title: Identification of ErbB-2 kinase domain motifs required for geldanamycin-induced degradation.
abstract: The ansamycin antibiotic geldanamycin (GA) induces the intracellular degradation of ErbB-2/neu. Degradation of ErbB-2 proceeds through cleavage(s) within the kinase domain, resulting in the formation of a 135 kDa ectodomain fragment and a fragment(s) of approximately 50 kDa containing the COOH-terminal region. On the basis of independent means of identification, two adjacent sequence motifs have been identified in ErbB-2 that are required for GA-induced degradation. These motifs encompass residues 776-783 and 784-786 within the NH(2)-terminal lobe of the ErbB-2 kinase domain. This is also a region in which the epidermal growth factor receptor and ErbB-2 kinase domains differ significantly in sequence. Although mutations in this region abrogate GA-induced ErbB-2 degradation, the tyrosine kinase activity of ErbB-2 is not disrupted. Interestingly, these ErbB-2 mutants are specifically resistant to GA-induced degradation but retain sensitivity to other drugs, such as staurospore and curcumin, which are also able to provoke ErbB-2 degradation.
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA.
authors.forename: Oleg
authors.initials: O
authors.lastname: Tikhomirov
authors.forename: Graham
authors.initials: G
authors.lastname: Carpenter
mesh_terms: D001483:Base Sequence; D016227:Benzoquinones; D001940:Breast; D002460:Cell Line; D017931:DNA Primers; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D047029:Lactams, Macrocyclic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D011809:Quinones / Q000494:pharmacology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
chemical_list: D016227:Benzoquinones; D017931:DNA Primers; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C001277:geldanamycin