TRPM7
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TRPM7 (TRP-PLIK, Chak1, LTRPC7) is a ubiquitous calcium-permeant ion channel with its own functional kinase domain (1). It is a member of the transient receptor potential (TRP) ion channel family implicated in control of calcium entry into the cell. TRP channels are a family of proteins that possess six membrane-spanning domains and are expressed in low numbers per cell to yield small net inward currents (3). Many of them show no cation selectivity, but are permeable to Ca2+. TRPM7 is unusual in that it permeates divalent cations such as Mg2+ and Ca2+ into cells, while demonstrating no selectivity for the cations it lets out (4).
The channel domain of TRPM7 is most closely related to the putative tumor suppressor, melastatin, the founding member of the TRPM family. The TRPM subfamily might be the most novel group with potential roles in Ca2+ signaling, control of cell-cycle progression, and cell motility.
1. Runnels, L. W., Yue, L. & Clapham, D. E. TRP-PLIK, a Bifunctional Protein with Kinase and Ion Channel Activities. Science 291, 1043-1047 (2001).
2. Runnels, L. W., Yue, L. & Clapham, D. E. The TRPM7 channel is inactivated by PIP2 hydrolysis. Nature Cell Biol. 4, 329-336 (2002).
3. Clapham, D. E., Runnels, L. W. & StrŸbing, C. The TRP Ion Channel Family. Nature Reviews Neuroscience 2, 387-396 (2001).
4. Nadler, M. J. Hermosura
MC, Inabe K, Perraud AL, Zhu Q, Stokes AJ, Kurosaki T, Kinet JP, Penner R,
Scharenberg AM, Fleig A. LTRPC7 is a MgáATP-regulated divalent
cation channel required for cell viability. Nature 411, 590-595 (2001).