Mechanistically, metformin activates the PP2A-GSK3β-MCL-1 pathway by inhibiting cancerous Inhibitor Of PP2A (CIP2A), a PP2A inhibitor, and hypoglycemia upregulates the B56δ, a PP2A regulatory subunit, eventually, the active PP2A-B56δ has higher affinity for GSK3β [124]. The gene discussed is PPP2R5D; the disease is Hypoglycemia.