ARMC1 (armadillo repeat containing 1) is a dual-localization protein that regulates mitochondrial distribution and dynamics through its association with key mitochondrial complexes. ARMC1 partitions between distinct complexes: it assembles with MIRO and the mitochondrial fission regulator (MTFR) to antagonize retrograde mitochondrial movement, while DNAJC11 facilitates its release from mitochondria, enabling mito-cytoplasmic shuttling that tunes steady-state mitochondrial distributions 1. As a peripheral component of the mitochondrial intermembrane space bridging complex (MICOS/MIB), ARMC1 associates with the outer mitochondrial membrane and interacts with other MICOS constituents; cells lacking ARMC1 display fragmented, less motile mitochondria despite normal cristae structure and respiration 2. Beyond mitochondrial dynamics, ARMC1 plays roles in oxidative stress regulation—mesenchymal stem cells upregulate ARMC1 to inhibit mitochondrial fission and enhance antioxidant capacity in renal fibrosis models, suggesting therapeutic potential 3. Clinically, ARMC1 expression is elevated in pancreatic adenocarcinoma and invasive breast carcinoma, with high expression associated with poor patient survival and advanced disease stages, positioning ARMC1 as a potential cancer biomarker [PMID:39773340; 45]. Additionally, ARMC1 expression correlates with psychological distress in individuals with childhood neglect 5.