TRPM

TRPM is a family of transient receptor potential ion channels ("M" standing for "wikt:melastatin"). Functional TRPM channels are believed to form tetramers. The TRPM family consists of eight different channels, TRPM1–TRPM8.
Unlike the TRPC and TRPV sub-families, TRPM subunits do not contain N-terminal ankyrin repeat motifs but, rather, contain entire functional proteins in their C-termini. TRPM6 and TRPM7, for example, contain functional α-kinase segments, which are a type of serine/threonine-specific protein kinase.
Permeability and activation.
The relative permeability of calcium and magnesium varies widely among TRPM channels. 
The mechanism of activation also varies greatly among TRPM channels. 
Functions.
Among the functional responsibilities of the TRPM channels are: