tailieunhanh - Báo cáo khoa học: Cell surface nucleolin on developing muscle is a potential ligand for the axonal receptor protein tyrosine phosphatase-r

Reversible tyrosine phosphorylation, catalyzed by receptor tyrosine kinases and receptor tyrosine phosphatases, plays an essential part in cell signaling during axonal development. Receptor protein tyrosine phosphatase-rhas been implicated in the growth, guidance and repair of retinal axons. | ễFEBS Journal Cell surface nucleolin on developing muscle is a potential ligand for the axonal receptor protein tyrosine phosphatase-ơ Daniel E. Alete1 Mark E. Weeks2 Ara G. Hovanession3 Muhamed Hawadle1 and Andrew W. Stoker1 1 NeuralDevelopment Unit Institute of Child Health University College London UK 2 Molecular Oncology CRUK Barts and The London Schoolof Medicine and Dentistry John Vane Centre UK 3 UPR 2228 CNRS UFR Biomedicale-Universite Rene Descartes Paris France Keywords affinity chromatography axon targeting nucleolin RAP assay receptor protein tyrosine phosphatases Correspondence A. W. Stoker NeuralDevelopment Unit Institute of Child Health University College London 30 Guilford Street London WC1N 1EH UK Fax 44 207 78314366 Tel 44 207 9052244 E-mail Received 21 April2006 revised 2 August 2006 accepted 15 August 2006 doi Reversible tyrosine phosphorylation catalyzed by receptor tyrosine kinases and receptor tyrosine phosphatases plays an essential part in cell signaling during axonal development. Receptor protein tyrosine phosphatase-r has been implicated in the growth guidance and repair of retinal axons. This phosphatase has also been implicated in motor axon growth and innervation. Insect orthologs of receptor protein tyrosine phosphatase-r are also implicated in the recognition of muscle target cells. A potential extracellular ligand for vertebrate receptor protein tyrosine phosphatase-r has been previously localized in developing skeletal muscle. The identity of this muscle ligand is currently unknown but it appears to be unrelated to the heparan sulfate ligands of receptor protein tyrosine phosphatase-r. In this study we have used affinity chromatography and tandem MS to identify nucleolin as a binding partner for receptor protein tyrosine phosphatase-r in skeletal muscle tissue. Nucleolin both from tissue lysates and in purified form binds to receptor protein tyrosine phosphatase-r ectodomains.