Regulation of Constitutive Cargo Transport from the trans-Golgi Network to Plasma Membrane by Golgi-localized G Protein βγ Subunits
Regulation of Constitutive Cargo Transport from the trans-Golgi Network to Plasma Membrane by Golgi-localized G Protein βγ Subunits
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DOI：
10.1074/jbc.m110.154963
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发表时间：
2010-10-15
影响因子：
4.8
通讯作者：
Wedegaertner, Philip B.
中科院分区：
文献类型：
--
作者：
Irannejad, Roshanak;Wedegaertner, Philip B.
在将G蛋白β γ（G β γ）亚基引入细胞后观察到的高尔基体片段化表明，G β γ参与了控制质膜（PM）转运载体的跨高尔基体网络（TGN）裂变的途径。然而，G β γ的亚细胞位置引起高尔基体分裂是未知的。此外，G β γ在调节TGN至PM转运中的作用尚未得到证实。在这里，我们报告了组成型或诱导型G β γ靶向高尔基体，而不是其他亚细胞位置，导致HeLa细胞中高尔基体的磷脂酶C和蛋白激酶D依赖性囊泡形成;高尔基体靶向的β（1）γ（2）也激活蛋白激酶D。此外，新的G β-γ抑制剂，gallein，和G β-γ-螯合蛋白，GRK 2ct，揭示了G β-γ是两个模型货物蛋白，VSV-G和ss-HRP的组成型PM运输所需的。重要的是，高尔基体靶向GRK 2ct，而不是PM靶向GRK 2ct，也阻断蛋白质转运到PM。为了进一步支持高尔基体定位的G β γ的作用，在HeLa细胞的高尔基体中检测到内源性G β。这些结果是第一次建立高尔基体定位的G β γ在调节蛋白质从TGN运输到细胞表面的作用。
Observations of Golgi fragmentation upon introduction of G protein beta gamma (G beta gamma) subunits into cells have implicated G beta gamma in a pathway controlling the fission at the trans-Golgi network (TGN) of plasma membrane (PM)-destined transport carriers. However, the subcellular location where G beta gamma acts to provoke Golgi fragmentation is not known. Additionally, a role for G beta gamma in regulating TGN-to-PM transport has not been demonstrated. Here we report that constitutive or inducible targeting of G beta gamma to the Golgi, but not other subcellular locations, causes phospholipase C- and protein kinase D-dependent vesiculation of the Golgi in HeLa cells; Golgi-targeted beta(1)gamma(2) also activates protein kinase D. Moreover, the novel G beta gamma inhibitor, gallein, and the G beta gamma-sequestering protein, GRK2ct, reveal that G beta gamma is required for the constitutive PM transport of two model cargo proteins, VSV-G and ss-HRP. Importantly, Golgi-targeted GRK2ct, but not a PM-targeted GRK2ct, also blocks protein transport to the PM. To further support a role for Golgi-localized G beta gamma, endogenous G beta was detected at the Golgi in HeLa cells. These results are the first to establish a role for Golgi-localized G beta gamma in regulating protein transport from the TGN to the cell surface.