LMO7 (LIM domain 7) is a multifunctional E3 ubiquitin ligase with diverse cellular roles spanning cardiac, pulmonary, hepatic, and immune functions. Primary Function: LMO7 acts as an E3 ubiquitin ligase mediating protein ubiquitination and degradation 1. It localizes to multiple intracellular compartments including the cell membrane, focal adhesions, nucleus, and mitochondria 2. Mechanism: LMO7 regulates critical signaling pathways through substrate-specific ubiquitination. In cardiac fibrosis, LMO7 isoforms (particularly LMO7-Δe20) activate TGF-β1 signaling by upregulating activator protein 1 3. In pulmonary fibrosis, LMO7 mediates SMAD7 degradation, stabilizing TGFβR1 and perpetuating TGF-β/SMAD signaling 1. In NASH, LMO7 suppresses disease by targeting TRIM47 for K48-linked ubiquitin degradation, inactivating JNK/p38 MAPK cascades 4. In innate immunity, phosphorylated LMO7 mediates STING K63-linked poly-ubiquitination, essential for STING activation and anti-tumor immunity 5. Disease Relevance: LMO7 dysregulation contributes to heart failure, pulmonary fibrosis, nonalcoholic steatohepatitis, and cancer progression 6, 7. Clinical Significance: Targeting LMO7 through genetic or pharmacological inhibition shows therapeutic promise for fibrotic diseases and cancer immunotherapy, with RBMS1 inhibition emerging as a potential LMO7-modulating strategy.