Drosophila Ric-8 interacts with the Gα12/13 subunit, Concertina, during activation of the Folded gastrulation pathway.
Drosophila Ric-8 interacts with the Gα12/13 subunit, Concertina, during activation of the Folded gastrulation pathway.
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DOI：
10.1091/mbc.e12-11-0813
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发表时间：
2013-11
影响因子：
3.3
通讯作者：
Rogers SL
中科院分区：
文献类型：
--
作者：
Peters KA;Rogers SL
介绍了一种用于研究细胞收缩的新型组织培养模型，并用于显示Fog信号通路的激活依赖于Ric-8，Ric-8优先结合和定位无活性的Cta。在Ric-8内鉴定了对Cta的结合和功能重要的保守残基。由α、β和γ亚基组成的异源三聚体G蛋白通过Gα亚基上的GDP交换为GTP而被激活。一般来说，Gα受配体结合的G蛋白偶联受体的鸟嘌呤核苷酸交换因子（GEF）活性刺激。然而，Gα亚基也可能被Ric-8家族成员以非经典方式激活，Ric-8家族是细胞质蛋白，也可作为Gα亚基的GEF。我们使用果蝇原肠胚形成期间活跃的信号通路作为模型系统来研究Ric-8/Gα相互作用。果蝇Gα12/13亚基（Concertina，Cta）是该途径的一个组成部分，在原肠胚形成过程中触发肌动球蛋白收缩是必需的。Ric-8突变体表现出与Cta突变体相似的原肠胚形成缺陷。在这里，我们使用一种新的组织培养系统来研究控制细胞形态发生所必需的细胞骨架重排的信号通路。我们表明，Ric-8通过与Cta的物理相互作用调节这一通路，并优先与非活性Cta相互作用，并指导其在细胞内的定位。我们还使用该系统进行Ric-8的结构-功能分析，并确定Cta相互作用和细胞收缩性所需的关键残基。
A novel tissue culture model for studying cellular constriction is introduced and used to show that activation of the Fog signaling pathway depends on Ric-8 and that Ric-8 preferentially binds and localizes inactive Cta. Conserved residues are identified within Ric-8 that are important for the binding and function of Cta. Heterotrimeric G proteins, composed of α, β, and γ subunits, are activated by exchange of GDP for GTP on the Gα subunit. Canonically, Gα is stimulated by the guanine-nucleotide exchange factor (GEF) activity of ligand-bound G protein–coupled receptors. However, Gα subunits may also be activated in a noncanonical manner by members of the Ric-8 family, cytoplasmic proteins that also act as GEFs for Gα subunits. We used a signaling pathway active during Drosophila gastrulation as a model system to study Ric-8/Gα interactions. A component of this pathway, the Drosophila Gα12/13 subunit, Concertina (Cta), is necessary to trigger actomyosin contractility during gastrulation events. Ric-8 mutants exhibit similar gastrulation defects to Cta mutants. Here we use a novel tissue culture system to study a signaling pathway that controls cytoskeletal rearrangements necessary for cellular morphogenesis. We show that Ric-8 regulates this pathway through physical interaction with Cta and preferentially interacts with inactive Cta and directs its localization within the cell. We also use this system to conduct a structure–function analysis of Ric-8 and identify key residues required for both Cta interaction and cellular contractility.