Function and Structure of Rotavirus NSP3
Michelle M. Becker, Stefan T. Arold, Stephen .K. Burley, Rahul C. Deo, Caroline M. Groft, Damien Vitour and Didier Poncet
from: Segmented Double-stranded RNA Viruses: Structure and Molecular Biology (Edited by: John T. Patton). Caister Academic Press, U.K. (2008)
Viruses cannot carry out the functions of life unless they are inside a host cell where they hijack cellular processes, controlling and diverting those processes to complete their own life tasks, often at the cell's expense. Examining how viruses short circuit the safety controls in place to regulate cellular events that are finely tuned to respond to changes in the environment can reveal concepts in both viral and cellular biology. Rotaviruses encode a protein, NSP3, known to intercept one cellular function, that of translation, such that capped, but not polyadenylated, viral mRNAs are preferentially translated in the presence of cellular mRNAs optimized for translation by the cellular machinery. The generalities of these interactions have been determined through molecular biology, but the specifics necessary for NSP3 to carry out the misdirection of the components of the translation apparatus are revealed only through detailed structural analysis. In this chapter, the interactions of NSP3 with eukaryotic initiation factor 4G and with the 3' end of viral RNA, as well as the contacts required to form NSP3 homodimers are discussed. In addition, a novel NSP3-interacting protein is presented and this protein, dubbed RoXaN (Rotavirus: X protein associated with NSP3), has no known function, however the potential contact between NSP3 and RoXaN bears intriguing similarities to interactions between other cellular proteins involved in cytoskeletal rearrangements through paxillin. All of this indicates that a single viral protein may have multiple functions during the viral life cycle through interactions with various cellular proteins and pathways, and these are revealed in intricate detail through structural studies read more ...