UBO-QIC (FR900359) is the only currently available G(q/11) protein inhibitor. However, its characterization has not been published, and we thus set out to do this. G(i), G(s) and G(q) protein-mediated responses were assessed utilizing endogenous or heterologously expressed receptors in Chinese hamster ovary cells. UBO-QIC, at 1 mu M, was an effective inhibitor of the G(q)-mediated responses, but was inactive at G(i)- and G(s) mediated responses. G(q/11) and G(16) responses were additionally compared in HEL92.1.7 cells, showing inhibition of G(q/11) responses. However, UBO-QIC also appeared to inhibit G(16). Further studies are required to establish its profile with respect to the different G(q)-family proteins. (C) 2015 Elsevier Inc. All rights reserved.