At the University of Konstanz, the Plant Physiology and Biochemistry research group found earlier unidentified molecular mechanisms by which plants tend to adapt to their surroundings. It is a significant basic knowledge during times of climate change.
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Plants have been exposed to continuous environmental changes, and their survival relies on their potential to sense and adjust to environmental stimuli. In the cell membrane, protein molecules tend to play a vital role in matching extracellular signals and intracellular reactions.
At present, the Plant Physiology and Biochemistry research group (University of Konstanz) has currently been successful in determining two deubiquitinating enzymes included in the molecular mechanism of this adaptation process.
The study has been reported in the current issue of Nature Communications.
The Amount of Protein Molecules is Crucial
In its adaptation process, the cell senses, for instance, pathogens or nutrients present in its surrounding. That is the job of unique protein molecules—the transporters and receptors, situated on the cell membrane isolating the cells within from the outside world. They are generated as well as degraded in the cell. It has been crucial for the plant’s signal perception and the number of such molecules.
The small signal protein named ubiquitin hooks on other proteins and thus guarantees that they have been degraded. Simultaneously, there are deubiquitylating enzymes that have the potential to reverse this effect by eliminating ubiquitins.
Biology professor Erika Isono’s group examined 18 of these deubiquitylating enzymes in the model plant Arabidopsis thaliana.
In collaboration with Karin Hauser, Michael Kovermann, and Christine Peter from the Department of Chemistry, the team discovered two such enzymes, designated OTU11 and OTU12.
This has been localized at the cell membrane and is actually involved in controlling the amount of cell membrane proteins.
OTU11 and OTU12 can shorten certain ubiquitin chains. This influences the degradation of the modified proteins.
Karin Vogel, Study Lead Author, University of Konstanz
Vogel describes the biochemical mechanism.
Also, the biologist discovered how they are triggered: by binding to negatively charged lipids on the cell membrane.
Previously Unknown Form of Activity Adjustment
This implies that the activity of such enzymes has been controlled in a tight manner. Various activation mechanisms for deubiquitylating enzymes are known earlier. In this context, the mechanism reported is an earlier unidentified form of activity adaptation.
Also, this regulation is so vital since the effect of deubiquitylating enzymes could have significant impacts on the cells’ function.
Our discovery shows that the deubiquitylating enzymes do not become active until they arrive at the membrane, where the lipids are located. This fits perfectly with the intracellular localization and function of the two enzymes.
Erika Isono, Professor and Chair, Plant Physiology and Biochemistry, University of Konstanz
In basic biological research, model plants have been utilized to examine basic biochemical and molecular biological mechanisms. The long-term aim is to improve agricultural yields, especially during times of climate change, as plant growing conditions could get altered as an impact.
It’s important that we understand at the molecular level how plants respond to the environment. The ubiquitin-dependent signaling pathway probably plays an important role in this process.
Erika Isono, Professor and Chair, Plant Physiology and Biochemistry, University of Konstanz
Journal Reference:
Vogel, K., et al. (2022) Lipid-mediated activation of plasma membrane-localized deubiquitylating enzymes modulate endosomal trafficking. Nature Communications. doi.org/10.1038/s41467-022-34637-3.