Recruitment of PLANT U-BOX13 and the PI4Kβ1/β2 Phosphatidylinositol-4 Kinases by the Small GTPase RabA4B Plays Important Roles during Salicylic Acid-Mediated Plant Defense Signaling in Arabidopsis
Recruitment of PLANT U-BOX13 and the PI4Kβ1/β2 Phosphatidylinositol-4 Kinases by the Small GTPase RabA4B Plays Important Roles during Salicylic Acid-Mediated Plant Defense Signaling in Arabidopsis
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DOI：
10.1105/tpc.114.134262
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发表时间：
2015-01-01
期刊：
影响因子：
11.6
通讯作者：
Nielsen, Erik
中科院分区：
文献类型：
--
作者：
Antignani, Vincenzo;Klocko, Amy L.;Nielsen, Erik
针对微生物病原体的保护涉及真核生物中细胞免疫应答的激活，并且这种细胞免疫可能涉及亚细胞膜运输的变化。在真核生物中，小单体调节性GTP酶的Rab GTP酶家族的成员在膜运输的调节中发挥突出作用。我们以前表明，RabA 4 B被招募到从trans-Golgi网络（TGN）隔室出现的囊泡中，并调节植物细胞中的极化膜运输。作为该调节的一部分，RabA 4 B募集密切相关的磷脂酰肌醇4-激酶（PI 4K）PI 4K β 1和PI 4K β 2脂质激酶。在这里，我们确定了第二个拟南芥RabA 4 B相互作用蛋白，植物U-BOX 13（PUB 13），最近已被确定发挥重要作用，在水杨酸（SA）介导的防御信号。我们发现PUB 13通过N-末端结构域与RabA 4 B相互作用，通过C-末端犰狳结构域与磷脂酰肌醇4-磷酸（PI-4P）相互作用。此外，我们证明了功能性荧光PUB 13融合蛋白（YFP-PUB 13）定位于TGN和高尔基体，PUB 13，PI 4K β 1和PI 4Kb 2是SA介导的诱导发病相关基因表达的负调节因子。总之，这些结果突出了RabA 4 B和PI-4P在SA依赖性防御反应中的作用。
Protection against microbial pathogens involves the activation of cellular immune responses in eukaryotes, and this cellular immunity likely involves changes in subcellular membrane trafficking. In eukaryotes, members of the Rab GTPase family of small monomeric regulatory GTPases play prominent roles in the regulation of membrane trafficking. We previously showed that RabA4B is recruited to vesicles that emerge from trans-Golgi network (TGN) compartments and regulates polarized membrane trafficking in plant cells. As part of this regulation, RabA4B recruits the closely related phosphatidylinositol 4-kinase (PI4K) PI4K beta 1 and PI4K beta 2 lipid kinases. Here, we identify a second Arabidopsis thaliana RabA4B-interacting protein, PLANT U-BOX13 (PUB13), which has recently been identified to play important roles in salicylic acid (SA)-mediated defense signaling. We show that PUB13 interacts with RabA4B through N-terminal domains and with phosphatidylinositol 4-phosphate (PI-4P) through a C-terminal armadillo domain. Furthermore, we demonstrate that a functional fluorescent PUB13 fusion protein (YFP-PUB13) localizes to TGN and Golgi compartments and that PUB13, PI4K beta 1, and PI4Kb2 are negative regulators of SA-mediated induction of pathogenesis-related gene expression. Taken together, these results highlight a role for RabA4B and PI-4P in SA-dependent defense responses.