Pertussis-toxin-sensitive Gα subunits selectively bind to C-terminal domain of neuronal GIRK channels:: evidence for a heterotrimeric G-protein-channel complex
Pertussis-toxin-sensitive Gα subunits selectively bind to C-terminal domain of neuronal GIRK channels:: evidence for a heterotrimeric G-protein-channel complex
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DOI：
10.1016/j.mcn.2004.10.009
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发表时间：
2005-02-01
影响因子：
3.5
通讯作者：
Slesinger, PA
中科院分区：
文献类型：
--
作者：
Clancy, SM;Fowler, CE;Slesinger, PA
神经元G蛋白门控内向整流钾（Kir 3; GIRK）通道被G蛋白偶联受体激活，所述G蛋白偶联受体选择性地与PTX敏感性（G（alphai/o））G蛋白相互作用。虽然已知G（β-γ）二聚体激活GIRK通道，但G（α-γ）亚基的作用仍不清楚。在这里，我们建立了G（α）亚基与神经元GIRK通道共免疫沉淀。体外结合研究导致在GIRK 2 C-末端结构域中鉴定出G（alphao）结合所必需的6个氨基酸。进一步的研究表明，G（α/β γ）异源三聚体通过G（α）而不是G（β γ）（.）G（α/o）结合受损的GIRK 2通道表现出受体激活电流减少，但保留正常的乙醇和G（β-γ）激活电流。最后，PTX不敏感的G（alphaq）或G（alphas）亚基不与GIRK 2 C末端结合。总之，这些结果表明，PTX敏感的G（α 1/o）亚基与GIRK 2 C-末端结构域的相互作用调节G-蛋白受体偶联，并可能是重要的建立特定的G（α 1/o）信号通路。(C)2004爱思唯尔公司All rights reserved.
Neuronal G-protein-gated inwardly rectifying potassium (Kir3; GIRK) channels are activated by G-protein-coupled receptors that selectively interact with PTX-sensitive (G(alphai/o)) G proteins. Although the G(betagamma) dimer is known to activate GIRK channels, the role of the G(alphai/o) subunit remains unclear. Here, we established that G(alphao) subunits co-immunoprecipitate with neuronal GIRK channels. In vitro binding studies led to the identification of six amino acids in the GIRK2 C-terminal domain essential for G(alphao) binding. Further studies suggested that the G(alphai/obetagamma) heterotrimer hinds to the GIRK2 C-terminal domain via G(alpha) and not G(betagamma)(.) G(alphai/o) binding-impaired GIRK2 channels exhibited reduced receptor-activated currents, but retained normal ethanol- and G(betagamma)-activated currents. Finally, PTX-insensitive G(alphaq) or G(alphas) subunits did not bind to the GIRK2 C-terminus. Together, these results suggest that the interaction of PTX-sensitive G(alphai/o) subunit with the GIRK2 C-terminal domain regulates G-protein receptor coupling, and may be important for establishing specific G(alphai/o) signaling pathways. (C) 2004 Elsevier Inc. All rights reserved.