Receptor tyrosine kinase, binding ligands of the EGF family and activating several signaling cascades to convert extracellular cues into appropriate cellular responses. Known ligands include spitz, gurken, vein and giant-lens. Transduces the signal through the ras-raf-MAPK pathway. Critical for the proliferation of imaginal tissues, and for the determination of both the antero-posterior and dorso-ventral polarities of the oocyte. In the embryo, plays a role in the establishment of ventral cell fates, maintenance of amnioserosa and ventral neuroectodermal cells, germ band retraction, cell fate specification in the central nervous system, and production and repair of the cuticle. During dorsal closure (DC) functions with the dpp- and ACK-signaling pathways to regulate expression of the myosin zip in the embryonic epidermis and amnioserosa (AS), and thus coordinate the progression of epidermal cell shape changes required for correct DC. In the embryonic epidermis, functions by negatively regulating dpp and consequently the dpp-dependent expression of the myosin zip. In the AS, negatively regulates the production/ and or secretion of a diffusible signal which, is produced by the ACK-signaling pathway, and acts in the AS and epidermal cells to promote zip expression. Also required in the AS to inhibit or delay apoptosis, and consequently slow the rate of DC. Therefore functions at multiple levels to negatively regulate morphogenesis during DC, suggesting that it acts as a general brake mechanism for adjusting the rate of dorsal closure to ensure that closure proceeds smoothly and without loss of epidermal integrity. During oogenesis, one of two tyrosine kinase chemoattractant receptors (Egfr and Pvr), that function in the border cells (BC) to detect guidance cues from the oocyte and transduce this information to the guidance pathway that regulate the collective migration of the BC cluster through the nurse cells to the oocyte.
