TY - JOUR
T1 - The α-subunit of the mammalian guanine nucleotide-exchange factor eIF-2B is essential for catalytic activity in vitro
AU - Craddock, Bridget L.
AU - Proud, Christopher G.
N1 - Funding Information:
This work was supported by Grants from the Wellcome Trust and the British Diabetic Association. B.L.C. was the recipient of a research studentship from the Biotechnology and Biological Sciences Research Council.
PY - 1996/3/27
Y1 - 1996/3/27
N2 - Eukaryotic initiation factor (eIF)-2B, the guanine nucleotide exchange factor for eIF-2, consists of five distinct subunits in both mammals and the yeast Saccharomyces cerevisiae. The exchange reaction mediated by eIF-2B can be regulated by phosphorylation of eIF-2 on its α-subunit. This represents a key control point in the initiation of translation. The functions of the individual subunits of the eIF-2B complex remain unclear. Mutational analysis in Saccharomyces cerevisiae suggested that the smallest subunit (the α) is dispensable for exchange, but required for the inhibition of eIF-2B by eIF-2(αP). Here we present evidence that, in mammalian cells, eIF-2Bα is essential for the activity of the complex, since preparations of eIF-2B lacking this subunit are not active in nucleotide exchange in vitro, although the complex still contains the β, γ, δ and ε subunits.
AB - Eukaryotic initiation factor (eIF)-2B, the guanine nucleotide exchange factor for eIF-2, consists of five distinct subunits in both mammals and the yeast Saccharomyces cerevisiae. The exchange reaction mediated by eIF-2B can be regulated by phosphorylation of eIF-2 on its α-subunit. This represents a key control point in the initiation of translation. The functions of the individual subunits of the eIF-2B complex remain unclear. Mutational analysis in Saccharomyces cerevisiae suggested that the smallest subunit (the α) is dispensable for exchange, but required for the inhibition of eIF-2B by eIF-2(αP). Here we present evidence that, in mammalian cells, eIF-2Bα is essential for the activity of the complex, since preparations of eIF-2B lacking this subunit are not active in nucleotide exchange in vitro, although the complex still contains the β, γ, δ and ε subunits.
UR - http://www.scopus.com/inward/record.url?scp=0029995664&partnerID=8YFLogxK
U2 - 10.1006/bbrc.1996.0495
DO - 10.1006/bbrc.1996.0495
M3 - Article
C2 - 8607853
AN - SCOPUS:0029995664
VL - 220
SP - 843
EP - 847
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 3
ER -