The THERMOSENSITIVE MALE STERILE 1 Interacts with the BiPs via DnaJ Domain and Stimulates Their ATPase Enzyme Activities in Arabidopsis

Abstract

The Arabidopsis TMS1 encodes a heat shock protein identical to the Hsp40 protein AtERdj3A and plays important roles in the thermotolerance of pollen tubes and other plant tissues. Despite its importance to plant growth and reproduction, little has been known about its mechanisms underlying thermotolerance of plants. In this study, the relationship between TMS1 and the Hsp70 proteins, Binding Immunoglobulin Proteins (BiPs) was explored to understand the molecular mechanisms of TMS1 in thermotolerance of plants. The expression of TMS1 was induced not only by heat shock, but also by dithiothreitol (DTT) and L-azetidine-2-carboxylic acid (AZC), similarly to the three BiP genes, indicating that TMS1 may be involved in unfolded protein response (UPR). The firefly luciferase complementary imaging (LCI), GST pull-down and ATPase enzyme activity assays demonstrated that the DnaJ domain of TMS1 could interact with BiP1 and BiP3, and could stimulate their ATPase enzyme activities. In addition, the expression level of TMS1 was reduced in the bzip28 bzip60 double mutant. These results suggest that TMS1 may function at the downstream of bZIP28 and bZIP60 and be involved in termotolerance of plants, possibly by participating in refolding or degradation of unfolded and misfolded proteins through interaction with the BiPs.

Genome-wide Association Studies Reveal Important Candidate Genes for theBacillus pumilusTUAT-1-Arabidopsis thalianaInteraction

“…Genes that are co-expressed with the candidate genes are also involved in abiotic stress response, such as HIPP26 gene, involved in Cd detoxification in plants, while the SRX gene participates in the signaling mechanism in response to photooxidative stress (Rey 2007 andTehseen 2010). Furthermore, there are several genes identified in this study, or co-expressed with them, that are involved in thermotolerance, such as DJC65, TMS1, DNAJ, and TMS1 (Chiu 2013, Ma 2015and Suzuki 2008. In our study, we also found a potential PGPB interaction gene, ERF9, which is an ethylene response factor that negatively regulates plant defense (Huang 2016).…”

“…Mutation in this gene affects the secretion of proteins and lipids, culminating in a visibly altered pollen surface (Iwata 2012). TIN1 is co-expressed with TMS1 (thermosensitive male sterile 1), a gene involved in thermotolerance in pollen tubes and response to heat shock treatment in seedlings (Ma 2015); BF1C, a regulator of thermotolerance, which encodes a protein that accumulates rapidly and is localized in the nuclei during heat stress (Suzuki 2008); and DNAJ, which encodes a chaperone belonging to heat shock protein family involved in response to various environmental stresses.…”

Association mapping of agronomic traits of canola (Brassica napus L.) subject to heat stress under field conditions

“…Heat stress affects the tapetum layer of pollen and reduces the nutrition supply, especially during microspore development. This shortage of nutrient supply affects the male gametogenesis, and hamper the formation of microspore cells and ultimately causes pod abortion (Ma et al, 2005).…”

Maintaining the factory: the roles of the unfolded protein response in cellular homeostasis in plants

“…J domain proteins (Hsp40) found in the ER lumen bind BiP proteins and stabilize their interactions with client unfolded proteins (Misselwitz et al, 1998;Yamamoto et al, 2008). ERdj3A, which is induced under ER stress, contains a Cterminal protein disulfide isomerase domain that has reductive capabilities on substrates in vitro (Yang et al, 2009), in addition to a HSP40 ATPase activity (Ma et al, 2015). This suggests that ERdj3A may act on a specific subset of client proteins.…”