title: Extracellular signal-regulated kinase activated by epidermal growth factor and cell adhesion interacts with and phosphorylates vinexin.
abstract: Extracellular signal-regulated kinase 1/2 (ERK1/2) is activated by various extracellular stimuli including growth factors and cytokines and plays a pivotal role in regulating cell proliferation and differentiation by phosphorylating nuclear transcription factors. Recently, it was reported that activated ERK1/2 also concentrates at adhesion sites and regulates cell spreading and migration. Vinexin is a focal adhesion protein regulating both cell spreading and growth factor signaling. We show here that vinexin was directly phosphorylated by ERK1/2 upon stimulation with growth factors. ERK1/2 phosphorylated the linker region of vinexin between the second and third SH3 domains. Site-directed mutagenesis revealed that ERK2 mainly phosphorylated the serine 189 residue of vinexin beta. Furthermore, vinexin beta interacted with ERK1/2 both in vitro and in vivo. Vinexin interacted with the active but not inactive form of ERK1/2. A putative DEF (docking for ERK FXFP) domain located in the linker region of vinexin was required for the interaction with ERK1/2 and efficient phosphorylation of vinexin beta by ERK2. Finally, we showed that cell adhesion to fibronectin also induced the association of vinexin beta with ERK2 and the phosphorylation of vinexin beta. Furthermore, vinexin and ERK were co-localized to the periphery of cells during cell spreading on fibronectin. Together, these results suggest that vinexin is a novel substrate of ERK2 and may play roles in ERK-dependent cell regulation during cell spreading as well as in growth factor-induced responses.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Mitsushima
authors.forename: Akira
authors.initials: A
authors.lastname: Suwa
authors.forename: Teruo
authors.initials: T
authors.lastname: Amachi
authors.forename: Kazumitsu
authors.initials: K
authors.lastname: Ueda
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kioka
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002448:Cell Adhesion; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005353:Fibronectins / Q000737:chemistry; D017353:Gene Deletion; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D041681:NIH 3T3 Cells; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D012694:Serine / Q000737:chemistry; D013997:Time Factors; D014162:Transfection; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D005353:Fibronectins; D008164:Luminescent Proteins; D009124:Muscle Proteins; C486523:SORBS3 protein, human; C117452:Sorbs3 protein, mouse; D049452:Green Fluorescent Proteins; D012694:Serine; D004815:Epidermal Growth Factor; D005982:Glutathione Transferase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010744:Phosphoric Monoester Hydrolases