FIGURE 6.

CaMKII autonomy is dependent on ATP concentration, but can be further stimulated even at the mm concentrations found within cells. A, stimulated and autonomous CaMKII activity toward syntide2 and AC2 was measured at 0.1 mm and 2 mm ATP. B, autonomy (ratio of autonomous to stimulated activity) was significantly higher at 2 mm ATP for both syntide2 and AC2 (and significantly higher for AC2 than for syntide2 at each ATP concentration) (p < 0.01, Student's t test; n = 5). However, most importantly, autonomy at for the R-substrate syntide2 was less than 40% even at 2 mm ATP concentration. Error bars show S.E. in both panels.