Amino acid substitutions in the pore helix of GluR6 control inhibition by membrane fatty acids.
Amino acid substitutions in the pore helix of GluR6 control inhibition by membrane fatty acids.
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DOI：
10.1085/jgp.200810009
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发表时间：
2008-07
影响因子：
3.8
通讯作者：
Huettner, James E.
中科院分区：
文献类型：
--
作者：
Wilding, Timothy J.;Fulling, Elisabeth;Zhou, Yun;Huettner, James E.
神经元海苷酸受体GluR5和GluR6亚基Q/R位点的RNA编辑可调节脂质来源调节剂（包括顺式不饱和脂肪酸花生四烯酸和二十二碳六烯酸）对通道的抑制作用。所有亚基都处于编辑(R)形式的Kainate受体通道受到这些化合物的强烈抑制，而在一个或多个亚基的Q/R位点包含谷氨酰胺(Q)的野生型受体对抑制具有抗性。在本研究中，我们对GluR6(Q)亚基的孔环中的残基进行了精氨酸扫描。将GluR6(Q) Q/R位点的- 19 ~ +7氨基酸单独突变为精氨酸，突变cdna在HEK 293细胞中以同质通道表达。除了一个单一的精氨酸取代突变体外，所有突变体都产生了功能通道。在Q/R位点下游+1至+6的位置上，仅观察到典型的野生型GluR6(Q)通道的弱抑制作用。然而，在Q/R位点上游的几个位置的精氨酸取代导致同质通道受到脂肪酸的强烈抑制，这是同质GluR6(R)通道的特征。基于与钾通道孔环的同源性，R取代诱导脂肪酸抑制易感性的位置远离细胞质，朝向M1和M3螺旋和周围的脂质。
RNA editing at the Q/R site in the GluR5 and GluR6 subunits of neuronal kainate receptors regulates channel inhibition by lipid-derived modulators including the cis-unsaturated fatty acids arachidonic acid and docosahexaenoic acid. Kainate receptor channels in which all of the subunits are in the edited (R) form exhibit strong inhibition by these compounds, whereas wild-type receptors that include a glutamine (Q) at the Q/R site in one or more subunits are resistant to inhibition. In the present study, we have performed an arginine scan of residues in the pore loop of the GluR6(Q) subunit. Amino acids within the range from −19 to +7 of the Q/R site of GluR6(Q) were individually mutated to arginine and the mutant cDNAs were expressed as homomeric channels in HEK 293 cells. All but one of the single arginine substitution mutants yielded functional channels. Only weak inhibition, typical of wild-type GluR6(Q) channels, was observed for substitutions +1 to +6 downstream of the Q/R site. However, arginine substitution at several locations upstream of the Q/R site resulted in homomeric channels exhibiting strong inhibition by fatty acids, which is characteristic of homomeric GluR6(R) channels. Based on homology with the pore loop of potassium channels, locations at which R substitution induces susceptibility to fatty acid inhibition face away from the cytoplasm toward the M1 and M3 helices and surrounding lipids.
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影响因子：
56.9
作者：
Doyle, DA;Cabral, JM;MacKinnon, R
通讯作者：
MacKinnon, R
影响因子：
2.5
作者：
Howe, JR
通讯作者：
Howe, JR
影响因子：
16.2
作者：
HUETTNER, JE
通讯作者：
HUETTNER, JE
影响因子：
4.7
作者：
Huettner, JE;Stack, E;Wilding, TJ
通讯作者：
Wilding, TJ
影响因子：
56.9
作者：
KEINANEN, K;WISDEN, W;SEEBURG, PH
通讯作者：
SEEBURG, PH