title: The human tyrosine kinase Kit and its gatekeeper mutant T670I, show different kinetic properties: Implications for drug design.
abstract: The tyrosine kinase Kit, a receptor for Stem Cell Factor, is involved, among others, in processes associated to cell survival, proliferation and migration. Upon physiological conditions, the activity of Kit is tightly regulated. However, primary mutations that lead to its constitutive activation are the causal oncogenic driver of gastrointestinal stromal tumours (GISTs). GISTs are known to be refractory to conventional therapies but the introduction of Imatinib, a selective inhibitor of tyrosine kinases Abl and Kit, significantly ameliorated the treatment options of GISTs patients. However, the acquisition of secondary mutations renders Kit resistant towards all available drugs. Mutation involving gatekeeper residues (such as V654a and T670I) influence both the structure and the catalytic activity of the enzyme. Therefore, detailed knowledge of the enzymatic properties of the mutant forms, in comparison with the wild type enzyme, is an important pre-requisite for the rational development of specific inhibitors. In this paper we report a thorough kinetic analysis of the reaction catalyzed by the Kit kinase and its gatekeeper mutated form T670I. Our results revealed the different mechanisms of action of these two enzymes and may open a new avenue for the future design of specific Kit inhibitors.
authors.affiliation: Institute of Molecular Genetics IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Kissova
authors.affiliation: Institute of Molecular Genetics IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy. Electronic address: maga@igm.cnr.it.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maga
authors.affiliation: Institute of Molecular Genetics IGM-CNR, via Abbiategrasso 207, 27100 Pavia, Italy. Electronic address: crespan@igm.cnr.it.
authors.forename: Emmanuele
authors.initials: E
authors.lastname: Crespan
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D015195:Drug Design; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics; D006801:Humans; D007700:Kinetics; D010455:Peptides / Q000378:metabolism; D017354:Point Mutation; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology; D019009:Proto-Oncogene Proteins c-kit / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D010455:Peptides; D047428:Protein Kinase Inhibitors; D000255:Adenosine Triphosphate; D019009:Proto-Oncogene Proteins c-kit
keywords: Drug resistance; Enzyme kinetics; Kit; Tyrosine kinases