Module 2: Figure PtdIns4,5P2 regulation of TRP channels
Regulation of TRP channels by agonist-dependent hydrolysis of PtdIns4,5P2.
A number of transient receptor potential (TRP) channels are opened (TRPM4, TRPM7 and TRPM8) or closed (TRPV1) when they are bound to PtdIns4,5P2. Upon stimulation by agonists that are coupled to phospholipase C (PLC), this lipid is hydrolysed, and its removal causes the channel to open (TRPV1) or closed (TRPM4, TRPM7 and TRPM8). The channel returns to the resting state when PtdIns4,5P2 re-associates with the lipid-binding site. The supply of PtdIns4,5P2 is maintained by the resynthesis of PtdIns and its sequential phosphorylation by PtdIns 4-kinase and PtdIns4P 5-kinase. The operation of this signalling system is particularly important in nociception (Module 10: Figure nociception).