skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Bimodal retrograde signaling disrupts a suppressor network and activates a key transcriptional activator to direct stress responses
Title: Bimodal retrograde signaling disrupts a suppressor network and activates a key transcriptional activator to direct stress responses
SUMMARY Plastid‐to‐nucleus communication, crucial for regulating stress‐responsive gene expression, has long intrigued researchers. This study reveals how the plastidial metabolite 2‐C‐methyl‐D‐erythritol‐2,4‐cyclopyrophosphate (MEcPP) orchestrates transcriptional reprogramming by modulating the rapid stress response element (RSRE), a conserved regulatory hub in the plant general stress response network. Yeast one‐hybrid assays identified HAT1, a class II HD‐Zip protein, as a negative regulator of RSRE. Genetic analyses, including HAT1 overexpression and knockdowns, confirmed its role in suppressing RSRE activity. Interaction assays uncovered a suppression network involving HAT1, the co‐repressor TOPLESS (TPL), and the nuclear importin IMPα‐9. Furthermore, HAT1 interacts with calmodulin‐binding transcription activator 3 (CAMTA3), a calcium/calmodulin‐binding transcription factor known to activate RSRE. AlphaFold modeling provided insights into the architecture of the HAT1‐RSRE complex and HAT‐CAMTA3 interaction, supported by conserved domains across plant species. Under stress condition, MEcPP accumulation promotes the 26S proteasomal degradation of TPL and IMPα‐9 while reduces auxin‐dependent HAT1 expression. Additionally, MEcPP enhances Ca2+influx, activating CAMTA3 and enabling it to bind RSRE, thereby initiating the transcription of stress response genes. This dual mechanism—dismantling suppressors (HAT1, TPL, and IMPα‐9) and activating CAMTA3—underscores MEcPP's central role in plastid‐to‐nucleus signaling. These findings emphasize MEcPP's pivotal function in dynamically regulating gene expression to maintain cellular homeostasis under environmental stress.  more » « less
Award ID(s):
2047396 2139805
PAR ID:
10661215
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Plant Journal
Date Published:
Journal Name:
The Plant Journal
Volume:
123
Issue:
6
ISSN:
0960-7412
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; (, Genome Biology)
    Abstract Background Many plant species exhibit genetic variation for coping with environmental stress. However, there are still limited approaches to effectively uncover the genomic region that regulates distinct responsive patterns of the gene across multiple varieties within the same species under abiotic stress. Results By analyzing the transcriptomes of more than 100 maize inbreds, we reveal many cis - and trans -acting eQTLs that influence the expression response to heat stress. The cis -acting eQTLs in response to heat stress are identified in genes with differential responses to heat stress between genotypes as well as genes that are only expressed under heat stress. The cis -acting variants for heat stress-responsive expression likely result from distinct promoter activities, and the differential heat responses of the alleles are confirmed for selected genes using transient expression assays. Global footprinting of transcription factor binding is performed in control and heat stress conditions to document regions with heat-enriched transcription factor binding occupancies. Conclusions Footprints enriched near proximal regions of characterized heat-responsive genes in a large association panel can be utilized for prioritizing functional genomic regions that regulate genotype-specific responses under heat stress. 
    more » « less
  2. ; ; ; ; ; ; (, Nucleic Acids Research)
    Abstract WhiB1 is a monomeric iron–sulfur cluster-containing transcription factor in the WhiB-like family that is widely distributed in actinobacteria including the notoriously persistent pathogen Mycobacterium tuberculosis (M. tuberculosis). WhiB1 plays multiple roles in regulating cell growth and responding to nitric oxide stress in M. tuberculosis, but its underlying mechanism is unclear. Here we report a 1.85 Å-resolution crystal structure of the [4Fe–4S] cluster-bound (holo-) WhiB1 in complex with the C-terminal domain of the σ70-family primary sigma factor σA of M. tuberculosis containing the conserved region 4 (σA4). Region 4 of the σ70-family primary sigma factors is commonly used by transcription factors for gene activation, and holo-WhiB1 has been proposed to activate gene expression via binding to σA4. The complex structure, however, unexpectedly reveals that the interaction between WhiB1 and σA4 is dominated by hydrophobic residues in the [4Fe–4S] cluster binding pocket, distinct from previously characterized canonical σ704-bound transcription activators. Furthermore, we show that holo-WhiB1 represses transcription by interaction with σA4in vitro and that WhiB1 must interact with σA4 to perform its essential role in supporting cell growth in vivo. Together, these results demonstrate that holo-WhiB1 regulates gene expression by a non-canonical mechanism relative to well-characterized σA4-dependent transcription activators. 
    more » « less
  3. ; ; ; (, Nature Communications)
    Abstract Under low-potassium (K+) stress, a Ca2+signaling network consisting of calcineurin B-like proteins (CBLs) and CBL-interacting kinases (CIPKs) play essential roles. Specifically, the plasma membrane CBL1/9-CIPK pathway and the tonoplast CBL2/3-CIPK pathway promotes K+uptake and remobilization, respectively, by activating a series of K+channels. While the dual CBL-CIPK pathways enable plants to cope with low-K+stress, little is known about the early events that link external K+levels to the CBL-CIPK proteins. Here we show that K+status regulates the protein abundance and phosphorylation of the CBL-CIPK-channel modules. Further analysis revealed low K+-induced activation of VM-CBL2/3 happened earlier and was required for full activation of PM-CBL1/9 pathway. Moreover, we identified CIPK9/23 kinases to be responsible for phosphorylation of CBL1/9/2/3 in plant response to low-K+stress and the HAB1/ABI1/ABI2/PP2CA phosphatases to be responsible for CBL2/3-CIPK9 dephosphorylation upon K+-repletion. Further genetic analysis showed that HAB1/ABI1/ABI2/PP2CA phosphatases are negative regulators for plant growth under low-K+, countering the CBL-CIPK network in plant response and adaptation to low-K+stress. 
    more » « less
  4. ; ; ; ; (, Molecular Microbiology)
    Abstract Bacteria contain conserved mechanisms to control the intracellular levels of metal ions. Metalloregulatory transcription factors bind metal cations and play a central role in regulating gene expression of metal transporters. Often, these transcription factors regulate transcription by binding to a specific DNA sequence in the promoter region of target genes. Understanding the preferred DNA‐binding sequence for transcriptional regulators can help uncover novel gene targets and provide insight into the biological role of the transcription factor in the host organism. Here, we identify consensus DNA‐binding sequences and subsequent transcription regulatory networks for two metalloregulators from the ferric uptake regulator (FUR) and diphtheria toxin repressor (DtxR) superfamilies inThermus thermophilusHB8. By homology search, we classify the DtxR homolog as a manganese‐specific, MntR (TtMntR), and the FUR homolog as a peroxide‐sensing, PerR (TtPerR). Both transcription factors repress separate ZIP transporter genes in vivo, andTtPerR acts as a bifunctional transcription regulator by activating the expression of ferric and hemin transport systems. We showTtPerR andTtMntR bind DNA in the presence of manganese in vitro and in vivo; however,TtPerR is unable to bind DNA in the presence of iron, likely due to iron‐mediated histidine oxidation. Unlike canonical PerR homologs,TtPerR does not appear to contribute to peroxide detoxification. Instead, theTtPerR regulon and DNA binding sequence are more reminiscent of Fur or Mur homologs. Collectively, these results highlight the similarities and differences between two metalloregulatory superfamilies and underscore the interplay of manganese and iron in transcription factor regulation. 
    more » « less
  5. ; ; (, The Plant Cell)
    Abstract At the heart of all biological processes lies the control of nuclear gene expression, which is primarily achieved through the action of transcription factors (TFs) that generally contain a nuclear localization signal (NLS) to facilitate their transport into the nucleus. However, some TFs reside in the cytoplasm in a transcriptionally inactive state and only enter the nucleus in response to specific signals, which in plants include biotic or abiotic stresses. These extra-nuclear TFs can be found in the cytosol or associated with various membrane systems, including the endoplasmic reticulum and plasma membrane. They may be integral proteins with transmembrane domains or associate peripherally with the lipid bilayer via acylation or membrane-binding domains. Although over 30 plant TFs, most of them involved in stress responses, have been experimentally shown to reside outside the nucleus, computational predictions suggest that this number is much larger. Understanding how extra-nuclear TFs are trafficked into the nucleus is essential for reconstructing transcriptional regulatory networks that govern major cellular pathways in response to biotic and abiotic signals. Here, we provide a perspective on what is known on plant extranuclear-nuclear TF retention, nuclear trafficking, and the post-translational modifications that ultimately enable them to regulate gene expression upon entering the nucleus. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email