title: Extracellular vimentin interacts with insulin-like growth factor 1 receptor to promote axonal growth.
abstract: Vimentin, an intermediate filament protein, is generally recognised as an intracellular protein. Previously, we reported that vimentin was secreted from astrocytes and promoted axonal growth. The effect of extracellular vimentin in neurons was a new finding, but its signalling pathway was unknown. In this study, we aimed to determine the signalling mechanism of extracellular vimentin that facilitates axonal growth. We first identified insulin-like growth factor 1 receptor (IGF1R) as a receptor that is highly phosphorylated by vimentin stimulation. IGF1R blockades diminished vimentin- or IGF1-induced axonal growth in cultured cortical neurons. IGF1, IGF2 and insulin were not detected in the neuron culture medium after vimentin treatment. The combined drug affinity responsive target stability method and western blotting analysis showed that vimentin and IGF1 interacted with IGF1R directly. In addition, immunoprecipitation and western blotting analyses confirmed that recombinant IGF1R bound to vimentin. The results of a molecular dynamics simulation revealed that C-terminal residues (residue number 330-407) in vimentin are the most appropriate binding sites with IGF1R. Thus, extracellular vimentin may be a novel ligand of IGF1R that promotes axonal growth in a similar manner to IGF1. Our results provide novel findings regarding the role of extracellular vimentin and IGF1R in axonal growth.
authors.affiliation: Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Shigyo
authors.affiliation: Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Kuboyama
authors.affiliation: Division of Chemo-Bioinformatics, Department of Translational Research, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sawai
authors.affiliation: Division of Chemo-Bioinformatics, Department of Translational Research, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Tada-Umezaki
authors.affiliation: Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Tohda
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001369:Axons / Q000187:drug effects / Q000378:metabolism*; D001665:Binding Sites; D002478:Cells, Cultured; D005110:Extracellular Space / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D014746:Vimentin / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D007328:Insulin; D014746:Vimentin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1