Steps in trans-translation. A ribosome remains stalled near the 3' end of broken mRNA, binds to alanine-charged tmRNA (orange), and switches from the broken message onto the open reading frame of the tmRNA allowing regular translation to resume. Upon reaching the tmRNA stop codon, the ribosome releases a hybrid protein with a degradation tag and joins the pool of active ribosomes.
Wower et al. Journal of Biology 2008 7:17 doi:10.1186/jbiol78