title: Targeted inhibition of the Shroom3-Rho kinase protein-protein interaction circumvents Nogo66 to promote axon outgrowth.
abstract: BACKGROUND
  Inhibitory molecules in the adult central nervous system, including NogoA, impede neural repair by blocking axon outgrowth. The actin-myosin regulatory protein Shroom3 directly interacts with Rho kinase and conveys axon outgrowth inhibitory signals from Nogo66, a C-terminal inhibitory domain of NogoA. The purpose of this study was to identify small molecules that block the Shroom3-Rho kinase protein-protein interaction as a means to modulate NogoA signaling and, in the longer term, enhance axon outgrowth during neural repair.
  
  
  RESULTS
  A high throughput screen for inhibitors of the Shroom3-Rho kinase protein-protein interaction identified CCG-17444 (Chem ID: 2816053). CCG-17444 inhibits the Shroom3-Rho kinase interaction in vitro with micromolar potency. This compound acts through an irreversible, covalent mechanism of action, targeting Shroom3 Cys1816 to inhibit the Shroom3-Rho kinase protein-protein interaction. Inhibition of the Shroom3-Rho kinase protein-protein interaction with CCG-17444 counteracts the inhibitory action of Nogo66 and enhances neurite outgrowth.
  
  
  CONCLUSIONS
  This study identifies a small molecule inhibitor of the Shroom3-Rho kinase protein-protein interaction that circumvents the inhibitory action of Nogo66 in neurons. Identification of a small molecule compound that blocks the Shroom3-Rho kinase protein-protein interaction provides a first step towards a potential new strategy for enhancing neural repair.
authors.affiliation: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA. dicksonh@umich.edu.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Dickson
authors.affiliation: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA. amwilbur@umich.edu.
authors.forename: Amanda
authors.initials: A
authors.lastname: Wilbur
authors.affiliation: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA. aareinke6@gmail.com.
authors.forename: Ashley A
authors.initials: AA
authors.lastname: Reinke
authors.affiliation: Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA. youngmat@umich.edu.
authors.forename: Mathew A
authors.initials: MA
authors.lastname: Young
authors.affiliation: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA. avojtek@umich.edu.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Vojtek
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000502:physiology; D049108:Cell Enlargement / Q000187:drug effects*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli; D057166:High-Throughput Screening Assays; D051379:Mice; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009185:Myelin Proteins / Q000378:metabolism*; D000070798:Nogo Proteins; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology; D011744:Pyrimidinones / Q000494:pharmacology*; D015363:Quinolones / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: C000605988:CCG-17444; D008840:Microfilament Proteins; D009185:Myelin Proteins; D000070798:Nogo Proteins; D047428:Protein Kinase Inhibitors; D011744:Pyrimidinones; D015363:Quinolones; D011994:Recombinant Proteins; C000603201:Rtn4 protein, mouse; C402112:Shrm protein, mouse; D054460:rho-Associated Kinases