Component of the protein complex eIF4F, which is involved in the recognition of the mRNA cap, ATP-dependent unwinding of 5'-terminal secondary structure and recruitment of mRNA to the ribosome. As a member of the eIF4F complex, required for endoplasmic reticulum stress-induced ATF4 mRNA translation (By similarity). eIF4F is a multi-subunit complex, the composition of which varies with external and internal environmental conditions. It is composed of at least EIF4A, EIF4E and EIF4G1/EIF4G3. Interacts with eIF3, mutually exclusive with EIF4A1 or EIFA2, EIF4E and through its N-terminus with PAPBC1. Interacts through its C-terminus with the serine/threonine kinases MKNK1, and with MKNK2. Appears to act as a scaffold protein, holding these enzymes in place to phosphorylate EIF4E. Interacts with EIF4E3. Interacts with CIRBP and MIF4GD. Interacts with RBM4. Interacts with HNRNPD/AUF1; the interaction requires RNA (By similarity). Directly interacts with EIF4G1 in an RNA-independent manner (By similarity). Phosphorylated at multiple sites in vivo. Phosphorylation at Ser-988 by PRKCA induces binding to MKNK1. Belongs to the eukaryotic initiation factor 4G family.