Potyvirus terminal protein VPg, effector of host eukaryotic initiation factor elF4E

• Published in: Biochimie 2006-07, Vol.88 (7), p.887-896
• Main Authors: Grzela, R, Strokovska, L, Andrieu, J-P, Dublet, B, Zagorski, W, Chroboczek, J
• Format: Article
• Language: English
• Subjects: Potato virus Y; Potyvirus
• ISSN: 0300-9084
• DOI: 10.1016/j.biochi.2006.02.012

Potyvirus RNA contains at the 5' end a covalently linked virus-encoded protein VPg, which is required for virus infectivity. This role has been attributed to VPg interaction with the eukryotic translation initiation factor elF4E, a cap-binding protein. We characterized the dissociation constants for the interaction of the potato virus Y VPg with different plant elF4Es and its isotoms and mapped the elF(iso)4E attachment region on VPg. VPg/elF4E interaction results in the inhibition of cell-free protein synthesis, and we show that it stems from the liberation of the cap moiety from the complex with elF4E. Since VPg does not attach the cap, it appears that VPg induces changes in the elF4E structure, diminishing its affinity to the cap. We show here that the initiation complex scaffold protein elF(iso)4G increases VPg interaction with elF(iso)4E. These data together suggest similar cap and VPg interactions with elF4E and characterize VPg as a novel elF4E-binding protein, which inhibits host protein synthesis at a very early stage of the initiation complex formation through the inhibition of cap attachment to the initiation factor elF4E.