Asian Natural Environmental Science Center, The University of Tokyo, Nishitokyo, Tokyo 188-0002, Japan.
Asian Natural Environmental Science Center, The University of Tokyo, Nishitokyo, Tokyo 188-0002, Japan; Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Biochem Biophys Res Commun. 2014 Feb 28;445(1):54-7. doi: 10.1016/j.bbrc.2014.01.106. Epub 2014 Jan 31.
Heterotrimeric G proteins (Gα, Gβ and Gγ) have pleiotropic roles in plants, but molecular mechanisms underlying them remain to be elucidated. Here we show that Arabidopsis Gβ (AGB1) interacts with NPH3, a regulator of phototropism. Yeast two-hybrid assays, in vitro pull-down assays and bimolecular fluorescence complementation assays showed that AGB1 and NPH3 physically interact. NPH3-null mutation (nph3) is known to completely abolish hypocotyl phototropism. Loss-of-function mutants of AGB1 (agb1-1 and agb1-2) showed decreased hypocotyl phototropism, and agb1/nph3 double mutants showed no hypocotyl phototropism. These results suggest that AGB1 is involved in the NPH3-mediated regulation of phototropism.
异三聚体 G 蛋白（Gα、Gβ 和 Gγ）在植物中具有多种作用，但它们的分子机制仍有待阐明。在这里，我们表明拟南芥 Gβ（AGB1）与向光性调节剂 NPH3 相互作用。酵母双杂交实验、体外下拉实验和双分子荧光互补实验表明 AGB1 和 NPH3 可发生物理相互作用。已知 NPH3 缺失突变（nph3）可完全消除下胚轴向光性。AGB1 的功能丧失突变体（agb1-1 和 agb1-2）表现出下胚轴向光性降低，而 agb1/nph3 双突变体则表现出无下胚轴向光性。这些结果表明，AGB1 参与了 NPH3 介导的向光性调节。
