title: Molecular cloning of a ligand for the EPH-related receptor protein-tyrosine kinase Htk.
abstract: Htk is a receptor protein-tyrosine kinase that is related to the EPH subfamily of tyrosine kinases. The receptor has a wide tissue distribution including expression in several myeloid hematopoietic cell lines. Using an Htk-Fc fusion protein, a protein ligand for this receptor was expression cloned from the murine kidney mesangial cell line SV40MES 13. The Htk ligand cDNA encodes a transmembrane protein of 336 amino acids. Binding competition experiments demonstrated a Kd of 535 pM for binding of Htk-Fc to the Htk ligand. Incubation of 3T3 cells expressing Htk with COS-7 cells expressing the ligand resulted in tyrosine phosphorylation of Htk. The ligand, like its receptor, is widely expressed and may function in a variety of tissues. However, we localized hematopoietic expression of Htk to the monocytic lineage, suggesting that the ligand may play a role in differentiation and/or proliferation of these cells.
authors.affiliation: Department of Molecular Biology, Genentech, Inc., South San Francisco, CA 94080.
authors.forename: B D
authors.initials: BD
authors.lastname: Bennett
authors.forename: F C
authors.initials: FC
authors.lastname: Zeigler
authors.forename: Q
authors.initials: Q
authors.lastname: Gu
authors.forename: B
authors.initials: B
authors.lastname: Fendly
authors.forename: A D
authors.initials: AD
authors.lastname: Goddard
authors.forename: N
authors.initials: N
authors.lastname: Gillett
authors.forename: W
authors.initials: W
authors.lastname: Matthews
mesh_terms: D016475:3T3 Cells; D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D015152:Blotting, Northern; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D036388:Ephrin-B2; D005260:Female; D005312:Fetal Blood; D005333:Fetus; D005920:Glomerular Mesangium / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D007668:Kidney; D007700:Kinetics; D008024:Ligands; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine; D011247:Pregnancy; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000378:metabolism*; D036224:Receptor, EphB4; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
chemical_list: D036388:Ephrin-B2; D008024:Ligands; D008565:Membrane Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D020794:Receptor Protein-Tyrosine Kinases; D036224:Receptor, EphB4