title: Intracellular substrates of brain-enriched receptor protein tyrosine phosphatase rho (RPTPrho/PTPRT).
abstract: Receptor protein tyrosine phosphatase rho (RPTPrho/PTPRT) is a transmembrane protein that is highly expressed in the developing and adult central nervous system. It is a member of the RPTP R2B subfamily, which includes PTPkappa, PTPmu and PCP-2. Glutathione-S-transferase (GST) pulldown assays were used to show that RPTPrho interacts with several adherens junctional proteins in brain, including E-cadherin, N-cadherin, VE-cadherin (cadherin-5), desmoglein, alpha, beta and gamma catenin, p120(ctn) and alpha-actinin. With the exception of E-cadherin and alpha-actinin, binding was considerably reduced at high sodium concentrations. Furthermore, immunoprecipitation phosphatase assays indicated that E-cadherin, and to a far lesser extent p120(ctn), were tyrosine dephosphorylated by a recombinant RPTPrho intracellular fragment, and thus, were likely to be primary substrates for RPTPrho. The interaction of RPTPrho with adherens junctional components suggests that this phosphatase may transduce extracellular signals to the actin cytoskeleton and thereby play a role in regulating cadherin-mediated cell adhesion in the central nervous system.
authors.affiliation: Department of Pharmacology, The Ohio State University, 333 W 10th Ave., Columbus, OH 43210, USA. besco.1@osu.edu
authors.forename: Julie A
authors.initials: JA
authors.lastname: Besco
authors.forename: Rob
authors.initials: R
authors.lastname: Hooft van Huijsduijnen
authors.forename: Adrienne
authors.initials: A
authors.lastname: Frostholm
authors.forename: Andrej
authors.initials: A
authors.lastname: Rotter
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism; D001923:Brain Chemistry / Q000502:physiology*; D015820:Cadherins / Q000378:metabolism; D051177:Catenins / Q000378:metabolism; D002460:Cell Line; D018076:DNA, Complementary / Q000096:biosynthesis; D004926:Escherichia coli / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis
chemical_list: D015820:Cadherins; D051177:Catenins; D018076:DNA, Complementary; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D011505:Protein-Tyrosine Kinases; C516865:PTPRT protein, human; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2