Caister Academic Press

Structure and Functions of the Orthoreovirus σ3 Protein

Leslie A. Schiff
from: Segmented Double-stranded RNA Viruses: Structure and Molecular Biology (Edited by: John T. Patton). Caister Academic Press, U.K. (2008)


Protein s3 serves a number of distinct roles in the orthoreovirus life cycle. First, as a major structural protein that forms the outermost layer of the reovirus particle, it imparts significant environmental stability to virions. Virion σ3 also plays a critical role as a determinant of cell entry, as it must be degraded from particles during their activation for membrane penetration. In addition, σ3 is one of the most abundant proteins synthesized in reovirus-infected cells. Early in infection σ3 is thought to serve a regulatory function through its capacity to bind dsRNA and interfere with dsRNA-activated innate immune pathways. Both the structural and regulatory functions are influenced by the capacity of σ3 to interact with its structural partner, μ1. High-resolution structures have been determined for both the 365-residue σ3 protein and σ3 in complex with its capsid partner μ1. This structural data has provided a framework around which new and existing biochemical and biological information can be analyzed to provide new insight into the molecular details of the reovirus life cycle read more ...
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