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. 2006 Oct 10;103(42):15635–15640. doi: 10.1073/pnas.0603344103

Fig. 1.

Fig. 1.

PIP3 inhibits CNGA2 channels but not CNGA3 channels. Representative traces from CNGA2 (A) and CNGA3 (B) before and after application of 10 μM PIP3. Currents were elicited by voltage steps to +50 and –50 mV in the presence of the indicated concentration of cyclic nucleotides. Data are representative of 12 patches for CNGA2 and 6 patches for CNGA3. (C) Two different patches containing CNGA2 channels activated by 1 mM cAMP and held at −50 mV were exposed to 10 μM or 1 μM PIP3 at 15 s (denoted by arrow). Data were normalized to the current level before PIP3 exposure. Representative CNGA2 (D) and CNGA3 (E) cyclic nucleotide dose–response relationships before (filled symbols) and after (open symbols) application of 10 μM PIP3. Hill parameters (K1/2, n) for CNGA2: (▾) cGMP = 1.6 μM, 2.2 before PIP3, and (▿) 21.5 μM, 2.1 after PIP3; (●) cAMP = 51.2 μM, 1.9 before PIP3, and (○) 1.4 mM, 1.5 after PIP3; for CNGA3: (▾) cGMP = 21.6 μM, 2.2 before PIP3, and (▿) 25.8 μM, 2.1 after PIP3; (●) cAMP = 1.8 mM, 1.3 before PIP3, and (○) 1.5 mM, 1.7 after PIP3. Open circles in E overlap and hide the filled circles. Data are representative of three separate experiments each for CNGA2 and CNGA3.