第一腺嘌呤核苷二磷酸核糖化相似因子之鳥糞嘌呤核苷酸交換因子的磷酸化可促進第一腺嘌呤核苷二磷酸核糖化相似因子活化之研究

Abstract

腺嘌呤核甘二磷酸核醣化因子(ADP-ribosylation factors,ARFs)在真核細胞的蛋白質運輸及細胞骨架的重組中扮演得很重要的角色。在酵母菌的研究當中已經知道第三腺嘌呤核甘二磷酸核醣化相似因子(Arl3p)會募集第一腺嘌呤核甘二磷酸核醣化相似因子(Arl1p)進而調控細胞中高基氏體(Golgi apparatus)的結構及功能。我們實驗室近來研究發現一種腺嘌呤核甘二磷酸核醣化因子(ARF)的鳥糞嘌呤核苷酸交換因子Syt1p會幫助Arl1p的活化並促進募集下游Imh1p到高基氏體上。過去的研究已經知道Syt1是磷酸化蛋白且發現了許多被磷酸化所調控的胺基酸位置。我們的研究更進一步確認Syt1確實可以被磷酸化所修飾，而研究中也發現Syt1鳥糞嘌呤核苷酸交換因子的活性可以被磷酸化所調控。在本篇研究中我們將更進一步探討磷酸化對Syt1的影響以及其修飾對於鳥糞嘌呤核苷酸交換因子的活性如何調控Arl1p活化。

ARF-like (ARL) proteins belong to the ARF family, which regulate several vesicular trafficking pathways as well as cytoskeletal organization. In Saccharomyces cerevisiae, Arl3p recruits Arl1p GTPase to regulate Golgi function and structure. Our lab recently reported that an ARF-GEF Syt1p promotes Arl1p activation to recruit Imh1p to the Golgi. Syt1p is a phosphoprotein which contains multiple phosphorylation modifications according to previous finding. Our current data also confirmed that Syt1p was modifid by multiple phosphorylation modification and its GEF activity can be regulated by phosphorylation. In this study, we further analysis the phosphorylation in ARF-GEF Syt1p and characterize the role on Arl1p activation.