Understanding the dynamics of vacuole trafficking and secretion for enhanced plant storage reserves
- Univ. of California, Riverside, CA (United States)
Vacuoles are essential in plants and serve roles in both protein and organelle degradation for reutilization and storage of high energy molecules such as storage proteins which are critical for seed germination under normal and stress conditions and impact biomass production and nutrition. In addition, plants secrete many different molecules such as cell wall components, lipids, waxes and others that are important for plant protection, structure and biomass. Vacuole accumulation and secretion are closely linked and highly regulated pathways within the endomembrane trafficking network. We have discovered many drug-like synthetic small molecules that can suppress vacuole trafficking and enhance secretion; other chemicals can enhance vacuole trafficking and suppress secretion. The ability of our compounds to modulate these pathways indicates that these pathways are tightly coupled and highly regulated. Thus, to achieve the goals of enhanced energy reserves or enhanced secretion it is essential to understand how this dynamic is controlled. Bioactive chemicals have provided us unique insight into natural mechanisms controlling the dynamics of vacuole trafficking and secretion that was not possible previously. One such compound, ES2, negatively modulates secretion while enhancing vacuole trafficking. This is the first compound discovered that targets an essential secretory complex known as the exocyst and will reveal important regulatory domains controlling secretion and vacuole trafficking. During the current funding period, we determined the structure of the EXO70A1 in plants and identifying its binding site. To understand the dynamics of vacuole trafficking it is key to have compounds that inhibit vacuole trafficking as well as enhancing it (ES2). We have used sophisticated image analysis to identify another novel compound ES17 that enhances secretion while negatively modulating vacuole trafficking (opposite of ES2). We have already made rapid progress. Our preliminary data indicates that ES17 very specifically targets a late stage of vesicle fusion with the tonoplast which is highly regulated. Thus, ES17 is an ideal compound to dissect the regulation of vacuole targeting dynamics. In addition, we have now synthesized a biotinylated version of ES17 that is fully functional, permitting the use of chemical proteomics to identify the cognate target with a high probability of success. We propose to investigate the ES17 target which can negatively modulate vacuole trafficking and combine this with knowledge of the ES2 target which can promote vacuole trafficking. Dissecting the mechanisms controlling the dynamics of secretion vs vacuole accumulation and the use of synthetic modulators will permit us to understand and regulate trafficking to enhance secretion to the plasma membrane and cell wall or the accumulation of biological energy reserves for increased biomass, nutritional value, stress resistance, and the secretion of specialized plant products.
- Research Organization:
- Univ. of California, Riverside, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- FG02-02ER15295
- OSTI ID:
- 1773501
- Report Number(s):
- DOE-UCR-FG02-02ER15295
- Resource Relation:
- Related Information: 1. Research article Rodriguez-Furlan C, Domozych D, Qian, W, Enquist, P-A, Li X, Zhang C, Schenk R, Winbigler HS, Jackson W, Raikhel NV, and Hicks GR (2019) Interaction between VPS35 and RABG3f is necessary as a checkpoint to control fusion of late compartments with the vacuole. Proc Natl Acad Sci USA 116:2191-21301.2. Review articleRodriguez-Furlan C, Raikhel NV and Hicks, GR (2017) Merging roads: chemical tools and cell biology to study unconventional protein secretion. J Exper Bot 69:39-46.3. Review articleRodriguez-Furlan C, Minina EA and Hicks GR (2019) Remove, Recycle, Degrade: Regulating Plasma Membrane Protein AccumulationThe Plant Cell 31: 2833-2854.
- Country of Publication:
- United States
- Language:
- English
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