Asian Natural Environmental Science Center (ANESC), The University of Tokyo, 1-1-1 Midori-cho, Nishitokyo-shi, Tokyo, 188-0002, Japan.
Plant Physiol Biochem. 2013 Oct;71:240-6. doi: 10.1016/j.plaphy.2013.07.024. Epub 2013 Aug 9.
Heterotrimeric G proteins (Gα, Gβ, Gγ) are signaling molecules conserved among eukaryotic species. The G proteins transmit signals via protein-protein interactions. By a yeast two-hybrid screen, we identified a bZIP protein, VIP1, as an Arabidopsis thaliana Gβ (AGB1)-interacting partner. The interaction between AGB1 and VIP1 was confirmed by an in vitro GST pull-down assay and a bimolecular fluorescence complementation (BiFC) assay. VIP1 was previously reported to be a regulator of osmosensory signaling. Interestingly, the BiFC pattern between AGB1 and VIP1 was speckled when cells were incubated in a hypotonic solution, but not when cells were incubated in a mannitol-containing hypertonic solution, suggesting that the subcellular localization of the AGB1-VIP1 complex is regulated by extracellular osmolarity and/or turgor pressure.
三聚体 G 蛋白（Gα、Gβ、Gγ）是真核生物中保守的信号分子。G 蛋白通过蛋白-蛋白相互作用传递信号。通过酵母双杂交筛选，我们鉴定了一种 bZIP 蛋白 VIP1 是拟南芥 Gβ（AGB1）的相互作用伙伴。通过体外 GST 下拉实验和双分子荧光互补（BiFC）实验证实了 AGB1 和 VIP1 之间的相互作用。VIP1 先前被报道为渗透压感应信号的调节剂。有趣的是，当细胞在低渗溶液中孵育时，AGB1 和 VIP1 之间的 BiFC 模式呈斑点状，但当细胞在甘露醇存在的高渗溶液中孵育时则不是，这表明 AGB1-VIP1 复合物的亚细胞定位受细胞外渗透压和/或膨压的调节。
