Sorafenib as an Inhibitor of RUVBL2

Abstract

RUVBL1 and RUVBL2 are highly conserved ATPases that belong to the AAA+ (ATPases Associated with various cellular Activities) superfamily and are involved in various complexes and cellular processes, several of which are closely linked to oncogenesis. The proteins were implicated in DNA damage signaling and repair, chromatin remodeling, telomerase activity, and in modulating the transcriptional activities of proto-oncogenes such as c-Myc and β-catenin. Moreover, both proteins were found to be overexpressed in several different types of cancers such as breast, lung, kidney, bladder, and leukemia. Given their various roles and strong involvement in carcinogenesis, the RUVBL proteins are considered to be novel targets for the discovery and development of therapeutic cancer drugs. Here, we describe the identification of sorafenib as a novel inhibitor of the ATPase activity of human RUVBL2. Enzyme kinetics and surface plasmon resonance experiments revealed that sorafenib is a weak, mixed non-competitive inhibitor of the protein’s ATPase activity. Size exclusion chromatography and small angle X-ray scattering data indicated that the interaction of sorafenib with RUVBL2 does not cause a significant effect on the solution conformation of the protein; however, the data suggested that the effect of sorafenib on RUVBL2 activity is mediated by the insertion domain in the protein. Sorafenib also inhibited the ATPase activity of the RUVBL1/2 complex. Hence, we propose that sorafenib could be further optimized to be a potent inhibitor of the RUVBL proteins.

Regulation of RUVBL1-RUVBL2 AAA-ATPases by the nonsense-mediated mRNA decay factor DHX34, as evidenced by Cryo-EM

“…Several reports indicate that RUVBL1 and RUVBL2 do not always share the same function in vivo ( Mao and Houry, 2017 ). The ATPase activity of RUVBL2 is several fold higher than RUVBL1 at least when expressed separately ( Nano et al, 2020 ), suggesting they do not function in the same way. Along the same lines, RUVBL2 shows several specialized functions in the context of the R2TP complex.…”

“…One exception is the C-terminal domain of RPAP3 that binds at the ATPase-face of the ring through the interaction with RUVBL2 but not RUVBL1 (Martino et al, 2018;Maurizy et al, 2018;Munoz-Hernandez et al, 2019). ATP binding or hydrolysis by RUVBL1 and/or RUVBL2 is essential to all the reported activities in cells (Izumi et al, 2010;Rajendra et al, 2014;Venteicher et al, 2008), but the purified proteins display very weak ATPase activity in vitro (Nano et al, 2020;Gorynia et al, 2011). Little is known about the function of RUVBL1-RUVBL2-mediated ATP hydrolysis or how this is regulated within the cell.…”

“…ATP binding or hydrolysis by RUVBL1 and/or RUVBL2 is essential to all the reported activities in cells ( Izumi et al, 2010 ; Rajendra et al, 2014 ; Venteicher et al, 2008 ), but the purified proteins display very weak ATPase activity in vitro ( Nano et al, 2020 ; Gorynia et al, 2011 ). Little is known about the function of RUVBL1-RUVBL2-mediated ATP hydrolysis or how this is regulated within the cell.…”

The AAA+ superfamily: a review of the structural and mechanistic principles of these molecular machines

“…Activities of the two range from transcriptional regulation, chromatin remodeling, DNA damage signaling and repair, assembly of macromolecular complexes (such as cTuRC (Zimmermann et al 2020)), cell cycle, and motility. These proteins are overexpressed in many cancer types, which is perhaps unsurprising given their role in so many cellular processes involved in cellular replication; identification of inhibitors is ongoing (Nano et al 2020). Because members of the TIP49 family are classical AAAþ proteins with a single AAAþ domain, they are here designated as Type I ATPases.…”

Regulation of RUVBL1-RUVBL2 AAA-ATPases by the nonsense-mediated mRNA decay factor DHX34, as evidenced by Cryo-EM

“…One exception is the C-terminal domain of RPAP3 that binds at the ATPase-face of the ring through the interaction with RUVBL2 but not RUVBL1 (Martino et al, 2018;Maurizy et al, 2018;Munoz-Hernandez et al, 2019). ATP binding or hydrolysis by RUVBL1 and/or RUVBL2 is essential to all the reported activities in cells (Izumi et al, 2010;Rajendra et al, 2014;Venteicher et al, 2008), but the purified proteins display very weak ATPase activity in vitro (Nano et al, 2020;Gorynia et al, 2011). Little is known about the function of RUVBL1-RUVBL2-mediated ATP hydrolysis or how this is regulated within the cell.…”