Translocation of proteins across the endoplasmic reticulum III. Signal recognition protein (SRP) causes signal sequence-dependent and site-specific arrest of chain elongation that is released by microsomal membranes.
Translocation of proteins across the endoplasmic reticulum III. Signal recognition protein (SRP) causes signal sequence-dependent and site-specific arrest of chain elongation that is released by microsomal membranes.
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DOI：
10.1083/jcb.91.2.557
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发表时间：
1981-11
影响因子：
7.8
通讯作者：
Blobel, G
中科院分区：
文献类型：
--
作者：
Walter, P;Blobel, G
先前观察到的（Walter，et al.1981 J. Cell Biol.91：545-550）SRP选择性抑制分泌蛋白（催乳素前体）的mRNA的无细胞翻译的作用在此显示是由信号序列诱导的和多肽链延伸中的位点特异性停滞引起的。估计SRP抑制的新生前催乳素链的Mr为8，000，对应于约70个氨基酸残基。由于前催乳素的信号序列包含30个残基，并且由于新生链的大约40个残基被掩埋在核糖体大亚基中（免受蛋白酶的影响），我们得出结论，这是SRP与新生链的氨基末端信号肽（从核糖体大亚基中出现）的相互作用，其调节翻译，从而导致链延长的停滞。这种阻滞在SRP介导的延长阻滞的核糖体与微粒体膜结合后释放，导致链完成并易位到微粒体囊泡中。
The previously observed (Walter, et al. 1981 J. Cell Biol. 91:545-550) inhibitory effect of SRP selectively on the cell-free translation of mRNA for secretory protein (preprolactin) was shown here to be caused by a signal sequence-induced and site-specific arrest in polypeptide chain elongation. The Mr of the SRP-arrested nascent preprolactin chain was estimated to be 8,000 corresponding to approximately 70 amino acid residues. Because the signal sequence of preprolactin comprises 30 residues and because approximately 40 residues of the nascent chain are buried (protected from protease) in the large ribosomal subunit, we conclude that it is the interaction of SRP with the amino-terminal signal peptide of the nascent chain (emerged from the large ribosomal subunit) that modulates translation and thereby causes an arrest in chain elongation. This arrest is released upon SRP-mediated binding of the elongation-arrested ribosomes to the microsomal membrane, resulting in chain completion and translocation into the microsomal vesicle.