GJA5 and atrial fibrillation: Owing to reduced atrial conduction velocity, the expression levels of phosphorylated compared to dephosphorylated Cx40 were assessed: The levels of phosphorylated Cx40 were found to be reduced concomitant with an increase in dephosphorylated Cx40 suggesting that gap junction complexes were compromised in this model of AF (Chen et al., 2004).