Recent studies have shown that the Rho-ROCK pathway is a novel therapeutic target in the treatment of various cardiovascular diseases, such as pulmonary hypertension and cerebral vasospasm21,22. Activation of Rho downstream of G12/13 is known to elicit an actomyosin-dependent contraction of aortic smooth muscle cells in an intracellular Ca2+-independent manner. Here, RHO is linked to pulmonary arterial hypertension.