According to a recent study by bioscientists at University of Rice, the fundamental cellular structures that are shared by the majority of life forms work together to promote growth in an actual plant organism. The results might provide insight into the corresponding cell mechanisms in humans.
A developing Arabidopsis thaliana seedling depends on the reserve of fats stored inside its cells in protein-coated pouches known as lipid droplets before it is mature enough to perform photosynthesis. These droplets’ energy-rich contents are mobilized in intracellular containers known as peroxisomes. According to the latest research, this collaboration necessitates a peroxisome enzyme that aids in the breakdown of the protein coating on lipid droplets. It was previously known that the enzyme MIEL1 lives in the cell nucleus, where it controls gene expression.
The question of whether the findings would also apply to MIEL1’s human counterpart, PIRH2, was raised by the discovery of a new function and location for the organism. According to a study published in the Proceedings of the National Academy of Sciences, additional experiments confirmed that PIRH2 associates with peroxisomes when expressed in Arabidopsis cells. A deeper comprehension of PIRH2’s cellular function may provide insights into cancer prevention and treatment because it plays a significant role in tumor development.
PIRH2 aids in the degradation of p53 in human cells, a well-known protein that regulates the growth of cells with damaged genomes. The p53 gene has been dubbed” the guardian of the genome” and has received a lot of attention for its function in suppressing tumors. Most cancers have mutations that interfere with its ability to function.
PIRH2 is one of the most extensively researched p53 regulators, making it directly related to cancer, according to Melissa Traver, a postdoctoral research associate at the Bartel lab and the study’s lead author. P53 is frequently mutated and implicated in many different cancers in numerous organs and cell types.
Traver, who is also a Rice graduate from the doctoral program in biochemistry and cell biology, continued,” Because of that, it’s an interesting gene to study.” ” Discovering more about it might help us understand how cancer develops and how to treat it.” I never imagined that I’d find myself reading cancer-related papers in a plant lab. It has been incredibly motivating and rewarding for me to discover something that may be more broadly applicable across systems. I started this project trying to answer a very, very specific question about plants.
The results supported Traver’s belief that basic research can have effects comparable to those of application-based science.
Traver remarked,” I’ve spent a lot of time defending fundamental science and emphasizing its necessity and intrinsic value.”
Traver studied the cellular processes that take place during Arabidopsis germination with Bonnie Bartel, Rice’s Ralph and Dorothy Looney Professor of BioSciences.
We’ve been researching how peroxisomes are made, what they do, and why they’re important in Arabidopsis for years, according to Bartel. ” During germination, when the plant experiences significant growth but is not yet mature enough to carry out photosynthesis, peroxisomes play an especially crucial role. This implies that it must make use of the lipids that the parent plant stores in the seed.
Because of the close relationship between these two organellesā one where fats are stored and one where they are processedā we began to become interested in lipid droplets. Protein coating prevents lipid droplets from coalescing with one another. We were curious as to how the cells eliminate this protein, known as oleosin.
Traver engineered a variant of the protein that was fluorescently marked in order to learn how oleosin is broken down.
According to Bartel,” We are geneticists, so when we want to understand something, we like to break it.” Melissa made the decision to search for plants that couldn’t break down this oleosin the way that wild plants can. She could see that the wildtype seedling was initially lit up due to the fluorescent tag on the oleosin. However, as the oleosin is broken down and lipids are consumed, the fluorescence fades.
The mutant seedlings, on the other hand, who are unable to break down oleosin, still exhibit fluorescence. Traver was able to pinpoint the gene that controls the plants’ capacity to break down oleosin by sequencing their genome and contrasting it with that of the wild type plant.
According to Bartel, the gene that is no longer active in mutant seedlings codes for MIEL1, a nuclear enzyme that aids in the degradation of transcription factors and proteins that control gene expression.
Traver carried out additional tests to determine whether MIEL1 is associated with peroxisomes or lipid droplets.
” Bartel said,” The unexpected thing Melissa discovered is that MIEL1 is actually localized at the peroxisome, despite acting on lipid droplets.” You don’t want to degrade the oleosin unless there are lipid droplets and peroxisomes nearby because they are dispersed throughout the cell. According to our theory, having this enzyme on the peroxisomes is a way to guarantee that the proper biochemistry takes place where it is required.
The results of the study imply that all eukaryotic life forms may exhibit a similar appearance to the enzyme-mediated interaction between peroxisomes and lipid droplets.
The following step, according to Traver, would be to conduct experiments using human cells or other animal models to determine whether similar mechanisms are at work.
The study was funded by the Robert A. Welch Foundation ( C – 1309 ), the National Institutes of Health( R35GM130338 ), P30CA91842, UL1TR002345, and R01GM129325.