PMC2195580_01
pH dependence of the H+ currents. (A) Currents elicited by a 5-s depolarizing pulse to +10 mV in cells perfused with alkaline (pH = 7.6, n = 20) or neutral (pH = 7.1, n = 7) pipette solutions containing 25 muM GTPgammaS. (B) Current-voltage relationship measured at a pipette pH of 6.1 ( ), 7.1 ( ), 7.6 ( ), and 8.1 ( ). The holding voltage was -60 mV (pH 6.1), -40 mV (pH 7.1), and -20 mV (pH 7.6 and 8.1), and bath pH was 7.1 in all conditions. Arrows indicate the H+ equilibrium potential for each condition. Data are mean +- SEM of >=7 experiments for each condition.
JEM982226.f4b.jpg
PMC2195580_01_JEM982226.f4b.jpg
F4
In ~30% of the cells, a transient (<10 s) outward current (presumably carried by K+) developed immediately after break-in (e.g., see Fig. 5 A, bottom left trace); this current was observed in both control and CGD cells.
The inward H+ currents are absent in CGD patients. Proton currents recorded in eosinophils from two CGD patients: a 6-yr-old Caucasian boy with X-linked CGD, who completely lacked the gp91phox subunit (X910), and a 34-yr-old Caucasian woman with a deficiency in p47 (A470). (A) Families of currents elicited by 5-s depolarizing steps ranging from 0 mV (CGD) or -20 mV (Control) to +50 mV, in conditions favoring inward currents (pHi = 7.6, 25 muM GTPgammaS). (B) Currents elicited by 5-s pulses from -60 mV to 0 mV, in conditions minimizing inward currents (pHi 6.1, 0.2 mM EGTA, no GTPgammaS). Traces are representative of >=8 experiments. (C) Current-voltage plot of proton currents measured in CGD cells under different activating conditions (pHi = 7.6, pHo = 7.1). Data are mean +- SEM of >=4 experiments for each condition.
JEM982226.f6.jpg
PMC2195580_01_JEM982226.f6.jpg
F6
The various free Zn2+ concentrations used in Fig. 7A and Fig.