TRPM7 channel
| Channel name | TRPM71,2,3,4,5,6,7 |
| Description | Kinase TRP channel |
| Other names | TRP-PLIK, LTRPC7, ChaK(1) |
| Molecular information | Human unigene: Hs0.512894, chr. 15q21 |
| Mouse unigene: Mm0.215171, chr. 2 F2 | |
| Associated subunits | Not established |
| Functional assays | Patch-clamp, calcium imaging |
| Current | Weakly voltage-sensitive cation current |
| Conductance | 105pS |
| Ion selectivity | PNa/PCa = 3:1 in outward direction; Na+, Ca2+, Mg2+ inward |
| Activation | Not established |
| Inactivation | Activation of receptors coupled to PLC hydrolyzes PIP2 to inactivate the channel |
| Activators | PIP2 |
| Gating inhibitors | None |
| Blockers | Mg2+ (EC50 ∼ 0.6 mM), La3+, polyamines |
| Radioligands | None |
| Channel distribution | Ubiquitous |
| Physiological functions | Cellular Mg2+ homeostasis proposed; potential for other trace metals, such as Zn2+, Mn2+; oxygen-glucose deprivation-induced calcium influx and neuronal death |
| Mutations and pathophysiology | Lethal in DT-40 cell line |
| Pharmacological significance | Not established |
| Comments | TRPM7 is a bifunctional protein with both ion channel and kinase activities; the protein autophosphorylates, but no other substrates are known |
chr., chromosome.
↵1. Runnels LW, Yue L, and Clapham DE (2002) The TRPM7 channel is inactivated by PIP2 hydrolysis. Nat Cell Biol 4:329-336
↵2. Runnels LW, Yue L, and Clapham DE (2001) TRP-PLIK, a bifunctional protein with kinase and ion channel activities. Science (Wash DC) 291:1043-1047
↵3. Nadler MJ, Hermosura MC, Inabe K, Perraud AL, Zhu Q, Stokes AJ, Kurosaki T, Kinet JP, Penner R, Scharenberg AM, et al. (2001) LTRPC7 is a Mg·ATP-regulated divalent cation channel required for cell viability. Nature (Lond) 411:590-595
↵4. Ryazanova LV, Pavur KS, Petrov N, Dorovkov MV, and Ryazanov AG (2001) Novel type of signaling molecules: protein kinases covalently linked with ion channels. Mol Biol 35:271-283
↵5. Yamaguchi H, Matsushita M, Nairn AC, and Kuriyan J (2001) Crystal structure of the atypical protein kinase domain of a TRP channel with phosphotransferase activity. Mol Cell 7:1047-1057
↵6. Aarts M, Iihara K, Wei WL, Xiong ZG, Arundine M, Cerwinski W, MacDonald JF, and Tymianski M (2003) A key role for TRPM7 channels in anoxic neuronal death. Cell 115:863-877
↵7. Kerschbaum HH, Kozak JA, and Cahalan MD (2003) Polyvalent cations as permeant probes of MIC and TRPM7 pores. Biophys J 84:2293-2305