The eukaryotic polypeptide chain releasing factor (eRF3/GSPT) carrying thetranslation termination signal to the 3 '-poly(A) tail of mRNA - Direct association of eRF3/GSPT with polyadenylate-binding protein
S. Hoshino et al., The eukaryotic polypeptide chain releasing factor (eRF3/GSPT) carrying thetranslation termination signal to the 3 '-poly(A) tail of mRNA - Direct association of eRF3/GSPT with polyadenylate-binding protein, J BIOL CHEM, 274(24), 1999, pp. 16677-16680
The mammalian GTP-binding protein GSPT, whose carboxyl-terminal sequence is
homologous to the eukaryotic elongation factor EF1 alpha, binds to the pol
ypeptide chain releasing factor eRF1 to function as eRF3 in the translation
termination. The amino-terminal domain of GSPT was, however, not required
for the binding. Search for other GSPT-binding proteins in yeast two-hybrid
screening system resulted in the identification of a cDNA encoding polyade
nylate-binding protein (PABP), whose amino terminus is associating with the
poly(A) tail of mRNAs presumably for their stabilization. The interaction
appeared to be mediated through the carboxyl-terminal domain of PABP and th
e aminoterminal region of GSPT, Interestingly, multimerization of PABP with
poly(A), which is ascribed to the action of its carboxyl-terminal domain,
was completely inhibited by the interaction with the amino-terminal domain
of GSPT. These results indicate that GSPT/eRF3 may play important roles not
only in the termination of protein synthesis but also in the regulation of
mRNA stability. Thus, the present study is the first report showing that G
SPT/eRF3 carries the translation termination signal to 3'-poly(A) tail ubiq
uitously present in eukaryotic mRNAs.