Module 2: Figure PtdIns4,5P2 regulation of K+ channels

Regulation of K+ channels by agonist-dependent hydrolysis of PtdIns4,5P2.

A number of different K+ channels are activated when they bind to PtdIns4,5P2. Upon stimulation by agonists that are coupled to phospholipase C (PLC), this lipid is hydrolysed to InsP3 and diacylglycerol (DAG), and this removal causes the channel to shut. The channel will open again when another PtdIns4,5P2 molecule associates with the lipid-binding site. The supply of PtdIns4,5P2 is maintained by the resynthesis of PtdIns and its rephosphorylation by PtdIns 4-kinase and then by PtdIns4P 5-kinase (Module 2: Figure InsP3/DAG recycling).