TABLE 4.

Regulation of sGC–membrane interaction by Ca²⁺.

Cells were lysed at 4°C in either 1.5 mM EGTA or 10 μM added Ca²⁺; the lysate was centrifuged at 4°C for 1 min at 14,000 × g. Guanylyl cyclase activity was measured at 22°C in the lysate, the supernatant fraction, or the pellet fraction with Mg²⁺-GTP in the absence or presence of 50 μM GTPγS. Data shown are the means and SD of two independent experiments in triplicate (n = 6). Experiment 5 is the reconstitution of the pellet of experiment 4 with the supernatant of experiment 1 (all indicated in yellow).