CAREER: Understanding Plastoglobule Lipid Droplet Function Through the ABC1 Atypical Protein Kinases

Michigan State University, East Lansing MI

Investigators

Abstract

This project seeks to uncover how members of the most abundant enzymes of plastoglobule lipid droplets of plant cells operate to promote stress tolerance and developmental transitions. Outcomes from this project will illuminate our understanding of this poorly understood component of the stress tolerance machinery common to all plants, with potentially far-reaching impacts for agricultural productivity and food security. Multiple educational programs will be provided, including an REU-style training program in the plant sciences for undergraduate students, materials for public outreach events such as the annual Fascination of Plants Day, and a proteomics instructional module for graduate students. This suite of programs will result in long-term impacts that develop novel educational opportunities for undergraduates, enhance course content for graduate students, and promote an appreciation among the general public of plants’ contribution to society, while fostering the career development of the PI’s trainees. Plastoglobule lipid droplets of plant chloroplasts are believed to be a major orchestrator of adaptive responses to environmental stresses. Yet, understanding of plastoglobule function remains limited to hypothetical models, lacking experimentally validated molecular functions. It is the objective of this project to elucidate the central role of all six plastoglobule-localized ABC1 protein kinases (ABC1Ks) in plastoglobule function. These ABC1Ks are the most abundant enzymes of the plastoglobule and are thought to serve as master regulators of plastoglobule function through phospho-regulation of the plastoglobule proteome. This project will characterize the protein kinase activity of each ABC1K, define the phospho-regulatory network of plastoglobules, dissect the functional relevance of the unique N- and C- terminal flanks of ABC1Ks, and unravel the biological functions of the ABC1Ks. These goals will be accomplished through a series of in vitro kinase assays with heterologously expressed ABC1Ks and phenotypic investigations of knock-out and over-expressor mutant lines, including a large-scale phosphoproteomic and lipidomic study. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.