Dok-R binds c-Abl and regulates Abl kinase activity and mediates cytoskeletal reorganization

J Biol Chem. 2003 Aug 8;278(32):30170-9. doi: 10.1074/jbc.M301339200. Epub 2003 May 30.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Motifs
  • Animals
  • Blotting, Western
  • COS Cells
  • Carrier Proteins / metabolism*
  • Catalysis
  • Cell Line
  • Cytoplasm / enzymology
  • Cytoskeleton / enzymology*
  • Cytoskeleton / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation
  • Epidermal Growth Factor / metabolism
  • Humans
  • Immunoblotting
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Models, Biological
  • Models, Genetic
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Plasmids / metabolism
  • Precipitin Tests
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Tertiary
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Proteins c-abl / metabolism*
  • Time Factors
  • Transfection
  • Tyrosine / metabolism
  • src Homology Domains

Substances

  • Actins
  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • DOK2 protein, human
  • Phosphoproteins
  • Tyrosine
  • Epidermal Growth Factor
  • Protein-Tyrosine Kinases
  • Proto-Oncogene Proteins c-abl