Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
Nebraska Center for Virology, Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
Cells. 2021 May 7;10(5):1128. doi: 10.3390/cells10051128.
Due to the redundancy of the genetic code most amino acids are encoded by multiple synonymous codons. It has been proposed that a biased frequency of synonymous codons can affect the function of proteins by modulating distinct steps in transcription, translation and folding. Here, we use two similar prototype K channels as model systems to examine whether codon choice has an impact on protein sorting. By monitoring transient expression of GFP-tagged channels in mammalian cells, we find that one of the two channels is sorted in a codon and cell cycle-dependent manner either to mitochondria or the secretory pathway. The data establish that a gene with either rare or frequent codons serves, together with a cell-state-dependent decoding mechanism, as a secondary code for sorting intracellular membrane proteins.
由于遗传密码的冗余性，大多数氨基酸都由多个同义密码子编码。有人提出，同义密码子的频率偏倚可以通过调节转录、翻译和折叠的不同步骤来影响蛋白质的功能。在这里，我们使用两个类似的原型 K 通道作为模型系统来研究密码子选择是否会影响蛋白质的分拣。通过监测 GFP 标记通道在哺乳动物细胞中的瞬时表达，我们发现这两个通道中的一个以密码子和细胞周期依赖的方式被分拣到线粒体或分泌途径中。这些数据表明，一个具有稀有或常见密码子的基因，以及一个依赖于细胞状态的解码机制，是分拣细胞内膜蛋白的二级密码。
