title: A family of receptor-linked protein tyrosine phosphatases in humans and Drosophila.
abstract: To understand the regulation of cell proliferation by tyrosine phosphorylation, characterization of protein tyrosine phosphatases (PTPase; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48) is essential. The human genes LCA (leukocyte common antigen) and LAR encode putative receptor-linked PTPases. By using consensus sequence probes, two additional receptor-linked PTPase genes, DLAR and DPTP, were isolated from Drosophila melanogaster. The extracellular segments of both DLAR and DPTP are composed of multiple immunoglobulin-like domains and fibronectin type III-like domains. The cytoplasmic region of DLAR and DPTP, as well as human LCA and LAR, are composed of two tandemly repeated PTPase domains. PTPase activities of immunoprecipitated LCA and LAR were demonstrated by measuring the release of phosphate from a 32P-labeled [Tyr(P)]peptide. Furthermore, the cytoplasmic domains of LCA, LAR, DLAR, and DPTP, expressed in Escherichia coli, have PTPase activity. Site-directed mutagenesis showed that a conserved cysteine residue is essential for PTPase activity.
authors.affiliation: Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA.
authors.forename: M
authors.initials: M
authors.lastname: Streuli
authors.forename: N X
authors.initials: NX
authors.lastname: Krueger
authors.forename: A Y
authors.initials: AY
authors.lastname: Tsai
authors.forename: H
authors.initials: H
authors.lastname: Saito
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D005796:Genes; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D017027:Protein Tyrosine Phosphatases; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004247:DNA; D010749:Phosphoprotein Phosphatases; D017027:Protein Tyrosine Phosphatases