酵母菌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對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

腺嘌呤核苷二磷酸核糖化因子(ADP-ribosylation factors, ARFs)在細胞中被認為扮演著調控囊泡運輸的重要角色。在酵母菌的研究中已經知道第三腺嘌呤核苷二磷酸核糖化相似因子(Arl3p)會募集第一腺嘌呤核苷二磷酸核糖化相似因子(Arl1p)，Arl1p可進一步募集下游Imh1p到反式高爾基氏網(trans Golgi network)上並調控高基氏體(Golgi apparatus)的結構與功能。我們實驗室近來的研究發現一種腺嘌呤核苷二磷酸核糖化因子的鳥糞嘌呤核苷酸交換因子(Syt1p)可活化Arl1p並促進Imh1p被募集到高基氏體上，然而目前對於Syt1p的活性調控仍不是很清楚。本研究中我們發現Syt1p的磷酸化對調控Arl1p活化的重要性並進一步探討Syt1p-Arl1p-Imh1p在細胞中參與在囊泡運輸的功能。

ARF-like (ARL) proteins regulate several vesicular trafficking pathways. In yeast, Arl3p recruits Arl1p GTPase, which is specifically required for recruiting golgin protein Imh1p to the trans-Golgi network (TGN), to determine Golgi function and structure. Our previous data reported that Syt1p, a Sec7 domain-containing protein, could promote the activation of Arl1p and recruitment of Imh1p to the TGN. However, the regulation of Syt1p activity toward Arl1p activation remains unclear. In this study, we demonstrate that phosphorylation of Syt1p play an important role in the regulation of Arl1p activation and provide the evidence to support that Syt1p-Arl1p-Imh1p pathway may participate in the vesicular trafficking inside the cells.