G3BP1 interacts directly with the FMDV IRES and negatively regulates translation

Abstract

RNA-protein interactions play a pivotal role in the function of picornavirus internal ribosome entry site (IRES) elements. Here we analysed the impact of Ras GTPase SH3 domain binding protein 1 (G3BP1) in the IRES activity of foot-and-mouth disease virus (FMDV). We found that G3BP1 interacts directly with three distinct sequences of the IRES element using RNA electrophoretic mobility-shift assays. Analysis of the interaction with domain 5 indicated that the G3BP1 binding-site is placed at the single-stranded region although it allows large sequence heterogeneity and the hairpin located upstream of this region enhances retarded complex formation. In addition, G3BP1 interacts directly with the polypyrimidine tract-binding protein and the translation initiation factor 4B (eIF4B) through the C-terminal region. Moreover, G3BP1 is cleaved during FMDV infection yielding two fragments, Ct-G3BP1 and Nt-G3BP1. Both fragments inhibit cap- and IRES-dependent translation, but the Ct-G3BP1 fragment shows a stronger effect on IRES-dependent translation. Assembly of complexes with G3BP1 results in a significantly reduced local flexibility of the IRES element, consistent with the negative effect of this protein. Our results highlight the IRES-binding capacity of G3BP1 and illustrate its function as a translation inhibitor.

Foot-and-Mouth Disease Virus Leader Protease Cleaves G3BP1 and G3BP2 and Inhibits Stress Granule Formation

“…Recently, G3BP1 was reported to bind to the internal ribosome entry site (IRES) of FMDV and function as a translation inhibitor, and it was shown that FMDV 3C pro induced the cleavage of G3BP1 (59). Interestingly both the N-terminal and C-terminal G3BP1 cleavage products maintained the negative effect on translation (59).…”

Rasputin a decade on and more promiscuous than ever? A review of G3BPs

“…G3BP1 associates directly to the three specific sequences of the internal ribosome entry site (IRES) elements of foot and mouth disease virus (FMDV) and the virus uses a similar mechanism to poliovirus to block G3BPs activity. During FMDV infection G3BP1 is also cleaved by its protease, 3C (3Cpro), yielding two fragments of G3BP (Ct-G3BP1, Nt-G3BP1) [121].…”

Impact of RNA–Protein Interaction Modes on Translation Control: The Versatile Multidomain Protein Gemin5

“…First, Gemin5 was pulled down with the IRES elements of foot‐and‐mouth disease virus (FMDV) and hepatitis C virus (HCV) . Second, Gemin5 was proteolyzed in FMDV‐infected cells, a feature shared with essential factors involved in gene expression control, such as eIF4G and other RBPs . Cleavage of Gemin5 at the RKAR amino acid motif yields p85, which is then cleaved at the TKRL sequence yielding p57.…”

“…[66] Second, Gemin5 was proteolyzed in FMDVinfected cells, [67] a feature shared with essential factors involved in gene expression control, such as eIF4G [68] and other RBPs. [69,70] Cleavage of Gemin5 at the RKAR amino acid motif yields p85, which is then cleaved at the TKRL sequence yielding p57. Both p85 and p57 are nonrepressive on IRES-dependent translation, although retain the capacity to interact with the IRES element.…”