CKB (creatine kinase B) is a key enzyme that catalyzes the reversible transfer of phosphate between ATP and creatine phosphate, playing essential roles in cellular energy metabolism and beyond 1. Beyond its classical metabolic function, CKB exhibits moonlighting activities as a protein kinase, phosphorylating glutathione peroxidase 4 (GPX4) at serine 104 to prevent ferroptosis and promote tumor growth 2. CKB promotes mitochondrial ATP production by suppressing mitochondrial calcium levels and preventing mitochondrial permeability transition pore activation, achieved through inhibition of AKT signaling 3. The protein serves as a biomarker for various diseases, showing strong associations with osteoporosis risk and potential utility in predictive modeling 4. CKB expression declines with aging in peripheral blood mononuclear cells, accompanied by increased AKT signaling, suggesting roles in age-related metabolic changes 3. Population-based studies have identified CKB as part of comprehensive proteomic profiles associated with disease risk and prognosis in large cohorts 56. These findings reveal CKB as a multifunctional protein with both metabolic and regulatory roles, making it a potential therapeutic target for cancer treatment and metabolic disorders.