FIGURE 7.
SCAMP2 decreases NKCC2 transport activity. Intracellular pH was measured in confluent monolayers of OKP cells as described under “Experimental Procedures.” The arrow indicates replacement with medium containing 20 mm NH4Cl (isosmotically substituted for NaCl). A, Na+-K+(NH4+)-2Cl− co-transport activity in OKP cells expressing Myc-NKCC2 (blue) in the absence (left) or presence (right) of SCAMP2. Results of representative experiments are shown. B, mean initial rate of pHi recovery (dpHi/dt) from an NH4+-induced alkaline load. Each bar represents the mean ± S.E. (error bar) rate of cell pH recovery (dpHi/dt, pH units/min) under different experimental conditions (OKP cells expressing Myc-NKCC-2, OKP cells co-transfected with NKCC2 and SCAMP2, and OKP cells co-transfected with NKCC2 and SCAMP2 in the presence of 0.1 mm bumenatide). *, p < 0.03 versus NKCC2 alone (NKCC2 alone, n = 3; NKCC2 with SCAMP2, n = 3).