title: Protein tyrosine phosphorylation and protein tyrosine nitration in redox signaling.
abstract: Reversible phosphorylation of protein tyrosine residues by polypeptide growth factor-receptor protein tyrosine kinases is implicated in the control of fundamental cellular processes including the cell cycle, cell adhesion, and cell survival, as well as cell proliferation and differentiation. During the last decade, it has become apparent that receptor protein tyrosine kinases and the signaling pathways they activate belong to a large signaling network. Such a network can be regulated by various extracellular cues, which include cell adhesion, agonists of G protein-coupled receptors, and oxidants. It is well documented that signaling initiated by receptor protein tyrosine kinases is directly dependent on the intracellular production of oxidants, including reactive oxygen and nitrogen species. Accumulated evidence indicates that the intracellular redox environment plays a major role in the mechanisms underlying the actions of growth factors. Oxidation of cysteine thiols and nitration of tyrosine residues on signaling proteins are described as posttranslational modifications that regulate, positively or negatively, protein tyrosine phosphorylation (PTP). Early observations described the inhibition of PTP activities by oxidants, resulting in increased levels of proteins phosphorylated on tyrosine. Therefore, a redox circuitry involving the increasing production of intracellular oxidants associated with growth-factor stimulation/cell adhesion, oxidative reversible inhibition of protein tyrosine phosphatases, and the activation of protein tyrosine kinases can be delineated.
authors.affiliation: Department of Biochemistry/Molecular Biology and CINTERGEN, Universidade Federal de São Paulo, São Paulo, Brazil. hpmonte@uol.com.br
authors.forename: Hugo P
authors.initials: HP
authors.lastname: Monteiro
authors.forename: Roberto J
authors.initials: RJ
authors.lastname: Arai
authors.forename: Luiz R
authors.initials: LR
authors.lastname: Travassos
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D004789:Enzyme Activation; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism; D009574:Nitro Compounds / Q000378:metabolism*; D010084:Oxidation-Reduction; D010766:Phosphorylation; D011487:Protein Conformation; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism; D018909:src Homology Domains
chemical_list: D007527:Isoenzymes; D009574:Nitro Compounds; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases; D017027:Protein Tyrosine Phosphatases; D020559:Monomeric GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins