Plants do not translocate themselves during growth or under environmental stresses. However, plants could perceive environmental cues and respond accordingly. For example, the abundance of certain proteins at the plasma membrane alter significantly under different conditions, such as nutrient availability, cell growth status, and biotic or abiotic stimulations. It is not well understood how plant cells control the delivery and turnover of these plasma membrane proteins during normal cell growth and under environmental stresses. Combining chemical treatment with a plant exocyst complex inhibitor and mass spectrometry analysis, we show that plant exocyst complex mediates fast delivery of proteins with diverse functions to the plasma membrane. We also identified a small molecule inhibitor that targets the catalytic domain of a large protein complex that is essential for plant cell wall biosynthesis at the plasma membrane. Using a combination of chemical genetics and live cell imaging analysis, we show that the exocytic transport of large protein complexes in plants is strictly related to the catalytic activities of these protein complexes. Catalytic inactive protein complexes are not selected for further transport at the early steps of exocytic trafficking, although these protein complexes might have been assembled properly. Our results add to current understanding of how plant exocytic transport machineries regulate spatiotemporal delivery of proteins for plant growth and environment adaptation.

Chemical biology in plant membrane trafficking and cell growth

2019 Spring National Meeting

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