title: Co-immunoprecipitation of Hsp101 with cytosolic Hsc70.
abstract: In animals and yeast, cytosolic Hsp70s function in concert with other molecular chaperones. Hsp70 is a major chaperone in the Hsp90 multi-chaperone complexes that participate in maturation of steroid receptors and several other proteins. Hsp70s also appear to form a complex with Hsp90 and Hsp110/sHsp. A 100 kDa protein was co-immunoprecipitated with cytosolic Hsc70 from maize seedlings (Zea mays). The presence of this complex was further confirmed using gel-filtration chromatography. Mass spectrometric analysis showed that the 100 kDa protein is homologous with Arabidopsis Hsp101. Treatment with apyrase enhanced the co-immunoprecipitation of Hsp101 with Hsc70, while ATP had the opposite effect. In the presence of carboxymethylated alpha-lactalbumin (CMLA), which is permanently unfolded, the complex dissociated. Based on these observations, it is concluded that Hsc70 and Hsp101 are present in a complex in the plant cytosol.
authors.affiliation: Plant Molecular and Cellular Biology Program, Department of Environmental Horticulture, University of Florida, Gainesville, FL 32611-0675, USA.
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Charles L
authors.initials: CL
authors.lastname: Guy
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001081:Apyrase / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics; D002845:Chromatography; D003600:Cytosol / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D047468:Immunoprecipitation; D007768:Lactalbumin / Q000378:metabolism; D008745:Methylation; D010449:Peptide Mapping; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D036226:Seedlings / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism*
chemical_list: C115569:HSP101 protein, plant; D018840:HSP70 Heat-Shock Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D007768:Lactalbumin; D001081:Apyrase