Abstract
OBJECTIVES - Heat-shock protein 90 (Hsp90) coordinates the regulation of diverse signaling proteins. We try to develop a new tool to explore the regulatory functions of Hsp90 in endothelial cells (ECs) instead of the existing chemical approaches. METHODS AND RESULTS - We designed a dominant-negative Hsp90 construct by site-direct mutagenesis of residue Asp-88 to Asn (D88N-Hsp90) based on the structure of the ATP/ADP-binding site. Recombinant wild-type Hsp90 protein binds ATP-Sepharose beads in manner inhibited by ATP or 17-AAG, a specific inhibitor for Hsp90, however the binding activity of D88N-Hsp90 was markedly reduced and the inhibitory effects of ATP or 17-AAG were negligible. The dimerization between endogenous Hsp90α and exogenous HA-Hsp90β was confirmed by immunoprecipitation, however the association between eNOS and D88N-Hsp90 was less than WT-Hsp90. Furthermore, adenoviral transduction of bovine aortic ECs with D88N-Hsp90 suppressed VEGF-induced phosphorylation of Akt, eNOS, and NO release and the inhibitory effect was blocked by okadaic acid. Moreover, D88N-Hsp90 abolished VEGF-stimulated Rac activation and suppressed VEGF-induced stress fiber formation. Transduction with D88N-Hsp90 decreased growth medium mediated migration of wild-type ECs, but not Akt1(-/-) ECs suggesting that Akt is key target of Hsp90. CONCLUSIONS - Our data demonstrate that dominant-negative Hsp90 modulates endothelial cell mobility mainly through PP2A-mediated dephosphorylation of Akt and Rac activation.
Original language | English (US) |
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Pages (from-to) | 105-111 |
Number of pages | 7 |
Journal | Arteriosclerosis, thrombosis, and vascular biology |
Volume | 28 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2008 |
Externally published | Yes |
Keywords
- ATP-binding
- Akt
- Dominant-negative
- Hsp90
- Migration
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine