title: Crystal structure of the tyrosine kinase domain of the hepatocyte growth factor receptor c-Met and its complex with the microbial alkaloid K-252a.
abstract: The protooncogene c-met codes for the hepatocyte growth factor receptor tyrosine kinase. Binding of its ligand, hepatocyte growth factor/scatter factor, stimulates receptor autophosphorylation, which leads to pleiotropic downstream signaling events in epithelial cells, including cell growth, motility, and invasion. These events are mediated by interaction of cytoplasmic effectors, generally through Src homology 2 (SH2) domains, with two phosphotyrosine-containing sequence motifs in the unique C-terminal tail of c-Met (supersite). There is a strong link between aberrant c-Met activity and oncogenesis, which makes this kinase an important cancer drug target. The furanosylated indolocarbazole K-252a belongs to a family of microbial alkaloids that also includes staurosporine. It was recently shown to be a potent inhibitor of c-Met. Here we report the crystal structures of an unphosphorylated c-Met kinase domain harboring a human cancer mutation and its complex with K-252a at 1.8-A resolution. The structure follows the well established architecture of protein kinases. It adopts a unique, inhibitory conformation of the activation loop, a catalytically noncompetent orientation of helix alphaC, and reveals the complete C-terminal docking site. The first SH2-binding motif (1349YVHV) adopts an extended conformation, whereas the second motif (1356YVNV), a binding site for Grb2-SH2, folds as a type II Beta-turn. The intermediate portion of the supersite (1353NATY) assumes a type I Beta-turn conformation as in an Shc-phosphotyrosine binding domain peptide complex. K-252a is bound in the adenosine pocket with an analogous binding mode to those observed in previously reported structures of protein kinases in complex with staurosporine.
authors.affiliation: Departments of Chemistry and Biology, Pharmacia S.p.A., Discovery Research, Viale Pasteur 10, 20014 Nerviano (MI), Italy. nikolaus.schiering@pharma.novartis.com
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Schiering
authors.forename: Stefan
authors.initials: S
authors.lastname: Knapp
authors.forename: Marina
authors.initials: M
authors.lastname: Marconi
authors.forename: Maria M
authors.initials: MM
authors.lastname: Flocco
authors.forename: Jean
authors.initials: J
authors.lastname: Cui
authors.forename: Rita
authors.initials: R
authors.lastname: Perego
authors.forename: Luisa
authors.initials: L
authors.lastname: Rusconi
authors.forename: Cinzia
authors.initials: C
authors.lastname: Cristiani
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002227:Carbazoles / Q000737:chemistry*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray / Q000379:methods; D004791:Enzyme Inhibitors / Q000737:chemistry*; D026121:Indole Alkaloids; D008715:Methionine; D008958:Models, Molecular; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D019859:Proto-Oncogene Proteins c-met / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D002227:Carbazoles; D004791:Enzyme Inhibitors; D026121:Indole Alkaloids; D011994:Recombinant Proteins; C049985:staurosporine aglycone; D008715:Methionine; D011505:Protein-Tyrosine Kinases; D019859:Proto-Oncogene Proteins c-met