ARPC3 is a core component of the Arp2/3 complex, a multiprotein machinery essential for actin polymerization. The complex nucleates branched actin networks in the cytoplasm to drive cell motility, and also functions in the nucleus where it regulates gene transcription and DNA repair by promoting actin polymerization in response to DNA damage. ARPC3 interacts with nucleation-promoting factors—including SPIN90, which can form dimers that bridge multiple Arp2/3 complexes to enable rapid assembly of complex actin architectures 1. ARPC3 dysregulation is implicated in multiple disease contexts. A 2025 study identified Charcot-Marie-Tooth disease as a new disease-gene association with ARPC3 2, and the gene has been identified as a hub gene in hepatitis delta virus-related hepatocellular carcinoma 3. In breast cancer, downregulation of ARPC3 via the MTSS1/ARPC3/F-actin pathway suppresses cell proliferation, migration, and lung metastasis 4. Recent evidence suggests nuclear cGAS regulates the miR-212-5p–ARPC3 axis to modulate VEGF-A-mediated angiogenesis and glioma progression 5. Genetic variation at the ARPC3 locus (rs3759384) associates with hypertriglyceridemia in severely obese patients through epigenetic mechanisms affecting promoter methylation 6. ARPC3 expression levels are dysregulated in chr12 obstructive pulmonary disease and osteosarcoma, and the protein mediates coronavirus assembly through interactions with the SARS-CoV-2 spike protein 7.