TYROSINE KINASE PHOSPHORYLATION OF GABA(A) RECEPTORS
TYROSINE KINASE PHOSPHORYLATION OF GABA(A) RECEPTORS
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DOI：
10.1016/0169-328x(95)00048-w
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发表时间：
1995-07-01
期刊：
影响因子：
--
通讯作者：
HARRIS, RA
中科院分区：
文献类型：
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作者：
VALENZUELA, CF;MACHU, TK;HARRIS, RA
用酪氨酸激酶pp 60（v-src）检测了纯化的牛脑GABA（A）受体的磷酸化。pp 60（v-src）磷酸化54-62 kDa和48-51 kDa的两条带，这两条带分别迁移到与抗β 2和γ 2GABA（A）受体亚基的抗血清识别的带大致相同的位置。含有β 1和γ 2L亚基的推定大细胞质环的细菌表达的蛋白质被pp 60（v-src）磷酸化，表明磷酸化位点位于这些亚基结构域中。酪氨酸激酶抑制剂染料木黄酮和酪氨酸磷酸酶抑制剂B-42和B-44抑制蝇蕈醇刺激的小鼠脑膜囊泡（微囊）中Cl-36（-）摄取。在抑制磷酸化的条件下裂解并重新密封的微囊中，酪氨酸磷酸化抑制素B44诱导的蝇蕈醇刺激的Cl-36（-）摄取抑制的幅度显著降低。在表达α 1 β 1和α 1 β 1 γ 2L亚基的非洲爪蟾卵母细胞中，染料木素和酪氨酸磷酸化抑制剂B-44也抑制GABA门控的Cl-电流。因此，蛋白酪氨酸激酶依赖性磷酸化似乎是调节GABA（A）受体功能的另一种机制。
Phosphorylation of purified bovine brain GABA(A) receptors by the tyrosine kinase, pp60(v-src) was examined. pp60(v-src) phosphorylated two bands of 54-62 kDa and 48-51 kDa that migrated to approximately the same position as bands recognized by antisera against the beta 2 and gamma 2 GABA(A) receptor subunits, respectively. Bacterially expressed proteins containing the putative large cytoplasmic loops of the beta 1 and gamma 2L subunits were phosphorylated by pp60(v-src), indicating that the phosphorylation sites are located in these subunit domains. The tyrosine kinase inhibitors, genistein and the tyrphostins B-42 and B-44, inhibited muscimol-stimulated Cl-36(-) uptake in mouse brain membrane vesicles (microsacs). The magnitude of the tyrphostin B44-induced inhibition of muscimol-stimulated Cl-36(-) uptake was significantly reduced in microsacs that were lysed and resealed under conditions that inhibit phosphorylation. GABA-gated Cl- currents were also inhibited by genistein and tyrphostin B-44 in Xenopus oocytes expressing alpha 1 beta 1 and alpha 1 beta 1 gamma 2L subunits. Consequently, protein tyrosine kinase-dependent phosphorylation appears to be another mechanism of regulating the function of GABA(A) receptors.