Connexin 45 (Cx45), encoded by the GJC1 gene, is expressed in cardiomyocytes and in developing vasculature in both endothelial and smooth muscle cells.nIn the heart, Cx45 along with Cx40 and Cx43, play a crucial role in normal electrical conduction and synchronous heart muscle contraction and important for the normal embryonic development of the heart6. Indeed Cx45 forms low conductance and voltage-sensitive gap junctions between the ventricular cardiac myocytes and the core conduction system. nStudies have showed that cardiac connexin Cx45 is upregulated in human failing hearts and has an important role in the regulation of endothelial-induced mural cell differentiation.