Figure 4.

Alternative models of Leish(IF4E-1/4E-IP1) function. (A) LeishIF4E-1 (IF4E-1, cyan) is a functional cap-binding protein and activates translation initiation. The binding of Leish4E-IP1 (4E-IP1, purple) inhibits translation initiation by preventing the binding of LeishIF4E-1 to the cap. (B) LeishIF4E-1 maintains mRNAs in a cap-dependent translational inactive state. Upon binding of Leish4E-IP1, LeishIF4E-1 dissociates from the cap, which frees the mRNAs and allows them to interact with a functional cap-binding protein (yellow) and to be actively translated. For clarity of the figure, proteins are not represented to scale.