Figure 6

Contractility assay. Wild type (wt) and 4R mutant of the core fragment of PRG were added to β-escin permeabilized pulmonary artery precontracted with pCa 6.7 solution containing 1 μM calmodulin and 2 μM GTP. Concomitant increase in force is consistent with activation of the RhoA pathway. The 4R mutant, 10–15 μM, induced significantly greater Ca²⁺-sensitized force than the wild type protein (p = 0.002; n = 11. The magnitudes of the responses are normalized to pCa 6.7-induced force developed before addition of the recombinant PRG variants.