Sequences in the amino termini of GABA rho and GABA(A) subunits specify their selective interaction in vitro.
Sequences in the amino termini of GABA rho and GABA(A) subunits specify their selective interaction in vitro.
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GABA rho 和 GABA(A) 亚基的氨基末端序列指定了它们在体外的选择性相互作用。
DOI：
10.1046/j.1471-4159.1998.70010040.x
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发表时间：
1998
影响因子：
4.7
通讯作者：
Cutting,GR
中科院分区：
文献类型：
--
作者：
Hackam,AS;Wang,TL;Guggino,WB;Cutting,GR
分子克隆显示，有六类亚基能够形成GABA门控氯离子通道受体。GABAA受体由α、β、γ、δ和ε/χ亚基组成，而GABAC受体似乎含有ρ亚基。然而，表现出GABAC反应的视网膜细胞表达α、β和ρ亚基，提高了GABAC受体可能是亚基类别的混合物的可能性。使用体外翻译的蛋白质，我们确定人GABA A受体亚基α1、α5和β1不与全长ρ1、ρ2或含有ρ亚基相互作用信号的ρ1 N末端结构域共免疫沉淀。为了探索这些明显排他的组合背后的分子机制，创建了嵌合亚基并测试了与野生型亚基的相互作用。将β1的N末端转移到ρ1上，产生了与α1亚基共免疫沉淀但不与ρ2亚基共免疫沉淀的β1ρ1嵌合体。此外，将ρ1亚基的N端与β1的相应区域交换，产生了一个ρ1β1嵌合体，该嵌合体干扰了异种卵母细胞中ρ1受体的表达，而全长β1亚基则没有影响。总之，这些结果表明，N末端的序列指导ρ亚基和GABAA亚基分别组装成GABA C和GABAA受体。
Molecular cloning has revealed that there are six classes of subunits capable of forming GABA‐gated chloride channel receptors. GABAAreceptors are composed of α, β, γ, δ, and ε/χ subunits, whereas GABACreceptors appear to contain ρ subunits. However, retinal cells exhibiting GABACresponses express α, β, and ρ subunits, raising the possibility that GABACreceptors may be a mixture of subunit classes. Using in vitro translated protein, we determined that human GABAAreceptor subunits α1, α5, and β1 did not coimmunoprecipitate with full‐length ρ1, ρ2, or the N‐terminal domain of ρ1 that contains signals for ρ‐subunit interaction. To explore the molecular mechanism underlying these apparently exclusive combinations, chimeric subunits were created and tested for interaction with the wild‐type subunits. Transfer of the N terminus of β1 to ρ1 created a β1ρ1 chimera that coimmunoprecipitated with the α1 subunit but not with the ρ2 subunit. Furthermore, exchanging the N terminus of the ρ1 subunit with the corresponding region of β1 produced a ρ1β1 chimera that interfered with ρ1 receptor expression inXenopusoocytes, whereas the full‐length β1 subunit had no effect. Together, these results indicate that sequences in the N termini direct assembly of ρ subunits and GABAAsubunits into GABACand GABAAreceptors, respectively.