title: Proteomics study reveals cross-talk between Rho guanidine nucleotide dissociation inhibitor 1 post-translational modifications in epidermal growth factor stimulated fibroblasts.
abstract: Following stimulation of NRK49F rat kidney fibroblast cells with epidermal growth factor, possible preemptive cross-talk between arginine methylation and serine and tyrosine phosphorylation was observed for Rho guanidine nucleotide dissociation inhibitor 1 (RhoGDI-1). Five dimethylation sites (Lys50, Lys52, Arg111, Arg152, Arg180) and two new phosphorylation sites (Tyr144, Ser148) were identified for RhoGDI-1. All presently known phosphorylation sites for RhoGDI-1 lie within the 10 residues immediately prior to the 3 sites for arginine dimethylation, and these dimethylation/phosphorylation modules may constitute functional switches. Consideration of structural data and other literature for RhoGDI-1 suggests that methylation and phosphorylation cooperatively affect formation of complexes with different Rho/Rac family proteins and that methylation may be crucial in partitioning of RhoGDI-1 between different functional roles. On the basis of results presented here, it can be implied that unidentified arginine methyltransferases may exist and that arginine methylation may have a greater role in cellular signaling processes than is currently recognized. The combined use of SILAC labeling of arginine (SILAC = stable isotope labeling by amino acids in cell culture), immobilized metal affinity chromatography based phosphoprotein enrichment, and mass spectrometry is clearly a useful method for this investigation.
authors.affiliation: Department of Medicine, University College London, 5 University Street, London.
authors.forename: Ida Chiara
authors.initials: IC
authors.lastname: Guerrera
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Keep
authors.forename: Jasminka
authors.initials: J
authors.lastname: Godovac-Zimmermann
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D002846:Chromatography, Affinity; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007553:Isotope Labeling / Q000379:methods; D008745:Methylation; D008969:Molecular Sequence Data; D010748:Phosphopeptides / Q000032:analysis; D010750:Phosphoproteins / Q000032:analysis; D010766:Phosphorylation; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D040901:Proteomics; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
chemical_list: D000596:Amino Acids; D020730:Guanine Nucleotide Dissociation Inhibitors; D010748:Phosphopeptides; D010750:Phosphoproteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D004815:Epidermal Growth Factor; D001120:Arginine; D020764:cdc42 GTP-Binding Protein