J. Biol. Chem., Vol. 261, Issue 25, 11466-11470, Sep, 1986
Recycling of messenger RNA cap-binding proteins mediated by eukaryotic initiation factor 4B
BK Ray, TG Lawson, RD Abramson, WC Merrick and RE Thach
The ability of polypeptide components of eukaryotic initiation factor (eIF)
4F to bind to the m7G cap of an mRNA, to be released from that mRNA, and
then to rebind to the cap of a second mRNA has been investigated. The
release and rebinding steps have been termed "recycling." It was found that
eIF-4B stimulates the recycling of the 24-26 kDa (p24) component of eIF-4F,
and perhaps of other components as well. By contrast, eIF-4A seemed to have
little or no effect on the recycling of eIF-4F components, either in the
presence or absence of eIF-4B. The recycled p24 is capable of cross-linking
to oxidized cap structures. The recycled factor is also able to stimulate
the cross- linking of added eIF-4A, which cross-links poorly in the absence
of eIF- 4F. By these criteria it seems likely that the recycled eIF-4F
components are active for a second round of translational initiation.