Abstract Body: The cyoskeleton anchors to desmosomes through plakophilin-2 (PKP2) in cardiomyocytes, contributing to intercalated disc integrity, which modulates mechanical coupling and electrical function in the heart. Pathogenic variants in PKP2 cause arrhythmogenic cardiomyopathy (ACM), yet the mechanistic relationship between specific PKP2 mutations, desmosome-cytoskeleton coupling, and associated arrhythmogenic propensity is not well understood. We developed a human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model of ACM harboring a heterozygous PKP2-L709F (PKP2^L709F) variant and compared PKP2^L709F cells to non-diseased control (Ctrl) and isogenic CRISPR/Cas9-corrected (PKP2^Corr) lines. iPSC-CMs were cultured using micropatterned substrates with physiological stiffness that promote adult-like sarcomere and intercalated disc structures. Total plakophilin-2 protein levels were decreased in PKP2^L709F iPSC-CMs consistent with computationally predicted instability and accelerated in vitro degradation relative to PKP2^Corr. Confocal imaging revealed disruption of the desmosome–actin–nuclear axis in PKP2^L709F iPSC-CMs: disorganized desmosomes accompanied by reduced levels of plakophilin-2 and Na_V1.5 at the intercalated disc, altered cytoskeletal organization, and altered nuclear morphology including decreased nuclear area. Integrated transcriptomic and proteomic analyses identified a dysregulation of cell structural proteins, consistent with impaired desmosome-cytoskeletal–nuclear coupling. Optical voltage and calcium mapping revealed slower longitudinal and more isotropic conduction consistent with reduced Na_V1.5, prolonged action potentials, and impaired calcium handling in PKP2^L709F iPSC-CMs. PKP2^L709F monolayers treated with isoproterenol (β-adrenergic agonist) and flecainide (Na⁺ channel blocker) exhibited severe conduction slowing and the emergence of reentrant activities, demonstrating a highly pro-arrhythmic substrate. Strikingly, this in vitro electrophysiological response mirrored the patient’s pro-arrhythmic response to flecainide treatment. CRISPR correction of the L709F variant partially rescued the structural and electrophysiological abnormalities in PKP2^Corr CMs, supporting variant pathogenicity. These findings demonstrate the disruption of the desmosome–cytoskeleton–nuclear axis in PKP2^L709F and suggest uncoupling as a potential early driver of ACM arrhythmogenesis.