title: Isolation of chicken phosphotyrosyl phosphatase cDNA sequences and identification of a brain-specific species related to human PTP zeta.
abstract: The first example of a chicken cDNA sequence encoding a phosphotyrosyl phosphatase (PTPase) has been identified and found to contain coding sequences for the entire cytoplasmic and membrane spanning domains as well as a portion of the extracellular region of a transmembrane PTPase resembling human PTP zeta. Like HPTP zeta, chicken PTP zeta contained two phosphatase domains (D1 and D2), and D2 lacked a critical cysteine residue required for catalytic activity. The entire intracellular portion of CPTP zeta was expressed in bacteria and shown to be capable of dephosphorylating both p-nitrophenylphosphate and reduced carboxyamidomethylated and maleyated lysozyme but not phosphoseryl casein. Genetic analysis indicated that the presence of D2 was required for full activity. CPTP zeta mRNA was identified as a single large transcript expressed exclusively in the brain of chick embryos at both early and late stages of embryogenesis. These results suggested that CPTP zeta may perform a brain-specific function and have a role in development.
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors.forename: R B
authors.initials: RB
authors.lastname: Rowley
authors.forename: J M
authors.initials: JM
authors.lastname: Lee
authors.forename: H B
authors.initials: HB
authors.lastname: Corbeil
authors.forename: R
authors.initials: R
authors.lastname: Charbonneau
authors.forename: K
authors.initials: K
authors.lastname: Jue
authors.forename: D L
authors.initials: DL
authors.lastname: Dankort
authors.forename: P E
authors.initials: PE
authors.lastname: Branton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology*; D002642:Chick Embryo; D003001:Cloning, Molecular; D004247:DNA; D004926:Escherichia coli; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D011994:Recombinant Proteins; D004247:DNA; D017027:Protein Tyrosine Phosphatases