The mammalian melastatin-related transient receptor potential (TRPM) is a subfamily of the TRP family. The family was named after the first member, melastatin (TRPM1), whose gene was identified in metastatic and benign melanomas.The TRPM proteins share structural homology with other members of the TRP superfamily channels; six putative transmembrane domains, and cytoplasmic N-terminus and C-terminus. However, due to their long N-terminus and C-terminus they were also named the long TRP channel family.The TRPM family consists of eight members designated as TRPM1-8 that can be further divided into four pairs: TRPM1 and TRPM3; TRPM2 and TRPM8; TRPM4 and TRPM5; and TRPM6 and TRPM7.The TRPM8 channel is the cold and menthol receptor activated by either cold temperatures(~28°C) or menthol.TRPM8 is expressed in dorsal root ganglia (DRGs) where about 5%-10% of the small diameter DRG neurons express the channel. In DRGs, TRPM8 expressing neurons do not express the TRPV1 channel.Overexpression of TRPM8 was found in prostate cancer cells. However, the physiological and pathological roles that these cells play is still elusive.In prostate, it was suggested that TRPM8 might play a possible role in the progression of cancer to the metastatic stage.
