Block of protein tyrosine phosphatase (PTP) by orthovanadate partially inhibits ICl,swell and prevents stimulation of ICl,swell upon block of Src by PP2. A: I-V relationships for currents in 1T solution, after 10 min of swelling in 0.7T solution, after exposure to 1 mM orthovanadate in 0.7T solution for 10 min (OV), and after addition of 10 μM PP2 for 10 min. B, C, D, and E: families of currents in 1T, 0.7T, 0.7T plus orthovanadate, and 0.7T plus orthovanadate and PP2 solution, respectively.