TRPM4 channel
| Channel name | TRPM41,2,3,4,5 |
| Description | Ca2+-activated Na+ channel |
| Other names | FLJ20041, LTRPC4, TRPM4b |
| Molecular information | Human unigene: Hs0.467101, chr. 19q13.33 |
| Mouse unigene: Mm0.349430, chr. 7 B3 | |
| Associated subunits | Not established |
| Functional assays | Patch-clamp, calcium imaging |
| Current | Steep outward rectification >0 mV; instantaneous I–V linear |
| Conductance | 25pS (isotonic monovalent) |
| Ion selectivity | PNa/PCa ∼100 (M4b) |
| Activation | Kact: 300–500 nM [Ca2+]i; >1 μM |
| Inactivation | Not established (Ca2+-regulated) |
| Activators | [Ca2+]i |
| Gating inhibitors | None |
| Blockers | M4a: 80 μM La3+, Gd3+ |
| M4b: intracellular free ATP4-, 1.7 μM, spermine, ADP | |
| Radioligands | None |
| Channel distribution | Probably ubiquitous |
| Physiological functions | Regulation of calcium oscillations in activated T lymphocytes |
| Myogenic cerebral artery constriction | |
| Mutations and pathophysiology | Not established |
| Pharmacological significance | Not established |
| Comments | VMCA is an unusual feature; decavanadate (2 μM) inhibits voltage dependence |
chr., chromosome; VMCA, voltage-modulated calcium-activated.
↵1. Launay P, Fleig A, Perraud AL, Scharenberg AM, Penner R, and Kinet JP (2002) TRPM4 is a Ca2+-activated nonselective cation channel mediating cell membrane depolarization. Cell 109:397-407
↵2. Nilius B, Prenen J, Droogmans G, Voets T, Vennekens R, Freichel M, Wissenbach U, and Flockerzi V (2003) Voltage dependence of the Ca2+-activated cation channel TRPM4. J Biol Chem 278:30813-30820
↵3. Earley S, Waldron BJ, and Brayden JE (2004) Critical role for transient receptor potential channel TRPM4 in myogenic constriction of cerebral arteries. Circ Res 95:922-929
↵4. Launay P, Cheng H, Srivatsan S, Penner R, Fleig A, and Kinet JP (2004) TRPM4 regulates calcium oscillations after T cell activation. Science (Wash DC) 306:1374-1377
↵5. Nilius B, Prenen J, Voets T, and Droogmans G (2004) Intracellular nucleotides and polyamines inhibit the Ca2+-activated cation channel TRPM4b. Pflugers Arch Eur J Physiol 448:70-75