Eukaryotes possess a variety of translational control mechanisms which function in the surveillance of mRNAs, discriminating between normal and aberrant translation elongation and termination, triggering mRNA decay. The three major evolutionarily conserved eukaryotic pathways are No-Go, Non-Stop and Nonsense-Mediated mRNA Decay. Recent findings suggest that stalling of the ribosome, due to mRNA secondary structure or translation into poly(A)-stretches, leads to ribosome collisions which are detected by No-Go/Non-Stop mRNA decay factors. Subsequent ribosome ubiquitination at the interface of two collided ribosomes is considered the signal for mRNA decay. Similarly, translation termination at a premature stop codon is slower than normal, leading to recruitment and activation of nonsense-mediated mRNA decay factors, including SMG1-8-9. Here, we detail new insights into the molecular mechanisms of these pathways.

真核生物具有多种翻译控制机制，其功能是监视 mRNA，区分正常和异常翻译延伸和终止，触发 mRNA 衰变。三种主要的进化上保守的真核途径是 No-Go、Non-Stop 和 Nonsense-Mediated mRNA Decay。最近的研究结果表明，由于 mRNA 二级结构或翻译成 poly(A) 延伸，核糖体的停滞会导致核糖体碰撞，这种碰撞由 No-Go/Non-Stop mRNA 衰减因子检测到。随后在两个碰撞核糖体界面处的核糖体泛素化被认为是 mRNA 衰变的信号。同样，过早终止密码子处的翻译终止比正常情况慢，导致无义介导的 mRNA 衰减因子（包括 SMG1-8-9）的募集和激活。这里，