THE HUMAN RYK CDNA SEQUENCE PREDICTS A PROTEIN CONTAINING 2 PUTATIVE TRANSMEMBRANE SEGMENTS AND A TYROSINE KINASE CATALYTIC DOMAIN

The human ryk tyrosine kinase cDNA was originally identified as a PCR- amplified cDNA fragment (JTK5) from K562 leukemia cells and found to r epresent a ubiquitously expressed gene (Partanen et al., 1990). The op en reading frame of human ryk, reported here, encodes a novel type of putative tyrosine kinase of 607 amino acid residues, having two potent ial transmembrane domains and homology to receptor tyrosine kinases, s uch as met (HGF/SF-R) and IGF-1R, in its catalytic domain. The gene ma ps to human chromosome 3q11-25. Expression of the 3.4 kb ryk mRNA was found in all human adult tissues examined.