title: Hierarchical disabled-1 tyrosine phosphorylation in Src family kinase activation and neurite formation.
abstract: There are two developmentally regulated alternatively spliced forms of Disabled-1 (Dab1) in the chick retina: an early form (Dab1-E) expressed in retinal precursor cells and a late form (Dab1-L) expressed in neuronal cells. The main difference between these two isoforms is the absence of two Src family kinase (SFK) recognition sites in Dab1-E. Both forms retain two Abl/Crk/Nck recognition sites implicated in the recruitment of SH2 domain-containing signaling proteins. One of the Dab1-L-specific SFK recognition sites, at tyrosine(Y)-198, has been shown to be phosphorylated in Reelin-stimulated neurons. Here, we use Reelin-expressing primary retinal cultures to investigate the role of the four Dab1 tyrosine phosphorylation sites on overall tyrosine phosphorylation, Dab1 phosphorylation, SFK activation and neurite formation. We show that Y198 is essential but not sufficient for maximal Dab1 phosphorylation, SFK activation and neurite formation, with Y232 and Y220 playing particularly important roles in SFK activation and neuritogenesis, and Y185 having modifying effects secondary to Y232 and Y220. Our data support a role for all four Dab1 tyrosine phosphorylation sites in mediating the spectrum of activities associated with Reelin-Dab1 signaling in neurons.
authors.affiliation: Department of Oncology, University of Alberta, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta, Canada T6G 1Z2.
authors.forename: Sachin
authors.initials: S
authors.lastname: Katyal
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Gao
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Monckton
authors.forename: Darryl
authors.initials: D
authors.lastname: Glubrecht
authors.forename: Roseline
authors.initials: R
authors.lastname: Godbout
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism*; D015816:Cell Adhesion Molecules, Neuronal / Q000276:immunology; D002478:Cells, Cultured; D002642:Chick Embryo; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000276:immunology; D005786:Gene Expression Regulation / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D009419:Nerve Tissue Proteins / Q000276:immunology; D016501:Neurites / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D000091042:Reelin Protein; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D012697:Serine Endopeptidases / Q000276:immunology; D014162:Transfection; D019061:src-Family Kinases / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D000906:Antibodies; D030161:Avian Proteins; D015816:Cell Adhesion Molecules, Neuronal; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D011973:Receptors, LDL; D011993:Recombinant Fusion Proteins; D000091042:Reelin Protein; C036053:VLDL receptor; D049452:Green Fluorescent Proteins; D019000:Phosphotyrosine; D019061:src-Family Kinases; C000717127:RELN protein, human; D012697:Serine Endopeptidases