Balduzzi R, Cupello A, Diaspro A, Ramoino P, Robello M
Unità INFM, Dipatrimento di Fisica, Università di Genova, Genoa, Italy.
Biochim Biophys Acta. 2001 May 28;1539(1-2):93-100. doi: 10.1016/s0167-4889(01)00097-0.
The expression of GABA(A) receptors in Xenopus oocytes injected with rat brain mRNA was studied by immunocytochemistry and evaluation of the distribution of fluorescent probes at the confocal microscope. The beta(2/3) subunit distributed exclusively on the membrane at the animal pole of the oocytes. Treatment of oocytes for 20 min with the protein tyrosine kinase inhibitor genistein, 200 microM, resulted in a lower presence of GABA(A) receptors on the membrane. The inactive genistein analogue daidzein, 200 microM, had no effect even with a 30 min treatment. Alkaline phosphatase but not a protein tyrosine phosphatase, when injected into oocytes, reduced GABA(A) receptor membrane expression. The data indicate that protein tyrosine phosphorylation modulates the expression on the plasma membrane of presynthesized GABA(A) receptors.
通过免疫细胞化学和在共聚焦显微镜下评估荧光探针的分布，研究了注射大鼠脑mRNA的非洲爪蟾卵母细胞中GABA(A)受体的表达。β(2/3)亚基仅分布在卵母细胞动物极的膜上。用200微摩尔的蛋白酪氨酸激酶抑制剂染料木黄酮处理卵母细胞20分钟，导致膜上GABA(A)受体的存在减少。200微摩尔的无活性染料木黄酮类似物大豆苷元，即使处理30分钟也没有效果。当注入卵母细胞时，碱性磷酸酶而非蛋白酪氨酸磷酸酶会降低GABA(A)受体的膜表达。数据表明，蛋白酪氨酸磷酸化调节预合成的GABA(A)受体在质膜上的表达。
