Biology subjects

Alary, B.

Publications and source records attributed to Alary, B..

3 recordsLinked to original sources

bioRxiv2025

Alternative splicing of PIF4 regulates plant development under heat stress

The Phytochrome-Interacting Factor 4 (PIF4) is a key player in the integration of multiple internal and external stimuli to optimize different aspects of plant development. While both the DNA encoding this transcription factor and its protein are known to be under tight control, no regulation at the RNA level has been previously reported. Our genomic analysis revealed that the exon/intron structure of the basic Helix-Loop-Helix (bHLH) DNA binding domain of PIF4 is conserved and pointed to skipping of an exon in this region specifically in response to heat stress. We then showed that this alternative splicing event downregulates PIF4 function under heat, which in etiolated seedlings induces photomorphogenic-related traits. Our results disclose a role for PIFs in plant responses to heat and reveal a new regulatory layer for the control of PIF4 function, underscoring the critical role of posttranscriptional regulatory processes in the molecular integration of environmental cues.

plant biology↗

bioRxiv2025

Every Piece of the Puzzle Matters: A Novel Zinc-Binding Site in the Luminal Domain of STIM1 Drives Clustering

STIM1 is pivotal in the tightly regulated mechanism controlling calcium homeostasis in the ER. It is activated by calcium dissociation from its EF-hand domain when ER calcium levels decrease, leading to its interaction with the ORAI channel to initiate calcium influx. Despite advancements in understanding the complex STIM1 machinery, including its domain organization and structural rearrangements upon activation, many aspects of this process remain poorly understood. In this study, we focused on a small conserved region situated upstream to the EF-hand, which has been previously shown to be involved in the modulation of STIM1 by ROS. Our findings reveal that this region binds zinc and plays a pivotal role in STIM1 activation by promoting its clustering, a process essential for the activation of calcium influx. These results revealed the functional importance of this domain and added a crucial piece to the puzzle of how calcium and zinc signaling are interconnected. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/659323v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@16efeborg.highwire.dtl.DTLVardef@1e15e96org.highwire.dtl.DTLVardef@108cad0org.highwire.dtl.DTLVardef@3b58b0_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2020

Adaptation to plant shade relies on rebalancing the transcriptional activity of the PIF-HFR1 regulatory module

Shade caused by the proximity of neighboring vegetation triggers a set of acclimation responses to either avoid or tolerate shade. Comparative analyses between the shade avoider Arabidopsis thaliana and the shade tolerant Cardamine hirsuta, revealed a role for the atypical basic-helix-loop-helix LONG HYPOCOTYL IN FR 1 (HFR1) in maintaining the shade-tolerance in C. hirsuta, inhibiting hypocotyl elongation in shade and constraining expression profile of shade induced genes. We showed that C. hirsuta HFR1 protein is more stable than its A. thaliana counterpart, contributing to enhance its biological activity. The enhanced HFR1 activity is accompanied by an attenuated PHYTOCHROME INTERACTING FACTOR (PIF) activity in C. hirsuta. As a result, the PIF-HFR1 module is imbalanced, causing a reduced PIF activity and attenuating other PIF-mediated responses such as warm temperature-induced hypocotyl elongation (thermomorphogenesis) and dark-induced senescence. By this mechanism and that of the already-known of phytochrome A photoreceptor, plants might ensure to properly adapt and thrive in habitats with disparate light amounts.

plant biology↗