Which came first - the messenger, the activator, or the receiver?

Plants have developed sophisticated signaling mechanisms to adapt to environmental changes, and secreted peptides play crucial roles. Sulfated tyrosine (sTyr) peptides are important regulators of plant growth, nutrient uptake, defense responses, and seed development. This study delves into the evolution of sTyr peptides, their receptors, and the enzyme tyrosylprotein sulfotransferase (TPST) that is responsible for their activation.

Poltergeist-Like 2 (PLL2)-dependent activation of herbivore defence distinguishes systemin from other immune signalling pathways.

Systemin, the first signalling peptide identified in plants, mediates induced resistance against insect herbivores and necrotrophic pathogens in tomato. Initially, systemin was conceived as a hormone-like, long-distance messenger that triggers systemic defence responses far from the site of insect attack. It was later found to rather act as a phytocytokine, amplifying the local wound response for the production of downstream signals that activate defence gene expression in distant tissues.

Understanding Ameliorating Effects of Boron on Adaptation to Salt Stress in Arabidopsis.

When faced with salinity stress, plants typically exhibit a slowdown in their growth patterns. Boron (B) is an essential micronutrient for plants that are known to play a critical role in controlling cell wall properties. In this study, we used the model plant Col-0 and relevant mutants to explore how the difference in B availability may modulate plant responses to salt stress.

Understanding the role of boron in plant adaptation to soil salinity.

Soil salinity is a major environmental constraint affecting the sustainability and profitability of agricultural production systems. Salinity stress tolerance has been present in wild crop relatives but then lost, or significantly weakened, during their domestication. Given the genetic and physiological complexity of salinity tolerance traits, agronomical solutions may be a suitable alternative to crop breeding for improved salinity stress tolerance.

The mechanism behind tenuazonic acid-mediated inhibition of plant plasma membrane H-ATPase and plant growth.

The increasing prevalence of herbicide-resistant weeds has led to a search for new herbicides that target plant growth processes differing from those targeted by current herbicides. In recent years, some studies have explored the use of natural compounds from microorganisms as potential new herbicides. We previously demonstrated that tenuazonic acid (TeA) from the phytopathogenic fungus Stemphylium loti inhibits the plant plasma membrane (PM) H-ATPase, representing a new target for herbicides.

Assaying the Effect of Peptide Treatment on H-Pumping Activity in Plasma Membranes from Arabidopsis Seedlings.

Extracellular acidification or alkalization is a common response to many plant-signaling peptides and microbial elicitors. This may be a result of peptide-mediated regulation of plasma membrane-localized ion transporters, such as the plasma membrane H-ATPase. Early responses to some signaling peptides can therefore be analyzed by assaying H-pumping across the plasma membrane.

Peptaibols Stimulate Plant Plasma Membrane H-ATPase Activity.

Because of their ability to promote growth, act as biopesticides, and improve abiotic stress tolerance, spp. have been used for plant seed coating. However, the mechanism for the promotion of plant growth remains unknown.

The invariant chain CD74 protein is a cell surface binding partner of TIMP-1 in breast cancer cells.

Tissue inhibitor of metalloproteinases-1 (TIMP-1) regulates the proteolytic activity of matrix metalloproteinases (MMPs), playing an important role in the homeostasis of the extracellular matrix. Beyond its well-known role in tissue maintenance, TIMP-1 has been associated with multiple MMP-independent cytokine-like functions. The protein structure of TIMP-1, with two distinct domains, one interacting with MMPs and another able to bind multiple partners, provides a rationale for this multifunctionality.

The evolution of plant proton pump regulation via the R domain may have facilitated plant terrestrialization.

Plasma membrane (PM) H-ATPases are the electrogenic proton pumps that export H from plant and fungal cells to acidify the surroundings and generate a membrane potential. Plant PM H-ATPases are equipped with a C‑terminal autoinhibitory regulatory (R) domain of about 100 amino acid residues, which could not be identified in the PM H-ATPases of green algae but appeared fully developed in immediate streptophyte algal predecessors of land plants. To explore the physiological significance of this domain, we created in vivo C-terminal truncations of autoinhibited PM H‑ATPase2 (AHA2), one of the two major isoforms in the land plant Arabidopsis thaliana.

The PSY Peptide Family-Expression, Modification and Physiological Implications.

Small post-translationally modified peptides are gaining increasing attention as important signaling molecules in plant development. In the family of plant peptides containing tyrosine sulfation (PSYs), only PSY1 has been characterized at the mature level as an 18-amino-acid peptide, carrying one sulfated tyrosine, and involved in cell elongation. This review presents seven additional homologs in all sharing high conservation in the active peptide domain, and it shows that PSY peptides are found in all higher plants and mosses.

Tetrahydrocarbazoles are a novel class of potent P-type ATPase inhibitors with antifungal activity.

We have identified a series of tetrahydrocarbazoles as novel P-type ATPase inhibitors. Using a set of rationally designed analogues, we have analyzed their structure-activity relationship using functional assays, crystallographic data and computational modeling. We found that tetrahydrocarbazoles inhibit adenosine triphosphate (ATP) hydrolysis of the fungal H+-ATPase, depolarize the fungal plasma membrane and exhibit broad-spectrum antifungal activity.

Identification of Antifungal H-ATPase Inhibitors with Effect on Plasma Membrane Potential.

The plasma membrane H-ATPase (Pma1) is an essential fungal protein and a proposed target for new antifungal medications. The compounds in a small-molecule library containing ∼191,000 commercially available compounds were screened for their ability to inhibit plasma membranes containing Pma1. The overall hit rate was 0.

Fusaric acid and analogues as Gram-negative bacterial quorum sensing inhibitors.

Taking advantage of microwave-assisted synthesis, efficient and expedite procedures for preparation of a library of fusaric acid and 39 analogues are reported. The fusaric acid analogues were tested in cell-based screening assays for inhibition of the las and rhl quorum sensing system in Pseudomonas aeruginosa and the lux quorum sensing system in Vibrio fischeri. Eight of the 40 compounds in the library including fusaric acid inhibited lux quorum sensing and one compound inhibited activity of the las quorum sensing system.

Cell-Type-Specific H+-ATPase Activity in Root Tissues Enables K+ Retention and Mediates Acclimation of Barley (Hordeum vulgare) to Salinity Stress.

While the importance of cell type specificity in plant adaptive responses is widely accepted, only a limited number of studies have addressed this issue at the functional level. We have combined electrophysiological, imaging, and biochemical techniques to reveal the physiological mechanisms conferring higher sensitivity of apical root cells to salinity in barley (Hordeum vulgare). We show that salinity application to the root apex arrests root growth in a highly tissue- and treatment-specific manner.

Demethoxycurcumin Is A Potent Inhibitor of P-Type ATPases from Diverse Kingdoms of Life.

P-type ATPases catalyze the active transport of cations and phospholipids across biological membranes. Members of this large family are involved in a range of fundamental cellular processes. To date, a substantial number of P-type ATPase inhibitors have been characterized, some of which are used as drugs.

Reduced expression of AtNUP62 nucleoporin gene affects auxin response in Arabidopsis.

Background: The plant nuclear pore complex has strongly attracted the attention of the scientific community during the past few years, in particular because of its involvement in hormonal and pathogen/symbiotic signalling. In Arabidopsis thaliana, more than 30 nucleoporins have been identified, but only a few of them have been characterized. Among these, AtNUP160, AtNUP96, AtNUP58, and AtTPR have been reported to modulate auxin signalling, since corresponding mutants are suppressors of the auxin resistance conferred by the axr1 (auxin-resistant) mutation.

Measuring H(+) Pumping and Membrane Potential Formation in Sealed Membrane Vesicle Systems.

The activity of enzymes involved in active transport of matter across lipid bilayers can conveniently be assayed by measuring their consumption of energy, such as ATP hydrolysis, while it is more challenging to directly measure their transport activities as the transported substrate is not converted into a product and only moves a few nanometers in space. Here, we describe two methods for the measurement of active proton pumping across lipid bilayers and the concomitant formation of a membrane potential, applying the dyes 9-amino-6-chloro-2-methoxyacridine (ACMA) and oxonol VI. The methods are exemplified by assaying transport of the Arabidopsis thaliana plasma membrane H(+)-ATPase (proton pump), which after heterologous expression in Saccharomyces cerevisiae and subsequent purification has been reconstituted in proteoliposomes.

Plasma Membrane H(+)-ATPase Regulation in the Center of Plant Physiology.

The plasma membrane (PM) H(+)-ATPase is an important ion pump in the plant cell membrane. By extruding protons from the cell and generating a membrane potential, this pump energizes the PM, which is a prerequisite for growth. Modification of the autoinhibitory terminal domains activates PM H(+)-ATPase activity, and on this basis it has been hypothesized that these regulatory termini are targets for physiological factors that activate or inhibit proton pumping.

On a quest for stress tolerance genes: membrane transporters in sensing and adapting to hostile soils.

Abiotic stresses such as salinity, drought, and flooding severely limit food and fibre production and result in penalties of in excess of US$100 billion per annum to the agricultural sector. Improved abiotic stress tolerance to these environmental constraints via traditional or molecular breeding practices requires a good understanding of the physiological and molecular mechanisms behind roots sensing of hostile soils, as well as downstream signalling cascades to effectors mediating plant adaptive responses to the environment. In this review, we discuss some common mechanisms conferring plant tolerance to these three major abiotic stresses.

Specific Activation of the Plant P-type Plasma Membrane H+-ATPase by Lysophospholipids Depends on the Autoinhibitory N- and C-terminal Domains.

Eukaryotic P-type plasma membrane H(+)-ATPases are primary active transport systems that are regulated at the post-translation level by cis-acting autoinhibitory domains, which can be relieved by protein kinase-mediated phosphorylation or binding of specific lipid species. Here we show that lysophospholipids specifically activate a plant plasma membrane H(+)-ATPase (Arabidopsis thaliana AHA2) by a mechanism that involves both cytoplasmic terminal domains of AHA2, whereas they have no effect on the fungal counterpart (Saccharomyces cerevisiae Pma1p). The activation was dependent on the glycerol backbone of the lysophospholipid and increased with acyl chain length, whereas the headgroup had little effect on activation.

The plasma membrane H(+) -ATPase AHA2 contributes to the root architecture in response to different nitrogen supply.

In this study the role of the plasma membrane (PM) H(+) -ATPase for growth and development of roots as response to nitrogen starvation is studied. It is known that root development differs dependent on the availability of different mineral nutrients. It includes processes such as initiation of lateral root primordia, root elongation and increase of the root biomass.

Active plasma membrane P-type H+-ATPase reconstituted into nanodiscs is a monomer.

Plasma membrane H(+)-ATPases form a subfamily of P-type ATPases responsible for pumping protons out of cells and are essential for establishing and maintaining the crucial transmembrane proton gradient in plants and fungi. Here, we report the reconstitution of the Arabidopsis thaliana plasma membrane H(+)-ATPase isoform 2 into soluble nanoscale lipid bilayers, also termed nanodiscs. Based on native gel analysis and cross-linking studies, the pump inserts into nanodiscs as a functional monomer.

Isolation of monodisperse nanodisc-reconstituted membrane proteins using free flow electrophoresis.

Free flow electrophoresis is used for rapid and high-recovery isolation of homogeneous preparations of functionally active membrane proteins inserted into nanodiscs. The approach enables isolation of integral and membrane anchored proteins and is also applicable following introduction of, e.g.

Purification of plant plasma membranes by two-phase partitioning and measurement of H+ pumping.

Purification of plasma membranes by two-phase partitioning is based on the separation of microsomal membranes, dependent on their surface hydrophobicity. Here we explain the purification of plasma membranes from a relatively small amount of material (7-30 g). The fluorescent probe ACMA (9-amino-6-chloro-2-metoxyacridine) accumulates inside the vesicles upon protonation.

Live imaging of intra- and extracellular pH in plants using pHusion, a novel genetically encoded biosensor.

Changes in pH are now widely accepted as a signalling mechanism in cells. In plants, proton pumps in the plasma membrane and tonoplast play a key role in regulation of intracellular pH homeostasis and maintenance of transmembrane proton gradients. Proton transport in response to external stimuli can be expected to be finely regulated spatially and temporally.