Research
We are hiring Postdoc Fellow/PhD for two newly funded projects!
Other Funding Opportunities for Postdoctoral Fellows:
- RGC Postdoctoral Fellowship Scheme
- CUHK Postdoctoral Fellowship Scheme
Other Funding Opportunities for PhD Students:
-Hong Kong PhD Fellowship Scheme
Research Interests
Autophagy and autophagosome formation in plants and green algae
Signalling mechanisms of selective autophagy in plant stress resistance
Lipid metabolism and membrane dynamics
Derived from the Greek word meaning "self-eating”, autophagy acts as a cleaning-up process by breaking down damaged or unwanted proteins/cellular structures, thereby balancing cellular homeostasis in almost all eukaryotes. A hallmark feature of the autophagic process is the formation of a double-membrane structure named the autophagosome which is required for the delivery of proteins/organelles/pathogens to the vacuole for degradation or recycling (Figure 1).
Understanding where the autophagosome forms and how ATG proteins are coordinated in this event is a central point of focus in autophagy. Most of the studies on plant autophagy have mainly relied on traditional methods (e.g., forward genetics), which are technically tedious for identifying plant-specific regulators as well as the related mechanical details. A plant-specific mechanism for autophagosome initiation and ATG machinery assembly with novel regulators may be operated to control the plant-unique development and growth process (Figure 2).
In future, we aim to unveil molecular mechanisms of autophagy as potential targets for future application in sustainable agriculture and renewable energy production. We will develop and use new tools such for plant autophagy to investigate the architecture of the autophagosome at both the molecular and structural levels. This would be a prerequisite for our better understanding the role of autophagy in specific stress responses and lipid metabolism in plants and algae.
The Enigma of Plant ATG9 Vesicles
ATG9 is the only transmembrane protein in the core ATG machinery, and resides on mobile compartments, termed ATG9 vesicles. Our previous study has shown Arabidopsis ATG9 proteins reside on distinct subcellular vesicles and play a unique role in autophagosome formation from the Endoplasmic Reticulum (Zhuang et al. PNAS 2017). However, the identity and regulatory mechanism of ATG9 vesicles in plants for autophagy remains obstacle. To conduct this line of scientific inquiry, an in-depth knowledge of ATG9 vesicles at different levels are essential for generating novel insights into the molecular mechanism of autophagy in plants.
Multiple Functions of SH3P2 in Plant Autophagy
Three SH3-domain Proteins (SH3P1, SH3P2, SH3P3) have been identified in the Arabidopsis genome, all of which contain a conserved N-terminus BAR (Bin-Amphiphysin-Rvs) domain (Lam et al., Plant Cell, 2001). The BAR domain has been well characterized as a membrane sensor to induce membrane curvature via tubulation, scission and actin assembly. Our data and that of others have demonstrated that SH3P2 has a membrane deformation ability and is involved in plant-specific developmental processes (e.g. cell plate formation) via interaction with clathrin coated vesicle (CCV) components (Ahn et al., Plant Cell, 2017; Nagel et al., PNAS, 2018; Adamowski et al., Plant Cell, 2018).
Interestingly, our study showed only SH3P2 responses to autophagic induction and interacts with ATG8 and colocalizes with the autophagosome marker ATG8 in transgenic plants (Zhuang et al., 2013). Furthermore, we have provided a novel structural basis in the binding specificity and plasticity of plant ATG8 for SH3P2 and the conserved autophagic receptor NBR1, revealing a the distinct interaction mode between ATG8 and SH3P2 in Arabidopsis (Sun et al., Autophagy 2021). Our recent observation shows accumulation of a SH3P2 mutation on mitochondria (labeled by Mitotracker), suggesting that SH3P2 might play a novel role in linking autophagy and mitochondria in Arabidopsis. We are particularly interested to explore the possible novel function(s) of mitochondria-associated SH3P2 in mitochondrial dynamics, and/or seletive mitochondria degradation (mitophagy).