In an ever-changing world, sustainability is paramount to maintaining our planet. Plant research is essential in this process, given the essential roles of plants in food chains, materials production, and maintaining our atmosphere. Plants isolate reactions involved in hormone production and in breaking down fats obtained from lipid droplets for energy in peroxisomes. These reactions support growth and development throughout the life cycle but create toxic byproducts that can damage the peroxisome and the entire cell if not degraded. This project focused on uncovering the mechanism responsible for ?taking the trash out? within cells. The goal was to identify signals responsible for targeting damaged or obsolete peroxisomes for decay in the model plant, Arabidopsis thaliana. Problems in this disposal process are believed to contribute to the aging processes in plants, as well as several peroxisome biogenesis disorders in humans. Plants share several subcellular compartments and functions with humans, including the nucleus, mitochondria, lipid droplets, and peroxisomes. Given that over half of peroxisomal proteins are conserved between plants and humans, peroxisome research in Arabidopsis impacts both agriculture and human health ? making it a vital process to study.

The cellular quality control used to manage damaged peroxisomes is a form of specialized autophagy (pexophagy) in which the cell creates a structure to engulf and discard the damaged peroxisome. This research leveraged the earlier findings that functional peroxisomes are targeted for destruction by an overzealous autophagy machinery when an Arabidopsis multifunctional protease protein is dysfunctional ? leading to the hypothesis that signals responsible for pexophagy are degraded or refolded by the multifunctional protease. Several studies, including identifying differences in mRNA and protein, were performed to identify potential interacting proteins and to further understand the functions of the multifunctional protease. In addition, validation studies and literature searches were performed to determine how and why various interactions regulate peroxisome function, pexophagy, and overall cellular health. By identifying the signals regulating peroxisome functions and health, we are beginning to elucidate the stressors that induce pexophagy, the effects of increased and decreased pexophagy, and how to selectively regulate the activity. 

The project was designed to include manageable subprojects that were executed by mentored undergraduates from historically underrepresented backgrounds. Five female undergraduate students successfully contributed to subprojects, four of which were from historically underrepresented backgrounds ? including one from a historically black college and one from a community college. One of the mentees, a female Hispanic student, is currently pursuing a PhD at Washington University in Plant Pathology. In addition, a female Afro-Hispanic student completed her associate's degree and is currently pursuing her BS in Biology at the University of Houston. The Fellow honed mentoring and management skills needed to successfully transition to running an independent research lab. Moreover, the collected data and results from this project have seeded additional funding from the National Institute of Health and will be essential for obtaining an independent position, where the continued elucidation of signaling pathways involved in peroxisomal quality control can be pursued. In summary, the research furthered our knowledge of peroxisomes while emphasizing the importance of plant biology research to underrepresented groups.

Last Modified: 12/21/2022
Modified by: Durreshahwar Muhammad