Τίτλος:
Interaction between the 90-kDa heat shock protein and soluble guanylyl
cyclase: Physiological significance and mapping of the domains mediating
binding
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
The 90-kDa heat shock protein (hsp90) regulates the stability and
function of many client proteins, including members of the NO-cGMP
signaling pathway. Soluble guanylyl cyclase (sGC), an NO receptor, was
recently reported to be an hsp90-interacting partner. In the present
study, we show that hsp90 binds to both subunits of the most common sGC
form (alpha(1)beta(1)) when these are expressed individually but only
interacts with beta(1) in the heterodimeric form of the enzyme.
Characterization of the region of hsp90 required to bind each subunit in
immunoprecipitation experiments revealed that residues 310 to 456 of
hsp90 interact with the sGC subunits. The region of beta(1) responsible
for binding to hsp90 beta was mapped using in vitro binding assays and
immunoprecipitation experiments and was found to lie in the regulatory
domain. The physiological importance of the hsp90/sGC interaction was
investigated by treating rat smooth muscle cells with the hsp90
inhibitors radicicol and geldanamycin (GA) and determining both sGC
activity and protein levels. Long-term ( 24 or 48 h) inhibition of hsp90
resulted in a strong decrease of both alpha(1) and beta(1) protein
levels and sGC activity. Moreover, incubation of smooth muscle cells
with the proteasome inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal
(MG132) blocked the GA-induced down-regulation of sGC. We conclude that
the N-terminal region of the beta(1) subunit mediates binding of the
heterodimeric form of sGC to hsp90 and that this interaction involves
the M domain of hsp90. Hsp90 binding to sGC regulates the pool of active
enzymes by affecting the protein levels of the two subunits.
Συγγραφείς:
Papapetropoulos, A
Zhou, ZM
Gerassimou, C
Yetik, G and
Venema, RC
Roussos, C
Sessa, WC
Catravas, JD
Περιοδικό:
Molecular Pharmacology
Εκδότης:
AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS
DOI:
10.1124/mol.105.012682
