Critical for defining the anterior-posterior and dorsal-ventral axes of the egg. May signal directly to dorsal follicle cells through the receptor torpedo (top). During oogenesis this signaling pathway instructs follicle cells to follow a dorsal pathway of development rather than the default ventral pathway. Interacts with cni. Associates with the membranous cortex of yolk granules. Transiently inserted into the cell membrane, and then reinternalized during yolk uptake. cni is required for its transport to the oocyte cell membrane. Expressed in nurse cells and oocyte up to oogenesis stage 7. Specifically accumulates in dorsal anterior corner of the oocyte during stages 9/10, at later stages expression is seen as an anterior ring. In stage 10 ovaries, it is concentrated between the oocyte nucleus and the adjacent oolemma. During vitellogenesis stage it can be detected at the oocyte surface, especially on the microvilli. It is also found at the microvilli covering the apical surface of the follicular epithelium and within follicle cells. Truncated N-terminus. Truncated N-terminus.