earticle

영어

In the endoplasmic reticulum (ER) elicit a highly conserved ER stress response called the unfolded protein response (UPR). Accumulation of misfolded proteins elicits signals by three types of ER stress sensor/transducer in mammal. Among them, ATF6 is a type II transmembrane protein normally retained in the ER. In this study, we have identified two membrane-associated basic domain/leucine zipper (bZIP) factors AtbZIP17 and AtbZIP28 in Arabidopsis thaliana as candidates for ER stress sensors/transducers similar to mammalian ATF6. AtbZIP17 and AtbZIP28 have N-terminal bZIP domain, a transmembrane segment, respectively. Truncated forms of AtbZIP17 and AtbZIP28 lacking the C-terminal domain were overexpressed in Arabidopsis. AtbZIP17 and AtbZIP28 overexpressed Arabidopsis showed upregulated the expression of ER chaperone genes in the absence of stress conditions. Interestingly, they growed bigger and more vigorously than WT in normal growth condition. Under stress conditions, AtbZIP17 and AtbZIP28 overexpression plants showed enhanced stress tolerance compare with that of WT plants. These results suggest that AtbZIP17 and AtbZIP28 function as sensor/transducer in Arabidopsis to mediate ER stress response related to UPR. [Supported by EB-NCRC & BK21 program]