Figure 6.

Light responses measured by whole-cell recording. (A) Gα_q^V303D mutants display greatly reduced responses to 10 msec flashes containing ∼10⁵ and 10⁶ effective photons. (B) Gα_q^V303D mutant’s response to 100 msec flashes containing 10⁵ photons was greatly reduced when compared with that of Gα_q¹ mutants. (C) A wild-type response is shown. (D) Summary data of peak amplitudes in response to flashes containing 10⁵ photons in wt (n = 11), Gα_q^V303D (n = 15), and Gα_q¹ (n = 7) mutants. The complete genotypes are as follows: w¹¹¹⁸ (wt); w¹¹¹⁸; Gα_q^V303D (V303D); w¹¹¹⁸; Gα_q¹ (Gα_q¹).