报告题目：Regulation of cellulose synthesis in plant cells
主讲人简介：Associate Professor（Tenured），Department of Biochemistry and Molecular Biology, Pennsylvania State University
A long-term goal of our research is to gain a deeper understanding of the regulation of cellulose biosynthesis so that the fundamental knowledge can be transferred for designing new cellulosic materials with diverse economic applications. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes (CSCs). My lab focuses on identification and characterization of novel components in CSCs and advancing our understanding in assembly, delivery, and regulation of CSCs. By a combination of proteomic, live-cell imaging, and genetic approaches, we set out to decipher how the steady level celluose synthase can be regulated by endocytosis, exocytosis, and recycling. Recent discovery of cellulose synthase interacting proteins (CSIs) begin to reveal mechanistic details underlying the co-alignment between cellulose microfibrils and cortical microtubules. The de novo secretion of CSCs is mediated by cooperation among a recently identified cellulose synthase interacting protein 1 (CSI1), exocyst complex, and a plant-specific protein PATROL1 in Arabidopsis thaliana. Upon delivery of CSCs to the plasma membrane, they synthesize cellulose microfibrils in a direction mirroring the underlying cortical microtubule in a CSI1-dependent manner. The retrieval of CSCs from the PM depends on clathrin-mediated endocytosis by two separate complexes: Adaptor complex (AP2) and TPLATE/TSET complex. Cellulose synthase protein represents a cargo protein that is not present in yeast and mammalian cells. Therefore, plants offer unique opportunities to characterize the function of endocytosis and exocytosis that may provide insights into the evolution of protein trafficking in eukaryotes.