Fig. 7.
Effect of localized AC activity on the spatial spread of cAMP signals. AC activity was concentrated within a single location on the plasma membrane while total cellular AC activity remained constant. PDE activity was evenly distributed throughout the cytosol. A: the spatial distribution of cAMP signals 5 min following activation of AC. Total cellular AC activity (141.2 nM/s) was sequestered at one location. D = 300 μm2/s. B: effect of increasing localized AC activity on normalized differences between maximum and minimum cAMP levels with effective cAMP diffusion coefficients of 300 (●), 30 (■), and 3 (▴) μm2/s. Minimum cAMP levels for simulations run at each effective diffusion coefficient (time, t, = 5 min) were as follows: D = 300 μm2/s, 1.33 ≤ [cAMP]min ≤ 1.41 μM; D = 30 μm2/s: 0.96 ≤ [cAMP]min ≤ 1.38 μM; D = 3 μm2/s: 0.033 ≤ [cAMP]min ≤ 1.16 μM.