May be a coreceptor along with FZD8 of Wnt proteins, such as WNT1, WNT3, WNT3A and WNT5A. Involved in neuron differentiation, axon guidance, corpus callosum establishment and neurite outgrowth. In response to WNT3 stimulation, receptor C-terminal cleavage occurs in its transmembrane region and allows the C-terminal intracellular product to translocate from the cytoplasm to the nucleus where it plays a crucial role in neuronal development. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Interacts with DVL1 (via PDZ domain). In cells that have undergone neuronal differentiation, the C-terminal cleaved part is translocated from the cytoplasm to the nucleus. Observed in all the tissues examined. The extracellular WIF domain is responsible for Wnt binding. Proteolytically cleaved, in part by presenilin, in response to WNT3 stimulation. Cleavage occurs during neuronal differentiation. Belongs to the protein kinase superfamily. Tyr protein kinase family. According to some authors, has impaired kinase activity. Extended N-terminus.