Receptor for members of the ephrin family (By similarity). Receptor for major sperm proteins (MSPs), that functions as sperm-sensing checkpoint which inhibits oocyte meiotic maturation and ovulation when sperm are not available for fertilization (PubMed:12533508). Specifically, functions to negatively regulates oocyte maturation and MAPK activation in the absence of MSPs (PubMed:12533508, PubMed:19853560). Required for the MSP-mediated increase in the basal sheath cell contraction rate in somatic cells (PubMed:12533508). Phosphorylates phosphatase daf-18/PTEN which probably promotes daf-18 degradation (PubMed:19853560). By inactivating daf-18, regulates positively insulin-like daf-2 signaling cascade (PubMed:9506518). Involved in interactions between neuronal substrate cells and a migrating epithelial sheet in head epidermis morphogenesis (PubMed:9506518). Also required for cell movements following gastrulation and during ventral closure of the epidermis (PubMed:9506518). Might play a role in spermatheca morphogenesis (PubMed:25529479). Involved in axon guidance of SDQL neurons during neurogenesis (PubMed:26903502). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Dephosphorylated by daf-18. Interacts (via kinase domain) with daf-18 (via C-terminus); the interaction is independent of vab-1 kinase activity. During ventral enclosure of the epidermis, expression is seen in clusters of presumptive head neuronal cells and several cells in the tail region. Early larvae show expression in the nerve ring and ventral nerve cord. Strong expression is also seen in the procorpus and terminal bulb of the pharynx. Expression in the nervous system is seen through to adulthood (PubMed:9506518, PubMed:19853560). Expressed in Z2/Z3 germline precursor cells and in oocytes (at protein level). Expressed in the vulva and in the spermatheca with accumulation in the apical regions of the organ (PubMed:25529479). Expressed in oocytes and sheath cells (PubMed:12533508). Expressed in larval stage L4. Autophosphorylated. RNAi-mediated knockdown results in impaired inhibition of oocyte maturation and ovulation in the presence of reduced numbers of self-derived sperm (PubMed:12533508). As a result, hermaphrodites lay increased numbers of unfertilized oocytes (PubMed:12533508). Reduced sheath cell contraction rate in somatic cells (PubMed:12533508). Belongs to the protein kinase superfamily. Tyr protein kinase family. Ephrin receptor subfamily.