Herb A, Burnashev N, Werner P, Sakmann B, Wisden W, Seeburg P H
Center for Molecular Biology, Heidelberg University, Germany.
Neuron. 1992 Apr;8(4):775-85. doi: 10.1016/0896-6273(92)90098-x.
A new ionotropic glutamate receptor subunit termed KA-2, cloned from rat brain cDNA, exhibits high affinity for [3H]kainate (KD approximately 15 nM). KA-2 mRNA is widely expressed in embryonic and adult brain. Homomeric KA-2 expression does not generate agonist-sensitive channels, but currents are observed when KA-2 is coexpressed with GluR5 or GluR6 subunits. Specifically, coexpression of GluR5(R) and KA-2 produces channel activity, whereas homomeric expression of either subunit does not. Currents through heteromeric GluR5(Q)/KA-2 channels show more rapid desensitization and different current-voltage relations when compared with GluR5(Q) currents. GluR6/KA-2 channels are gated by AMPA, which fails to gate homomeric GluR6 receptor channels. These results suggest possible in vivo partnership relations for high affinity kainate receptors.
一种新的离子型谷氨酸受体亚基，称为KA-2，从大鼠脑cDNA中克隆出来，对[3H]海人酸具有高亲和力（KD约为15 nM）。KA-2 mRNA在胚胎和成年大脑中广泛表达。同源性KA-2表达不会产生对激动剂敏感的通道，但当KA-2与GluR5或GluR6亚基共表达时可观察到电流。具体而言，GluR5(R)和KA-2共表达会产生通道活性，而单独任何一个亚基的同源性表达都不会。与GluR5(Q)电流相比，通过异源GluR5(Q)/KA-2通道的电流显示出更快的脱敏和不同的电流-电压关系。GluR6/KA-2通道由AMPA门控，而AMPA不能门控同源性GluR6受体通道。这些结果表明高亲和力海人酸受体可能存在体内伙伴关系。
