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A heat shock protein 90 binding domain in endothelial nitric-oxide synthase influences enzyme function. J Biol Chem 2007 Dec 28;282(52):37567-74

Date

11/01/2007

Pubmed ID

17971446

DOI

10.1074/jbc.M706464200

Scopus ID

2-s2.0-38049170908   50 Citations

Abstract

Previous reports suggest heat shock protein 90 (hsp90) associates with endothelial nitric-oxide synthase (eNOS) to increase nitric oxide (*NO) generation. Ansamycin inhibition of chaperone-dependent activity increases eNOS generation of superoxide anion (O(2)(*)) upon enzyme activation. In the present study we identify where hsp90 binds to eNOS using overlapping decoy peptides based on the amino acid (aa) sequence of eNOS (291-420). B1, B2, and B3 peptides inhibited hsp90 association with eNOS in cell lysates from proliferating bovine aortic endothelial cells. B2 (aa 301-320), common to both B1 and B3, decreased stimulated *NO production and hsp90 association in bovine aortic endothelial cells. The B2/B3 peptide was redesigned to TSB2 that includes a TAT protein transduction domain and shortened to 14 aa. TSB2 impaired vasodilation of isolated facialis arteries in vitro and in vivo and increased eNOS-dependent O(2)(*) generation in native endothelial cells on mouse aortas, whereas a control peptide, TSB(Ctr), which has the four glutamic acids in TSB2 substituted with alanine, showed no such effects. Site-directed mutagenesis of eNOS at 310, 314, 318, and 323 Glu to Ala yields an eNOS mutant that exhibited reduced hsp90 association and generated O(2)(*) rather than *NO upon activation. Together, these data demonstrate that hsp90 associates with eNOS at aa 310-323. Moreover, a decoy peptide based on this sequence is sufficient to displace hsp90 from eNOS and uncouple eNOS activity from *NO generation. Thus, Glu-310, Glu-314, Glu-318, and Glu-323 in eNOS, although each does not do much by itself, synergistically they increase "cooperativity" in the association step that is critical for maintaining hsp90-eNOS interactions and promoting coupled eNOS activity. Such chaperone-dependent signaling may play an important role in modulating the balance of *NO and O(2)(*) generation from eNOS and, therefore, vascular function.

Author List

Xu H, Shi Y, Wang J, Jones D, Weilrauch D, Ying R, Wakim B, Pritchard KA Jr

Author

Kirkwood A. Pritchard PhD Professor in the Surgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Aorta
Cattle
Cell Proliferation
Enzymes
HSP90 Heat-Shock Proteins
Humans
Mice
Mice, Inbred C57BL
Models, Biological
NG-Nitroarginine Methyl Ester
Nitric Oxide
Nitric Oxide Synthase Type III
Peptides
Protein Structure, Tertiary
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a