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Introduction Dilated cardiomyopathy (DCM) is a major cause of heart failure, marked by ventricular dilation, reduced contractility, and increased myocardial stiffness. While structural changes are well known, the cellular mechanisms—especially those involving cardiomyocyte connectivity—are less understood. The intercalated disc (ICD), a key junction between cardiomyocytes, undergoes remodelling in DCM. LIM domain proteins, involved in mechanotransduction, may play a role in this process. This study aimed to identify and characterize a mechanosensitive protein complex involving LIM domain proteins at the ICD and to explore its role in cardiomyocyte mechanosignaling.Methods Neonatal rat cardiomyocytes were cultured on PDMS substrates with tunable stiffness (6 kPa for neonatal tissue, 66 kPa for fibrotic myocardium). Immunostaining, co-immunoprecipitation, and proteomics were used to study protein localization and interactions. An N-Cadherin tension sensor measured mechanical tension at the ICD.Results Ten LIM domain proteins linked to heart failure were screened for stiffness-dependent ICD localization. Dyxin/LMCD1 emerged as a key candidate, showing consistent ICD localization and structural effects under high stiffness. LMCD1 overexpression induced ICD abnormalities, including increased width, resembling DCM pathology. LMCD1 loss elevated ICD tension, confirmed via the N-Cadherin sensor. Proteomics revealed a novel LMCD1-associated complex including FAT1, Tec kinase, WAVE3, and β-actin, all co-localizing with β-catenin at the ICD. Several of these proteins are linked to cardiac disease, underscoring the relevance of this complex.Discussion This study reveals a stiffness-sensitive protein complex at the ICD involving LMCD1, suggesting a role in mechanotransduction and pathological remodelling in DCM. These findings offer new insights into mechanical stress sensing and potential therapeutic targets in heart failure.