title: Signaling between focal adhesion kinase and trio.
abstract: The Trio guanine nucleotide exchange factor functions in neural development in Caenorhabditis elegans and Drosophila and in the development of neural tissues and skeletal muscle in mouse. The association of Trio with the Lar tyrosine phosphatase led us to study the role of tyrosine phosphorylation in Trio function using focal adhesion kinase (FAK). The Lar-interacting domain of Trio is constitutively tyrosine-phosphorylated when expressed in COS-7 cells and was highly phosphorylated when it was co-transfected with FAK. Co-precipitation studies indicated that Trio binds to the FAK amino-terminal domain and to the FAK kinase domain via its SH3 and kinase domains, respectively. Tyrosine-phosphorylated FAK and Trio were present mainly in the detergent-insoluble fraction of cell lysates, and co-expression of Trio and FAK resulted in increased amounts of Trio present in the detergent-insoluble fraction. Immunofluorescence of cells co-transfected with FAK and Trio revealed significant co-localization of the proteins at the cell periphery, indicating that they form a stable complex in vivo. A FAK phosphorylation site, tyrosine residue 2737, was identified in subdomain I of the Trio kinase domain. Additionally, in vitro phosphorylation assays and in vivo co-expression studies indicated that Trio enhances FAK kinase activity. These results suggest Trio may be involved in the regulation of focal adhesion dynamics in addition to effecting changes in the actin cytoskeleton through the activation of Rho family GTPases.
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA. Quintas_Medley@dcfi.harvard.edu
authors.forename: Quintus G
authors.initials: QG
authors.lastname: Medley
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: Buchbinder
authors.forename: Kouichi
authors.initials: K
authors.lastname: Tachibana
authors.forename: Hai
authors.initials: H
authors.lastname: Ngo
authors.forename: Carles
authors.initials: C
authors.lastname: Serra-Pagès
authors.forename: Michel
authors.initials: M
authors.lastname: Streuli
mesh_terms: D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D017173:Caenorhabditis elegans; D002522:Chlorocebus aethiops; D004330:Drosophila; D029721:Drosophila Proteins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020662:Guanine Nucleotide Exchange Factors; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018482:Muscle, Skeletal / Q000502:physiology; D016296:Mutagenesis; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D018909:src Homology Domains
chemical_list: D029721:Drosophila Proteins; D020662:Guanine Nucleotide Exchange Factors; D010750:Phosphoproteins; D011994:Recombinant Proteins; C490975:Trio protein, mouse; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse; D017346:Protein Serine-Threonine Kinases; C099628:TRIO protein, human; C490974:trio protein, Drosophila