Protein tyrosine phosphorylation in synaptic vesicles.
Protein tyrosine phosphorylation in synaptic vesicles.
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突触小泡中的蛋白质酪氨酸磷酸化。
DOI：
10.1073/pnas.85.3.762
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发表时间：
1988
影响因子：
11.1
通讯作者：
P. Greengard
中科院分区：
文献类型：
--
作者：
Dennis T. Pang;James K. T. Wang;F. Valtorta;F. Benfenati;P. Greengard
本文研究了Mn~（2+）和原钒酸盐对大鼠前脑突触囊泡蛋白酪氨酸磷酸化的影响。观察到高水平的内源性蛋白酪氨酸磷酸化。四个主要的磷蛋白，具有105，94，38和30 kDa的表观分子量，被证明含有磷酸酪氨酸。38 kDa的磷蛋白被确定为突触素（p38），一个很好的特点，整合膜蛋白的突触囊泡。其他三种含磷酸酪氨酸的蛋白质以与突触素相同的方式分布在所有亚细胞组分中。像突触素，两个高分子量的磷酸酪氨酸蛋白质（105和94 kDa）被发现是糖蛋白凝集素层析。突触体蛋白酪氨酸磷酸化是一个囊泡内反应，并在3分钟内达到最大水平的50%。Triton X-100，非离子去污剂，抑制内源性蛋白质底物的酪氨酸磷酸化，但不磷酸化的外源性底物，聚（Glu80，-Tyr20）。在突触体中也证实了突触泡蛋白的酪氨酸磷酸化，表明突触泡蛋白的酪氨酸磷酸化发生在完整的神经末梢中。
Protein tyrosine phosphorylation in purified synaptic vesicles from rat forebrain has been studied in the presence of Mn2+ and orthovanadate. High levels of endogenous protein tyrosine phosphorylation were observed. Four major phosphoproteins, with apparent molecular masses of 105, 94, 38, and 30 kDa, were shown to contain phosphotyrosine. The 38-kDa phosphoprotein was identified as synaptophysin (p38), a well-characterized integral membrane protein of synaptic vesicles. The three other phosphotyrosine-containing proteins distributed in the same manner as synaptophysin in all subcellular fractions. Like synaptophysin, the two high molecular weight phosphotyrosine proteins (105 and 94 kDa) were found to be glycoproteins by lectin chromatography. Tyrosine phosphorylation of synaptophysin was an intravesicular reaction and reached 50% of maximal level within 3 min. Triton X-100, a nonionic detergent, inhibited tyrosine phosphorylation of endogenous protein substrates but not the phosphorylation of an exogenous substrate, poly(Glu80,-Tyr20). Tyrosine phosphorylation of synaptophysin was also demonstrated in synaptosomes, indicating that tyrosine phosphorylation of synaptic vesicle proteins occurs in intact nerve terminals.