Vipp1 is required for basic thylakoid membrane formation but not for the assembly of thylakoid protein complexes
Vipp1 is required for basic thylakoid membrane formation but not for the assembly of thylakoid protein complexes
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DOI：
10.1016/j.plaphy.2007.01.005
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发表时间：
2007-02-01
影响因子：
6.5
通讯作者：
Vothknecht, Ute C.
中科院分区：
文献类型：
--
作者：
Aseeva, Elena;Ossenbuehl, Friederich;Vothknecht, Ute C.
Vipp1（质体中的囊泡诱导蛋白 1）存在于蓝藻和叶绿体中，对于类囊体的形成至关重要。 Vipp1 含量减少至野生型含量约 20% 的拟南芥突变体植物在早期就会出现白化病。我们认为这种剧烈的表型是由于剩余的 Vipp1 蛋白无法组装成同源寡聚复合物所致，这表明寡聚化是 Vipp1 功能的先决条件。在 Delta vipp1 突变体背景中表达的 Vipp1-ProteinA 融合蛋白能够恢复寡聚化并恢复光合自养生长。含有与野生型中 Vipp1 相当的量的 Vipp1-ProteinA 的植物表现出野生型表型。然而，Vipp1-ProteinA 蛋白含量减少的植物生长迟缓，并且颜色明显比野生型苍白。这种表型是由类囊体膜含量减少和随之而来的光合作用减少引起的。就这些植物中形成的类囊体膜而言，它们与蛋白质-色素复合物正确组装并且具有光合作用活性。这有力地支持了 Vipp1 在基本类囊体膜形成中的功能，而不是在类囊体蛋白复合物的功能组装中的功能。有趣的是，电子显微镜分析表明，突变植物中的叶绿体并没有同样受到 Vipp1 短缺的影响。事实上，在同一个细胞的细胞器中可以观察到类囊体发育的各种不同阶段，从野生型样叶绿体到几乎没有类囊体的质体。 (c) 2007 年 Elsevier Masson SAS。版权所有。
Vipp1 (vesicle inducing protein in plastids 1) is found in cyanobacteria and chloroplasts where it is essential for thylakoid formation. Arabidopsis thaliana mutant plants with a reduction of Vipp1 to about 20% of wild type content become albinotic at an early stage. We propose that this drastic phenotype results from an inability of the remaining Vipp1 protein to assemble into a homo-oligomeric complex, indicating that oligomerization is a prerequisite for Vipp1 function. A Vipp1-ProteinA fusion protein, expressed in the Delta vipp1 mutant background, is able to reinstate oligomerization and restore photoautotrophic growth. Plants containing Vipp1-ProteinA in amounts comparable to Vipp1 in the wild type exhibit a wild type phenotype. However, plants with a reduced amount of Vipp1-ProteinA protein are growth-retarded and significantly paler than the wild type. This phenotype is caused by a decrease in thylakoid membrane content and a concomitant reduction in photosynthetic activity. To the extent that thylakoid membranes are made in these plants they are properly assembled with protein-pigment complexes and are photosynthetically active. This strongly supports a function of Vipp1 in basic thylakoid membrane formation and not in the functional assembly of thylakoid protein complexes. Intriguingly, electron microscopic analysis shows that chloroplasts in the mutant plants are not equally affected by the Vipp1 shortage. Indeed, a wide range of different stages of thylakoid development ranging from wild-type-like chloroplasts to plastids nearly devoid of thylakoids can be observed in organelles of one and the same cell. (c) 2007 Elsevier Masson SAS. All rights reserved.