One of the key roles of the 12-subunit eukaryotic translation initiation factor 3 (eIF3) is to promote the formation of the 43S and 48S pre-initiation complexes (PICs). However, particular contributions of its individual subunits to these two critical initiation reactions remained obscure. Here, we adapted formaldehyde gradient cross-linking protocol to translation studies and investigated the efficiency of the 43S and 48S PIC assembly in knockdowns of individual subunits of human eIF3 known to produce various partial subcomplexes. We revealed that eIF3d constitutes an important intermolecular bridge between eIF3 and the 40S subunit as its elimination from the eIF3 holocomplex severely compromised the 43S PIC assembly. Similarly, subunits eIF3a, c and e were found to represent an important binding force driving eIF3 binding to the 40S subunit. In addition, we demonstrated that eIF3c, and eIF3k and l subunits alter the efficiency of mRNA recruitment to 43S PICs in an opposite manner. Whereas the eIF3c knockdown reduces it, downregulation of eIF3k or eIF3l increases mRNA recruitment, suggesting that the latter subunits possess a regulatory potential. Altogether this study provides new insights into the role of human eIF3 in the initial assembly steps of the translational machinery.

• MeSH
• eukaryotický iniciační faktor 3 genetika   MeSH
• formaldehyd farmakologie   MeSH
• lidé MeSH
• malé podjednotky ribozomu eukaryotické genetika   MeSH
• messenger RNA genetika   MeSH
• proteiny asociované s mikrotubuly genetika   MeSH
• proteosyntéza genetika   MeSH
• reagencia zkříženě vázaná farmakologie   MeSH
• ribozomy genetika   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• EIF3C protein, human MeSH Prohlížeč
• EIF3D protein, human MeSH Prohlížeč
• EIF3K protein, human MeSH Prohlížeč
• EIF3L protein, human MeSH Prohlížeč
• eukaryotický iniciační faktor 3 MeSH
• formaldehyd MeSH
• messenger RNA MeSH
• proteiny asociované s mikrotubuly MeSH
• reagencia zkříženě vázaná MeSH