Light-gated channelrhodopsin sparks proton-induced calcium release in guard cells

Huang, Shouguang; Shen, Like; Roelfsema, M. Rob G.; Becker, Dirk; Hedrich, Rainer

doi:10.1126/science.adj9696

Cited by 9 publications

(2 citation statements)

References 46 publications

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“…Interestingly, acetate caused transient long-term [Ca 2+ ] cyt increase (Figure 2A), likely due to its higher pKa, leading to cytosolic acidification (Felle 1988), H + -induced Ca 2+ release from the ER (Huang et al, 2023), and fluorescence quenching (Supplemental Figure 2A; Nagai et al, 2004).…”

Section: Resultsmentioning

confidence: 99%

A drought stress-responsive metabolite malate modulates stomatal responses through G-protein-dependent pathway

Mimata,

Gong,

Pei

et al. 2024

Preprint

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Drought poses a significant environmental threat to global agricultural production and distribution. Plant adaptation to dehydration stress involves intricate biological processes with substantial changes in metabolite composition. In this study, we investigated the role of tricarboxylic acid (TCA) cycle metabolites in drought tolerance in grapevine and Arabidopsis. Metabolome analysis revealed that malate, citrate, and isocitrate were upregulated over time in detached grapevine leaves. Five out of 10 organic acids tested, including TCA cycle metabolites, elicited increases in cytosolic free Ca2+concentration ([Ca2+]cyt) in guard cells. Eight out of 10 directly activated a major anion channel in guard cell SLAC1, suggesting that SLAC1 is a general sensor of carboxylic acids. Furthermore, malate alone remarkably induced stomatal closure, which required increases in [Ca2+]cytin guard cells and activation of SLAC1. Pharmacological experiments suggested that cyclic ADP-ribose (cADPR), cAMP and inositol trisphosphate (IP3) act as second messengers essential for malate-induced [Ca2+]cytelevation and stomatal closure. G-proteins, which regulate second messenger production, were identified as components of malate signaling. These results indicate that malate plays a key role in connecting metabolic regulation and drought tolerance. As TCA cycle intermediates are key players in stress responses in mammals as well, we propose that they are common stress-responsive signal molecules mediated by G-protein-dependent signal cascades in both the animal and plant kingdoms.

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Section: Resultsmentioning

confidence: 99%

A drought stress-responsive metabolite malate modulates stomatal responses through G-protein-dependent pathway

Mimata,

Gong,

Pei

et al. 2024

Preprint

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“…Proton are among the fundamental particles of the universe and among the main components in most solutions in living organisms. At least two types of membrane receptors, ion channels and GPCRs, sense proton concentrations in the extracellular environment and induce cellular signaling to adapt to changes in the environmental pH 1,3,19,20 . By solving a total of 7 cryo-EM structures of GPR4 and GPR68 in different pH conditions and performing structural comparisons and functional analyses, we were able to provide structural insights into the proton sensing and activation of two membrane G protein-coupled receptors.…”

Section: Discussionmentioning

confidence: 99%

Structural basis and biased signaling of proton sensation by GPCRs mediated by extracellular histidine rearrangement

Sun,

Guo,

Zhu

et al. 2024

Preprint

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Proton sensing by membrane G protein-coupled receptors (GPCRs) is crucial in controlling the breathing rate, bone formation, and cardiovascular and kidney functions. However, the structural basis and mechanistic insights of proton sensing-induced GPCR activation remains unclear. Here, we report seven cryo-EM structures of GPR4 and GPR68, two well-known proton-sensing receptors, at different pH values and in complex with Gs or Gq trimers. Structural inspection, structure-based pKa calculations, and mutational and computational analyses revealed that the protonation of two conserved extracellular histidines in ECL2 and TM6, HECL2-45.47 and H7.36, induced polar network formation and other conformational changes to tether TM6 to ECL2, and these changes constitute the central common mechanisms of the proton-induced activation of both GPR4 and GPR68. Unexpectedly, proton sensation by specific extracellular histidine determined biased G protein subtype coupling of GPR4. Moreover, GPR68 has an additional pH-sensing residue, H842.67, whose protonation facilitates tighter interactions between TM2, ECL1 and ECL2, which may contribute to the more acidic optimal pH range for GPR68 activation than for GPR4 activation. The propagation path connecting proton-sensing histidines to the toggle switch and the structural basis of the Gs and Gq coupling of GPR4 and GPR68 were characterized. In summary, our study provides structural and mechanistic insights into the proton sensing, activation and downstream effector coupling mechanisms of two proton-sensing GPCRs.

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Early signaling enhance heat tolerance in Arabidopsis through modulating jasmonic acid synthesis mediated by HSFA2

Guo,

Zuo,

Wang

et al. 2024

International Journal of Biological Macromolecules

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Light-gated channelrhodopsin sparks proton-induced calcium release in guard cells

Cited by 9 publications

References 46 publications

A drought stress-responsive metabolite malate modulates stomatal responses through G-protein-dependent pathway

A drought stress-responsive metabolite malate modulates stomatal responses through G-protein-dependent pathway

Structural basis and biased signaling of proton sensation by GPCRs mediated by extracellular histidine rearrangement

Early signaling enhance heat tolerance in Arabidopsis through modulating jasmonic acid synthesis mediated by HSFA2

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