植物ABC转运蛋白利用ATP水解提供能量将底物进行逆浓度梯度转运，在植物的生长和发育过程中起着非常重要的作用。生长素在特定的细胞合成后需要转运至不同的组织来行使生理功能，ABCB1作为一种重要的ABC转运蛋白在细胞膜上参与了对生长素的转运。然而，我们发现ABCB1在拟南芥twd1-6突变体背景下被滞留在内质网中并且被快速降解，特别是twd1-6和ABCB1蛋白能够共同定位于内质网。尽管我们目前对动物、酵母和植物细胞中糖蛋白在内质网中的质量控制和降解机制有了一定的了解，但是对转运蛋白的内质网滞留和降解途径认识还十分有限。在本项目申请中，我们以遗传学为基础，结合生物化学和细胞生物学研究手段，研究ABCB1在内质网中的质量控制机制。同时，我们还探索植物生长过程中ABCB1是如何来协同油菜素内酯信号和生长素的运输。

ABC transporters are essential for plant growth and development, which can transport complex organic materials against concentration gradients energized by ATP. Auxin are synthesized in specialized cells and are transported to target tissues. ABCB1, an ABC transporter, has been shown to be involved in auxin transport in plasma membrane. However, we found a single missense Arabidopsis twd1(twisted dwarf1) mutant, twd1-6, in which ABCB1 was retained in the ER and rapidly degraded. Especially, twd1-6 is co-localized with ABCB1 in the ER. Despite primary understanding of ERQC/ERAD of glycosylated proteins has been ascertained through investigating yeast, mammalian and plant cells, the functional studies of the ERQC/ERAD processes on membrane transporter proteins remained rather limited. In this study, we will focus on the folding, maturation, and degradation of ABCB1 to screen and identify the components involved in these processes by using genetics methods combined with biochemical and cell biology approaches. In addition, we are going to explore the critical roles of ABCB1 in the interactions between BR signaling and auxin transport during plant growth.