The initial phase in the development of myocardial hypertrophy involves factors, such as endothelin-1, angiotensin-II, and adrenergic agonists at the cell membrane, binding to the G-protein coupled receptors (Fig 3), and several interdependent signaling cascades that include G-proteins, GTPases such as Ras, RhoA and Rac, and kinases such as ERK/MAPK and PKC [9]. The gene discussed is EDN1; the disease is cardiac hypertrophy.