What effect does unphosphorylated 4E-BP1 have on translation?

Could you elaborate on the specific role that unphosphorylated 4E-BP1 plays in regulating translation processes? How does its lack of phosphorylation impact its ability to interact with other proteins and ultimately affect the rate and efficiency of protein synthesis? Are there any known downstream effects or pathways that are modulated by the unphosphorylated state of 4E-BP1?