The Role of the NPA-Binding, Plasma Membrane Aminopeptidase AtAPM1 in Cellular Trafficking and Auxin-Regulated Growth

谷胱甘肽氨基肽酶如哺乳动物胰岛素反应性氨基肽酶（IRAP）和CD13 （APN）是双重功能蛋白，在细胞膜成分的细胞运输中起重要作用。谷胱甘肽功能缺陷被认为是导致II型糖尿病和改变膳食胆固醇摄取的原因。作为一种植物谷胱甘肽，APM1似乎调节了控制植物激素生长素运动的细胞机制，而生长素是植物极性建立和维持所必需的。与IRAP和APN一样，APM1是一种具有酶和运输功能的双功能蛋白。APM1在多重耐药/ p糖蛋白的细胞运输中起作用，并似乎调节其他重要的发育机制。拟南芥apm1突变体表现出严重的发育缺陷，只能通过生长素处理部分改善。哺乳动物IRAP和APN对固醇依赖性内吞循环的调节表明APM1的机制功能。本研究的目的是确定APM1的作用机制，并确定其对生长素运输的影响。拟议的项目将会。确定APM1在生长和发育中的位置和时间。APM1调控生长素依赖和独立的发育过程将被研究。绘制APM1的膜拓扑结构，阐明APM1功能的机制。APM1调节固醇依赖循环的膜转运蛋白，包括那些运输生长素将被研究。3. 将APM1功能分配到酶和运输结构域，并确定负责运输活动的膜结构域。将确定特定APM1蛋白结构域与膜转运体的相互作用。该项目具有创新性，因为它探索了植物中蛋白质运输和激素调节的先前未描述的机制。此外，该研究可能为gluzincin蛋白在植物和动物中的功能提供新的见解。更广泛的影响：操纵APM1功能可用于改变植物形态和生产力。因此，拟议的项目可能会增加农业和观赏作物的价值。此外，从该项目中获得的对谷胱甘肽调控的进一步了解可能会导致II型糖尿病、肥胖和胆固醇代谢的新疗法的发展。研究结果将在科学期刊和实验室网站上公布。重要的进展将在科普文献中进行宣传。该项目还将培养至少一名膜生物学、生理学、分子生物学和细胞生物学综合方法的博士生。此外，该项目每年将以同样的技术征聘和培训一名夏季本科生实习生，以鼓励这些学生从事研究生研究教育和研究事业。实习生将从为传统上代表性不足的基础生物学研究群体服务的机构中招聘。

Gluzincin aminopeptidases such as the mammalian Insulin Responsive Aminopeptidase (IRAP) and CD13 (APN) are dual function proteins that play essential roles in the cellular trafficking of membrane components. Defects in gluzincin function are thought to contribute to type II diabetes and altered uptake of dietary cholesterol. A plant gluzincin, APM1 appears to regulate cellular mechanisms that control the movement of the phytohormone auxin, which is required for the establishment and maintenance of plant polarity. Like IRAP and APN, APM1 is a bifunctional protein with both enzymatic and trafficking functions. APM1 functions in the cellular trafficking of Multiple Drug Resistance/ P-glycoproteins and appears to modulate other important developmental mechanisms as well. Arabidopsis apm1 mutants exhibit severe developmental defects that that can be only partially ameliorated by auxin treatment. A mechanistic function for APM1 is suggested by the regulation of sterol-dependent endocytotic cycling by mammalian IRAP and APN. The goal of the proposed research is to identify the mechanisms of APM1 action and determine their impact on auxin transport. The proposed project will1. Determine where and when APM1 functions in growth and development. APM1 regulation of auxin dependent and independent developmental processes will be examined.2. Map the membrane topology of APM1 and elucidate the mechanisms underlying APM1 function. APM1 regulation of sterol-dependent cycling of membrane transport proteins including those that transport auxin will be studied. 3. Assign APM1 functions to enzymatic and trafficking domains and identify the membrane domains responsible for trafficking activity. Interactions of specific APM1 protein domains with membrane transporters will be determined.The proposed project is innovative as it explores a previously undescribed mechanism of protein trafficking and hormonal regulation in plants. Further, the proposed research is likely to provide new insights into gluzincin protein function in both plants and animals. Broader Impacts: Manipulation of APM1 function can be used to alter plant form and productivity. As such, the proposed project can potentially increase the value of agricultural and ornamental crops. Further, enhanced understanding of gluzincin regulation derived from this project can lead to the development of new therapies for type II diabetes, obesity, and sterol metabolism. The results will be promulgated by publication in scientific journals and on the laboratory website. Important advances will be publicized in popular scientific literature.The project will also train at least one PhD student in integrated approaches to membrane biology, physiology, molecular biology, and cell biology. Further, the project will recruit and train one summer undergraduate intern each year in the same techniques in order to encourage those students to pursue a graduate research education and research career. Interns will be recruited from institutions serving traditionally under-represented populations in basic biological research.