人類的Ninein蛋白質藉由其N端和C端來調控其在細胞中表現的位置

Diverse N-terminal and C-terminal domains of hNinein control its centrosomal and preinuclear localization

沈之翔(Chich-hsiang Shen)

指導教授 ： 洪義人

高雄醫學大學/醫學院/醫學研究所/碩士(2005年)

摘要

中心體在脊索動物細胞的結構裡面扮演著一個重要的微管束聚集與生成的中心胞器.且不論他的重要性質，有關他的組成構型和分子調控機制目前還有許多地方尚待釐清。在本文中，我們的主要研究材料是一個存在中心體中，叫Ninein的重要蛋白質，我們發現Ninein有著五種不同的isoform，分別是isoform1，isoform2，isoform4，isoform5，和isoform6。其中isoform1，isoform2和isoform5在Hela細胞中過度表現，都存在於中心體上。然而，isoform4和isoform6在Hela細胞中過度表現，則存在於細胞核的周圍。此外，藉由胺基酸排序我們可以發現，這五種Ninein的isoform有著不同的N端和C端。為了要深入了解是否這些不同的N端和C端會造成Ninein在細胞中的性狀不同，因此我們做了一些結構上的拆解來研究這些問題。經由我們的研究發現,在Ninein C端1985到2010的位置為一個類似coiled-coil domain的片段，它可能是一個Ninein登上中心體所需的重要片段。此外，我們在Ninein N端也發現，在36到236的位置也是一個對於Ninein在中心體或圍繞在核旁的重要片段。另外,我們還發現獨存於isoform4 N端1-41的片段，可能會照成在中心體的Ninein往核旁移動。這些片段都會影響Ninein在細胞中的分布。

關鍵字

gamma tubulin ； 中心體 ； Ninein

並列摘要

Centrosome is the major microtubule organizing center in mammalian cells that plays a critical role in a variety of cellular events by controlling nucleation and anchoring processes. Despite its significance, the molecular mechanisms underlying the structure and function of the centrosome remain to be determined. Herein we describe the identification of five isoforms of human Ninein which is an important centrosome component. These hNinein isoforms exhibit the centosomal (isoform1, 2, 4, 5 and 6) and perinuclear (isoform4 and 6) localization and all of them have the ability to recruit r-tubulin when GFP-tagged fusion proteins are expressed transiently in mammalian cells. Furthermore, there are diverse N-terminus and C-terminus in hNinein isoforms. In order to investigate the roles of diverse N-terminal and C-terminal domains in five hNinein isoforms, we undertook structure-functional analysis of hNinein in mammalian cells. In agreement with a recent study, we found that the coiled-coil domain (1985-2010aa) existing in all hNinein isoforms except isoform6 may play a critical role in centrosome localization and the N-terminal region (36-236aa) of all hNinein isoforms seems to be essential for both centrosome and perinuclear localization of hNinein. Moreover, we found that the specific N-terminal domain (1-41aa) in hNinein isoform4 may promote itself moving from centrosome to perinuclear as isoform6.

並列關鍵字

gamma tubulin ； Ninein ； Centrosome

參考文獻

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