C-Abl Dependent Tyrosine Phosphorylation of theCo-chaperone Aha1 Regulates Interaction with Hsp90

ABSTRACT: The ability of Heat Shock Protein 90 (Hsp90) to hydrolyze ATP is essential for its chaperone function. The co-chaperone Aha1 stimulates Hsp90 ATPase activity tailoring the chaperone function to specific “client” proteins. The intracellular signaling mechanisms directly regulating Aha1 association with Hsp90 remain unknown. Here we show that c-Abl kinase phosphorylates Y223 in human Aha1 (hAha1) promoting its interaction with Hsp90. This also increases Hsp90 ATPase activity,enhancesHsp90 interaction with kinase clients,and compromises the chaperoning of non-kinase clients such as glucocorticoid receptor and CFTR. Suggesting a new regulatory paradigm, we find that Y223 phosphorylation leads to ubiquitination and degradation of hAha1 in the proteasome. Finally pharmacologic inhibition of c-Abl prevents hAha1 interaction with Hsp90 thereby, hypersensitizing cancer cells to Hsp90 inhibitors bothin vitro and ex vivo.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (ncbitaxon:9606)

SUBMITTER: Mehdi Mollapour  

PROVIDER: MSV000080713 | MassIVE | Tue Mar 28 23:29:00 BST 2017

SECONDARY ACCESSION(S): PXD001737

REPOSITORIES: MassIVE