Figure 7. MYPT1 phosphorylation at Ser668 is increased upon stimulation with the TXA₂ analogue, U46619, in permeabilized and intact pulmonary artery SM but not by high [K⁺] stimulation in intact SM.

(A) U46619 (300 nM) (n = 3) but not high [K⁺] stimulation increases phosphorylation of MYPT1 Ser668 in intact pulmonary artery smooth muscle. (B) Increasing Ca²⁺ to pCa7.0 with and without U46619 (300 nM) induced Ca²⁺ sensitized force in α-toxin permeabilized SM significantly increased phosphorylation of MYPT1 at Ser668 compared to control muscles in G1 solution pCa<8.0 (59±9.6%, n = 10, p<0.01).