Selection and Delivery of Substrates to the Essential Clp Protease Complex in Plastids of Arabidopsis Thaliana

智力优势：质体是存在于每个植物细胞中的基本细胞器。质体包括叶绿体（在植物和藻类中产生光合作用能量的部位）、淀粉质体（在根和块茎中储存淀粉）和色质体（在果实中积累类胡萝卜素）。据预测，植物基因组中约14%的基因编码质体蛋白，强调了质体对植物生物学的重要性。本项目关注模式植物拟南芥中必需质体定位Clp蛋白酶机制的功能和底物。ClpPR蛋白酶是一个双环状复合体，包含10种不同的ClpPR蛋白，其中大多数是胚胎发生或幼苗发育所必需的。附着在桶上的是小的clps1,2蛋白，其功能未知，是光合生物所特有的。细胞内蛋白酶具有多种功能，在识别底物时必须具有高度选择性。质体定位的Clp蛋白对质体的生物发生和分化显然很重要，但其在质体中的作用机制，包括Clp底物和底物识别机制尚不清楚。该项目的目标是鉴定Clp蛋白酶底物及其降解信号，确定ClpS在向Clp蛋白酶系统输送底物中的作用，确定ClpT1、T2作为Clp系统特定质体组分的功能，并在体内测试目标1、2和3（或新文献）中鉴定的潜在底物和降解信号（degrons）。更广泛的影响：该项目将有助于确定Clp蛋白酶系统的分子功能和组织，以及其底物和底物识别机制。了解Clp蛋白水解机制和底物识别信号的作用对于控制蛋白质稳定性也至关重要，目的是改善质体作为过量生产具有营养或其他附加价值的外源蛋白质的场所。该研究将为本科生、研究生和博士后提供植物分子遗传学和生物化学的多学科培训。PI将参加为高中教师举办的课程开发研讨会，为课堂开发基于基因组学的模块。

Intellectual Merit:Plastids are essential organelles that are present in every plant cell. Plastids include chloroplasts, the sites of photosynthetic energy generation in plants and algae, amyloplasts, which store starch in roots and tubers, and chromoplasts, which accumulate carotenoids in fruits. Around 14% percent of genes in the plant genome are predicted to encode plastid proteins, underlining the importance of the plastid for plant biology. This project concerns the function and substrates of the essential plastid localized Clp protease machinery in the model plant Arabidopsis. The ClpPR protease is a double ring shaped complex containing 10 different ClpPR proteins, most of which are essential for embryogenesis or seedling development. Attached to the barrel are small ClpS1,2 proteins with unknown function and unique to photosynthetic organisms. Intracellular proteases have many functions and must be highly selective in recognizing their substrates. The plastid-localized Clp proteins are clearly important for plastid biogenesis and differentiation, but their mechanism of action in plastids, including Clp substrates and substrate recognition mechanisms, are unknown. The objectives of the project are to identify Clp protease substrates and their degradation signals, to determine the role of ClpS in substrate delivery to the Clp protease system, to determine the function of ClpT1,T2 as a specific plastid component of the Clp system, and to test potential substrates and degradation signals (degrons) identified in objectives 1, 2 and 3 (or in new literature) in vivo. Broader impacts: This project will help to determine the molecular function and organization of the Clp protease system, as well as its substrates and substrate recognition mechanisms. Understanding the role of the Clp proteolytic machinery and substrate recognition signals is also critical to control protein stability with the objective to improve the plastid as the site for overproduction of foreign proteins with nutritional or other added value. The proposed research will provide multi-disciplinary training in plant molecular genetics and biochemistry at the undergraduate, graduate and post-doctoral levels. The PI will participate in curriculum development workshops for high school teachers to develop genomics-based modules for the classroom.