Annual Report 2014–15

發現影響植物發育的特有蛋白 細胞是生命體的基本單位，而細胞中的 細胞器是植物不可或缺的「器官」。 每個植物細胞內都有諸多不同類的細胞 器，每一類細胞器含有不同的蛋白質， 負責行使其特定功能，並最終決定植物 的生長發育。任何生命個體都會經歷 生死的過程，細胞裏的蛋白質也有其合 成和降解的輪迴過程。所有蛋白質， 例如膜蛋白，在行使完其功能後，會被 標記上特定的「死亡信號」，並被分選 到多囊泡體內腔中，最終會被運送至溶 酶體或液泡中降解，而降解後產生的 氨基酸會被細胞重新利用。 生命科學學院姜里文教授（中）帶領 的科研團隊，找到了一個可以調控植物 細胞多囊泡體形成的植物特有蛋白。他 們結合細胞生物學、生物化學和遺傳學 等方法，發現編碼該蛋白的基因缺失， 會導致多囊泡體形成障礙，影響膜蛋白 的降解，並最終致使植物發育異常。 研究成果對今後深入理解植物的生長 機制提供了新思路。該發現在2014年 11月刊於《當代生物學》。 mutation to the coiled-coil domain containing 88C (CCDC88C) gene. The Human Genome Organization Gene Nomenclature Committee approved the use of ‘SCA40’ to describe this new type of SCA. The new findings have opened up opportunities for clinical geneticists to provide genetic testing and counselling services to patients, and shed new light on finding therapeutic directions. The work has been published in the Journal of Medical Genetics in September 2014. New Plant-specific Protein Found While cells are the basic unit of life, the organelles inside the cell are the essential ‘organs’ of the plant. Each cell contains many different kinds of organelles, and each type of organelle comprises different proteins to perform their specific functions that control the plant growth and development. Like all the organisms that have a life cycle of birth and death, proteins in the cells also have their own cycles of production and degradation. After finishing their functions, all the proteins like membrane proteins are usually labeled by the ‘dead signals’ and sorted into the intraluminal vesicles of multivesicular bodies (MVBs), which fuse with vacuoles/ lysosomes for protein degradation and recycling of degraded products such as amino acids. A research team led by Prof. Jiang Liwen ( centre ) of the School of Life Sciences discovered a new plant-specific protein player regulating the biogenesis of MVBs in plant cells. Using a combination of cellular, biochemical and genetic approaches, they have demonstrated that knock-out of the gene encoded this protein causes the defect of MVB formation and plant development. These findings, which shed new light on the molecular mechanisms of organelle biogenesis and function in plants, were published in the Current Biology in November 2014. 野生型和突變體植物中的多囊泡體 Multivesicular bodies in wild type and mutant plant cells 野生型 Wild type 突變體 Mutant 香港中文大學年報 CUHK Annual Report 2014 – 2015 23