CCDC8 is a core component of the 3M complex, which regulates microtubule dynamics and genome integrity, though the precise mechanism remains unclear 1. The protein exclusively localizes to the plasma membrane where it is phosphorylated by CK2 and GSK3, enabling sequential binding with OBSL1 and then CUL7 to form the membrane-assembled 3M E3 ubiquitin ligase complex 2. CCDC8 physically interacts with OBSL1 but not directly with CUL7, suggesting a hierarchical assembly pathway 3. The 3M complex targets substrates including LL5β, a plasma membrane protein regulating cell migration 2. CCDC8 deficiency disrupts growth factor signaling, specifically impairing GH signaling pathways while leaving IGF1 signaling intact 4. Mutations in CCDC8 cause 3M syndrome 3, an autosomal recessive primordial growth disorder characterized by severe pre- and postnatal growth retardation and distinctive facial features 35. Mouse studies demonstrate that Ccdc8 deletion impairs trophoblast migration and placental development, resulting in intrauterine growth restriction and perinatal lethality 2. Beyond growth regulation, CCDC8 may contribute to cardiomyocyte apoptosis through the TNF signaling pathway during myocardial ischemia-reperfusion injury 6.