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. 1997 Feb 18;94(4):1512–1516. doi: 10.1073/pnas.94.4.1512

Figure 3.

Figure 3

Effects of mutations in the QXXER motif on G protein modulation. Tail currents were recorded following paired test pulses. A 4-ms test pulse (test 1) to the indicated test potential was applied from the holding potential of −60 mV. After 1s, a 10-ms conditioning prepulse to +100 mV was applied, the cell was repolarized to −60 mV for 10 ms, and a second 4-ms test pulse (test 2) to the same potential as test 1 was applied. Tail currents were normalized to the largest tail current in each series of test pulses, and means ± SEM were plotted against test pulse potential. An increase in tail current after test 2 compared with test 1 indicates facilitation. The current traces shown in each panel were recorded during and after test 1 and test 2 at +30 mV. ▵, Control intracellular solution, test 1; ○, GTP[γS], test 1; •, GTP[γS], test 2. (A) α1A. (B) α1C. (C) α1A/AQIAA. (D) α1A/QQIEE. (E) α1A/QQLEE. (F) α1C/QQLER.