The role of the transmembrane domain in determining the targeting of membrane proteins to either the inner envelope or thylakoid membrane
The role of the transmembrane domain in determining the targeting of membrane proteins to either the inner envelope or thylakoid membrane
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DOI：
10.1111/j.1365-313x.2011.04735.x
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发表时间：
2011-12-01
期刊：
影响因子：
7.2
通讯作者：
Keegstra, Kenneth
中科院分区：
文献类型：
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作者：
Froehlich, John E.;Keegstra, Kenneth
叶绿体膜蛋白可以靶向于三种不同的膜系统，即外膜(OEM)、内膜(IEM)和类囊体膜。叶绿体的这种复杂结构极大地增加了研究针对叶绿体内不同膜亚室的蛋白质的挑战。在这项研究中，我们研究了跨膜结构域(TMD)在引导膜蛋白进入IEM或类囊体膜中所起的作用。利用IEM蛋白Arc6(叶绿体6的积累和复制)，我们用来自不同IEM和类囊体膜蛋白的不同TMD交换了Arc6的停止转移TMD，并监测了这些Arc6杂交蛋白的亚细胞定位。我们发现，当Arc6 TMD被来自不同类囊体膜蛋白的TMD取代时，这些ArC6(ThylTMD)杂合蛋白可以被定向到类囊体膜上，而不是IEM。相反，当类囊体膜蛋白STN8(状态转移蛋白激酶8)或Plsp1(质体I信号肽酶1)的TMD被Arc6的停止转移TMD取代时，STN8和Plsp1在IEM处停止。根据我们的研究，我们得出结论，TMD在将完整的膜蛋白靶向IEM或类囊体膜上起着关键作用。
Chloroplastic membrane proteins can be targeted to any of three distinct membrane systems, i.e. the outer envelope membrane (OEM), inner envelope membrane (IEM), and thylakoid membrane. This complex structure of chloroplasts adds significantly to the challenge of studying protein targeting to various membrane sub-compartments within a chloroplast. In this investigation, we examined the role played by the transmembrane domain (TMD) in directing membrane proteins to either the IEM or thylakoid membrane. Using the IEM protein, Arc6 (Accumulation and Replication of Chloroplasts 6), we exchanged the stop-transfer TMD of Arc6 with various TMDs derived from different IEM and thylakoid membrane proteins and monitored the subcellular localization of these Arc6-hybrid proteins. We showed that when the Arc6 TMD was replaced with a TMD derived from various thylakoid membrane proteins, these Arc6(thylTMD) hybrid proteins could be directed to the thylakoid membrane rather than to the IEM. Conversely, when the TMD of the thylakoid membrane proteins, STN8 (State Transition protein kinase 8) or Plsp1 (Plastidic type I signal peptidase 1), was replaced with the stop-transfer TMD of Arc6, STN8 and Plsp1 were halted at the IEM. From our investigation, we conclude that the TMD plays a critical role in targeting integral membrane proteins to either the IEM or thylakoid membrane.