The TRPM7 channel is inactivated by PIP(2) hydrolysis.
TRPM7 (ChaK1, TRP-PLIK, LTRPC7) is a ubiquitous, calcium-permeant ion channel that is unique in being both an ion channel and a serine/threonine kinase. The kinase domain of TRPM7 directly associates with the C2 domain of phospholipase C (PLC). Here, we show that in native cardiac cells and heterologous expression systems, G alpha q-linked receptors or tyrosine kinase receptors that activate PLC potently inhibit channel activity. Numerous experimental approaches demonstrated that phosphatidylinositol 4,5-bisphosphate (PIP(2)), the substrate of PLC, is a key regulator of TRPM7. We conclude that receptor-mediated activation of PLC results in the hydrolysis of localized PIP(2), leading to inactivation of the TRPM7 channel.
Pubmed ID: 11941371 RIS Download
Animals | Carbachol | Cell Line | Cholinergic Agonists | Diglycerides | Heart | Humans | Hydrolysis | Ion Channels | Membrane Proteins | Models, Biological | Myocardium | Patch-Clamp Techniques | Phosphatidylinositol 4,5-Diphosphate | Protein Kinase C | Protein Kinases | Protein Structure, Tertiary | Protein-Serine-Threonine Kinases | Rats | Receptor, Muscarinic M1 | Receptors, Muscarinic | Recombinant Fusion Proteins | TRPM Cation Channels | Two-Hybrid System Techniques | Type C Phospholipases | Yeasts