title: Dok-R binds c-Abl and regulates Abl kinase activity and mediates cytoskeletal reorganization.
abstract: Dok-R, also known as Dok-2/FRIP, belongs to the DOK family of signaling molecules that become tyrosine-phosphorylated by several different receptor and cytoplasmic tyrosine kinases. Tyrosine phosphorylation of DOK proteins establishes high affinity binding sites for other signaling molecules leading to activation of a signaling cascade. Here we show that Dok-R associates with c-Abl directly via a constitutive SH3-mediated interaction and that this binding requires a PMMP motif in the proline-rich tail of Dok-R. The Dok-R-Abl interaction is further enhanced by an active c-Abl kinase, which requires the presence of its SH2 domain. Interaction of Dok-R with c-Abl also results in an increase in c-Abl tyrosine phosphorylation and kinase activity. Furthermore, we demonstrate that this increase in kinase activity correlates with a concomitant increase in c-Abl-mediated biological activity as measured by the formation of actin microspikes. Our data are the first to demonstrate that Dok-R and c-Abl interact in both a constitutive and inducible fashion and that Dok-R influences the intracellular kinase and biological activity of c-Abl.
authors.affiliation: Division of Molecular and Cellular Biology, Sunnybrook and Women's College Health Sciences Centre, Toronto M4N 3M5, Canada.
authors.forename: Zubin
authors.initials: Z
authors.lastname: Master
authors.forename: Jennifer
authors.initials: J
authors.lastname: Tran
authors.forename: Aseem
authors.initials: A
authors.lastname: Bishnoi
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Chen
authors.forename: John M L
authors.initials: JM
authors.lastname: Ebos
authors.forename: Paul
authors.initials: P
authors.lastname: Van Slyke
authors.forename: Robert S
authors.initials: RS
authors.lastname: Kerbel
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Dumont
mesh_terms: D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002384:Catalysis; D002460:Cell Line; D003593:Cytoplasm / Q000201:enzymology; D003599:Cytoskeleton / Q000201:enzymology* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D008957:Models, Genetic; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D016315:Proto-Oncogene Proteins c-abl / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C115089:DOK2 protein, human; D010750:Phosphoproteins; D014443:Tyrosine; D004815:Epidermal Growth Factor; D011505:Protein-Tyrosine Kinases; D016315:Proto-Oncogene Proteins c-abl