Plays a role in promoting translation. Interacts with eukaryotic translation initiation factor eIF4E1 (PubMed:23716590, PubMed:26294658). Also interacts with eukaryotic translation initiation factor 3 complex members eif3-S9/eif3b, Int6/eif3e and eIF-3p40/eif3h and with CG3225 (PubMed:23716590). In germ line cells, predominantly cytoplasmic and accumulates in the perinuclear nuage during oogenesis but disappears from there around stage 8. Expressed throughout oogenesis with particularly high levels in germ line stem cells and cystoblasts and decreasing levels in subsequent divisions. Around stage 8, remains detectable in nurse cells and oocytes and expression increases in follicle cells where it persists until late oogenesis, both in stretched cells and in columnar follicle cells (at protein level). Binds to eIF4E1 using a novel tripartite interface in the C-terminal domain comprising a canonical helix which engages the eIF4E1 dorsal surface, a non-canonical helix which engages the eIF4E1 lateral surface and an auxiliary helix that lies anti-parallel to the canonical helix on the eIF4E1 dorsal surface. The tripartite binding mode compromises its ability to compete with eIF4G1 for binding to eIF4E1 but once bound, the complex is very stable and is resistant to competition by eIF4G1. Mutants are viable and fertile but 14-21% of embryos fail to hatch, displaying variable segmentation defects affecting anterior-posterior patterning. Mutant ovaries are generally smaller with fewer late-stage oocytes than controls and females lay fewer eggs. Reduced cap-dependent translation. The name 'Mextli' derives from the Aztec god of storms and war.