title: Identification of a gene encoding a typical gamma-carboxyglutamic acid domain in the tunicate Halocynthia roretzi.
abstract: We report the identification of a gene capable of encoding a novel Gla (gamma-carboxyglutamic acid) protein from the tunicate Halocynthia roretzi, a primitive member of the phylum Chordata. We call this new hypothetical protein Gla-RTK; it has a Gla domain typical of human vitamin K-dependent coagulation factors, a transmembrane domain, and a receptor tyrosine kinase domain. The receptor tyrosine kinase domain is very similar to the ARK (adhesion-related kinase) family of receptor tyrosine kinases. The ARK family includes Axl, Tyro3, and c-Mer. This gene also encodes a propeptide that binds to the human gamma-glutamyl carboxylase within a range of affinities observed for mammalian propeptides. The cDNA for this putative protein is found distributed throughout the oocyte and embryo but the cDNA is apparently not transcribed except during oogenesis. One of the most interesting aspects of this hypothetical protein is that its Gla domain is highly homologous to the Gla domain of Gas6, a ligand for Axl, while its receptor tyrosine kinase domain is highly homologous to Axl.
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA.
authors.forename: C-P
authors.initials: CP
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Yagi
authors.forename: P J
authors.initials: PJ
authors.lastname: Lin
authors.forename: D Y
authors.initials: DY
authors.lastname: Jin
authors.forename: K W
authors.initials: KW
authors.lastname: Makabe
authors.forename: D W
authors.initials: DW
authors.lastname: Stafford
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001779:Blood Coagulation Factors / Q000737:chemistry / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009866:Oogenesis / Q000502:physiology; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic; D014561:Urochordata / Q000737:chemistry / Q000235:genetics; D014812:Vitamin K / Q000378:metabolism
chemical_list: D001779:Blood Coagulation Factors; D018076:DNA, Complementary; D010455:Peptides; D014812:Vitamin K; D015055:1-Carboxyglutamic Acid; D020794:Receptor Protein-Tyrosine Kinases