Resumo

CONTRERAS-TREVINO, Hugo I.  e  PADILLA-NORIEGA, Luis. Regulation of translation mediated by rotavirus protein NSP3. TIP [online]. 2018, vol.21, suppl.1, e20180152.  Epub 02-Dez-2020. ISSN 1405-888X.  https://doi.org/10.22201/fesz.23958723e.2018.0.152.

The study of the mechanisms used by different viruses to control host cell translation and favor the expression of viral proteins has been very instructive to know fundamental cellular mechanisms that regulate translation. Species A rotavirus (RVA) NSP3 protein is capable of inhibiting the translation of cellular mRNAs as a consequence of its binding to the translation initiation factor eIF4G and of stimulating the translation of viral mRNAs as a consequence of its binding to the UGACC sequence at their 3’-end. It has been proposed that NSP3 inhibits translation by interference with the circularization of the 5’-3’-ends of cellular mRNAs mediated by eIF4E-eIF4G-PABP (poly-A binding protein), and simultaneously it has been proposed that NSP3 stimulates translation of RVA mRNAs by circularization, in a way analogous to that performed by PABP on cellular mRNAs. However, the importance of NSP3 dimerization assisted by chaperone HSP90 in its inhibitory function of cell translation is unknown. Recently, the importance of NSP3 dimerization intermediates on its inhibitory function on host cell translation was explored, and it was found that point mutations in the coiled-coil region affect the formation of NSP3 dimers and partially preserve its host cell translation inhibitory function. In addition, it was found that NSP3 dimers degrade more rapidly than dimerization intermediates. These data demonstrate that the function of NSP3 is acquired prior to the appearance of dimers and suggests that the proteasome susceptibility of the different oligomeric forms of NSP3 are relevant in the establishment of the inhibitory function of cell translation.

Palavras-chave : NSP3; dimerization intermediates; proteostasis; translation inhibition.