Poly(A)-binding protein-interacting protein 1 binds to eukaryotic translation initiation factor 3 to stimulate translation.
Poly(A)-binding protein (PABP) stimulates translation initiation by binding simultaneously to the mRNA poly(A) tail and eukaryotic translation initiation factor 4G (eIF4G). PABP activity is regulated by PABP-interacting (Paip) proteins. Paip1 binds PABP and stimulates translation by an unknown mechanism. Here, we describe the interaction between Paip1 and eIF3, which is direct, RNA independent, and mediated via the eIF3g (p44) subunit. Stimulation of translation by Paip1 in vivo was decreased upon deletion of the N-terminal sequence containing the eIF3-binding domain and upon silencing of PABP or several eIF3 subunits. We also show the formation of ternary complexes composed of Paip1-PABP-eIF4G and Paip1-eIF3-eIF4G. Taken together, these data demonstrate that the eIF3-Paip1 interaction promotes translation. We propose that eIF3-Paip1 stabilizes the interaction between PABP and eIF4G, which brings about the circularization of the mRNA.
Martineau
Yvan
Y
Department of Biochemistry, McGill University, Montreal, Québec, Canada.
Derry
Mélanie C
MC
Wang
Xiaoshan
X
Yanagiya
Akiko
A
Berlanga
Juan José
JJ
Shyu
Ann-Bin
AB
Imataka
Hiroaki
H
Gehring
Kalle
K
Sonenberg
Nahum
N
D000596:Amino Acids; D039621:Eukaryotic Initiation Factor-3 / Q000737:chemistry / Q000378:metabolism*; D039603:Eukaryotic Initiation Factor-4G / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D010446:Peptide Fragments / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000378:metabolism*; D039122:Poly(A)-Binding Protein I / Q000378:metabolism; D011485:Protein Binding; D014176:Protein Biosynthesis; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*
D000596:Amino Acids; D039621:Eukaryotic Initiation Factor-3; D039603:Eukaryotic Initiation Factor-4G; C111580:PAIP1 protein, human; D010446:Peptide Fragments; D010448:Peptide Initiation Factors; D039122:Poly(A)-Binding Protein I; D020033:Protein Isoforms; D021122:Protein Subunits; D016601:RNA-Binding Proteins; D012313:RNA