PPP1R12A and atrial fibrillation: ROCK activity, measured as MYPT-1 phosphorylation, was found to be increased in dialysis patients with atrial fibrillation compared to dialysis patients without atrial fibrillation [62], and to correlate with the expression of connexin40 (Cx40), a membrane protein relevant for rapid cell–cell transfer of action potential in the heart, as well as with the left atrial systolic volume and the left ventricular mass, again identifying a connection between ROCK activity and cardiovascular–renal remodeling [63].