The ATPase activity of molecular chaperone HSP60 is inhibited by immunosuppressant mizoribine

Abstract

The molecular chaperone HSP60 is a chaperonin homolog of GroEL. We had previously shown that the immunosuppressant mizoribine is bound directly to HSP60 and inhibited its chaperone activity. However, the inhibitory mechanisms of HSP60 by mizoribine have not yet been fully understood. In the present study, we investigated the influence of mizoribine on a folding cycle of HSP60 and co-chaperone HSP10. Our results showed that mizoribine inhibited the folding cycle of HSP60/HSP10. The ATPase activity of HSP60/HSP10 was decreased in the presence of mizoribine and the dissociation of HSP10 from HSP-60 was also decreased by mizoribine. The same functions of GroEL and/or GroES were slightly affected by mizoribine. Based on our findings, we discuss the inhibitory mechanisms of HSP60 by mizoribine.

Targeting Heat Shock Proteins 60 and 70 of Toxoplasma gondii as a Potential Drug Target: In Silico Approach

“…The ability of these compounds to interact with the conserved residues Interdiscip Sci Comput Life Sci at the active site suggests that they may contribute toward the ATP-/ADP-binding function which may attributed as potential inhibitor. Interestingly, none of the short-listed compounds from the virtual screening studies resemble potential inhibitors as found in the literatures for both Hsp60 and Hsp70 from various organisms [60][61][62].…”

Chaperonotherapy for Alzheimer’s Disease: Focusing on HSP60

“…Additionally, mizoribine (6) activity was related to the inhibition of the dissociation of the co-chaperonin HSP10 from the HSP60/HSP10 complex. In the case of mizoribine (6), there was a significant difference in the activities observed with prokaryotic and eukaryotic HSP60 in that GroEL/GroES systems were not significantly affected by mizoribine (6) [134].…”

“…One strategy aims at targeting HSP60 cysteine residues either as oxidizable sites [128] or for covalent binding, presumably through interaction with an electrophilic compound [129][130][131]. The other approach targets ATP binding and hydrolysis sites-functions, thus affecting those ATP-dependent conformational changes of HSP60 which are crucial for the protein folding function [132][133][134].…”

“…Unfortunately, these issues are rarely addressed in comprehensive studies [129,134], thus leaving several unanswered questions concerning current HSP60 inhibitors. As a consequence, the lack of information on the mechanism of action of several promising HSP60-targeting drugs promotes the supporting role of biomolecular computational studies.…”

Measurement of enzyme activity using a plug-based electrochemical microdevice

“…The sample ATPase we used was GroEL [5]. A substrate solution including ATP (final concentration: 3 mM) [6] and PEP and an enzyme solution containing GroEL, PK, POx, FAD, and TPP were prepared. Here, a problem to be considered was that the enzymatic reactions were still in progress while conducting the coulometric analysis, resulting in excess production of H 2 O 2 .…”