On 27 August at 10:15 Ivan Kisly will defend his doctoral thesis „The pleiotropic functions of ribosomal proteins eL19 and eL24 in the budding yeast ribosome”.
Professor of Molecular Biology Jaanus Remme, Institute of Molecular and Cell Biology , Univeristy of Tartu
Senior Research Fellow of Molecular Biology Tiina Tamm, Institute of Molecular and Cell Biology, Univeristy of Tartu
RNA molekulaarbioloogia professor Denis LJ Lafontaine, PhD, Molekulaarbioloogia jaaMeditsiini Instituut, Brüsseli Vaba Ülikool (Université Libre de Bruxelles, ULB), Brüssel, Belgia.
Protein biosynthesis is known to be the dominant energy consuming process in cells. It is no wonder that alterations in this process disturb cell physiology and lead to a variety of diseases. Proteins are exclusively synthesized by large macromolecular complexes called ribosomes. Ribosome structure and mechanism of their function have been extensively studied, but many aspects of the ribosomal machinery are still obscure. Structural studies demonstrate that in all domains of life (Bacteria, Archaea and Eukarya) ribosomes consist of RNAs and proteins that are organized into a small and a large ribosomal subunit. Structure of the eukaryotic ribosome is distinctive by a comprehensive neuron-like network of interactions between ribosomal proteins. An important part of this network is assigned to contacts between ribosomal subunit – intersubunit bridges that guide movements of subunits during protein synthesis. Two ribosomal proteins, eL19 and eL24, are in the focus of the present study. Both proteins consist of three structural domains that can be divided into archaea/eukaryote-specific and eukaryote-specific domains. Mutational analysis of eL19 and eL24 revealed that archaea/eukaryote-specific domains ensure formation of the proper structure of the large ribosomal subunit. The eukaryote-specific domains of eL19 and eL24 extend far from the large ribosomal subunit and form intersubunit bridges eB12 and eB13, respectively. The data show for the first time that eukaryote-specific bridges eB12 and eB13 support protein synthesis by stabilizing the association of ribosomal subunits. The current thesis demonstrates that archaea/eukaryote-specific and eukaryote-specific domains of proteins eL19 and eL24 bear distinctive functions. Altogether, a link between structural organization and functionality of the eukaryotic ribosomes is uncovered in this study.