ATP-Binding Cassette B4, an Auxin-Efflux Transporter, Stably Associates with the Plasma Membrane and Shows Distinctive Intracellular Trafficking from That of PIN-FORMED Proteins
ATP-Binding Cassette B4, an Auxin-Efflux Transporter, Stably Associates with the Plasma Membrane and Shows Distinctive Intracellular Trafficking from That of PIN-FORMED Proteins
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DOI：
10.1104/pp.112.196139
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发表时间：
2012-06-01
期刊：
影响因子：
7.4
通讯作者：
Cho, Hyung-Taeg
中科院分区：
文献类型：
--
作者：
Cho, Misuk;Lee, Zee-Won;Cho, Hyung-Taeg
生长素转运蛋白的胞内转运与植物的多种发育过程有关。虽然PIN形成的生长素外排蛋白的动态运输途径已被深入研究，ATP结合盒蛋白亚家族B蛋白（ABCB;另一组生长素外排载体）的运输仍然在很大程度上未被表征。在这项研究中，我们解决了ABCB 4在拟南芥（拟南芥）根表皮细胞的细胞内运输。药理学分析表明，ABCB 4几乎没有再循环之间的质膜和内体，虽然它缓慢内吞通过裂解空泡途径。光漂白分析后的荧光恢复显示，ABCB 4强烈保留在质膜中，进一步支持ABCB 4的非循环属性。ABCB 4的内吞作用不依赖于Gnom-LIKE 1功能，ABCB 4对布雷菲德菌素A的敏感性需要鸟嘌呤核苷酸交换因子而不是Gnom。ABCB 4的这些细胞内运输的特征与PIN形成的蛋白形成了鲜明的对比，表明ABCB 4可能是细胞生长素稳态的基本和组成性生长素外排转运蛋白。
Intracellular trafficking of auxin transporters has been implicated in diverse developmental processes in plants. Although the dynamic trafficking pathways of PIN-FORMED auxin efflux proteins have been studied intensively, the trafficking of ATP-binding cassette protein subfamily B proteins (ABCBs; another group of auxin efflux carriers) still remains largely uncharacterized. In this study, we address the intracellular trafficking of ABCB4 in Arabidopsis (Arabidopsis thaliana) root epidermal cells. Pharmacological analysis showed that ABCB4 barely recycled between the plasma membrane and endosomes, although it slowly endocytosed via the lytic vacuolar pathway. Fluorescence recovery after photobleaching analysis revealed that ABCB4 is strongly retained in the plasma membrane, further supporting ABCB4's nonrecycling property. The endocytosis of ABCB4 was not dependent on the GNOM-LIKE1 function, and the sensitivity of ABCB4 to brefeldin A required guanine nucleotide exchange factors for adenosyl ribosylation factor other than GNOM. These characteristics of intracellular trafficking of ABCB4 are well contrasted with those of PIN-FORMED proteins, suggesting that ABCB4 may be a basic and constitutive auxin efflux transporter for cellular auxin homeostasis.