N-CADHERIN INVOLVEMENT IN CARDIAC MYOCYTE INTERACTION AND MYOFIBRILLOGENESIS

N-cadherin is a cell-surface, Ca2+-dependent adhesion molecule found i n intercalated disks and extrajunctional sites in the myocardium. In t his paper we show that antibodies specific for N-cadherin inhibit the contraction of both interacting and single myocytes isolated from embr yonic chicken hearts. Quantitative electron microscopy revealed that a nti-N-cadherin significantly decreases cell-cell contact between inter acting myocytes, consistent with a role for N-cadherin as a cell-cell adhesion molecule. In addition, quantitative electron microscopy showe d that anti-N-cadherin treatment of cardiomyocytes results in a signif icant reduction in the cytoplasmic area occupied by myofibrils, implyi ng that N-cadherin also plays a role in myofibrillogenesis. We propose that N-cadherin, in addition to mediating cardiac myocyte interaction , promotes myofibril formation necessary for functional activity of th e myocardium. (C) 1994 Academic Press,Inc.