title: Differently spliced cDNAs of human leukocyte tyrosine kinase receptor tyrosine kinase predict receptor proteins with and without a tyrosine kinase domain and a soluble receptor protein.
abstract: Leukocyte tyrosine kinase (LTK) is a tyrosine kinase that has been suggested to be specific for hematopoietic cells and neuronal cells and reported as an unusual membrane protein lacking an extracellular domain. Here we report the cloning of a human LTK cDNA clone containing the complete open reading frame of a putative receptor tyrosine kinase protein. The extracellular domain of the receptor protein is larger than previously predicted. Furthermore, we have cloned a set of cDNAs representing differently spliced human LTK mRNAs. These cDNAs predict a truncated receptor protein lacking the tyrosine kinase domain and a soluble receptor protein that has neither a transmembrane nor a tyrosine kinase domain. Our results suggest that the LTK gene produces not only the putative receptor tyrosine kinase for unknown ligand but also multiple protein products that may have different functions.
authors.affiliation: Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Toyoshima
authors.forename: H
authors.initials: H
authors.lastname: Kozutsumi
authors.forename: Y
authors.initials: Y
authors.lastname: Maru
authors.forename: K
authors.initials: K
authors.lastname: Hagiwara
authors.forename: A
authors.initials: A
authors.lastname: Furuya
authors.forename: H
authors.initials: H
authors.lastname: Mioh
authors.forename: N
authors.initials: N
authors.lastname: Hanai
authors.forename: F
authors.initials: F
authors.lastname: Takaku
authors.forename: Y
authors.initials: Y
authors.lastname: Yazaki
authors.forename: H
authors.initials: H
authors.lastname: Hirai
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA; D005260:Female; D015723:Gene Library; D006801:Humans; D015151:Immunoblotting; D007962:Leukocytes / Q000378:metabolism*; D008969:Molecular Sequence Data; D010920:Placenta / Q000378:metabolism; D011061:Poly A / Q000302:isolation & purification / Q000378:metabolism; D011247:Pregnancy; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D012333:RNA, Messenger; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection
chemical_list: D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D011061:Poly A; D012313:RNA; D004247:DNA; D011505:Protein-Tyrosine Kinases