The putative G protein-coupled receptor GrlD mediates extracellular polyphosphate sensing in Dictyostelium discoideum.
The putative G protein-coupled receptor GrlD mediates extracellular polyphosphate sensing in Dictyostelium discoideum.
复制标题
盘基网柄菌中假定的 G 蛋白偶联受体 GrlD 介导细胞外多磷酸盐传感。
DOI：
10.1091/mbc.e18-10-0686
复制
发表时间：
2019
影响因子：
3.3
通讯作者：
Gomer,RichardH
中科院分区：
文献类型：
--
作者：
Suess,PatrickM;Tang,Yu;Gomer,RichardH
五个或五个以上的正磷酸盐通过高能的磷酸酸酐键结合在一起，是高度普遍存在的无机分子，称为聚磷酸盐。聚磷酸作为一种信号分子在真核细胞中引发了一系列的反应，但这些效应的中介机制尚不清楚。增殖盘基网眼菌细胞积聚胞外聚磷酸盐。在与静止期细胞相似的胞外浓度下，多聚磷酸抑制蛋白酶体的活性和增殖，并诱导聚集。在这里，我们确定GrlD是一种可能的G蛋白偶联受体，介导细胞外多聚磷酸与细胞表面的结合。缺乏GrlD的细胞对聚磷酸盐诱导的蛋白酶体抑制、聚集或增殖抑制没有反应。多聚磷酸盐对细胞-基质黏附和细胞骨架F-肌动蛋白水平的影响也因营养物质的可利用性而不同，这些影响也是由GrlD介导的。饥饿的细胞还会积累胞外多聚磷酸。用胞外多聚磷酸酶处理的饥饿细胞不能有效地聚集，这表明多聚磷酸在饥饿诱导的网柄金藻的发育过程中也起着信号分子的作用。综上所述，这些结果表明，真核细胞使用G蛋白偶联受体来介导对细胞外多聚磷酸的感觉和反应。
Five or more orthophosphates bound together by high-energy phosphoanhydride bonds are highly ubiquitous inorganic molecules called polyphosphate. Polyphosphate acts as a signaling molecule eliciting a number of responses in eukaryotic cells, but the mechanisms mediating these effects are poorly understood. ProliferatingDictyostelium discoideumcells accumulate extracellular polyphosphate. At extracellular concentrations similar to those observed in stationary phase cells, polyphosphate inhibits proteasome activity and proliferation, and induces aggregation. Here we identify GrlD as a putative G protein–coupled receptor that mediates binding of extracellular polyphosphate to the cell surface. Cells lacking GrlD do not respond to polyphosphate-induced proteasome inhibition, aggregation, or proliferation inhibition. Polyphosphate also elicits differential effects on cell-substratum adhesion and cytoskeletal F-actin levels based on nutrient availability, and these effects were also mediated by GrlD. Starving cells also accumulate extracellular polyphosphate. Starved cells treated with exopolyphosphatase failed to aggregate effectively, suggesting that polyphosphate also acts as a signaling molecule during starvation-induced development ofDictyostelium. Together, these results suggest that a eukaryotic cell uses a G protein–coupled receptor to mediate the sensing and response to extracellular polyphosphate.