title: Protein partners in the life history of activated fibroblast growth factor receptors.
abstract: Fibroblast growth factor receptors (FGFRs) are a family of four transmembrane (TM) receptor tyrosine kinases (RTKs) which bind to a large family of fibroblast growth factor (FGF) ligands with varying affinity and specificity. FGFR signaling regulates many physiological and pathological processes in development and tissue homeostasis. Understanding FGFR signaling processes requires the identification of partner proteins which regulate receptor function and biological outputs. In this study, we employ an epitope-tagged, covalently dimerized, and constitutively activated form of FGFR1 to identify potential protein partners by MS. By this approach, we sample candidate FGFR effectors throughout the life history of the receptor. Functional classification of the partners identified revealed specific subclasses involved in protein biosynthesis and folding; structural and regulatory components of the cytoskeleton; known signaling effectors and small GTPases implicated in endocytosis and vesicular trafficking. The kinase dependency of the interaction was determined for a subset of previously unrecognized partners by coimmunoprecipitation, Western blotting, and immunocytochemistry. From this group, the small GTPase Rab5 was selected for functional interrogation. We show that short hairpin (sh) RNA-mediated depletion of Rab5 attenuates the activation of the extracellular-regulated kinase (ERK) 1/2 pathway by FGFR signaling. The strategic approach adopted in this study has revealed bona fide novel effectors of the FGFR signaling pathway.
authors.affiliation: CR-UK Growth Factor Group, School of Biosciences, University of Birmingham, Birmingham, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Vecchione
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Cooper
authors.forename: Kimberley J
authors.initials: KJ
authors.lastname: Trim
authors.forename: Shiva
authors.initials: S
authors.lastname: Akbarzadeh
authors.forename: John K
authors.initials: JK
authors.lastname: Heath
authors.forename: Lee M
authors.initials: LM
authors.lastname: Wheldon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D017468:Receptors, Fibroblast Growth Factor / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D020761:rab1 GTP-Binding Proteins / Q000378:metabolism; D020696:rab5 GTP-Binding Proteins / Q000172:deficiency / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D017468:Receptors, Fibroblast Growth Factor; D005346:Fibroblast Growth Factors; D020928:Mitogen-Activated Protein Kinases; D020761:rab1 GTP-Binding Proteins; D020696:rab5 GTP-Binding Proteins