BIOSYNTHESIS AND AXONAL-TRANSPORT OF RAT NEUROHYPOPHYSEAL PROTEINS AND PEPTIDES
BIOSYNTHESIS AND AXONAL-TRANSPORT OF RAT NEUROHYPOPHYSEAL PROTEINS AND PEPTIDES
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DOI：
10.1083/jcb.73.2.366
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发表时间：
1977-01-01
影响因子：
7.8
通讯作者：
BROWNSTEIN, MJ
中科院分区：
文献类型：
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作者：
GAINER, H;SARNE, Y;BROWNSTEIN, MJ
在大鼠视上核（SON）附近注射的35 S-半胱氨酸迅速掺入蛋白质中。这些35 S-半胱氨酸标记的蛋白质在SON中（注射后1-24 h）通过聚丙烯酰胺凝胶电泳分离，并分析凝胶上放射性蛋白质的分布。进样后1小时，约73%的放射性出现在2个峰中（均约为20，000 MW）。随着时间的推移，这些峰（推定的neurophysin前体）减少，因为12，000 MW峰（含有2种不同的neurophysin）的放射性增加。20，000和12，000 MW蛋白质都被转运到大鼠下丘脑-神经垂体系统的轴突（正中隆起）和神经末梢（垂体后叶）区域。较大的前体蛋白转化为较小的neurophysin似乎发生，在很大程度上，在轴突运输的轴突内。除了精氨酸加压素和催产素之外，还在SON中合成了六种不同的35 S-半胱氨酸标记的肽（< 2500 MW），并将其运输到垂体后叶，在那里它们与标记的neurophysin一起在细胞外Ca的存在下通过K去极化释放。这些数据提供了支持的假设，即神经垂体肽（加压素和催产素）和neurophysins来自翻译后裂解的蛋白质前体合成的SON，转换过程中可以发生在轴突运输的神经分泌颗粒。
35S-cysteine injected adjacent to the supraoptic nucleus (SON) of the rat is rapidly incorporated into proteins. These 35S-cysteine-labeled proteins in the SON (1-24 h after injection) were separated by polyacrylamide gel electrophoresis, and the distribution of radioactive proteins on the gels was analyzed. One hour after injection, about 73% of the radioactivity appeared in 2 peaks (both about 20,000 MW). With time, these peaks (putative precursors of neurophysin) decreased, as a 12,000 MW peak (containing 2 distinct neurophysins) increased in radioactivity. Both the 20,000 and 12,000 MW proteins are transported into the axonal (median eminence) and nerve terminal (posterior pituitary) regions of the rat hypothalamo-neurohypophysial system. Conversion of the larger precursor protein to the smaller neurophysin appears to occur, in large part, intra-axonally during axonal transport. Six distinct 35S-cysteine-labeled peptides (< 2500 MW), in addition to arginine vasopressin and oxytocin, are also synthesized in the SON and transported to the posterior pituitary where they are released together with labeled neurophysin by K depolarization in the presence of extracellular Ca. These data provide support for the hypothesis that the neurohypophysial peptides (vasopressin and oxytocin) and neurophysins are derived from the post-translational cleavage of protein precursors synthesized in the SON, and that the conversion process can occur in the neurosecretory granule during axonal transport.