Functional characterization of phosphatidylinositol transfer proteins in yeast and Arabidopsis and their potential use to increase aluminum tolerance in plants

点击翻译按钮获取中文摘要

Phosphatidylinositol (PtdIns) transfer proteins (PITPs), found in all eukaryotes, regulate signaling events at the interface between lipid metabolism and membrane trafficking. Sec14, the major yeast PITP is required to coordinate phospholipid (PL) metabolism with biogenesis of secretory vesicles at the trans-Golgi network (TGN). Our recent breakthrough in solving structures of Sec14 homolog Sfh1 in complex with PtdIns, phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) allowed for the first time a structural appreciation of how Sec14 proteins bind their physiological substrates and suggested a mechanism by which Sec14 presents PtdIns to a lipid-modifying enzyme during an interfacial exchange reaction with PtdCho. The proposed research is based on our discovery that two members of the Sec14 family from yeast and Arabidopsis increase aluminum (Al) tolerance when ectopically expressed in yeast. Aluminum is toxic to plants, animals and microbes and represents one of the biggest limitations to crop production worldwide. We will 1) investigate how lipid binding of these Sec14 homologues translates into biological activity and increased Al tolerance, 2) identify their downstream lipid and protein targets and 3) develop strategies to increase Al tolerance in plants. Our functional studies will be guided by the structural information on lipid binding and will include unbiased genome wide screens. We anticipate that our work will give us more insight on the regulation of lipid signaling and the biology of the enigmatic family of Sec14proteins in plants.