Ligand-independent activation of Gq. (A) Graph depicting the fluorescence resonance energy transfer (FRET) ratio (yellow fluorescent protein:monomeric Turquoise (YFP:mTq)) change upon the application of a hypotonic (Hypo) stimulus, followed by the addition of histamine (100 μmol/l) in HeLa cells expressing Gαq-mTqΔ6, Gβ1 and YFP-Gγ2 (n = 5; error bars depict SE). (B) HeLa cells overexpressing the H1 receptor showed significant activation of Gq when the osmolality of the medium was reduced (Hypo). Subsequent addition of histamine yielded additional activation of Gq (n = 5).
Adjobo-Hermans et al. BMC Biology 2011 9:32 doi:10.1186/1741-7007-9-32