ROR1，also known as Neurotrophic tyrosine kinase, receptor-related 1, belongs to the ROR subfamily of Tyr protein kinase family,a protein kinase superfamily. It has very low kinase activity in vitro and is unlikely to function as a tyrosine kinase in vivo. Human ROR1 is a type I transmembrane protein with 937 amino acids (aa) in length. It contains a 29 aa signal sequence, a 377 aa extracellular domain (ECD), a 21 aa transmembrane segment, and a 510 aa cytoplasmic region. Human ROR1 shares 97% and 58% aa sequence identity with mouse ROR1 and human ROR2, respectively. ROR1 may act as a receptor for wnt ligand WNT5A which may result in the inhibition of WNT3A-mediated signaling. ROR1 expressed strongly in human heart, lung and kidney, but weakly in the CNS. Its Isoform Short is strongly expressed in fetal and adult CNS and in a variety of human cancers, including those originating from CNS or PNS neuroectoderm.
