Redox‐dependent translocation of the heat shock transcription factor AtHSFA8 from the cytosol to the nucleus in Arabidopsis thaliana

Abstract

a b s t r a c tThe hypothesis is tested that some heat stress transcription factors (HSFs) are activated after formation of inter-or intramolecular disulfide bonds. Based on in silico analyses we identified conserved cysteinyl residues in AtHSFA8 that might function as redox sensors in plants. AtHSFA8 represents a redox-sensitive transcription factor since upon treatment of protoplasts with H 2 O 2 YFP-labeled HSFA8 was translocated to the nucleus in a time-dependent manner. Site-directed mutagenesis of the conserved residues Cys24 and Cys269 blocked translocation of HSFA8 to the nucleus. The findings concur with a model where HSFA8 functions as redox sensing transcription factor within the stress-responsive transcriptional network.

Heat shock transcription factors in banana: genome-wide characterization and expression profile analysis during development and stress response

“…In this study, multiple of abiotic and biotic stress-responsive MaHsfs were also identified, in accordance with previous studies of Hsf gene family in other plant species12345. Based on the clues from transcript pattern, the in vivo roles of several plant Hsfs have been revealed.…”

“…Plant heat shock responses are mediated by heat shock elements (HSEs, nTTCnnGAAnnTTCn), which are widely present in the upstream of the heat shock proteins (HSPs)12345. The first specific transcription regulator that is responsible for HSE bindng, was characterized and confirmed as heat stress transcription factor (Hsf) in yeast ( Saccharomyces cerevisiae )6.…”

“…(i) the highly structured N-terminal DNA-binding domain (DBD), that is responsible for binding HSEs in the promoters of several HSPs; (ii) the oligomerization domain (HR-A/B), that is connected to the DBD by a flexible linker; (iii) nuclear export signal (NES) of motif –LFGV- and nuclear localization signal (NLS), (iv) C-terminal activator motic, also known as AHA motif 89101112. According to the flexible linker of variable length (about 15–80 amino acids) and the oligomerization domain (HR-A/B), plant Hsfs can be divided into at least three types, including class A (A1, A2, A3, A4, A5, A6, A7, A8, A9), class B (B1, B2, B3, B4) and class C (C1, C2)129101112.…”

Molecular mechanisms governing plant responses to high temperatures

“…It was proposed that HSFA4a, HSFA8 and HSFA1s can function as ROS sensors to regulate the expression of HS‐induced oxidation‐related genes in plants (Miller and Mittler ; Dickinson et al ). Mutation of conserved cysteine residues (Cys 24 and Cys 269 on HSFA8, but Cys 153 and Cys 357 on HSFA1d) inhibits the H 2 O 2 ‐induced nuclear translocation of HSFA8 (Giesguth et al ), as well as impairs HSFA1d's ability to activate the expression of APX2 under high‐light conditions (Jung et al ). However, HS treatment did not induce the nuclear translocation of HSFA8, suggesting that the redox‐sensing function of HSFA8 may not directly regulate HS‐related gene expression (Giesguth et al ).…”

Group VII Ethylene Response Factors in Arabidopsis: Regulation and Physiological Roles

“…Thiol-disulfide transitions, on the other hand, are frequently associated with redox regulation in plants. For instance, intra-or intermolecular Cys-Cys formation is believed to determine the nuclear localization of the redox TF HSFA8 in response to H 2 O 2 (Giesguth et al, 2015). Despite the fact that redox-sensitive nonclustered cysteines have been identified and examined in plant transcription factors before (Schmidt and Schippers, 2015), they have never been found to belong to the set of Met-Cys initiating ("MC") proteins.…”