| First Author | Nilius B | Year | 2003 |
| Journal | J Biol Chem | Volume | 278 |
| Issue | 33 | Pages | 30813-20 |
| PubMed ID | 12799367 | Mgi Jnum | J:84761 |
| Mgi Id | MGI:2669774 | Doi | 10.1074/jbc.M305127200 |
| Citation | Nilius B, et al. (2003) Voltage dependence of the Ca2+-activated cation channel TRPM4. J Biol Chem 278(33):30813-20 |
| abstractText | TRPM4 is a Ca2+-activated but Ca2+-impermeable cation channel. An increase of [Ca2+]i induces activation and subsequent reduction of currents through TRPM4 channels. This inactivation is strikingly decreased in cell-free patches. In whole cell and cell-free configuration, currents through TRPM4 deactivate rapidly at negative potentials. At positive potentials, currents are much larger and activate slowly. This voltage-dependent behavior induces a striking outward rectification of the steady state currents. The instantaneous current-voltage relationship, derived from the amplitude of tail currents following a prepulse to positive potentials, is linear. Currents show a Boltzmann type of activation; the fraction of open channels increases at positive potentials and is low at negative potentials. Voltage dependence is not due to block by divalent cations or to voltage-dependent binding of intracellular Ca2+ to an activator site, indicating that TRPM4 is a transient receptor potential channel with an intrinsic voltage-sensing mechanism. Voltage dependence of TRPM4 may be functionally important, especially in excitable tissues generating plateau-like or bursting action potentials. |
