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Analysis of co‐chaperone interactions with Hsp90 (567.7)
Author(s) -
Wolmarans Annemarie,
LaPointe Paul
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.567.7
Subject(s) - hsp90 , chaperone (clinical) , mutant , heat shock protein , microbiology and biotechnology , complementation , biochemistry , chemistry , biology , gene , medicine , pathology
Heat shock protein 90 (Hsp90) is a highly abundant, ATP‐dependent molecular chaperone that is present in all eukaryotic cells. It is essential for the maturation and regulation of a specific set of substrate (client) proteins, many of which are key players in oncogenesis. Hsp90, as a homodimer, acts in the context of a complicated ATPase cycle. Co‐chaperone proteins guide and modulate Hsp90 through its functional cycle in order to mature clients, by binding to one or more of Hsp90’s domains in a sequential manner. To address Hsp90’s conformational requirements for cycle progression, we analyze two specific co‐chaperones, Aha1 and Sba1, which bind to Hsp90 in its closed, ATP‐bound state. We have constructed 14 Hsp90 variants harboring mutations in the N terminus of Hsp90 which have the potential to block the binding of Aha1 and Sba1. Several N‐terminal mutants show promising results as they are weakly stimulated by Aha1 or cannot be inhibited by Sba1 from the Aha1‐stimulated rate. Interestingly, one specific mutant harboring the D132K mutation does not interact with Sba1. Analysis of these five mutants in combination with previously characterized Hsp90 mutants will allow for the restriction of either Sba1 or Aha1 to one monomer of Hsp90 or the other. This subunit complementation strategy will bring insight into how Aha1 and Sba1 act asymmetrically on Hsp90. Grant Funding Source : Supported by CIHR