞骨架主要组分之一的α-微管蛋白进行了荧光定位。结果表明:类整合素蛋白主要分布在质膜上。与对照相比,用与类整合素蛋白特异结合的5肽GRGDS处理后,质膜上类整合素的分布更为均匀,微管的排列密度降低,而用不与类整合素蛋白特异结合的GRGDS类似物SDGRG处理则对类整合素蛋白分布和微管蛋白的排列均无明显影响。微管蛋白解聚剂或稳定剂处理改变类整合素在质膜上的分布。这些结果表明类整合素蛋白与微管蛋白间有复杂的相互作用。

Plant cell wall-plasma membrane-cytoskeleton （CW-PM-CSK） continuum plays important roles in the regulation of plant responses to environmental cues. It has been found in our previous study that an integrin-like protein identified in Arabidopsis and Zea mays plasma membrane mediates the interactions between cell wall and plasma membrane and cell responses to osmotic stress. In the present study, the co-localization of integrin-like protein and α-tubulin and their possible interactions were investigated in the root cells of maize using an indirect immuninofluorescence technique combined with pharmacological approach. As compared with the control, after treatment with GRGDS, a synthetic peptide con- tained the RGD domain which binds specifically to integrin-like protein, the integrin-like protein was distributed more evenly over the plasma membrane and the density of α-tubulin array became lower. However, treatment with SDGRG, a GRGDS analog which does not contain the RGD domain, had no influences on them. Microtubule-depolymering or -stabilizing reagents exerted their effects either on the distribution over the plasma membrane or on the expression of integrin-like protein. The above results showed that the distribution of integrin-like protein on plasma membrane was closely linked to the alignment of microtubule arrays. Integrin-like protein mediates the interaction between cell wall and plasma membrane, and this interaction in return affected the alignment of microtubule arrays. Changes in cytoskeleton dynamics had significant effect on the distribution of integrin-like protein on the plasma membrane. These results strongly suggest that there are interactions between integrin-like protein and cytoskeleton in plant cells which are very complicated. It is worthy of extensive study to work out the mechanisms of plant responses to intracellular and extracellular signals.