Geisler Markus, Kolukisaoglu H Uner, Bouchard Rodolphe, Billion Karla, Berger Joachim, Saal Beate, Frangne Nathalie, Koncz-Kalman Zsuzsanna, Koncz Csaba, Dudler Robert, Blakeslee Joshua J, Murphy Angus S, Martinoia Enrico, Schulz Burkhard
Institute of Plant Biology, University of Zurich, CH 8008-Zürich, Switzerland.
Mol Biol Cell. 2003 Oct;14(10):4238-49. doi: 10.1091/mbc.e02-10-0698. Epub 2003 Aug 7.
Null-mutations of the Arabidopsis FKBP-like immunophilin TWISTED DWARF1 (TWD1) gene cause a pleiotropic phenotype characterized by reduction of cell elongation and disorientated growth of all plant organs. Heterologously expressed TWD1 does not exhibit cis-trans-peptidylprolyl isomerase (PPIase) activity and does not complement yeast FKBP12 mutants, suggesting that TWD1 acts indirectly via protein-protein interaction. Yeast two-hybrid protein interaction screens with TWD1 identified cDNA sequences that encode the C-terminal domain of Arabidopsis multidrug-resistance-like ABC transporter AtPGP1. This interaction was verified in vitro. Mapping of protein interaction domains shows that AtPGP1 surprisingly binds to the N-terminus of TWD1 harboring the cis-trans peptidyl-prolyl isomerase-like domain and not to the tetratrico-peptide repeat domain, which has been shown to mediate protein-protein interaction. Unlike all other FKBPs, TWD1 is shown to be an integral membrane protein that colocalizes with its interacting partner AtPGP1 on the plasma membrane. TWD1 also interacts with AtPGP19 (AtMDR1), the closest homologue of AtPGP1. The single gene mutation twd1-1 and double atpgp1-1/atpgp19-1 (atmdr1-1) mutants exhibit similar phenotypes including epinastic growth, reduced inflorescence size, and reduced polar auxin transport, suggesting that a functional TWD1-AtPGP1/AtPGP19 complex is required for proper plant development.
拟南芥FKBP样亲环蛋白扭曲矮化1（TWD1）基因的无效突变会导致多效性表型，其特征是细胞伸长减少以及所有植物器官的生长方向紊乱。异源表达的TWD1不表现出顺反肽基脯氨酰异构酶（PPIase）活性，也不能互补酵母FKBP12突变体，这表明TWD1通过蛋白质-蛋白质相互作用间接发挥作用。用TWD1进行酵母双杂交蛋白质相互作用筛选，鉴定出编码拟南芥多药抗性样ABC转运蛋白AtPGP1 C末端结构域的cDNA序列。这种相互作用在体外得到了验证。蛋白质相互作用结构域的定位表明，AtPGP1令人惊讶地与含有顺反肽基脯氨酰异构酶样结构域的TWD1 N末端结合，而不是与已被证明介导蛋白质-蛋白质相互作用的四三肽重复结构域结合。与所有其他FKBP不同，TWD1被证明是一种整合膜蛋白，与其相互作用伙伴AtPGP1共定位于质膜上。TWD1还与AtPGP1的最接近同源物AtPGP19（AtMDR1）相互作用。单基因突变体twd1-1和双基因突变体atpgp1-1/atpgp19-1（atmdr1-1）表现出相似的表型，包括叶片向下弯曲生长、花序大小减小和极性生长素运输减少，这表明功能性的TWD1-AtPGP1/AtPGP19复合物是植物正常发育所必需的。
