Professor

Department of Plant Biology
huji@msu.edu

Research: Molecular Mechanisms of Energy Organelle Dynamics and Interorganellar Interaction and Communication

In eukaryotic cells, biochemical reactions are compartmentalized in specific subcellular organelles. Plant mitochondria, peroxisomes, and chloroplasts are essential organelles in development and coordinate in a number of metabolic pathways required for energy capture, conversion, and metabolism. The Hu laboratory is interested in understanding molecular mechanisms underlying the dynamic behavior of peroxisomes and mitochondria and the role of these organelles in regulating photosynthesis and in plant interaction with the environment.

For adaptation, subcellular organelles can alter their abundance, morphology, and protein composition depending on the developmental and environmental conditions. One research goal of the Hu lab is to elucidate molecular mechanisms by which peroxisomes and mitochondria proliferate/divide, move/distribute, and turnover to ultimately understand how organelle dynamics contribute to plant robustness and stress response. To this end, we have identified and characterized components of the machineries that govern the biogenesis, division and proliferation of peroxisomes and mitochondria (Fig. 1) and revealed transcriptional and post-translational regulatory mechanisms of these processes. Recent efforts discovered the regulatory role of proteases and ubiquitin-proteasome mediated proteolysis in peroxisome and mitochondrial biogenesis and division, as well as adaptor proteins involved in the motility of these organelles along the cytoskeleton. We have also established a deep-learning framework to rapidly classify organelle morphology with the goal to facilitate large-scale screens for mutants in organelle dynamics.

The Hu lab also collaborates with other labs in the PRL and on campus to study the impact of peroxisomal metabolism on photosynthesis, and the role of photorespiration in stress response. Using the Dynamic Environment Phenotype Imager (DEPI), we have screened our collection of Arabidopsis peroxisome mutants and identified mutants showing photosynthetic deficiencies under light conditions that are more relevant to the natural environment, revealing regulatory links between photorespiration and photosynthesis under dynamic environmental conditions (Fig. 2). We are also exploring the role of photorespiration in plant-pathogen interaction.

Our research has agricultural and economical relevance, as knowledge gained may provide molecular bases for developing strategies for rational engineering of crop plants to improve metabolism, bioenergy production, and defense against environmental stresses. Our research may also provide useful information to biomedical studies in curing human peroxisomal and mitochondrial diseases.