title: Novel Hsp90 partners discovered using complementary proteomic approaches.
abstract: Hsp90 is an essential eukaryotic molecular chaperone that stabilizes a large set of client proteins, many of which are involved in various cellular signaling pathways. The current list of Hsp90 interactors comprises about 200 proteins and this number is growing steadily. In this paper, we report on the application of three complementary proteomic approaches directed towards identification of novel proteins that interact with Hsp90. These methods are coimmunoprecipitation, pull down with biotinylated geldanamycin, and immobilization of Hsp90beta on sepharose. In all, this study led to the identification of 42 proteins, including 18 proteins that had not been previously characterized as Hsp90 interactors. These novel Hsp90 partners not only represent abundant protein species, but several proteins were identified at low levels, among which signaling kinase Cdk3 and putative transcription factor tripartite motif-containing protein 29. Identification of tetratricopeptide-repeat-containing mitochondrial import receptor protein Tom34 suggests the involvement of Hsp90 in the early steps of translocation of mitochondrial preproteins. Taken together, our data expand the knowledge of the Hsp90 interactome and provide a further step in our understanding of the Hsp90 chaperone system.
authors.affiliation: Department of Membrane Enzymology, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands. p.a.tsaytler@uu.nl
authors.forename: Pavel A
authors.initials: PA
authors.lastname: Tsaytler
authors.forename: Jeroen
authors.initials: J
authors.lastname: Krijgsveld
authors.forename: Soenita S
authors.initials: SS
authors.lastname: Goerdayal
authors.forename: Stefan
authors.initials: S
authors.lastname: Rüdiger
authors.forename: Maarten R
authors.initials: MR
authors.lastname: Egmond
mesh_terms: D020816:Amino Acid Motifs; D045744:Cell Line, Tumor; D016384:Consensus Sequence; D056849:Cyclin-Dependent Kinase 3 / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011485:Protein Binding; D040901:Proteomics; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; C493165:HSP90AB1 protein, human; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; C108485:TOMM34 protein, human; C087296:TRIM29 protein, human; D014157:Transcription Factors; D056849:Cyclin-Dependent Kinase 3