Phosphoinositide Cycle

The phosphoinositide cycle (PI-cycle) is a central lipid signaling pathway in eukaryotic cells responsible for the synthesis, interconversion, and regeneration of phosphatidylinositol (PI) and its phosphorylated derivatives (phosphoinositides). These molecules act as molecular switches regulating diverse processes including cell signaling, membrane trafficking, cytoskeletal dynamics, and calcium homeostasis. Upon stimulation, enzymes like phospholipase C (PLC) hydrolyze PI(4,5)P₂ into diacylglycerol (DAG) and inositol trisphosphate (IP₃), both acting as secondary messengers. Dysregulation can lead to impaired signal transduction, defective vesicular trafficking, aberrant cell proliferation/cancer, and neurological dysfunctions. Mutations affecting enzymes or regulatory proteins are linked with metabolic disorders and cancers.

Other names

PI-cyclePhosphoinositide signaling pathwayPIP cycle

Modulation of phosphoinositide synthesis or degradation, affecting downstream signaling pathways.