XB-IMG-128507
Xenbase Image ID: 128507
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Figure 2. Mutation of critical ligand-discrimination residue (D609) within CNGA3 alters the PIP3-induced increase in relative cAMP efficacy. (A) Diagram illustrating the basic topology of CNGA3 subunits (green), which are comprised of six transmembrane domains, with N- and C-terminal regions located on the intracellular side of the membrane. The light green cylinder represents the Cα helix of the CNBD. The asterisk indicates a critical ligand-discrimination residue, aspartic acid at position 609 (D609) within the CNBD. (B) Representative current traces elicited by 1 mM cGMP (green) or 10 mM cAMP (red) before and after 1 µM PIP3, for CNGA3 D609K and D609M channels. The arrowhead indicates Imax elicited by cGMP in the presence of PIP3. (C) Summary of the effects of 1 µM PIP3 on the current elicited by saturating cAMP or cGMP, for CNGA3 wild-type, D609K, or D609M channels; *, P < 0.05 compared with wild-type channels, n = 4–5. The broken horizontal line refers to a ratio of one, equivalent to no change in the parameter after PIPn application. Error bars indicate mean ± SEM. Image published in: Dai G et al. (2013) © 2013 Dai et al. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |