Ribosome heterogeneity as a new element of translation regulation

All living cells depend on the fine-tuning of gene expression and protein biosynthesis. Ribosomes, the molecular machines at the center of translation, have been previously considered the invariable driving force of protein production. However, recent studies indicated that the ribosomes are actively involved in the regulation of translation, influencing the control of translation initiation, the elongation speed, and the mRNA translation selectivity. This is due to the presence of subpopulations of the ribosomes, which differ in rRNAs and protein composition, their modifications and protein stoichiometry. In this publication, we focused our attention on the ribosomal heterogeneity in eukaryotes, which results from the changes in the stoichiometry of the ribosomal proteins and the existence of protein paralogs.