Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia; Faculty of Bioengineering and Bioinformatics, M. V. Lomonosov Moscow State University, Moscow 119234, Russia.
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia.
J Biol Chem. 2019 May 24;294(21):8630-8639. doi: 10.1074/jbc.RA118.006856. Epub 2019 Apr 16.
Polyadenylate-binding protein (PABP) stimulates translation termination via interaction of its C-terminal domain with eukaryotic polypeptide chain release factor, eRF3. Additionally, two other proteins, poly(A)-binding protein-interacting proteins 1 and 2 (PAIP1 and PAIP2), bind the same domain of PABP and regulate its translation-related activity. To study the biochemistry of eRF3 and PAIP1/2 competition for PABP binding, we quantified the effects of PAIPs on translation termination in the presence or absence of PABP. Our results demonstrated that both PAIP1 and PAIP2 prevented translation termination at the premature termination codon, by controlling PABP activity. Moreover, PAIP1 and PAIP2 inhibited the activity of free PABP on translation termination However, after binding the poly(A) tail, PABP became insensitive to suppression by PAIPs and efficiently activated translation termination in the presence of eRF3a. Additionally, we revealed that PAIP1 binds eRF3 in solution, which stabilizes the post-termination complex. These results indicated that PAIP1 and PAIP2 participate in translation termination and are important regulators of readthrough at the premature termination codon.
多聚腺苷酸结合蛋白（PABP）通过其 C 末端结构域与真核多肽链释放因子 eRF3 相互作用来刺激翻译终止。此外，另外两种蛋白质，多聚（A）结合蛋白相互作用蛋白 1 和 2（PAIP1 和 PAIP2），结合 PABP 的相同结构域并调节其与翻译相关的活性。为了研究 eRF3 和 PAIP1/2 竞争 PABP 结合的生物化学，我们在存在或不存在 PABP 的情况下量化了 PAIP 对翻译终止的影响。我们的结果表明，PAIP1 和 PAIP2 通过控制 PABP 活性，防止在过早终止密码子处发生翻译终止。此外，PAIP1 和 PAIP2 抑制游离 PABP 在翻译终止上的活性，但是，在结合 poly(A) 尾后，PABP 对 PAIPs 的抑制作用不敏感，并在 eRF3a 存在的情况下有效地激活翻译终止。此外，我们揭示了 PAIP1 在溶液中与 eRF3 结合，稳定了终止后复合物。这些结果表明，PAIP1 和 PAIP2 参与翻译终止，并作为过早终止密码子通读的重要调节剂。
