ER-Anchored Transcription Factors bZIP17 and bZIP28 Regulate Root Elongation

ER-Anchored Transcription Factors bZIP17 and bZIP60 Regulate Triterpene Saponin Biosynthesis inMedicago truncatula1[OPEN]

“…6B). Similar observations of a feedback loop to the other ER stress branch were made for the bZIP60 transcript levels in a double bzip17 bzip28 mutant in A. thaliana line (Kim et al, 2018). Conversely, no feedback on bZIP17 expression was observed in the bZIP60 KD hairy root lines (Supplemental Fig.…”

“…It is plausible to assume that because of the crucial roles of these bZIP factors for plant physiology, simultaneous loss-of-function of both, is not viable. Accordingly, homozygous triple bzip17 bzip28 bzip60 A. thaliana mutants present a dwarf phenotype with infertile flowers (Kim et al, 2018). Nonetheless, the data obtained with the M. truncatula bZIP17 KD line support a potential role of at least bZIP17 as a negative attenuator of the TS pathway.…”

“…No significant difference in bZIP17 gene transcript levels were observed in MKB1 KD roots compared to CTR roots. However, given that activation and translocation of AtbZIP17 occurs posttranslationally following proteolytic cleavage in the Golgi (Liu et al, 2007a;Zhou et al, 2015;Kim et al, 2018), the lack of transcriptional elicitation of bZIP17 does not exclude that its activity could be enhanced by loss of MKB1 function or by MeJA elicitation. This possibility was not further investigated, however, given that this would demand extensive additional experimentation and that the results for bZIP60 were more indicative of the activation of an ER stress response.…”

“…Eukaryotic cells install signaling networks in response to ER stress, through ER stress sensors that are tethered at the ER membrane. In the model plant A. thaliana, several ER stress-specific sensors, including INOSITOL-REQUIRING ENZYME 1 (IRE1), the basic leucine zipper (bZIP) TFs bZIP17 and bZIP28, and the NAC TFs NAC062 and NAC089, have been reported (Liu et al, 2007a;Iwata et al, 2008;Liu and Howell, 2010a;Moreno et al, 2012;Yang et al, 2014a;Yang et al, 2014b;Henriquez-Valencia et al, 2015;Kim et al, 2018).…”

Multiple ER-to-nucleus stress signaling pathways become active duringPlantago asiatica mosaic virusandTurnip mosaic virusinfection inArabidopsis thaliana

“…The second major pathway is mediated by bZIP17 and bZIP28. Under normal conditions, bZIP17 and bZIP28 reside in the ER membrane (Angelos et al , 2017, Kim et al , 2018). The Bcl-2–associated athanogene 7 (BAG7) is an ER-localized co-chaperone that under regular conditions associates with bZIP28 and BiP in the ER (Williams et al , 2010, Li et al , 2017) (Srivastava et al , 2013).…”