FIGURE 4.
Knockdown of IRBIT results in Ca2+-dependent inhibition of NHE3 activity. A, PS120/NHE3V cells were transfected with shRNA targeting IRBIT or control shRNA. Each effective shRNA (sh-1 or sh-2) knocked down IRBIT expression in PS120 cells by ∼75%. Representative traces of Na+-dependent pH recovery in PS120/NHE3V cells treated with control (B) or sh-1 (C) in the presence of absence of thapsigargin (Tg) are shown. D, NHE3 activities in PS120/NHE3V cells transfected with control, sh-1, or sh-2 determined at pHi 6.6 are shown. *, p < 0.01 compare with the control. IB, immunoblot.