Evolutionarily Conserved and Non-Conserved Roles of Heterotrimeric Gα Proteins of Plants
Evolutionarily Conserved and Non-Conserved Roles of Heterotrimeric Gα Proteins of Plants
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DOI：
10.1093/pcp/pcac045
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发表时间：
2022-05-14
影响因子：
4.9
通讯作者：
Dodds，Audrey
中科院分区：
文献类型：
--
作者：
Pandey，Sona;Choudhury，Swarup Roy;Dodds，Audrey
异三聚体g蛋白在许多真核生物中调节多种信号通路。在植物中，g蛋白主要是从几种模式被子植物和一种苔藓中被鉴定出来的。即使在这个小群体中，它们似乎也会对植物表型产生不同的影响：g蛋白是单子房存活所必需的，是适应所必需的，但在双子房中不是必需的，在大多数小立壶属植物中，g蛋白是完成生命周期和从配子体向孢子体过渡所必需的。典型的g蛋白异源三聚体由三个亚基组成：一个Gα，一个Gβ和一个Gγ。Gα蛋白是一种催化活性的GTPase，在其活性构象中，与下游效应物相互作用以转导信号。在整个植物进化谱系中，Gα蛋白表现出高度的序列保守性。为了探索这种序列保守在多大程度上转化为它们的功能，我们将已经充分表征的拟南芥Gα蛋白突变体gpa1与来自不同植物谱系的Gα蛋白和酵母gpa1进行了互补，并评估了AtGPA1控制的不同表型的转基因植株。结果表明，以拟南芥为代表的单子叶植株和拟南芥为代表的单子叶植株的Gα蛋白可以完全补充所有gpa1表型。然而，尽管所有Gα蛋白都能部分或完全补充各种外源信号所表现出的表型，但基生植物Gα却不能补充gpa1突变体所表现出的发育表型。我们的研究结果为g蛋白在植物中的进化保守功能提供了一个独特的视角。
Heterotrimeric G-proteins modulate multiple signaling pathways in many eukaryotes. In plants, G-proteins have been characterized primarily from a few model angiosperms and a moss. Even within this small group, they seem to affect plant phenotypes differently: G-proteins are essential for survival in monocots, needed for adaptation but are nonessential in eudicots, and are required for life cycle completion and transition from the gametophytic to sporophytic phase in the mossPhyscomitrium (Physcomitrella) patens. The classic G-protein heterotrimer consists of three subunits: one Gα, one Gβ and one Gγ. The Gα protein is a catalytically active GTPase and, in its active conformation, interacts with downstream effectors to transduce signals. Gα proteins across the plant evolutionary lineage show a high degree of sequence conservation. To explore the extent to which this sequence conservation translates to their function, we complemented the well-characterized Arabidopsis Gα protein mutant,gpa1, with Gα proteins from different plant lineages and with the yeast Gpa1 and evaluated the transgenic plants for different phenotypes controlled by AtGPA1. Our results show that the Gα protein from a eudicot or a monocot, represented by Arabidopsis and Brachypodium, respectively, can fully complement allgpa1phenotypes. However, the basal plant Gα failed to complement the developmental phenotypes exhibited bygpa1mutants, although the phenotypes that are exhibited in response to various exogenous signals were partially or fully complemented by all Gα proteins. Our results offer a unique perspective on the evolutionarily conserved functions of G-proteins in plants.