Emerin (EMD) is an X-linked inner nuclear envelope protein with critical roles in nuclear organization and architecture. Primary function: EMD stabilizes and promotes actin polymerization by binding and stabilizing the pointed end of growing filaments, forming a nuclear actin cortical network [UniProt]. Mechanism: EMD inhibits beta-catenin activity by preventing its nuclear accumulation through a CRM1-dependent export pathway [UniProt] and links centrosomes to the nuclear envelope via microtubule association [UniProt]. Together with BAF, EMD contributes to nuclear envelope stiffness and facilitates proper localization of prelamin-A/C [UniProt]. Disease relevance: Mutations in EMD cause Emery-Dreifuss muscular dystrophy type 1 (EDMD1), characterized by muscle weakness and cardiac complications. A novel nonsense mutation (c.C57G, p.Y19X) was identified in a Han Chinese family presenting with EDMD1 and cardiac arrhythmia 1. Mechanistically, emerin knockdown impairs mitochondrial oxidative phosphorylation capacity, reduces electron transport chain complexes I and IV, and disrupts mitochondrial networks through downregulation of PGC1α, DRP1, and fusion-related proteins 1. Clinical significance: Understanding emerin's role in cardiac mitochondrial bioenergetics suggests targeting mitochondrial function may provide therapeutic strategies for EDMD1-associated cardiac disorders 1.